HANDBOOK - · PDF file4.7 Dimensioning WWTPs – TAUW calculation tool ... • Iller Bank (Bank of Provinces) is responsible for WWTP project-design, tendering and

Tools for Waste Water Treatment in Small and Medium Sized Municipalities in Turkey

HANDBOOK

2 Handbook October 2010


Table of contents

Acknowledgement........................................................................................... 5

1 Introduction................................................................................................ 7 1.1 Background................................................................................................................7 1.2 Structure ....................................................................................................................7

2 Legislative/ institutional framework ........................................................ 9 2.1 Introduction ................................................................................................................9 2.2 Legislative framework ................................................................................................9 2.3 Institutional framework .............................................................................................12

3 Tools for organisation, management & financing................................ 15 3.1 Introduction ..............................................................................................................15 3.2 Recommendations for improved organisation, management and financing ............15

4 Technical Approaches and Tools .......................................................... 19 4.1 Introduction ..............................................................................................................19 4.2 General recommendations for improved waste water treatment .............................19 4.3 State-of-the-art activated sludge configuration types...............................................20

4.3.1 Control of sludge bulking ..................................................................................21 4.3.2 Configuration biological phosphorus removal...................................................22 4.3.3 Configuration choice .........................................................................................23 4.3.4 Configuration types...........................................................................................24

4.4 Innovative techniques ..............................................................................................27 4.5 Design Criteria .........................................................................................................29

4.4.1 Screens.............................................................................................................29 4.4.2 Sand removal....................................................................................................29 4.4.3 Pre settling........................................................................................................29 4.4.4 Biological ..........................................................................................................30 4.4.5 Aerator types ....................................................................................................31 4.4.6 Secondary settling ............................................................................................32 4.4.7 Air purification ...................................................................................................33 4.4.8 Sludge digestion ...............................................................................................33 4.4.9 Sludge dewatering ............................................................................................34

4.6 Automatisation .........................................................................................................34 4.6.1 Introduction .......................................................................................................34 4.6.2 Aeration control.................................................................................................35

4.7 Dimensioning WWTPs – TAUW calculation tool......................................................37

5 Operation and Maintenance ................................................................... 39 5.1 Introduction ...................................................................................................................39 5.2 Organisation, management and finances .....................................................................39 5.3 Operation ......................................................................................................................41 5.4 Maintenance .................................................................................................................42


Annexes.......................................................................................................... 43

Colophon........................................................................................................ 73


Acknowledgement

The past two years we have successfully co-operated with a vast number of enthusiastic Turkish colleagues in the framework of the Dutch-Turkish Government-to-Government programme. Several pilots, trainings and working meetings were held on the topic of waste water treatment in small and medium sized municipalities. These experiences resulted in the development of this Handbook. We would sincerely like to thank the experts involved of the following organisations for their contribution to the project and for their enthusiasm and valuable input: • Iller Bank • The Ministry of Environment and Forestry (MoEF) • Turkish Municipalities Union (TMU)

We hope that everyone enjoyed the co-operation as much as we did, and we are looking forward to continuation of our co-operation in the very near future. Yours truly, The project team: Corinne van Voorden (Ameco) Nicola Bekker (Ameco) Hans Jansen (TAUW ) Mike van Boldrik (TAUW) Paul Telkamp (TAUW) Gerard Rundberg (World Waternet) Otto Ferf Jentink (World Waternet) Cavit Soydas (World Waternet) Monique van der Straaten (NL Agency) Fatih Altunkaynak (IBS) Seyla Ergenekon (IBS) Tamer Atabarut (IBS)



1 Introduction

1.1 Background

This Handbook was developed in the framework of the project “Development of an Appropriate Methodology for Wastewater Treatment in Small and Medium Sized Municipalities in Turkey” (G2G08/TR/7/2), a Government-to-Government project funded by the Dutch Government. The purpose of the project was to contribute to the implementation of Council Directive 91/271/EEC of 21 May 1991 concerning urban wastewater treatment. By 2017 all small and medium sized municipalities in Turkey (2.000 - 50.000 p.e.) should have access to waste water treatment. Specific priorities include: • Identification of sustainable technological solutions which are appropriate for small and medium

sized municipalities and which comply with the Urban Waste Water Treatment Directive. • Improving management and organisation of waste water treatment (development of water unions,

co-operation within the chain, training). • Improving the operation and maintenance of (existing) waste water treatment plants (allocation of

human and financial resources, improving efficiency, training). The purpose of this Handbook is to provide organisational, managerial and financial tools for waste water treatment in small and medium sized municipalities. The Handbook is meant for professionals and experts working in the field of waste water treatment (local, regional and national authorities, municipalities and other associated organisations). For small and medium sized municipalities, the definition according to the Urban Waste Water Treatment Directive (UWWTD) is used, namely municipalities with a population equivalent of 2000-50.000. This means in Turkey approximately 2500 municipalities still need to get access to waste water treatment.

1.2 Structure

The first chapter of the Handbook provides an overview of the legal and institutional framework for waste water treatment. This chapter is followed by a chapter with recommendations and tools for improved organisation and management of waste water treatment and a chapter on tools in the technological field. The topic of operation and maintenance of WWTPs is included as a separate chapter, due to its importance.



2 Legislative/ institutional framework

2.1 Introduction

This chapter provides an overview of the legislative framework and of the institutional setting for waste water treatment. Some future challenges have been identified when it comes to responsibilities and duties related to waste water treatment.

2.2 Legislative framework

Taking into consideration (waste) water treatment, the following Turkish legislative documents have been harmonised with European directives: • UWWTD; • Water Framework Directive; • Drinking Water Directive; • Quality of Surface Water intended for the abstraction of Drinking Water Directive; • Directive on Dangerous Substances Discharged into Water; • Nitrate Directive; and • Bathing Water Directive. The two Turkish regulations that regulate UWW discharges, based on the UWWTD Council Directive 91/271/EEC of 21 May 1991 (UWWTD), are: • By-law on UWWT, in which the collection, treatment and discharge of urban wastewater on

UWWP’s is arranged. • By-law on Control of Water Pollution, whose aim is to regulate the water pollution of all discharges

of households and industries on surface water.


ENVIRONMENTAL LAW(2872-1983)(5491-2006)

ENVIRONMENTAL LAW(2872-1983)(5491-2006)

By-Law on Control of Water Pollution

(2004)

By-Law on Control of Water Pollution

(2004)

T.CMINISTRY OF ENVIRONMENT AND FORESTRY

Establishment Law(4856 – 2003)

T.CMINISTRY OF ENVIRONMENT AND FORESTRY

Establishment Law(4856 – 2003)

NOTIFICATIONS

Notification of Sample Getting and Analyze Methods

Notification of Technical Methods

Notification of AdministrativeMethods

NOTIFICATIONS

Notification of Sample Getting and Analyze Methods

Notification of Technical Methods

Notification of AdministrativeMethods

By-Law on Urban Wastewater Treatment

(2006)

By-Law on Urban Wastewater Treatment

(2006)

By-Law on Control of Pollution Grown out of Dangerous Materials in the Water and Environment (2005)

The Regulation on the Quality of the Surface Water From Which Drinking Water is Obtained or Planned to be Obtained(2005)

By-Law on Control of Soil Pollution (2005)

By-Law on Control of Pollution Grown out of Dangerous Materials in the Water and Environment (2005)

The Regulation on the Quality of the Surface Water From Which Drinking Water is Obtained or Planned to be Obtained(2005)

By-Law on Control of Soil Pollution (2005)

Sensitive and less sensitivewater areas communique

concerning urban waste watertreatment regulation

(2009)

Sensitive and less sensitivewater areas communique

concerning urban waste watertreatment regulation

(2009)

Figure 1: overview of relevant wastewater legislation

(Source: Country Report presentation by Fatih Topbaş (MoEF), 3 March 2008) Figure 2 shows a schematic diagram of the legislation of discharges on public UWWTPs and surface water. In each step the applicable articles of both By-laws are provided.

Figure 2: Legislation for discharges

Handbook October 2010

12

In Annex 1 the articles of both By-laws in Figure 2 are explained. As shown in Figure 2 the most important steps in the UWWT ‘chain’ are the following: • Treatment requirements of urban waste water. • Requirements for construction and maintenance of sewer systems of controlling

discharges. o Granting discharge permissions and control of industrial waste water on sewer

systems by municipalities. o Control of discharges quality: both influent and effluent of UWWTP by the MoEF. o Granting discharge permissions and control of industrial waste water directly on

surface water by the MoEF.

2.3 Institutional framework

To control discharges, an efficient working institutional framework is necessary. The steps mentioned above have to be followed by the responsible institutions. These duties and responsibilities are described in more detail below. General duties and responsibilities • The MoEF is responsible for wastewater discharge principles, sectoral discharge

standards, legal permissions related discharging to the receiving environment, controlling and monitoring, financing, and approval of WWT projects.

• The General Directorate of State Hydraulic Works can construct WWTPs if necessary for special situations.

• The Ministry Of Agriculture And Rural Affairs is responsible for nitrate pollution controlling and monitoring.

• Iller Bank (Bank of Provinces) is responsible for WWTP project-design, tendering and construction when a municipality asks for loan or credit from the Iller Bank. In addition, Iller Bank provides technical services upon request of municipalities.

• The Metropolitan Municipality and other municipalities are responsible for establishment of sewage system and UWWTPs, maintenance, improvement and operation.


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Duties and responsibilities related to industrial discharges on public UWWTP

1. Municipalities provide data of analysis of measurements of industrial discharges on sewerage systems

2. Municipalities check whether the wastewater conforms with Article 44 and Table 25 of the By-law on Control of Water Pollution

3. Control regular intervals

4. Permission is given by the municipality to the company

5. In case of food/dairy industries, municipality measures discharges and checks whether pre-treatment is necessary;

6. Change permits when necessary (conditions Table 25 of the By-law on Control of Water Pollution)


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Duties and responsibilities for discharges of public UWWTP on surface water

Future challenges • The requirements of the UWWTD have been incorporated in Turkish laws and

regulations; however a more integrated approach to the waste water and other environmental directives could be developed.

• Municipalities extend permits for industrial discharges into the sewerage system but do not check the quality of these discharges; to improve the control of discharges the capacity at regional and local authority level should be enhanced.

• The Enforcement of regulation could be improved. The Provincial Directorate of the MoEF is responsible for monitoring the operational performance of the UWWTP. The MoEF would prefer municipalities to carry out these tasks too, but there is insufficient capacity to do so.

1. A permit application is sent to the provincial office of the MoEF

2. The provincial office of the MoEF checks whether the application conforms to the Notification about Administrational Methods of the By-law on Control of Water Pollution

3. The provincial office of the MoEF checks whether the wastewater conforms to Article 37 (Table 5 - 21) of the By-law on Control of Water Pollution

4. Within 2 months a permission certificate is extended to the municipality by the provincial office of the MoEF

5. The municipality takes samples. Data are kept for three years

6. The provincial office of the MoEF checks the discharge permission values with own measurements

7. The provincial office of the MoEF makes a status report of all the public UWWTP discharges in their region every two years and sends it to the MoEF in Ankara

8. The MoEF in Ankara evaluate the result of regions every two years;

9. The Provincial office of the MoEF, together with the municipalities, prepares an implementation program to implement the By-law


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3 Tools for organisation, management

& financing

3.1 Introduction

Municipalities are held responsible for the realisation, operation and maintenance of UWWTPs and financing waste water services. By 2012 all municipalities with more than 50,000 p.e. and by 2017 all municipalities with more than 2,000 p.e., should have access to waste water treatment. There are about 2,500 small and medium sized municipalities (with a population equivalent between 2,000-50,000) that still need to get access to waste water treatment. To be able to treat financing and construction requests from municipalities in an efficient way, some organisational recommendations are provided. The operation and maintenance of UWWTPs could be improved considerably when considering efficiency measures, organisational and financial tools. Recommendations are provided to improve operation and maintenance.

3.2 Recommendations for improved organisation, management and financing

1) Co-operation between municipalities and the establishment of water unions The common practice of constructing UWWTP’s in small and medium sized municipalities is individual municipalities realising a plant, with assistance from either the Iller Bank, from MoEF, with support of other investors, or on their own. The operation and maintenance of UWWTPs is carried out separately by each municipality. Due to the small scale of the UWWTPs is it difficult to realise cost efficient UWWT solutions and viable organisation of operation and maintenance. Efficiency could be improved in situations where a UWWTP serves more than municipality. The costs associated with the realisation and functioning of such plants could be significantly reduced. Resources, particularly human resources, could also be maximised if municipalities cooperate in the investment, construction, operation and maintenance of one UWWTP. MoEF initiated the establishment of water unions and combined UWWT for more than one municipality. Some municipalities started a co-operation for waste water treatment; however co-operation is often hampered because financial obligations are not met by one of the partnering municipalities. Management systems should be elaborated which support a sound co-operation. Annex 2 provides an overview of possible organisation forms for the establishment of water unions.


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2) Co-operation between MoEF, Illerbank and municipalities Improved co-operation between MoEF, Iller bank and municipalise will support common decision-making on waste water regulation, priorities and practices. Annex 3 shows a decision making model developed for Iller Bank. The model is a proposed situation for an optimal process. Current practices are not in line with this model yet, but are currently being negotiated. 3) Role municipalities; polluters pay principle, staff In the present situation a municipality takes the initiative to start the realization of a WWTP and asks Iller Bank or the Ministry of Environment for support. The municipality is not involved in the construction off the WWTP. The municipality gets involved only when the construction is finalised. Then the operations and maintenance has to be organised under the responsibility of the municipality. This often results in insufficient operation and maintenance practices. Municipalities should be more closely involved in the process of designing and building the WWTPs and in considerations related to the operation and maintenance after the construction of the plants. This enhances the feeling of ownerships and responsibility. The following activities should be undertaken by municipalities: • Organisation of the collection of fees from the “polluters”; these fund could cover

investment, exploitation - and maintenance costs • Calculate the tariff/tax for waste water treatment and the moment of introduction • Arranging staff for operation and maintenance • Communicate about necessity of waste water treatment to there inhabitants. 4) Attention for costs of Operation and Maintenance in Feasibility studies Feasibility studies for the construction of smaller UWWTP’s do not include financial considerations for operation and maintenance (i.e. studies prepared by Iller Bank). Multiple costs such as for energy, operation, maintenance and staffing should be taken into consideration for at least 30 years when designing the UWWTPs. Including financial considerations in the stage of the feasibility studies could considerably impact the decision on appropriate small-scale UWWT techniques (e.g. automation and other energy efficient aerators). 5) Supervision during construction The constructed UWWTP’s are not always in line with the initial design. Building failures or bad quality can be the course of large amounts of money needed for maintenance or renovations earlier then necessary. Increased supervision during the construction of the UWWTPs could address this problem. Arrange inspection on the building process by qualified staff. 6) Unification UWWTPs There are insufficient qualified personnel for operating UWWTPs at municipal level. Therefore unification of the UWWT processes, especially of neighbouring municipalities is favourable. When plants are similar, personnel can easily be exchanged between the different UWWTPs. 7) Involve the public The public could be involved more frequently in the process of waste water treatment. Involving the public in decision-making on water regulation/management will enhance their commitment towards waste water treatment and their understanding about having to pay for waste water treatment.


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8) Review tendering process In general there are three forms of tendering, the Traditional forms, Design & Construct and Public Private (see annex See annex 4: forms of tendering) The D&C and Public Private form of tendering are currently not executed in Turkey. The traditional form is most relevant as then the construction can be controlled maximal. With respect to the current form of tendering, the following can be notified: • In the pre-design phase only investment costs are considered. The exploitation costs are

not included. Also in the final design phase the exploitation costs seem to get little attention. As exploitation costs are as important as the investment costs for the end-user it is recommended to pay more attention to the exploitation costs. Including both costs within the design prevents that a system is chosen that might be cheap to build but has high exploitation costs.

• The use of a Multi Criteria Analysis (see annex) supports taking a decision based on various criteria

9) Subsidy on energy costs In October 2010, the WWTP energy incentive regulation was published. This regulates the financing of a percentage of the energy cost of urban and industrial properly operated WWTPs (the actual percentage still needs to be determined). Municipalities can apply for this subsidy 10) Consider outsourcing The most important cost components of the operation of WWTPs are the personnel and electricity costs (see table below). Municipalities can either operate the plants themselves or outsource the operation to a private company. Outsourcing has certain advantages:. The private sector is always more flexible in hiring personnel and is more efficient in controlling personnel expenditures. Another advantage of outsourcing is the flexibility in procurements. The state procurement rules are less flexible and usually it takes a long time to buy spare parts or chemicals for the treatment plants. In case of outsourcing, procurement will be realised by the private company who doesn’t have to follow the public procurement rules. Description Unit cost, EUR Energy consumption 0,10 per kWh

Manpower, management 24.000 per year

Manpower, technicians 16.800 per year

Manpower, labour 7.000 per year

Precipitation chemicals 200 per tonne

Polymers 3,8 per Kg

Transport of sludge 0,20 per tonne per km 11) Be aware of the costs To support with the estimation of costs of operation and maintenance, a table is presented in Annex 5. This table provides a general guideline for costs op operation and maintenance.


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4 Technical Approaches and Tools

4.1 Introduction

Based on assessments of existing UWWTPs in Turkey, general technical recommendations are provided for improved waste water treatment. Paragraph 4.3 provides an overview of appropriate waste water treatment technologies, taking into consideration the UWWT Directive. Paragraph 4.4 elaborates on innovative techniques. Design criteria are elaborated and automation is profoundly discussed as an important efficiency measure. A tool is provided for dimensioning WWTPs and Operation and Maintenance is referred to in the final paragraph.

4.2 General recommendations for improved waste water treatment

Based on an assessment of existing UWWTPs in Turkey, the following general recommendations are given: 1) Analyse the influent and effluent of the UWWTP frequently in order to determine

the efficiency The actual efficiency of the UWWTPs is often not known and the characteristics of the influent and effluent are not adequately analysed. It is very important to know the efficiency of a UWWTP. 2) Installation of online oxygen measurement and control the amount of oxygen

input Often, it is found that aeration devices at UWWTPs are switched off. This is done to decrease the energy costs; however this also decreases the efficiency of the UWWTP considerably. It is advised to install an online oxygen measurement that controls the oxygen input (see also point 3). 3) Installation of more online measurements in order to improve the operation of the

UWWTP In addition to online flow measurement, there are often no online measurements installed at UWWTPs. This makes it difficult to operate a UWWTP. Especially an online oxygen measurement in the activated sludge tank is important. The surface aerators should be controlled by this online oxygen measurement. In this way you make sure that the amount of oxygen input is related to the current load of the UWWTP. Oxygen (=energy) does not have to be wasted in this way. In general more online measurements result in less time needed for operators. A good balance in online measurements could be considered.

4) Assess the necessity of chlorination in effluent The current operation of UWWTPs is often poor which results in a bad effluent quality. If the treatment process is properly controlled with among other things the mentioned oxygen measurement, chlorination seems unnecessary. Building costs and operational costs will decrease considerably. Another accompanied advantage is that working with the hazardous chloric gas is not needed anymore.


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5) Reduce construction costs by layout improvements In general the existing UWWTPs are composed of many buildings, Long pipelines, Many distribution chambers. Combining buildings and a more logical layout will reduce construction cost significantly.

6) Efficiency in design Some UWWTPs are built taken into account possible future expansion. At the time of designing and constructing the UWWTP this might seem cost efficient, however in practice building costs will be higher than necessary. The installed components for future expansion will be subject to depreciation (due to weather influences, pollution by wastewater etc.) and will most probably need to be renewed at the time of expanding the UWWTP. Furthermore, the technique for UWWTP’s can change considerable in time.

7) Take safety measures for operators Safety measures should be taken to optimise working conditions for operators, for example installing a safety work switch at a pump or another electric device ensures that there is no electric current flowing anymore. This ensures safe working conditions when maintenance is performed. Another safety measure is a safety cords in the activated sludge tanks. Safety cords are installed a few metres before surface aerators and propulsors. The function of the safety cords is that if someone accidentally falls into an activated sludge tank he or she pulls the safety cord. By pulling the safety cord the propulsors and surface aerators are stopped to prevent physical injuries. 8) Training of operators In general the training executed by the contractor is mainly technical (how to switch things on and off) and less technological. 9) Keep MLSS (Mixed Liquid Suspended Solids) content under or on the design

value 10) Arrange final destination for dewatered sludge

4.3 State-of-the-art activated sludge configuration types

Taking into consideration that Turkey wants to comply with the Urban Waste Water Treatment Directive, activated sludge UWWTPs are found to be the most appropriate plants for small and medium sized municipalities. Other treatment forms include for example SBR (Sequence Batch Reactor) and lagoons (see annex 6 small size technologies for domestic waste water treatment) which are more simplified and economical feasible, however UWWTD requirements with respect to Nitrate and Phosphate removal are not met. Activated sludge UWWTPs consist of simultaneous and multi compartment systems. The multi compartment systems are in the Netherlands at the forefront of smart technology for UWWTPs. The multi compartment systems prevent bulking sludge and are focussed on optimal biological nitrogen and phosphate removal. The following paragraphs discuss the process choices and configurations forms.


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4.3.1 Control of sludge bulking

Research results have shown that it is possible to design a UWWTP at an SVI (Sludge Volume Index) of 120 ml/g, but certain conditions are essential: 1) The most important factor is to create a sufficient fraction of aerobic sludge in the aerated reactor at temperatures below 15 °C. This is crucial for ensuring a sufficiently low SVI. The forming of Microtrix parvicella has to be inhibited as much as possible as this is the major cause of bulking sludge at such low loads and extensive nitrogen removal. The following figure presents the relationship (indicative) between the relative fraction of aerobic sludge (x-axis) and SVI (y-axis). This is based on experiments in Germany and lab scale practical results in South Africa. In this figure it can be seen that a very low fraction of aerobic sludge provides a good SVI and a high fraction gives a good SVI. The IWA (International Water Association) mentions a fraction larger than 50%, Casey mentions 60% and Kruit uses 80% as the limit above which you have the best guarantee for a good SVI. So the different sources do not fully agree with each other. At temperatures > 15 °C the shape of the filaments will change (more like elbows). Because of this change of shape the filaments will not play a relevant role anymore in the formation of bulking sludge.

Figure 3: Trend of the relative SVI as a function of the fraction of aerobic sludge 2) Microtrix parvicella is a hydrophobic filamentous bacterium with a low growth rate but a high substrate affinity. It can only grow at higher fatty acids and reduced N and S, below (micro-aerophilic) aerobic conditions. Under anoxic conditions Microtrix parvicella is not able to grow, but it is still able to adsorb higher fatty acids. An aerobic tank with an oxygen concentration >1.5 mg/l and a sufficiently high aerobic sludge fraction will result in a low ammonia concentration in the effluent. This creates a competitive disadvantage for Microtrix parvicella. 3) Plug-flow conditions in the anaerobic tank (if applicable) and pre-denitrification tank (if applicable) also support the penetration of higher fatty acids in the floc, making them less available for Microtrix parvicella in the aerobic tank.

R e la t ie S V I e n F ra c tie O 2 s lib

0

2 0

4 0

6 0

8 0

1 0 0

1 2 0

0 2 0 4 0 6 0 8 0 1 0 0

F r a c t ie a e r o o b s l ib

Re

lati

ev

e S

VI (

%)

R w zi’s in N L m et B Z V /N van 2 ,8 -3 ,0kom en veel voor

ST O W A L ich t-slibonderzoek

IW A C asey K ru it


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4) A pre-denitrification tank with a certain minimum contact time after the anaerobic tank also encourages the formation of the correct bacteria and prevents the growth of Microtrix parvicella due to the lack of simultaneous conditions In the fixed anoxic reactor Microtrix parvicella is not able to grow, but it can absorb higher fatty acids. However other micro-organisms can also adsorb higher fatty acids under these circumstances, but these micro-organisms can grow and prove to be more competitive. A pre-denitrification tank contributes to the selection of the appropriate flocculation bacteria. The plug flow configuration results in a substrate gradient resulting in adsorption of COD and (higher) fatty acids on the floc. 5) A facultative tank for nitrification in winter and denitrification in summer might be necessary This is depending on the BOD/N ratio in the wastewater (see paragraph 5.3.4). Summarized Sludge bulking problems resulting from Microtrix parvicella only occurs at lower temperatures (< 15 °C). In summer Microtrix parvicella is irrelevant. The filamentous bacteria will get a different shape at temperatures above 15 °C and don’t contribute anymore to the sludge bulking problem. In practice this means that at temperatures above 15 °C the fraction of aerobic sludge and the ammonium concentration (in relation to prevention of sludge bulking) is not as critical.

4.3.2 Configuration biological phosphorus removal

For biological phosphorus removal in the main process flow (activated sludge system) two configurations can be distinguished: the Phoredox process and the UCT process (University of Cape Town Process). In the following figure the Phoredox process and the UCT process are schematically shown.

Figure 4: Schematic representation of Phoredox and UCT process. The only (but essential) difference between these configurations is the location of the entry of the return sludge and recirculation A. At the Phoredox process the return sludge is recycled to the anaerobic tank. In the UCT process the return sludge is recycled to the anoxic tank and is transported to the anaerobic tank by separate recirculation (recirculation A). In case of the Phoredox process a part of the anaerobic reactor will be anoxic due to the recycle of nitrate-containing return sludge. This mainly occurs at low temperatures and high loads.


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Due to this effect a disturbance of the Bio-P process will occur. Especially in the winter phosphate concentration in the effluent can become higher. The effect of inhibited phosphate removal may last for several weeks. The UCT process is designed in such a way that in the fixed anoxic tank full denitrification occurs. In this way the anaerobic tank will stay strictly anaerobic throughout the year. This has the following advantages: • The UCT process uses less (or no) chemicals. The UCT process is therefore more

durable than the Phoredox process. • The system is independent of the return sludge flow. • All fatty acids will be used for the biological P−removal, which reduces the P

concentration in the effluent. Besides the more efficient phosphorus removal also more BOD is available for the denitrification which results in a faster denitrification process.

4.3.3 Configuration choice

The amount of compartments within a UWWTP for nitrogen removal is based on the BOD/N ratio (Dutch guideline). The following figure presents the relation between the BOD/N ratio and the amount of compartments.

BOD/N ratio influent

Aerobic volume

Anoxic volume

Perc

enta

ge o

f nee

ded

anox

ican

d ae

robi

c vo

lum

e

BOD/N ratio influent

Aerobic volume

Anoxic volume

Perc

enta

ge o

f nee

ded

anox

ican

d ae

robi

c vo

lum

e

Figure 5

The figure above shows three areas which represent the amount of compartments needed: 1. no fixed anoxic volume needed simultaneous (BOD/N ratio approx. > 5) 2. fixed anoxic volume needed (BOD/N ratio approx. > 2.5 and < 5) 3. fixed anoxic and facultative volume needed (BOD/N ratio approx. < 2.5) So for a BOD/N ratio above approximately 5 one simultaneous compartment can be used, like a carrousel system. With a BOD/N ratio lower than approximately 5 and higher than approximately 2.5 two compartments are needed. If the BOD/N ratio is even lower a third compartment is needed. The two lines represent the percentage of aerobic and anoxic volume needed for a good nitrogen removal. So for instance if a BOD/N ratio of 4 is applicable, you need about 30% anoxic volume and 70% of aerobic volume.


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4.3.4 Configuration types

In recent history purification processes were always held in one tank and the various processes took place simultaneously. These simultaneous processes are not always efficient. By using different tanks for different processes ideal conditions can be reached which lead to optimal speed of the processes. In this paragraph different process configuration are presented like UCT, BCFS ®, Phoredox and simultaneous nitrification/denitrification, with and without biological phosphorus removal. UCT-Process

spuislib

Figure 6

In the anaerobic reactor the selection for the bio-P bacteria takes place. In the first anoxic reactor (Anox 1) pre-denitrification takes place. In this reactor the nitrate in the return sludge is reduced with the residual biodegradable COD from the anaerobic tank. Then the sludge without nitrate is recycled to the anaerobic tank (recirculation A). In this process the volatile fatty acids are completely for the bio-P bacteria. In a second anoxic reactor (Anox 2) the nitrate is denitrified that was formed in the aerobic reactor (Aerobic). In the aerobic reactor nitrification takes place and the remaining biodegradable COD is degraded. The formed nitrate is recycled from the aerobic reactor to the anoxic tank (with recirculation B) for denitrification. In this system all volatile fatty acids will be beneficial for the bio-P bacteria. That’s why in this system the biological phosphate removal is prior over the nitrogen removal. In the Netherlands the UCT process is mainly used in combination with Chemical-Biological Nitrogen and Phosphate Removal (UCT-BCFS ® process).


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BCFS® process

spuislib

Figure 7

The influent enters the anaerobic zone. After the anaerobic zone the mix of wastewater and sludge enters the other compartments starting with the selector (contact tank), the anoxic zone 1 (fixed anoxic reactor), anoxic zone 2 (facultative reactor) and the aerobic reactor. The process is regulated by controlling the different recirculation flows (recirculation A, B and C). The last aerobic reactor is oxygen regulated. Additional phosphorus removal is achieved by extracting phosphate-rich water from the anaerobic zone through a so-called stripper tank. A metal solution will be added to this phosphate-rich stream and the stream is transported to a sludge thickener where precipitation occurs. Phoredox process

spuislib

Figure 8

In the anaerobic reactor the selection for bio-P bacteria takes place. In the first anoxic reactor (Anox 1) pre-denitrification takes place. Nitrate is fed by the recirculation from the aerobic reactor towards Anox 1. In the first aerobic reactor nitrification takes place and the remaining biodegradable COD is degraded. In order to limit the recirculation the remaining nitrate is denitrified in a second anoxic reactor (Anox 2). In the following aerobic reactor the sludge is ‘refreshed’. The return sludge is recycled to the anaerobic reactor. The first part of the anaerobic tank will be anoxic because there is still some remaining nitrate left in the return sludge.


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In this system a part of the volatile fatty acids will be beneficial for the denitrification and not for the bio-P bacteria. In this system the nitrogen removal is prior over the biological phosphate removal. The original Phoredox process is based on complete plug flow reactors which results in 5 different reactors. In the Netherlands the last three reactors are almost always combined to one carrousel reactor (simultaneous (de)nitrification). Within this carousel reactor the same zones can be distinguished. In the following figure the Phoredox process is shown as used in the Netherlands.

spuislib

Figure 9

Simultaneous process with/without Bio-P

Figure 10


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The simultaneous (de)nitrification takes place in one reactor. The reactor is a circulation reactor with one ore more aerated and non-aerated zones. The process conditions will fluctuate between aerobic and anoxic conditions continuously as a result of the different zones. The simultaneous process can reach very low nitrate concentrations. De simultaneous process can lead to a high SVI. Therefore the settling tanks need to be designed for a SVI of 150 ml/g. For the UCT or Phoredox process the design SVI is 120 ml/g. For the realization of Bio-P removal a separate anaerobic tank before the circulation system needs to be installed.

4.4 Innovative techniques

In the previous paragraph a lot of attention has been paid to state-of-the-art activated sludge systems. Besides these systems there are also new innovative techniques on the market. Within this paragraph some innovative techniques are described. Anammox®, Oland, SHARON, DEMON and BABE These are all techniques for removal of nitrogen in wastewater. These techniques consume less oxygen than conventional activated sludge systems, but they are only appropriate for highly concentrated nitrogen streams like rejection water from dewatering digested sludge. Also the operation of these techniques is more complex than the operation of conventional activated sludge systems. By treating the rejection water with one of these techniques the amount of nitrogen that will return to the activated sludge plants will be considerably reduced. These kinds of techniques are only cost-effective at large UWWTPs with anaerobic digesting tanks. So these kinds of techniques are not appropriate for the small and medium sized municipalities. Sand filtration Sand filtration can be used when the effluent demands are strict (for instance N < 5 mg/l and P-total < 0,5 mg/l). This might be the case when effluent is discharged to sensitive areas. Sand filtration can be placed as a post treatment after the (secondary) settling tanks for lowering the nitrogen, phosphorus and suspended solids. MembraneBioReactor (MBR) With a MBR a high effluent quality can be obtained. The footprint of a MBR is relatively small which makes it interesting for situations where the available space is limited or if the land value is high. Disadvantages of an MBR are the high energy consumption, high investment cost and the complexity of the operation. For the small and medium sized municipalities it is advised to only consider a MBR when the needed area for a conventional activated sludge system is not available. NeredaTM With this innovative technique the bacteria do not grow in the form of a floc but in compact granules. It is stated that the energy consumption will reduce considerably and less surface is needed because there is no need for separate settling tanks. This technique is promising, but has not been proven on full-scale yet. The complexity of Nereda is possibly higher than with a conventional activated sludge system and also the robustness is not known yet. At this moment the first full-scale installation for urban waste water is built in the Netherlands. The start-up is planned for 2011. As this technique is not a proven technique (yet), it is not recommended to apply this in Turkey at this moment.


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In addition to the above mentioned innovative techniques there is also another innovative approach called New Sanitation (or Decentralised Sanitation). New sanitation is based on separation at source within a household. Within a household we can distinguish different wastewater streams, namely: • Black water (consists of urine, faeces and an amount of flushing water and is a

concentrated stream) • Grey water (coming from kitchen, bathroom and washing machine and is a relatively

slightly polluted stream). • Rain water (least polluted stream)

Rain water

Grey water

Black water

Alternativelyseparate urine

Food waste

Rain water

Grey water

Black water

Alternativelyseparate urine

Food waste

Figure 11 For the Turkish situation rain water is already kept separately from the black and grey water. But the concentrated black water is still mixed with the less polluted grey water. So the polluted stream is mixed with the less polluted stream. Concentrated black water (which can be obtained with for instance vacuum toilets) contains almost all nutrients and pathogens and all medicines and hormones. Keeping the black water separated from the relatively slightly polluted grey water results in opportunities to produce biogas, recover phosphorus and effectively treat the medicines and hormones if desired. As New Sanitation already starts within a household it is in many cases only worth considering with the development of new urban areas or large scale renovations.


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4.5 Design Criteria

In this section, an overview is given of design criteria of the different parts of a waste water treatment plant.

4.4.1 Screens

• Screen width: 6 mm (or less) • At least 1 screen, but better double screen • Use concrete protection • Material: steel IP65 (3 mm thickness) • Use aluminum for covering the channel • Design based on rain water flow • A by-pass must be foreseen • Screen must be in operate for more then 95% • Steering: level difference and flow

4.4.2 Sand removal

• Build from concrete or steel • Use concrete protection (lining) • Use aluminum for covering the channel • Design based on rain water flow • Surface load: between 20-40 m/hr

4.4.3 Pre settling

• Maximum tank diameter: 30 – 45 meter • Surface load: 2-4 m/hr (av. 2,5 m/h) • Site depth: 1,5 – 2 meter • Concentration outgoing sludge: 0,5-2,0 % ds Component Without pre

settling Normal pre settling

With precipitation

Advanced pre treatment (PE)

Solids COD

0% 0%

30-40 % 25-35 %

60-80 % 35-60 %

60-90 % 30-60 %

BOD 0% 20-30 % 45-70% 40-50 % P-total N-total

0% 0%

10-20 % 5-10%

60-90 % 15-30 %

20-35 % 10-30 %

BOD:N:P Outlet pre set.

24:6:1 BOD/N = 4,0

21:6:1 BOD/N = 3,5

10:5:1 BOD/N = 2,0

13:5:1 BOD/N = 2,6


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4.4.4 Biological

Activated sludge Bacteria and other micro organisms such as ciliates, flagellates, amoeba, etc. consume the pollution from the waste water in the biological stages of the waste water treatment: Phosphate removal, denitrification and nitrification. General design rules for all biological stages: • Dry solids content (DS) of activated sludge on average 4-5 g/l • Water temperature 10 ºC – 30 ºC (Dependent on season) • Sludge Volume Index (SVI) ≤ 120 ml/g. If SVI > 150 ml/g possibly bulking sludge • Size of settling tank is based on SVI and dry solids content • Sludge load between 0,05 – 0,25 kg BOD/kg DS.day (depending on nitrification and

temperature) • pH value: 6,5 – 8,0 Biological phosphate removal tank Dissolution of phosphate by bacteria in the anaerobic tank is followed by an increased bacterial phosphorous uptake in the aerobic stage (nitrification tank). Biological phosphorous removal can be used as an alternative or in combination with P-precipitation. • Oxygen content in phosphate removal tank ≤ 0,5 mg/l • Preferably low NO3

- content • Minimal amount of mixed compartments in sequence to create a plug flow: 4 • Hydraulic retention time (HRT) ±1 hour (depending of the amount easily biodegradable

COD). See the table below. Unit without pre

settling With pre settling

HRT BOD < 10% COD influent Min 120 60 BOD 10-15% COD influent Min <60 60 BOD > 15-20% COD influent Min 45 45 Minimal amount of compartments - 4 4 Chemical phosphate removal Phosphate precipitation is chemical P-removal by addition of metal salts (Fe, Al) or of lime (seldom) in the pre settling tank, the aeration tank or the secondary settling tank. • Netto metal versus P dosage: 3 mol Me/mol P Denitrification tank Conversions: NO3

- -> N2 • Oxygen content ≤ 0,5 mg/l • Optimal pH value: 6,8 – 7,7 • BOD5/N ratio: 4-5 • Recirculation from nitrification tank dependent of the required NO3 removal • Size of denitrification tank depending on denitrification rate (mostly dependent of

available BOD, temperature and pH) and NO3 requirements. Example average denitrification rate at 10 ºC : 0,2 kg N/kg DS.day. Example average denitrification rate at 20 ºC : 1,0 kg N/kg DS.day.

• Size of denitrification tank between 20% - 65% of total nitrification/denitrification space. If more space is required an external C-source must be added to meet the effluent N requirements.


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Nitrification tank Conversions: NH4

+ -> NO2- and NO2

- -> NO3 - • Oxygen content > 1.0 – 2.0 mg/l • Optimal pH value: 7.0 – 8.0 • Sufficient aerobic sludge age (dependent on temperature and sludge load). At 10 ºC, a

minimal aerobic sludge age of 10 days is required for nitrification. This equals a sludge load of maximally 0.15 kg BOD/kg DS.day.

• No toxic substances • Preferably low NH4 and NO2 content • The aerobic volume must be aerobic for > 80%. • Size of nitrification tank is based on a maximal sludge load of 0.15 kg BOD/kg DS.day

(depending on the required minimal aerobic sludge age in relation to the temperature, DS content, etc).

• The nitrification rate is mostly dependent of DS content, temperature and pH.

4.4.5 Aerator types

Main part of the activated sludge tank is the nitrification zone. In this zone ammonium will be converted to nitrate. This process uses oxygen that can be provided by a different kind of aerators. There are two main groups of aerators: • surface aerators • bubble aerators

Aeration systems

Bubble aerator Surface aerator

rotorfastrotatingvert.s. aerat.

slowrotatingvert.s. Aerat.

Finebubble

coarsebubble

Traditional Disk shape

innovativeDisk shape

Membraneelements

ceramicelements

Air20%

jet aerators

platestubesdisk

downflowjetaerators

Aeration systems

Bubble aerator Surface aerator

rotorfastrotatingvert.s. aerat.

slowrotatingvert.s. Aerat.

Finebubble

coarsebubble

Traditional Disk shape

innovativeDisk shape

Membraneelements

ceramicelements

Air20%

jet aerators

platestubesdisk

downflowjetaerators

Figure 12

These two main groups contain different systems with different specifications. One of the main issues is the energy consumption in relation to oxygen input. The following table presents the relation between oxygen and energy use for the most used aerators.


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Type of aerator O2 input per kW Bubble aerator: plates (fine bubbles) 4,5 – 5,5 kg O2/kW Bubble aerator: disks (fine bubbles) 4,0 – 5,0 kg O2/kW Surface aerator.: Vertical shaft slow speed (high efficient) 2,0 – 2,2 kg O2/kW Surface aerator: Vertical shaft slow speed 1,6 – 1,8 kg O2/kW Surface aerator: Vertical shaft (high speed rotating) 1,4 – 1,6 kg O2/kW Surface aerator: rotor 1,2 – 1,7 kg O2/kW The following table presents the operational aspects between bubbles and surface aerators. description Bubble aerators Surface aerators (vertical

shaft) reliability ++ +++ serviceability + +++ suitability +++ +++ Sustainable energy +++ + Sustainable noise and smell +++ +++ experience ++ +++ substitutability + +++ capacity +++ +++

4.4.6 Secondary settling

Clarification process is a process in which the sludge settles and the purified water is decanted. • SVI 125 – 150 ml/g • Surface load depending on SVI

SVI Required surface load (m/h) < 80 ml/g < 0.3 – 0.5

80-150 ml/g < 0.5 – 0.8 > 150 ml/g < 0.3 – 0.5

• Flow rate < 1 cm/sec • Settling time (HRT) 3-4 hour • Surface settling tank (m2) = influent flow (m3/h)/ surface load (m/h) • Average side depth: 1.5 – 2 meter • Average concentration outgoing sludge: 0,8 % ds • Diameter Center feed well/Clifford (inlet : 15-20% of the diameter of the settling tank • Depth Center feed well/Clifford: 2/3 of side depth of the settling tank • Required flocculation time in Center feed well/Clifford: 3-5 min • Settling tanks with a diameter > 40 m: a deflection is used to prevent shot circuit between

the inlet and the outlet of the sludge. • Diameter of the deflection is 1.1 – 1.2 x the diameter of the Center feed well/Clifford • The space between the edge of the deflection and the depth of the Center feed

well/Clifford must be > 1 m • The space between the bottom of the deflection and the bottom of the tank must be >1m • With regard to the settling tank bridge :

Diameter settling tank < 30 m: length bridge is 0.5 x diameter settling tank Diameter settling tank 25-40 m: length bridge is 0.75 x diameter settling tank Diameter settling tank > 40 m: length bridge is 1 x diameter settling tank


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4.4.7 Air purification

Purification of the air from the anaerobic and anoxic process tanks, such as the screens and sand removal, the pre settling tank, anaerobic phosphate tank, denitrification tank and sludge buffers. • A biological air filter can be used, consisting of mulch and compost or lava • Dimensions of the lava filter are based on the required amount of air to be purified and

the amount of H2S, depending on what is more critical • Dimensions of the amount of air volume to be purified: 10x the volume of enterable

spaces (for example a space of 10 m3 -> 100 m3/h air will need to be purified) 3x the volume of spaces that are not entered

• Air load lava filter: 100 m3 air/m2/h • H2S load lava filter: 20 g H2S/m3/h • Water spraying: minimal 20 l/m2/h for every 15 minutes at least 1 minute in operation • The whole surface needs to be sprayed • Minimal diameter lava filter 1 m. Height according to supplier • Piping in GVK or HPE • A fan placed on the press side and constructed in synthetic material and with condense

removal • H2S detection necessary to switch on the fan if necessary

4.4.8 Sludge digestion

Anaerobic biological process, converting waste sludge to CH4 and CO2 • Size of digestion tank depends on the hydraulic retention time (which depends on the

temperature) Applied value Advised design

value Unit

Temperature 27-37 33 ºC HRT 15-30 20 days Mixing Mix energy 7 W/m3 Operation time 25 % of time • Optimal pH 6.5 – 7.5 • COD:N:P is 1000:5:1 • No toxic compounds • The wall surface of the digester must be isolated (Warmth friction is at least 3 m2/K/W • Manholes for inspection necessary (1 x 1 m) • The type and material of the digester must be chosen depending on the project


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4.4.9 Sludge dewatering

Physical reduction of the sludge volume is caused by using a belt press or a sludge centrifuge. For dimensioning the sludge dewatering, see table below. Parameter Applied value Advised design

value Unit

Belt press Guaranteed DS% 17-32 20 % Operational time 100 100 hour/week Water recovery > 95 98 % Polymer use 3-8 7 g PE/kg DS Centrifuge Guaranteed DS% 17-32 22 % Operational time 100 100 hour/week Water recovery > 95 97 % Polymer use 5-15 10 g PE/kg DS In case a belt press is chosen, measures must be taken for air purification.

4.6 Automatisation

4.6.1 Introduction

Use of automated systems will increase the efficiency of plants substantially. In general, the components of the UWWTPs in small and medium sized municipalities are served on and off manually. The operation and control of the machinery can be made easier and more efficient by using simple controllers and timers. There is no need for using complicated hardware or software. With smart process control- equipment and adjustments the high workload of the operators will be reduced (they are available 24 hours a day). The automatic operation of the systems will also reduce the energy use in the UWWTP: • Using better quality measuring equipment and applying extra level switches will prevent

flooding or running the pumps dry. • The use of more measuring sensors (Level, Oxygen, flow) and using more feedback for

targeted control of the machinery and more linearity of the process ensure a stable process operation of the system.

• Many process fluctuations, switching the machinery on and off too frequently without feedback, disrupt the desired process results.

• Execution of an energy assessment of the plant components with energy efficient alternatives of machines is expected to increase improvements, which will reduce the energy demand and therefore lower the yearly operating costs. The functioning of existing UWWTPs can be improved by some relatively small adjustments like online measurement equipment and automated process control equipment.

Mainly the small UWWTPs have to be equipped with next measuring and controlling instruments. It will reduce the cost of operation and maintenance. • Level switch • Level sensor • Flow sensor • Oxygen sensor • Controller


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For the bigger installations has to be use: • Process Logic Controls • SCADA an event loggers • Alarm and warning systems • Communication systems • Net work • Remote control

4.6.2 Aeration control

Different aeration control schemes can be made. In the following text three aeration control schemes are discussed. Oxygen control scheme Within the oxygen control scheme the oxygen concentration is measured in the activated sludge tank. The measured oxygen concentration is compared to the oxygen set point. Depending on the difference between the measured oxygen concentration, the set point and the tendency of the change in oxygen concentration, the PI-controller sends out a signal between 0 to 100% to the blowers or aerators. Depending on the size of this signal the capacity of the blowers is reduced or one or more of the aerators are switched on or off. In the following figure the control scheme is visualized.

Figure 13

Ammonium/oxygen control scheme The ammonium/oxygen control schema is a so called cascade-automatisation. This means that the aerators are still controlled by the oxygen control scheme, while the oxygen set point is determined by the ammonium control scheme. The ammonium concentration is measured in the activated sludge tank. This concentration is compared to the ammonium set point. Depending on the difference between the measured ammonium concentration, the set point and tendency of the change in ammonium concentration, the PI-controller sends out a signal between 0 to 100%. This output value of the ammonium control scheme determines the oxygen set point. The oxygen set point can be limited between two values with a limiter. The aeration is then controlled according to the oxygen control scheme as described in the previous section. In the following figure the control scheme is visualized.


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Figure 14

Nitrate/ammonium/oxygen control scheme The nitrate/ammonium/oxygen regulation can also be described as a so called cascade-automatisation. In this control scheme the ammonium set point is determined by the nitrate concentration in the activated sludge tank. The ammonium control scheme determines the oxygen set point and thereby the oxygen control scheme. The oxygen control scheme sends out a signal to the aerators. The nitrate content is measured in the activated sludge tank. If the nitrate concentration is above a specified value (set point), the ammonium set point will be increased with a specified value. If the nitrate content is below a specified value, the ammonium set point will be decreased with a specified value. If the nitrate content is between the minimum and maximum value, the ammonium set point will be set to the average value of the minimum and maximum set points of ammonium. The control scheme will proceed as previously described in the ammonium/oxygen control scheme. In the following figure the control scheme is visualized.

Figure 15


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4.7 Dimensioning WWTPs – TAUW calculation tool

The TAUW calculation tool is an Excel spreadsheet for dimensioning wastewater treatment plants. It is also possible to calculate the annual average N-total value in the effluent of existing plants (calculating backwards). The effect of seasonally dependent loads can also be calculated. The calculations regarding the activated sludge are based on the German HSA model. In the calculation tool the nitrification is set to as a temperature-dependent process instead of the static conversion as in the HSA model. The nitrate formed (from ammonium) is the input for the HSA-calculation for the effluent nitrate value. This model for nitrogen removal gives the opportunity to calculate the annual average N-total effluent value even if there is a time period where the temperature is below the design temperature. Different process configurations (UCT, mUCT, BCFS®, Phoredox and carrousel) can de dimensioned or fitted within the calculation tool. Besides the HSA-model several other modules are included within the tool such as a module for the aeration and a module for the settling tanks. For the usability of the calculation tool a navigation toolbar is included. Using a calculation tool is of course convenient because there is no need anymore to dimension a UWWTP on paper and saves time, but using a calculation tool is only useful if the background of the model is understood and the user knows how results should be interpreted. Otherwise there is a considerable risk that the design made is not appropriate. Annex 7 includes information on the TAUW Calculation Tool.


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39

5 Operation and Maintenance

5.1 Introduction

The operation and maintenance of UWWTPs could be improved considerably when considering efficiency measures, planning, organisational, managerial and financing issues. This chapter provides an overview of recommendations which could be taken into account.

5.2 Organisation, management and finances

1) Co-operation between municipalities and the establishment of water unions The common practice of constructing UWWTP’s in small and medium sized municipalities is individual municipalities realising a plant, with assistance from either the Iller Bank, from MoEF, with support of other investors, or on their own. The operation and maintenance of UWWTPs is carried out separately by each municipality. Due to the small scale of the UWWTPs is it difficult to realise cost efficient UWWT solutions and viable organisation of operation and maintenance. Efficiency could be improved in situations where a UWWTP serves more than municipality. The costs associated with the realisation and functioning of such plants could be significantly reduced. Resources, particularly human resources, could also be maximised if municipalities cooperate in the investment, construction, operation and maintenance of one UWWTP. MoEF initiated the establishment of water unions and combined UWWT for more than one municipality. Some municipalities started a co-operation for waste water treatment; however co-operation is often hampered because financial obligations are not met by one of the partnering municipalities. Management systems should be elaborated which support a sound co-operation. Annex 2 provides an overview of possible organisation forms for the establishment of water unions. 2) Co-operation between MoEF, Illerbank and municipalities Improved co-operation between MoEF, Iller bank and municipalise will support common decision-making on waste water regulation, priorities and practices. 3) Role municipalities; polluters pay principle, staffing In the present situation a municipality takes the initiative to start the realization of a WWTP and asks Iller Bank or the Ministry of Environment for support. The municipality is not involved in the construction off the WWTP. The municipality gets involved only when the construction is finalised. Then the operations and maintenance has to be organised under the responsibility of the municipality. This often results in insufficient operation and maintenance practices. Municipalities should be more closely involved in the process of designing and building the WWTPs and in considerations related to the operation and maintenance after the construction of the plants. This enhances the feeling of ownerships and responsibility.


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The following activities should be undertaken by municipalities: • Organisation of the collection of fees from the “polluters”; these fund could cover

investment, exploitation - and maintenance costs • Calculate the tariff/tax for waste water treatment and the moment of introduction • Arranging of staff for operation and maintenance • Communicate about necessity of waste water treatment to there inhabitants. 4) Attention for costs of Operation and Maintenance in Feasibility studies Feasibility studies for the construction of smaller UWWTP’s do not include financial considerations for operation and maintenance (i.e. studies prepared by Iller Bank). Multiple costs such as for energy, operation, maintenance and staffing should be taken into consideration for at least 30 years when designing the UWWTPs. Including financial considerations in the stage of the feasibility studies could considerably impact the decision on appropriate small-scale UWWT techniques (e.g. automation and other energy efficient aerators). 5) Supervision during construction The constructed UWWTP’s are not always in line with the initial design. Building failures or bad quality can be the course of large amounts of money needed for maintenance or renovations earlier then necessary. Increased supervision during the construction of the UWWTPs could address this problem. Arrange inspection on the building process by qualified staff. 6) Unification UWWTPs There are insufficient qualified personnel for operating UWWTPs at municipal level. Therefore unification of the UWWT processes, especially of neighbouring municipalities is favourable. When plants are similar, personnel can easily be exchanged between the different UWWTPs. 7) Involve the public The public could be involved more frequently in the process of waste water treatment. Involving the public in decision-making on water regulation/management will enhance their commitment towards waste water treatment and their understanding about having to pay for waste water treatment. 8) Review tendering process In general there are three forms of tendering, the Traditional forms, Design & Construct and Public Private (see annex See annex 4: forms of tendering) The D&C and Public Private form of tendering are currently not executed in Turkey. The traditional form is most relevant as then the construction can be controlled maximal. With respect to the current form of tendering, the following can be notified: • In the pre-design phase only investment costs are considered. The exploitation costs are

not included. Also in the final design phase the exploitation costs seem to get little attention. As exploitation costs are as important as the investment costs for the end-user it is recommended to pay more attention to the exploitation costs. Including both costs within the design prevents that a system is chosen that might be cheap to build but has high exploitation costs.

• The use of a Multi Criteria Analysis (see annex) supports taking a decision based on various criteria


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9) Subsidy on energy costs

In October 2010, the WWTP energy incentive regulation was published. This regulates the financing of a percentage of the energy cost of urban and industrial properly operated WWTPs (the actual percentage still needs to be determined). Municipalities can apply for this subsidy.

10) Consider outsourcing The most important cost components of the operation of WWTPs are the personnel and electricity costs (see table below). Municipalities can either operate the plants themselves or outsource the operation to a private company. Outsourcing has certain advantages. The private sector is always more flexible in hiring personnel and is more efficient in controlling personnel expenditures. Another advantage of outsourcing is the flexibility in procurements. The state procurement rules are rigid and usually it takes a long time to buy spare parts or chemicals for the treatment plants. In case of outsourcing, procurement will be realised by the private company who doesn’t have to follow the public procurement rules. 11) Be aware of costs To support with the estimation of costs of operation and maintenance, a table is presented in Annex 5. This table provides a general guideline for costs op operation and maintenance.

5.3 Operation

Focal points for the operation of UWWTPs include: 1) Monitoring Regular sampling of the effluent water is needed to be able to measure if the effluent water meets the standards. By monitoring the quality, energy consumption can be organised more efficiently 2) Automation Automation provides the operator with regular information; this information can be used to improve the performance of the installation which will result in better effluent water quality and efficient use of the installation 3) Staff, co-operation, exchange of knowledge • Involve trained staff with knowledge and experience on waste water treatment • Facilitate exchange of knowledge between the operators and maintenance staff by

holding meetings on regular basis • Initiate co-operation with plants of neighbouring municipalities 4) Manuals The Iller Bank provides complete operation manuals.


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5.4 Maintenance

Focal points for the maintenance of UWWTPs include: 1) Development of a maintenance plan • Develop a (digital) maintenance scheme • Describe the daily maintenance tasks • Develop a plan for maintenance for a period of e.g. five years ahead (based on work

hours on parts of the installation) • Plan financing based on the maintenance plan • Take care of equipment (tools) that is used for maintenance 2) Staff, co-operation, exchange of knowledge • Involve trained staff with knowledge and experience on waste water treatment • Facilitate exchange of knowledge between the operators and maintenance staff by

holding meetings on regular basis • Initiate co-operation with plants of neighbouring municipalities 3) Take safety measures


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Annexes

Main articles By-Laws Annex 1 Organisation forms water unions Annex 2 Decision Making Model WWT Annex 3 Forms of tendering Annex 4 Operation and Maintenance Costs of WWTPs Annex 5 Small scale technologies for waste water treatment Annex 6 Tauw calculation tool Annex 7


44


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ANNEX 1: MAIN ARTICLES BY-LAWS Discharge into sewerage systems By-law on UWWT According to Article 9, the principles of discharging the industrial waste water to the sewerage system, municipalities ensure that industrial waste water discharge to the sewerage system are subject to permission for connection on sewerage system (government cares for all kind of waste water). By-law on Control of Water Pollution According to Article 25, basic principles for discharge on sewerage system, when there is a sewerage system, preference is given to discharging waste water to the sewerage systems instead of treatment and direct discharge on surface water. In Article 44, permission for companies to discharge on the sewerage system is described: • Permission is given by the municipality. • It’s a written document for household water and industrial waste water. Article 45 refers to limitations of discharging to sewerage systems: • In case of separate systems, rain or drainage water is not connected to the sewerage

system. • Companies must build balance pools before connection to a sewerage system. Article 47 concerns maximum values parameters. Standards for discharges on sewerage systems are provided in Table 25 in the By-law. In Article 48, maximum values for pre-treatment for food/diary industries are provided in Table 5 and 25 of the By-law. With more than 10% of total flow and pollutant rate of the sewerage system, the company must establish special pre-treatment facilities. Treatment public UWWTP and discharge into surface water By-law on UWWT Article 7 and 8 are concerned with the treatment requirements for UWW: • Discharge standards/ values/ criteria Table 1 Annex IV (in By-Law) • In sensitive areas standards/ values/ criteria Table 2 Annex IV (in By-Law) • Principles sensitive area’s in Annex I (in By-Law) • Evaluation of monitoring results in Annex II (monitoring method, number of annually

samples, in By-Law) Article 10 deals with permission for discharging wastewater with biologically degradable compounds directly into surface water: • Municipalities will be ensured that the biologically degradable waste water originating

from the facilities belonging to the industrial sectors that are mentioned under Annex-III (in By-law) and that cannot enter the UWWT facilities due to technical and economic reasons and discharged industrially to e.p. of 4000 or more, is in conformity with the discharge standards stated under Tables 5 and 6 of the By-law on The Control of Water Pollution.

• The permission for discharging to the receiving environment is subject to the Article 37 of the By-law on Control of Water Pollution.

Article 12 is less stringent then secondary treatment for collection areas 2.000-10.000 p.e. in less sensitive area’s in the following cases:


46

• Such discharges are shown to be in conformity with the control procedures laid down in Annex II (In By-Law)

• Comprehensive studies indicate that such discharges will not adversely effect the environment. The municipality must send the outcome of the studies mentioned above to the MoEF at least once a year.

• The MoEF shall ensure that the identification of less sensitive areas is reviewed at intervals of no more than four years.

Article 14 addresses monitoring and control: • Provincial office of MoEF monitors the compliance of the discharges. • The municipality monitors the discharges of waste water made by industries of Annex III

(allowed direct discharges with biological degradable compounds, in By-Law). • The provincial directive of the MoEF sends the information of control every two year to

the MoEF, or on request. Article 15 refers to evaluation: • Provincial office of MoEF makes a status report of all the public UWWTP discharges in

their region every two year and sends it to MoEF Ankara. • The provincial directive MoEF prepares an implementation program to implement the By-

law together with the municipalities. • The MoEF evaluates the result of regions every two year. By-law on Control of Water Pollution Article 26 is concerned with responsibility for measurement and control: • Municipality as owner of the public UWWTP is responsible for the amount and quality

control of waste water, decrease of pollution, appropriate to given waste water discharge values. Data are kept by the municipality during three years.

• Provincial offices of the MoEF control whether these activities are realized and control this with own measurements; these measurements of MoEF are paid by the municipality.

Article 32 contains standards and values for household discharge referring to Table 21. The discharge standards were defined in four categories depending on BOD5 loads or equivalent population. It is getting more stringent with the increase of load/population. However, it refers only discharge parameters of BOD5, COD, SS and pH. Table 21 differs from the values for discharges in Table 1 and Table 2 of the By-law on UWWT due to the fact that the By-law on UWWT is the most recently published By-law. New UWWTPs should comply with Table 1 or 2 of the By-law on UWWT and the existing UWWTPs should comply with Table 21 of the By-law on Control of Water Pollution. According to Article 37 on the basis discharge permission: • All kinds of household or industrial wastewater discharges have to have permission for

discharging from the Provincial office of the MoEF. • Permission given by the Provincial office of the MoEF is valid for five years. • Basis of permission are the standards/values/criteria in Table 5 – 21. • Realizing limits: twelve months after notification of the limitations. In Article 39, limitations and cancellation of permissions is presented. When discharge permission is exceeded, a penalty is given two times with a period to make the necessary amendments. If the company does not provide the required discharge conditions, the discharge permission is cancelled. Article 40 concerns process permitting: • The administration has to give permission at least within 2 months after the permission

application. • Permission certificates are renewed periodically. In the phase of this renewing, the

probable changes of mentioned features, amount of waste water and pollution,


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realization of required technological; precautions, necessity of new precautions, measurement programs are controlled.

• When there are changes mentioned above, the applicant must begin to permission procedures again and take a permission certificate again.


48


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ANNEX 2: ORGANISATION FORMS FOR WATER UNIONS Based on experiences in the Netherlands, the following organization forms can be considered for combined waste water treatment for more than one municipality: 1. One of the co-operating municipalities takes the responsibility for the operations and

maintenance of the UWWTP; One of the municipalities, for instance the one in which the UWWTP has been constructed, or the largest municipality, takes the responsibility for the operations and maintenance of the collection pipe and the UWWTP. The other municipality/ municipalities pay an equal part of the total costs. This can be calculated on the p.e. input, or on the volume of influent, or even on the numbers of inhabitants of the municipalities.

2. The municipalities establish a union or foundation, with responsibility for the UWWTP residing within this union or foundation; By participation of more then two municipalities a union or a foundation could be helpful. This offers greater independence during the application of local policies by the municipalities in their operations. This union/foundation can, on a yearly basis, make a calculation of the total cost of the UWWTP. The municipalities can then decide how to collect their contribution for the UWWTP. The collection of the contribution can be done by the union/foundation or by the municipality itself.

3. The municipalities establish a “water board” as an independent organization; The difference between this organization form and the one mentioned above is that a water board has its own independent board (elected).

4. Several municipalities establish a union or Waterboard for managing more then one UWWTP; A step further is to establish an organization that operates and maintains several UWWTPs. Waternet in the Netherlands operates and maintains 12 UWWTP’s in the surroundings of Amsterdam. The benefit is more efficiency and the capability to acquire experts in different fields required for management and operation of the plants (waste water treatment, operations, maintenance but also on legislation, permits, enforcement and financing/taxes). Besides it is easier to recover the costs for these plants.

5. Source out the operations and maintenance of the UWWTP(s) to a private company. It is also possible to outsource all activities, or some activities, to a private company. The municipality can decides which activities should be outsourced and which will be carried out by the municipality itself; This form could be efficient when there is more than one private company specialized in this field. If not, there will be limited competition and it will be difficult to set a list of demands.

Organisation forms for

combined UWWT Advantage Possible bottlenecks

1 One of the municipalities is responsible for management and organisation of the UWWTP

Clear organisation form

The municipality who is not responsible might lack performing financial contributions for operation and maintenance Capacity needed at Municipality

2 Development of union or foundation by municipalities

Shared responsibility

Differences in political priorities /policy issues might hamper reaching common solutions Capacity needed at Municipalities for Organisation and Management

3 Establishment of Water Board, with elected independent members

Independent management and organisation (elected board); facilitating

Lack of commitment of municipal public officers; Capacity needed at municipalities/MoEF to organise elections for Board members


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decision-making

4 Establishment of Water Board for managing several UWWTPs

Efficiency, return on investment reached within relative short period

Capacity required at municipalities/MoEF to organise the Water Board, elections etc.

5 Outsourcing of Operation and Maintenance of UWWTPs to private company

Capable experts available

Availability of professional private companies; capacity needed at municipality for tendering procedures/managing private companies

General remarks: • Differences between municipalities need to be considered (geographical barriers, climate

issues, waste water characteristics, etc.). • Capacity needed at municipalities for organisation and management of waste water

treatment.


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ANNEX 3: DECISION MAKING MODEL WWT See following pages.


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53


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ANNEX 4: FORMS OF TENDERING In principal three forms of tendering can be distinguished, namely 1. Traditional 2. Design & Construct 3. Public Private Each form of tendering has its own process steps. The following subparagraphs present the process steps for each form of tendering. Traditional tendering Within the traditional tendering four process steps/phases can be distinguished. The following overview shows the four process steps including its sub steps (if applicable). 1. Pre-design

a) Points of Departure/preconditions b) System choice c) Technological design /dimensioning main components d) PFD’s e) Process control scheme f) Basic design – lay-out g) Basic information equipment h) Civil calculations

2. Final design 3. Construction 4. Completion Phase 1: Pre-design 1. Points of Departure/preconditions In the Netherlands it is common to look 30 years ahead. This timeframe is related to the lifetime of the civil works. At this sub step the loads of the future WWTP are determined, biologically as well as hydraulically. The loads are based on the current situation of the existing WWTP + the prognosis for 30 years. The prognosis is based on the building plans of the county, building plans of the involved municipalities and expected industry. The future effluent demands are of course part of this sub step. The points of departure/preconditions are (almost) always determined by the water boards.

2. System selection In general the system selection starts with an exploration of possibilities. In many cases this starts with a brainstorm session between the involved water board and the contracted engineering firm. The result of the exploration is a number of different system possibilities/alternatives. Remark: in some cases the water board has a specific preference for a system configuration. The different alternatives are elaborated; the technological dimensioning will be performed for each alternative and a rough cost evaluation (investment and exploitation costs) is made for each alternative. In some cases a specific system configuration already prevails after the elaboration of the alternatives. In other cases no specific alternative prevails and a qualitative multi criteria analysis (MCA) is needed. A MCA consists of different aspects like the yearly costs, sustainability (e.g. energy, chemicals), robustness, risks and complexity for the operators. These aspects are just examples. The exact aspects are decided in consultation with the involved water board. Each aspect will be assigned a weighing factor (e.g. between 1 and 3). An aspect with a higher weighing factor means that that aspect is more important than the aspect with a lower


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weighing factor. The elaborated system possibilities are set next to each other within the MCA table. Subsequently the different alternatives are rated. This could be rated with numbers (e.g. from – 3 till +3) or with plus signs and minus signs (e.g. from -- till ++). Each aspect is multiplied with the rate given to the specific system possibility. This adds up to a final score. The MCA should give a clear picture of the qualitative differences between the different alternatives. In the following table an example is included.


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MULTI CRITERIA ANALYSIS

No AspectWeighing factor

Alternative 1 Alternative 2 Alternative 3 Alternative 4

1 Costs (total yearly costs) 3 0 - 0 0Sustainability 3 -- - + ++Sustainability: total

2a Energy (elektricity, gas, transport)2 ++ - 0 0

2b Chemicals 2 -- 0 ++ ++

2c Sludge production 2 -- - 0 0

2d Emissions to air 1 0 + 0 +

2e Needed area 1 0 0 -- -

2f Noise 1 0 0 0 0

Subtotal Costs and sustainability -- -- + ++Risks

3 Operation during construction phase 1 + 0 0 -

4 Construction time and construction stages (effect on effluent quality)

1 + + 0 0

5 Complexity of operation and maintenance 1 - 0 + -

Certainty 2 0 - + -Certainty: total

6a Failure during normal operation 1 0 0 0 -

6c Proven technology 1 + - + 0

6d Risks of floating sludge 1 + -- 0 -

Robustness 1 - - + +Robustness: total

7a Effluent demands1

7b Higher load / wrong prognosis1

8 Tender risks in relation to suppliers 1 + - + 0

Subtotal Risks9 Innovativity 1 0 ++ 0 +

- - ++ +Total

2

6

7


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The total score of the MCA is placed next to the building costs and the exploitation costs for each alternative. Based on this total overview the system configuration of the future WWTP is chosen. The inclusion of a MCA for the system selection means that the cheapest alternative does not always prevail. In the following table an example is presented. Although alternative 1 has the lowest buildings costs and alternative 4 has the lowest exploitation costs, alternative 3 was the one that prevailed.

Criteria Alternative 1 Alternative 2 Alternative 3 Alternative 4Building costs 3.060.850€ 7.256.450€ 7.602.400€ 6.640.200€ Exploitation costs 1.702.146€ 1.809.392€ 1.691.728€ 1.635.685€ Qualitative criteria -- -- ++ +

3. Technological design / dimensioning main components This sub step is a further elaboration of the one made at sub step C “System selection”. The system configuration is chosen and now the main components need to be dimensioned / checked, such as: • Flows • Volumes • Oxygen input • Diameters • Sludge production • Sludge treatment This dimensioning is only from a technical point of view. Mechanical or civil engineering is not included

4. PFD’s Based on the dimensioning of the main component in sub step C a PFD (Process Flow Diagram) is made. The PFD gives an overview of the process flow of the WWTP and the flow to/of every component is included. In the following figure shows an example of a PFD. Within this specific PFD two flows are mentioned: the flow between brackets is the dry weather flow, the other flow is the rain weather flow.


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5. Process control scheme Within this sub step the basic automatisation controls are determined. So where do we need to install on-line measurements and how can the process be controlled? For example: • Automatic control of blowers based on ammonia sensor in AT • Automatic control for excess sludge based on MLSS sensor in AT This sub step is performed by the discipline electrotechnic in cooperation with the discipline technology. In the following figure an example is given of a process control scheme for the aeration in an activated sludge tank.

6. Basic design – lay-out In this sub step the basic design is made. The size of for instance the activated sludge tanks and settling tanks are known and the lay out can be made. This sub step is mainly performed by the discipline civil engineering. Almost no complete new WWTPs are built in the Netherlands. This means that we are confronted with mainly (large) renovations/adjustments on-site. Fitting all the new components within the available space can be quite a puzzle. The following figure presents an example of a lay-out of a WWTP.


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7. Basic information equipment Within this sub step a preliminary equipment list is made for all the components of the future WWTP. The needed space for the equipment is estimated based on experience. This sub step is executed by the discipline mechanical engineering. In many cases sub step F (basic design – lay-out) is performed simultaneously with this sub step (basic information equipment)

Civil calculations: when sub step A till G are executed the civil calculations can be made. The civil calculations include: • hydraulics • building height • construction depth • well point system • foundation Phase 2: Final design After the pre-design phase the final design can be made. The final design is more or less a further detailed elaboration of the pre-design and includes: • Definitive PFD • Functional design • Definitive equipment list • Electrical installation • P&ID’s • Exact costs


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Phase 3: Construction When the final design is made the construction phase can start. A contractor is assigned for the construction. In many cases the contracted engineering firm is responsible for the supervision of the construction phase. Phase 4: Completion When the construction is (almost) done the completion phase starts. Within the completion phase the following activities can be distinguished: • ‘Pre’ completion

o Site Acceptance Test (SAT) o Wet testing o Functional testing o Process control test

• Start up procedure is made • Scheme operation and maintenance is made • Training of operator(s) • The process is optimized • ‘Final’ completion Design & Construct Design & Construct (D&C) is a form of tendering where a consortium is responsible for as well the design as the construction. A D&C can basically be distinguished in eight steps/phases, namely: 1. Water board makes specification of demands 2. Tender consortium is formed and action plan is made 3. Tender evaluation, signing contract 4. Purchase order placed 5. Detail design by consortium 6. Construction process 7. Commissioning, start up 8. Hand over to client Phase 1: Water board makes specification of demands Before a D&C can start a specification of demands has to be made by the end-user. For the Dutch case this is a water board. The specification of demands contains the following items: • Hydraulics • Influent specifications • Effluent specifications • Design specification • Energy consumption (kWh/person equivalent) • Regulations from permits • Criteria for tender selection • Material choices (most cases) Within this form of tendering there is still a relatively strong control by the water board on the chosen solutions. When the specification of demands is done, it can be put out to tender. Phase 2: Tender consortium is formed and action plan is made When the work is put up to public tender several consortia are formed. A tender consortium usually consists of a consultant, a civil contractor and a mechanical & electrical (M&E)


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contractor. There is some freedom to fill own expertise of the consortium. When a tender consortium is formed a risk assessment within the consortium is executed. If the consortium is ‘stable’ the involved companies/organisations sign an agreement where the cooperation is put down in writing. Based on the specification of demands an exploration for possible alternatives starts. Every alternative has to be checked if it fully complies with the specification of demands. In this phase there is usually the possibility to ask questions to the water board. In the end one alternative/solution is left/chosen. For this solution an action plan is made. The action plan contains the following aspects: • Process technology and design choices • Design and realisation • Operation and maintenance • Costs of exploitation • Project management • Drawings and calculations The water board will select the consortium that translates the specification of demands the most effectively into an appropriate design (technically and financially). So the action plan has to be carefully composed. Phase 3: Tender evaluation, signing contract The water board will evaluate the action plans of the different consortia. In some cases a consultancy firm assists the water board. Finally one consortium will be chosen. After this decision the contract has to be made and of course signed by the involved parties. The contract contains aspects like price, guarantee, mile stones, payment conditions, planning, etc. Phase 4: Purchase order placed Phase 5: Detail design by consortium In phase 2 the basic design is already made. Within this phase this design is further detailed and extended. This phase includes the following aspects: • Definitive PFD • Functional design • Definitive equipment list • Electrical installation • P&ID’s Phase 6: Construction process This phase is more or less the same as with the traditional tendering. The main differences are that with D&C less supervision by client/water board is necessary, less involvement of client/ water board at selecting brands and materials and the overall planning is dealt with by the consortium. Phase 7: Commissioning, start-up When the construction phase is done the commissioning of the WWTP can start. This phase is more or less the same as phase 4 of the traditional tendering. Before the wastewater will actually be treated several tests need to be performed, namely: • Site Acceptance Test (SAT) • Wet testing • Functional testing • Process control test


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Also a manual for operation and maintenance is made and a start up procedure is written. When these steps are performed the real start up of the WWTP can be executed. After the start up the operators are trained. When all these steps are performed the WWTP is ready for the last phase: hand over to client. Phase 8: Hand over to client In this phase the WWTP is officially handed over to the client. In this phase the client will receive the final operation and maintenance manual. Usually the handing over to the client is accompanied with a formal opening ceremony. After the guarantee period the client will pay the outstanding amount (final payment). Public Private Partnership (PPP) The PPP form of tendering is basically a D&C, but extended with the following responsibilities: • Finance • Operational aspects • Maintenance Of course it has to comply with legislation. Characteristics of the PPP form of tendering are: • Design process in less time • Construction in less time • Less supervision • Mostly less costs • “No” influence on process by client • Solid contract is necessary • Rock hard starting points • Financial solid partner required This form of tendering is quite new in the Netherlands. Up to now only one WWTP in the Netherlands (WWTP Harnaschpolder) is designed and operated in a PPP form.


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ANNEX 5: OPERATOIN AND MAINTENANCES COSTS OF WWTP

Costs of operation & maintenance - UWWTP *WWTP 30000 pePopulation 16000 inhabitants

Fixed costs Object description total Average %Electricity Water treatment -€

Aeration -€ Sludge treatment -€

750 MWh 65.00€ per MWh 48,750.00€ sub 48,750.00€ 17.82

Chemicals dewatering polymeer 2400 kg 3.50€ per kg 8,400.00€ thickenning polymeer 0 kg per kg -€ phosphorus removal Ferro salts 0 ton per ton -€ effluent chlorine disinfection chlor 0 ton per ton -€

8,400.00€ 3.07Residual screenings 250 m3 5.00€ per m3 1,250.00€

grid sand 100 m3 5.00€ per m3 500.00€ industrial waste water kg per kg -€

1,750.00€ 0.64Sludge treatment dewatering sludge, 1200 ton 5.00€ per ton 6,000.00€

transportation dewatered sludge 1200 ton 2.00€ per ton 2,400.00€ -€

8,400.00€ 3.07Water use drinking water serving polymer production, 480 m3 0.50€ per m3 240.00€

drinking water serving buildings 100 m3 0.50€ per m3 50.00€ 290.00€ 0.11

tax WVO-tax pe per pe -€ -€ -€ 0.00

67,590.00€ 24.70

Variable costs Object description total Average %Maintenance Instrumentation Flow 3 pc 3000 9,000.00€

Oxygen, 1 pc 4000 4,000.00€ Nitrate 1 pc 5000 5,000.00€

18,000.00€ 6.58Mechanical equipment pumps 10 pc 1000 10,000.00€

blowers 2 pc 5000 10,000.00€ mixers 3 pc 1000 3,000.00€ belt filter 1 pc 120000 120,000.00€

-€ Cleaning -€

143,000.00€ 52.27Organization Staff expenses Manager 1 fte 20000 per fte 20,000.00€

Technologist 0.5 fte 10000 per fte 5,000.00€ employee 4 fte 5000 per fte 20,000.00€

45,000.00€ 16.45

206,000.00€ 75.30

273,590.00€ 100.00

cost p.p.e 17.10€ * This is a cost-calculation sheet for benchmarking UWWTP's in the Netherlands. Filled in figures are not real.

total budget

used tariff

used tariff

total investment

Total variable costs


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ANNEX 6: Small size technologies for domestic wastewater treatment Small size technologies for waste water treatment that could be applied are: 1) Lagoons/wetlands/ponds 2) Anaerobic digestion 3) SBR These technologies do not meet the effluent requirements with respect to Nitrogen and Phosphorous as incorporated in the Urban Waste Water Treatment Directive, however could be used as solutions in case no funding for treatment technologies is available and some treatment has to be initiated. 1) Lagoons Wastewater treatment can be realised in ponds, wetlands or lagoons. These are artificial marshes or swamps, created for anthropogenic discharge such as wastewater or sewage treatment, and as habitat for wildlife, or for land reclamation after mining or other disturbance. Natural wetlands act as bio-filters, removing sediments and pollutants such as heavy metals from the water, and constructed wetlands can be designed to emulate these features. The aerobic alternative is an aerated lagoon system. Wastewater lagoons

Wastewater lagoons have been used as a process for wastewater treatment for centuries. In the 1920's artificial ponds were designed and constructed to receive and stabilize

wastewater. By 1950, the use of ponds had become recognized as an economical wastewater treatment method for small municipalities and industries. As of 1980, approximately 7,000 waste stabilization lagoons were in use in the U.S. Today, one third of all secondary wastewater treatment facilities include a pond system of one type or another. Of these, just over 90% are for flows 1 MGD or less. But ponds can be used for larger cities for wastewater treatment as well. Some of the largest pond systems in USA are in Northern California, serving such cities as Sunnyvale (pop. 105,000), Modesto (pop. 150,000), Napa (pop. 175,000), and Stockton (pop. 275,000). The major advantages of lagoon systems are their low cost (investment and operation) and their minimal need for operator attention. The effluent is disinfected by the long hydraulic retention times in the system and effluent can be applied for irrigation purposes because of higher nutrient levels. Chlorine is not required for disinfection. The main drawback is the long retention times in the ponds and subsequently the relatively large area required. But, if the pond is well designed it can be an attractive addition in the landscape. Phosphate is not greatly removed with this system, but if the effluent is applied for irrigation in agricultural areas this can be an advantage. Also, phosphate can be removed by applying iron dosing. The pond can be aerated or non-aerated. The minimal energy requirement of the non-aerated pond is attractive where aeration costs are an issue. Types of aerated lagoons or basins: There are many methods for aerating a lagoon or basin: − Motor-driven floating surface aerators


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− Motor-driven submerged aerators − Motor-driven fixed-in-place surface aerators − Injection of compressed air through submerged diffusers. A Typical Surface-Aerated Basing (using motor-driven floating aerators) Ponds or basins using floating surface aerators achieve 80 to 90% removal of BOD with retention times of 1 to 10 days. The ponds or basins may range in depth from 1.5 to 5.0 metres. In a surface-aerated system, the aerators provide two functions: they transfer air into the basins required by the biological oxidation reactions, and they provide the mixing required for dispersing the air and for contacting the reactants (that is, oxygen, wastewater and microbes). Typically, the floating surface aerators are rated to deliver the amount of air equivalent to 1.8 to 2.7 kg O2/kWh. However, they do not provide as good mixing as is normally achieved in activated sludge systems and therefore aerated basins do not achieve the same performance level as activated sludge units. Biological oxidation processes are sensitive to temperature and, between 0 °C and 40 °C, the rate of biological reactions increase with temperature. Most surface aerated vessels operate at between 4 °C and 32 °C. Aerated lagoon technology, especially that of high-performance systems, is one of the most misunderstood technology in wastewater treatment. This misunderstanding is largely the result of its evolution from the technology of facultative lagoons, in which algae play a vital role and hydraulic retention times are long. In fact, the technology of high-performance aerated lagoons has much in common with that of activated sludge. With proper design and operation, aerated lagoons can deliver effluents that meet limits of 30 mg/L, both for TSS and CBOD5. Furthermore, with modification or with the addition of low-tech process units, they can be designed to nitrify. The major advantages of aerated lagoon systems are their low cost and their minimal need for operator attention. Experience in swine wastewater treatment Animal operations with limited land area can avoid the need for offsite waste disposal if management options that increase the farm's capacity to treat wastewater are adopted. One promising option is the use of constructed wetlands to reduce wastewater pollutants prior to land application. Treatment wetlands generally have one of two designs, either continuous marsh or marsh-pond-marsh. While swine wastewater treatment by continuous marsh wetlands has been studied extensively, treatment by marsh-pond-marsh wetlands has not. We investigated the ability of marsh-pond-marsh wetlands to reduce pollutants in swine wastewater. The objective of this research was to determine how the presence of a pond section affects NH3 volatilization from constructed wetlands treating wastewater from a confined swine operation. Ammonia (NH3) volatilization is an undesirable mechanism for the removal of nitrogen (N) from wastewater treatment wetlands. To minimize the potential for NH3 volatilization, it is important to determine how wetland design affects NH3 volatilization. Wastewater was added at different N loads to six constructed wetlands of the marsh–pond–marsh design that were located in Greensboro, North Carolina, USA. A large enclosure was used to measure NH3 volatilization from the marsh and pond sections of each wetland in July and August of 2001. Ammonia volatilized from marsh and pond sections at rates ranging from 5 to 102 mg NH3–N m–2 h–1. Pond sections exhibited a significantly greater increase in the rate of NH3 volatilization (p < 0.0001) than did either marsh section as N load increased. At N loads greater than 15 kg ha–1 d–1, NH3 volatilization accounted for 23 to 36% of the N load. Furthermore, NH3 volatilization was the dominant (54–79%) N removal mechanism at N loads greater than 15 kg ha–1 d–1. Without the pond sections, NH3 volatilization would have been a minor contributor (less than 12%) to the N balance of these wetlands. To minimize NH3 volatilization, continuous marsh systems should be preferred over marsh–pond–marsh systems for the treatment of wastewater from confined animal operations.


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2) Anaerobic digestion Anaerobic digestion is a treatment that reduces highly concentrated (industrial) wastewaters and domestic wastewater sludge under anoxic conditions and at higher temperatures (>30°C) and releases biogas. Biogas is an attractive energy source. Anaerobic treatment could be attractive in Turkey because the technique is innovative, it creates biogas as energy source and the ambient temperature is higher than in Holland. Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen. It is widely used to treat wastewater sludges and organic waste because it provides volume and mass reduction of the input material. As part of an integrated waste management system, anaerobic digestion reduces the emission of landfill gas into the atmosphere. Anaerobic digestion is widely used as a renewable energy source because the process produces a methane and carbon dioxide rich biogas suitable for energy production helping replace fossil fuels. Also, the nutrient-rich digestate can be used as fertiliser. The digestion process begins with bacterial hydrolysis of the input materials in order to break down insoluble organic polymers such as carbohydrates and make them available for other bacteria. Acidogenic bacteria then convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. Acetogenic bacteria then convert these resulting organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide. Methanogens, finally are able to convert these products to methane and carbon dioxide. Previously, the technical expertise required to maintain anaerobic digesters coupled with high capital costs and low process efficiencies had limited the level of its industrial application as a waste treatment technology.[3] Anaerobic digestion facilities have, however, been recognised by the United Nations Development Programme as one of the most useful decentralised sources of energy supply, as they are less capital intensive than large power plants. 3) SBR The SBR (Sequenching Batch Reactor) is an aerobic biological waste water treatment. The waste water is brought into a large reactor where it comes into contact with the micro-organisms (active sludge, M.O.) and where oxygen is injected in a controlled manner. These micro-organisms convert the poluttion into carbon dioxide (CO2) and new biomass. This process requires a lot of oxygen wich is injected with different aeration techniques. The nitrogenbonds are also converted into nitrate (nitrification). An appropriated process control converts this nitrate into nitrogengas (denitrification). The advantages of a SBR are: − Simplicity of process control and maintenance. − Large buffering capacity and hence protection against peak loads and periods of low

demands. − Simple adjustment to the nitrification- and denitrification processes in relation to the

nitrogen load. − No need for a separate sludge clarifier. − The specific control of the waste water supply into the aeration tank reduces the

production of floating sludge. − A low loaded system will produce relatively low amounts of sludge in comparison with a

high loaded system. The sludge mineralisation also reduces the smell.


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The construction sizes are available from 4 to 50,000 population equivalents


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ANNEX 7: TAUW CALCULATION TOOL


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Colophon

This Handbook was developed in the framework of the project “Development of an Appropriate Methodology for Wastewater Treatment in Small and Medium Sized Municipalities in Turkey” (G2G08/TR/7/2), a Government to Government project supported by the Dutch government. Governmental parties – The Netherlands

Wereld Waternet, Amsterdam

Agentschap NL (NL Agency NL Environment), The Hague

Governmental parties – Turkey

Iller Bank, Ankara

Ministry of Environment and Forestry (MoEF), Ankara

Implementing organisations

Ameco, Utrecht, the Netherlands (www.ameco-ut.nl)

Tauw, Deventer, The Netherlands (www.tauw.nl)

IBS Research & Consultancy, Istanbul, Turkey (www.ibs.research.com)

Funding organisation

NL EVD International/Netherlands Ministry of Economic Affairs (www.evd.nl/business)


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Documents

HANDBOOK - · PDF file4.7 Dimensioning WWTPs – TAUW calculation tool ... • Iller Bank (Bank of Provinces) is responsible for WWTP project-design, tendering and