Clarifications - europa.rs 08SER01 … · Web viewPlease confirm that it is enough we to confirm this with Declaration. Where no such document or certificate is issued in the country

EUROPEAN UNIONDELEGATION TO THE REPUBLIC OF SERBIA

Finance and Contracts Section

Belgrade, 16/09/2010

STH/SC D(2010) 05230

CONTRACTING AUTHORITY’S CLARIFICATIONS no. 2

Waste water treatment and sewage collection project Veliki Backi Kanal - Kula and Vrbas municipalities

Publication ref.: EuropeAid/128697/C/WKS/RS

Tender no.: 08SER01/13/31

No Question Answer

1Please specify and advise: the carbon hardness of both drinking water and municipal wastewater in the project region (Kula & Vrbas) accordingly.

Due to variation of carbon hardness of the water quality in the source, the water treatment in the regional water supplies is controlling the hardness to be in the average admissible values as per the EU water quality directives.

2

Please advise and confirm an the plan horizon of the tenderThe first development stage 2020 (not 2013, not 2018, in diverse clauses)The final development stage 2030 (not 2020, in diverse clauses)

Confirmed, the design horizons are:

Phase I – 2020

Phase II – 2030

Please see Article 3.1.5.4.1 of the Volume 3 Section 1 and also Corrigendum no. 1 to the Tender Dossier.

3

Please confirm:

Vol III Sec 2 P20/63 population-specific grease production of 1/1000 L/(PE-a). Please advise, whether this value as applied as 100% grease or grease-water-mix. If this value is applied as 100% grease, please specify water content (Vol.-%) of the grease-water-mix for design of grease chambers and pumps.

Tenderer would like to mention, that this grease production rate seems extreme low so that the targeted grease removal has not to be considered, which means, no coarse bubble aeration system would be necessary for this case.

Please advice exactly, in the case that another value of population specific grease production shall be applied for the design calculation.

Tenderers should consider that in this table the unit l /PE x m, i.e.litres per population equivalent per month.

Please see Corrigendum no. 1 to the Tender Dossier.

4 Numbers of process tanks: The indicated number of two tanks for PST, AST and FST is the minimum number

Vladimira Popovica 40/V, 11070 Belgrade, SerbiaTel: +(381 11) 3083-200 / Fax: +(381 11) 3083-201 / E-mail: [email protected]

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mailto:[email protected]

CONTRACTING AUTHORITY’S CLARIFICATIONS No. 2

No Question AnswerPlease confirm that the given numbers of process tanks with regard to Primary Sedimentation Tank (Vol III Sec 2 P22/63), Activated Sludge Tank (Vol III Sec 2 P27/63) as well as Final Sedimentation Tank (Vol III Sec 2 P31/63) shall remain the same (two tanks each process unit) for both the First Stage (2020) and the Final Stage (2030).

Tenderer would like to advise that the process tanks should be built firstly for the First Stage 2020, and additional process tanks should be built for the Final Stage 2030. In case additional process tanks will be intended for the Final Stage 2030, please advise the exactly numbers of process tanks applied.

required for the First Stage. Tenderers should decide on the final numbers of tanks for the Second stage in accordance to their proposed design considering the minimum requirement stated above.


5

Primary Sedimentation Tank (Vol III Sec 2 P22-23/63)

Quote: “…shall be designed and completed as parallel operated longitudinal concrete basins with horizontal flow…” but all the drawings given (P&I, D, Layout Plan and Hydraulic profile in Vol V) show primary sedimentation tanks applied as circle types. Please advise and confirm, which specification - Volume III or Volume V – Is herewith prevail.

Tenderers can propose PST as suggested in Volume 5 and in accordance to ATV standards for circular shaped tanks with rotating scraper systems.


6

Please confirm the required effluent concentration of Ptot

Vol III Sec 2 P8/63: 2mg/l by 2020, 1mg/l by 2030

Vol III Sec 2 P28/63: 1mg/l by both 2020 and 2030.

Which value shall be prevail as the design standard?

It is confirmed the required effluent concentration is in accordance to Vol III Sec 2 P8/63: 2mg/l by 2020, 1mg/l by 2030.

Where the tenderers should consider the reduction of 2mg/l to 1mg/l in the design of the tertiary treatment stage.

Please see Corrigendum no. 1 to the tender Dossier.

7Please advised percentage of active substance of FeCl3 (41% solution) itemised in Vol III Sec 2 P28/63.

Tenderer should calculate the percentage in accordance to their proposed design solutions.


8 Final Sedimentation Tank (FST):

Quote “…Return sludge rate, RV:≤1.5Qmin & ≤0.75Qmax,…” Which value will be prevail in case that the values of 1.5Qmin and 0.75Qmax have large discrepancies, which will effect the size of the return sludge pumps applied.

Tenderer would like to advise, that 1.5Qmin will not satisfy the process requirement on the one side, on the other side, the actually RV should be calculated by the process design according to DWA A-131,

Tenderer should apply the Return sludge rate, RV in accordance to his process design requirements in order to have a competitive bid in accordance to the tender requirements. Recommendations of the DWA A-131 can be applied.

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No Question Answerwhich is definitely different in compare to values of both 1.5Qmin and 0.75Qmax . However, the calculated RV would be adequate for the using process design.

9

DS content of the excess sludge:

The final dry solids content of thickened ES (%) is given by ≥2.5% (Greavity Pre-thickener ES Optional, Vol III Sec 2 P38/63), while the same item is give by ≥5% (Raw sludge Pumping Station Optional, Vol III Sec P40/63).

Please advise and confirm which value is prevail for the design.

It is confirmed that 2.5% ES should be considered.


10

Density of dosent (Lime dosing Ca(OH)2)

The density of Ca(OH)2 (powdery) given is 2.24g/dm3 (Vol III sec 2 P46/63), which seems extreme low.

Please advise and confirm the density of Ca(OH)2 (powdery).

Tenderer should propose his design density of Ca(OH)2.


11

Sludge digestion Optional:

Quote: “…it shall be sized for the second phase (design horizon 2013)…” (Vol III Sec 2 P 40-41/63, also in the table of design criteria)

Please clarify and confirm, for which design horizon the sludge digestion shall be designed.

It should be design horizons as specified in answer to the question no. 7 above.


12

Please specify and advise:

The detailed dimensions of the available area for the CWWTP Kula & Vrbas according to Volume V.

All dimensions required by tenderers for the available area should be calculated from the coordinates given in drawings of Volume 5.

13

Please specify and advise:

The applied scales of the give layout plan in the tender documents Volume V.

The plans of Volume 5 are to be considered as sketches.

14 Volume 3, Section 1, Chapter 3.1.2.9 defines the Contract limits. Please specify clearly the lengths in meters of

a. Medium voltage connection linesb. Potable water connection linesc. Telecom connection linesd. Access road

Between the existing connection points and the boundary of the parcel, where the new WWTP shall be constructed resp. the meters for each item outside the parcel, which have to be offered.

Medium voltage connection lines are not part of the tender Potable water connection lines are not part of the tender. Contractor shall provide connection manhole to which the potable water will be connected by others. Telecom connection lines are not part of the tender. Access road should be completed in approximate length of 70m as connection to the asphalt road in front of the location.

All required installation within WWTP location boundaries are duty of the Contractor.

Please see Corrigendum no. 1 to the Tender

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No Question Answer

Dossier.

15

Please confirm, that Volume 3, Section 1, Chapter 3.1.5.2.6, Clause 1, “Grease and Grit Removal Plants” means, that also aerated grit and grease removal channels (twin-trap) shall be covered as a principle source of odour but not only rotostrainer and the grit treatment unit.

No, the grit removal channels should not be covered.

16

Volume 3, Section 1, Chapter 3.1.5.2.6, Clause 1 states, that “septic sludge acceptance and treatment facilities” shall be covered. The subsequent specifications do not mention any septic sludge acceptance and treatment facilities.

Therefore, please state clearly, if “septic sludge acceptance and treatment facilities” have to be delivered and – if yes – please provide clear specifications.

Septic sludge acceptance and treatment are not subject of the tender.

Please see Corrigendum no. to the Tender Dossier.

17

Volume 3, Section 1, Chapter 3.1.5.2.6, Clause 1 states that “scum collecting and treatment facilities” shall be covered. Please confirm clearly, the primary sedimentation tanks and secondary sedimentation tanks have not to be covered.

Yes, confirmed.

18

Volume 3, Section 1, Chapter 3.1.5.3.10 specifies the total opening width of the access gate by 4,0m. Therefore, please confirm that 4,0m width is sufficient for the access road.

Access road width should be in accordance with prevailing standards min. 6m, while access gate is to be 4,0m in accordance to Volume 3, Section 1 Chapter 3.1.5.3.3.

19

Please confirm, that for the main proposal, the following effluent limits have to be kept:

BOD5 25mg/l

COD 125mg/l

Tot-N 15mg/l

Tot-P 2mg/l

SS 35mg/l

We confirmed that these are the effluent limits after the secondary treatment stage as per Chapter 3.2.2.6 of Volume 3 Section 2.

20

Please confirm, that the “intermediate pumping station (existing)” named in volume 3, Section 2, Chapter 3.2.3.1, clause “biological wastewater treatment” is not an Employer’s Requirement for the main proposal as this item is not named/specified anywhere within specifications resp. the drawings of the conceptual design included in the tender documents.

It is confirmed. No intermediate pumping station is subject of the Employer’s Requirements as per Chapter 3.2.3.1 Volume 3 Section 2.

21

Please confirm, that Volume 3, Section 2, Chapter 3.2.3.2, second sentence should be read as “…anaerobic stabilisation of primary and secondary sludge…” instead of “…biological stabilisation of primary and secondary sludge…”.

Confirmed.


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No Question Answer

22

Please confirm, that the maximum inflow through the inlet pump station (flow into WWTP) has to be considered as follows:

Design horizon 2020 830l/s

Design horizon 2030 960l/s

Confirmed as per Chapter 3.2.4.2.1.1 of Volume 3 Section 2.

23

Please confirm, that the difference between storm weather flow (1.250l/s) and 830l/s (design horizon 2020) resp. 960l/s (design horizon 2030) have to be deducted via the bypass channel described within Volume 3, Section 2, Chapter 3.2.2.4.

Confirmed.

24

Please confirm, that the maximum flow data nominated for the grit and grease removal (Volume 3, Section 2, Chapter 3.2.4.2.1.4, 1.250l/s) and the distribution chamber (Volume 3, Section 2, Chapter 3.2.4.2.2.4, 1.250l/s) are not correct and shall be read as 830l/s (design horizon 2020) resp. 960l/s (design horizon 2030).

Maximum flow data for the grit and grease removal chambers are as per design horizons is given in Article 3.2.4.2.1.4 of Volume 3 Section 2. Storm water flow of 1.250l/s and more should be diverted through the bypass described Volume 3, Section 2, Chapter 3.2.2.4.

25

Please confirm, that screening presses have to be implemented for the fine screens only but not for the coarse screens (Volume 3, Section 2, chapter 3.2.4.2.1.2, table)

Confirmed.

26

Please confirm, that the fine and coarse screens have to be dimensioned in accordance to the flow rate of the final extension (2030, 960 l/s) in accordance to Volume 3, Section 2, Chapter 3.2.4.2.1.2, first sentence below table for the actual main proposal.

Therefore, please that the first sentence of the chapter is irregular.

It is confirmed that the screens, the screen house and accompanying auxiliary rooms should be dimensioned and constructed for the maximum flow of 960l/s.

Chapter 3.2.4.2.1.2 of Volume 3 Section 2.

Please see also Corrigendum no. 1 to the Tender Dossier regarding the design horizon.

27

In accordance to Volume 3, Section 2, Chapter 3.2.4.2.1.4, please confirm that both suction and blade scraper are applicable in accordance to the descriptions.

Confirmed.

28

In accordance to Volume 3, Section 2, Chapter 3.2.4.2.1.4, (“…shall be provided for sand washing…”), page 21, fifth clause, please confirm if a grit washer (not grit classifier) has to be offered obligatory.

Tenderers should obligatory offer grit classifier.

Chapter 3.2.4.2.1.4, Volume 3 Section 2. sixth paragraph.

29

In accordance to Volume 3, Section 2, Chapter 3.2.4.2.1.5, table, please confirm, that the retention time of 0,5h for Q(max) is an obligatory design requirement as well as the nominated pre-treatment efficiency.

Tenderers should define the optimal retention time in accordance to their proposed design to reach the nominated pre-treatment efficiency.


30 Within Volume 3, Section 2, Chapter 3.2.4.2.1.5, longitudinal PSTs are described but within Volume

Please see Corrigendum no. 1 to the Tender Dossier and the response to Question 5.

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No Question Answer3, Section 4, 3.4.12.3 and 3.4.12.4, circular scrapers are described. The drawings attached to the tender documents show circular PSTs, too.

Please confirm that the Tenderer is free to choose the shape of the PSTs (circular or longitudinal) for the main proposal.

31

In accordance to Volume 3, Section 2, Chapter 3.2.4.2.2.1, the AST shall be situated within the existing longitudinal secondary clarifiers. Please confirm, that no existing longitudinal secondary clarifiers are available and therefore, the Tenderer is free to choose the shape of the PSTs (circular or longitudinal) for the main proposal but has to design the tanks in accordance to ATV A 131 and intermittent or pre-denitrification process technology.

It is confirmed that no secondary clarifiers are existing. The tenderer is free to choose shape of the PST. Tenderer can design the tanks in accordance to the ATV A 131 and intermittent or pre-denitrification process technology as per indication in Volume 5.

32Please confirm, that the re-loads shown within Volume 3, Section 2, Chapter 3.2.4.2.2.1, are obligatory for the process design.

Tenderer should calculate re-loads in accordance with his proposed design.

33

Please confirm that for ASTs it is obligatory to implement the aeration system as a fine bubble aeration system incl. blower unit in accordance to Volume 3, Section 2, Chapter 3.2.4.2.2.1 and 3.2.4.2.2.3 and that the last section of the table within Volume 3, Section 2, Chapter 3.2.4.2.2.1, Surface Aeration, is not applicable.

It is confirmed that for ASTs it is obligatory to implement the aeration system as a fine bubble aeration system incl. blower unit in accordance to Volume 3, Section 2, Chapter 3.2.4.2.2.1 and 3.2.4.2.2.3. The last section of the table within Volume 3, Section 2, Chapter 3.2.4.2.2.1, Surface Aeration, is not applicable.


34

Please confirm, that in accordance to Volume 3, Section 2, Chapter 3.2.4.2.2.1, page 27 two DO-meters for each AST are obligatory (contradiction to the table in the same chapter).

Tenderer should consider minimum two DO-meters. The final number of DO-meters should be determined by the tenderer in accordance to their process control and SCADA design.


35

Please confirm that for the dimensioning of P-precipitation agent storage capacity, 2mg/l as effluent limit have to be considered for the main proposal but not 1mg/l as written in the table of Volume 3, Section 2, Chapter 3.2.4.2.2.2.

Please see Corrigendum no. 1 to the Tender Dossier. Please also see response to Question no 6.

36Please confirm, that the total supernatant flow of 10 l/PE*d (Volume 3, Section 2, Chapter 3.2.4.2.2.4, table) has to be considered obligatory for the design.

The tenderer should consider the supernatant flow in the distribution chambers in accordance to his proposed design solution.


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No Question Answer

37

Please confirm, that both the first and the second clause of Volume 3, Section 2, Chapter 3.2.4.2.2.5 are not applicable (“… first phase 2013” and “… in the rehabilitated, existing circular secondary clarifiers…”).

Please see responses to Question no 2.

38

Please confirm that the stated ISV of 120mg/l and max. thickening time of 2,0h are obligatory design values for the biological stage (Volume 3, Section 2, Chapter 3.2.4.2.2.5, table). Please confirm that he dimensions of the FSTs have to be calculated in accordance to the design basic values.

The Tenderer shall propose his design parameters in accordance to his calculations. The Volume 3, Section 2, Chapter 3.2.4.2.2.5, table are stated as indicative. It is confirmed that his dimensions of the FSTs have to be calculated in accordance to the design basic values.


39Please state clearly, how many pre-thickener units (Volume 3, Section 2, Chapter 3.2.4.3.1.2, table) shall be considered as obligatory minimum number.

It is recommended minimum one pre-thickener unit as obligatory as per Volume 3, Section 2, Chapter 3.2.4.3.1.2, first paragraph.


40Please state clearly, if the supernatant pumping station (Volume 3, Section 2, Chapter 3.2.4.3.3.4) shall be considered as optional.

Supernatant pumping station should be considered as obligatory.

Please see Volume 3, Section Chapter 3.2.4.3.3.4, first paragraph.

41Please state clearly, how many transformers shall be offered at minimum (Volume 3, Section 5, Chapter 3.5.1.1)

Minimum two transformers should be offered with capacity for the first phase as per Volume 3, Section 5, Chapter 3.5.1.1.


42

Please confirm explicitly that Volume 3, Section 1, Chapter 3.1.5.4.6, clause c, is an obligatory design requirement as this requirement has a significant influence on the hydraulic design.

It is confirmed that Volume 3, Section 1, Chapter 3.1.5.4.6, clause c, is an obligatory design requirement.

43

According to Volume 3, Section 2, Chapter 3.2.4.3.3.3, the sludge storage area is an optional item. According to the price schedule, the sludge storage area is not optional. Please clarify.

The sludge storage area is obligatory requirement.


44According to price schedule 2.22, a “sludge transport vehicle” shall be offered. If this is correct, please specify the vehicle.

The sludge transport vehicle should not be quoted.


45 Please state clearly, if the P-precipitation station (Volume 3, Section 2, 3.2.4.2.2.2) is “optional” for the main proposal or not.

P-precipitation station is obligatory requirement. The Costs should be included in Price Schedule 2.13 – Lump Sums.

Volume 3, Section 2, Chapter 3.2.4.2.2.2

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No Question Answer


46

Reference: Vol. III, Sec. 2, 3.2.4.1./12, Vol. I, Sec. 1/16 (General part)

“The Tenderers are free to submit alternative technological design proposals in accordance to the specified influent and effluent standards and overall process requirements for wastewater & sludge treatment”… (Volume III, Section 2, chapter 3.2.4.1., page12).

At the other hand, in Instruction to Tenderers (Volume I, Section 1, chapter 16., page 13) defines that alternative technological design proposal are not allowed. Taking in mind these two definitions, it is not clear if alternative technological design is allowed or not.

Please, clarify.

There is no contradiction, according to Volume 1, Section 2, 3.2.3.3 Tenderer should consider that no alternative other than low loaded (extended aeration) process, as defined in Volume 3 Section 2, will be acceptable.

In Volume 3, Section 2, 3.2.4.1, clause 4 “ the selection and design of technological solutions, by fulfilling the process requirement defined for low loaded (extended aeration), and equipment is at the discretion of the Tenderer.

47

Reference: Vol. III, Sec. 2, 3.2.4.2.2./24 (P removal)

Requested method of Phosphorus removal is chemical precipitation by dosing of Ferric Chloride (FeCl3), only.

Please, clarify is no biological phosphorus removal required?

Biological phosphorus removal must be considered within the design part of tertiary treatment and space must be allowed.

Volume 3, Section 2, Chapter 3.2.4.2.2, first paragraph.

48

Reference: Vol. III, Sec. 2, 3.2.4.2.2.1./26, Vol. III, Sec. 2, 3.2.4.2.2.1./26 (AST)

In the table in the AST chapter min. temperature of water is defined 10/12 0C. Please, clarify what is minimum temperature required?

As per Vol.3, Sec. 2, Chapter 3.2.4.2.2.1./26 (AST) the Tenderer should prepare his proposed design for min. temperature of the plant influent water in accordance to ATV at 12 0C. From here the Tenderer can derive the water temperature through his design in the AST.


49

Reference: Vol. III, Sec. 2, 3.2.4.2.2.1./26, Vol. III, Sec. 2, 3.2.4.2.2.1./26 (AST)

In the same table in the AST chapter Sludge Loads (BDS) is defined as range from 0.05 to 0.1 kg DS/m3d, these values are typical not for Sludge Loads in kg DS/m3d, but for F/M ratio in kg BOD5/kg MLSS-d. Please, clarify.

As per Vol.3, Sec. 2, Chapter 3.2.4.2.2.1./26 (AST) the Tenderer should prepare his proposed design influent water quality for each plant unit which will enable him to guaranty his designed plant functionality.


50 Reference: Vol. III, Sec. 2, 3.2.4.3.1.3./38 & 3.2.4.3.1.2./40 (ES Thickening)

In table on page 40, thickened Excess Sludge concentration is indicated as more or equal to 5.0% DS and in another table 38 the concentration should

The tender should pay attention that 2.5% DS refers to gravity pre-thickener before sludge drying bed disposal or further thickening with the optional items. The 5.0% DS clearly refers to the required minimum concentration of DS

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No Question Answerbe more or equal to 2.5% DS. Which concentration target is correct?

for raw sludge pumping station lifting the sludge to the digester(s).

51

Reference: Vol. III, Sec. 2, 3.2.4.3.2.1./42 (Sludge Digesters)

“The digester mixing system shall be provided in accordance to the design of the digester, i.e. egg-shaped or flat bottom .”

Please, clarify if egg-shaped or flat bottom digesters can be proposed?

The shape of the digesters is at the Tenderer discretion. Vol 3. Sec 2. Chapter 3.2.4.3.2.1.

52

Reference: Vol. III, Sec. 2, 3.2.4.2.1.2./18, 3.2.4.2.1.4./22, 3.2.4.2.1.5./24, 3.2.4.2.2.5./32, 3.2.4.2.2.6./34, 3.2.4.3.1.2./39, 3.2.4.3.2.1./42 (Screening Plant, Grit Removal, PST, FST…)

Tender request that all internal steel works (ladders, platforms, etc.) shall be made from stainless steel (W 1.4571/BS 320 S 31/316Ti). All internal pipes shall be made from Stainless steel (W 1.4571/BS 320 S 31/316Ti), or polyethylene (HDPE). Also, Tender request that all submerged metal parts (of equipment) shall be made in Stainless steel W 1.4571 (BS 320 S 31/316Ti).

Is it acceptable to change stainless steel from 316Ti to 304 (for water and sludge) and to leave 316Ti to 316 (for biogas)?

No, it is not acceptable considering the usual aggressivety in the environment of the installed steel structures.

53

Ref.Tender Documents Volume III – Section 5 (Requirements for Electrical Works) – 3.5.2.3.11 Telecontrol Systems

Please indicate all Stations or Network connections or Automation/control Groups which are part of the Tender BOQ and require _LOCAL_ Station Control Units with Telemetry (i.e. “DIN EN 60870-6-802/A1:2006”) connections to other stations or to/from the central SCADA/PLC.

We would like to mention that from our point of view of the entire system control of WWTP and its BOQ we don’t find any need for remoting data/process connections via Telephone Line (or wireless).

The Tenderer should propose a distribution control system as per the Vol 3, Sec 5,Chapter 3.5.6.1 to establish control system of WWTP with PLCs . The SCADA shall have no remote data processing via telephone line.

54

Ref.: Drawings FormatIn Volume 5, we find some drawings in PDF format and we would appreciate to have them in CAD format, in order to, be able to work with them.

Tenderers should consider that CAD format drawings can only be made available to the successful tenderer within the award of contract procedure.

55 Ref.: Contract Limits Points

On the drawings included in Volume 5, the contract limits points are not indicated, as a consequence, we

In addition to the response to question no. 59, Tenderers should verify their required data from the Site Visit and in relation to the

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No Question Answerare not able to design and quantify in an accurate way some parts of the plant.

We require drawings in CAD format (topography, plant layout...) showing the following limit points:

- Inlet point

- Discharge point

- Portable water

- Telephone line

- Power supply

provided geographical coordinates.

Please see Corrigendum 1 to the Tender Dossier.

56

Ref.: Geotechnical Report Translation

The Geotechnical report in Volume 5 is in Serbian language, so, we would appreciate the translation into English to get relevant information that affects the conceptual design.

Unfortunately, no translation of the Geotechnical report exists.

57

Ref.: CD

It is not clear if the project also must be delivered in a CD.

Yes, all project documentation should be also delivered on CD in Word, Excel and CAD as related


58

In material requirements for mechanical equipment, the requested stainless steel material (where needed) is 316Ti. This grade is usual in salt water applications, or where chlorides content in water is high. Please confirm if stainless steel grade 304/L is allowed for parts in contact with treated water. If not, please specify the maximal content of chlorides in treated water, as it may have big influence on biological treatment process.

Reference to response on Question no. 52. Tenderers should consider that the waste water has the normal sulphates concentration which requires the 316Ti and also has the normal chlorides concentration of communal waste water.

59

In the Vol.3, pg. 7/63 of Process requirements, it is stated that the Tendered shall offer basic dewatering of sludge. In the Vol. 4, for Tender value, Sludge drying beds are defined for pricing. However, in Vol.5, drawings, there is no information about the drying beds. Please, specify the technical requirements for ‘basic sludge dewatering’ to be included in the ‘Main proposal’

The sludge dewatering and storage area is obligatory requirement in drying beds.


60How the price for optional items will be valued, since the Letter of Tender will contain only the price for main proposal?

If and when the optional items are to be considered, the tenderers offered prices will be evaluated by comparison of the producers’ prices.

61 Regarding the mandatory submittals given within the form 4.6.10, please provide more detail about the following:

Specify the drawing No 12 : Sludge/liquid

The drawing no. 12 for the sludge liquid separation should be for thickener as per Vol 3. Section 2. Chapter 3.2.4.3.1.1.

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No Question Answer

separation – plan

Is this a primary or secondary tank, maybe thickener or digester ?

62

Regarding the mandatory submittals given within the form 4.6.10, please provide more detail about the following:

Clarify the following shortcuts from drawings No 13 & 14 from the following list :

RAS?

SAS?

MBR?

SST


63


What do you mean by plan? Is this same as ’layout’.

For example, in Drawing No. 16: Effluent discharge system – plan, there is no preferred scale, but in Drawing No. 8 >Grid and grease removal chamber – plan and sections, scale is given.

Yes, it is to be considered as layout. Tenderers shall prepare and submit all drawings in scale as indicated in Form 4.6.10 table. Where not required specific scale, tenderers can provide drawings “not in scale”

64


in Drawing No. 20 : Blower station – plan , scale ‘V’ is not understood ?

As in all other relevant drawings the scale should be 1:100.


65


in the form 4.6.10 - Civil, Electrical and Mechanical Works Material Information Lists are required within the Offer. Given the comprehensive coverage of Employer’s requirements – Vol.3, please confirm that the filling of the Schedules of Particulars is sufficient to satisfy this Tender requirement.

Tenderer should submit with their tender their proposed materials for the Civil, Electrical and Mechanical Works which correspond to the requirements defined in the Employer’s Requirement, Volume 3. The submission shall be organised in a “Material Information Lists”

66 About Tender Waste Water treatment and sewerage collection project Great Backa Canal - municipalities of Vrbas and Kula Central Waste Water Treatment Plant (CWWTP).Does the above mentioned tender can participate companies from the United Arab Emirara?And under what conditions.Please briefly.But urgency.UAE is a member of the EU.

Please see Article 3.1 of the Volume 1, Instruction to tenderers.

Participation in tendering is open to all legal persons participating either individually or in a grouping (consortium) or tenderers which are established in one of the Member States of the European Union or in a country or territory of the regions covered and/or authorised by the specific instruments applicable to the IPA programme under

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No Question Answer

which the contract is financed.

UAE does not belong to any of the eligible groups of countries.

67

The separation efficiency of the particles >0.25mm is defined in the technical specifications as 100%. The hydraulic retention time in the grit and grease removal chamber is given as 10 min by wet weather flow. We would mention that this value is extreme long considering the dry weather flow conditions.Based on our praxis experiences, the hydraulic retention time by wet weather flow with 5 min will reach separation of the particles >0.25mm with 95% efficiency.Please clarify and confirm, whether contractor’s process design is allowed to apply 5 min as HRT by wet weather flow and 95% separation efficiency of particles >0.25mm.

The design of the Tenderer shall comply with the specified requirements “..separation efficiency of the particles >0.25mm is defined in the technical specifications as 100%.” This is due to existence of combined sewerage collection system in the towns networks.

It is acceptable to reduce the parameters as proposed in the question,”... the hydraulic retention time by wet weather flow with 5 min will reach separation of the particles >0.25mm with 95% efficiency”


68

According to the Client’s Requirements, the sludge storage area shall be considered and designed for 250 days. Should this value be applied for the process design both for the case of storing anaerobic and dewatered sludge and the case of storing un-stabilised sludge?

We may mention in case that the sludge treatment facilities (options per tender requirement) would not be applied the quantity and the characteristics of the un-stabilised sludge will not allow to store these sludge for 250 days.

Please clarify and confirm, whether the Contractor’s process design should apply 250 days for sludge in both cases.

Please refer to response on Question no. 59 and also please see Corrigendum no. 1 to the Tender Dossier.

69 The Tender Dossier Volume 1, Section 1, item 1.2 page 4 states: “In accordance with the applicable rules on invitations to tender, preference will not be given to local tenderers.”

On the other hand according of Tender Dossier item 12.1.9: “....The relevant key staff must fulfil applicable requirements of the Planning and Construction Act of the Republic of Serbia, i.e. possession of license for at least one civil, mechanical and electrical engineer posses the following experience:...and in Form 4.6.1.2. is recommended with NB.” Licences, as required by the Construction law of the Republic of Serbia are to be enclosed for the relevant Key staff above.”

Please clarify this discrepancy. Is it possible to explain if the principal experts can have engineering licences from the chambers of engineers in EU

No preference will be given to any local tenderers as stated in Volume 1, Section 1, item 1.2 page 4. Legal requirements for the Licensing processare stipulated in the Law for Planning andConstruction published in the official gazette72/2009 and 81/2009 Clause 151.In principle, any sufficiently experiencedprofessional can obtain the required licence.The Law defines requirement for licensing ofCivil, Mechanical and Electrical engineers.Only the relevant Key staff, of the form 4.6.1.2, must possess the relevant professional licences as required by the Construction law of the Republic of Serbia and other relevant legal provisions. Please be referred to the noteunder the table in Form 4.6.1.2. regarding therequirement to enclose in your tender proposal

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No Question Answer

countries?the licences of relevant staff, i.e. for the Civil,Mechanical and Electrical Engineer.

70

According to the Volume III/Section 1/ point 3.1.2.6-Provisional Time schedule the “Indicative period time from the Commencement date” incl. Contractor’s Preliminary design (4 months), Final design (6 months) and Detail design (7 months) is 17 months.

In case that the Preliminary design (PD) prepared by the Contractor deviates considerably from the technical solution presented in the tender, the Contractor’s PD may be subject to new approval by approval and permitting should be taken into account by the Contractor.

In any case, to have a complete design the Contractor would need a total time of 17 to 18 months for design only. The total construction time including design is 24 months. We consider it impossible to allow for civil construction, mechanical and electrical supplies and installation and testing only the remaining 6 months.

Please clarify:

- Is it possible to start with works like site investigation, surveying, levelling, excavation, foundation works, backfilling and other works before the design is ready?

- Is it possible to reduce the above mentioned design periods to a total of 6-7 months and if yes please advice how in relation to the Employers Provisional Time Schedule (3.1.2.6)

Tenderers shall be aware in the Time Schedule is requested “Indicative period time from the Commencement date” resulting in total of 7 (seven) months tentative design period. The total construction time including design is 24 months.

With regards to the Works Programme, it is up to the Contractor to propose the timing and sequence of the works.

In accordance with Article 137 of the Construction law of the Republic of Serbia, the Contractor with the approval from the Supervisor could start with works like site investigation, surveying, levelling, etc before the design is approved.

71

According to Volume 1, Section 2, 3.2.3.3 “Adjusted Process Design” as we think, that this clause is in contradiction to Volume 1, Section 2, clause 16, “Variant Solutions”.

Please explain Volume 3, Section 2, 3.2.4.1,clause 4 “The Tenderers are free to submit alternative technological design proposals in accordance to...” as we think, that this clause is in contradiction to Volume 1, Section 1, clause 16, “Variant Solutions”.

There is no contradiction, according to Volume 1, Section 2, 3.2.3.3 Tenderer should consider that no alternative other than low loaded (extended aeration) process, as defined in Volume 3 Section 2, will be acceptable.

In Volume 3, Section 2, 3.2.4.1, clause 4 “ the selection and design of technological solutions, by fulfilling the process requirement defined for low loaded (extended aeration), and equipment is at the discretion of the Tenderer.

72Please confirm, that i.e., the requirements stated in Volume 3, Section 1, 3.1.5.4.2, “Contractor’s Design Proposal” are obligatory.

The requirements stated in Volume 3, Section 1, 3.1.5.4.2, “Contractor’s Design Proposal” are obligatory.

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73

Please confirm that the single treatment facilities as listed within Volume 3, Section 1, 3.1.5.3.1, listing 1. to 31, are obligatory process items (i.e. separate biology treatment tanks and separate secondary settlement tanks).

It is confirmed, single treatment facilities as listed within Volume 3, Section 1, 3.1.5.3.1, listing 1. to 31, are obligatory process items (i.e. separate biology treatment tanks and separate secondary settlement tanks).

74 Volume 3, Section 2, 3.2.2.1 defines two design phases, namely 2020 and 2030.

Volume 3, Section 2, 3.2.2.2 shows design phases, 2022 and 2030.

Volume 3, Section 2, 3.2.3.3 shows design phases, 2013.

Volume 3, Section 2, 3.2.4.2.1.2 defines for construction (first phase) 2013 and for the final phase 2020.



Volume 3, Section 2, 3.2.4.2.2.6 defines for construction (first phase) 2013

Volume 3, Section 2, 3.2.4.3.2 defines for second phase 2013

Volume 3, Section 2, 3.2.4.3.2.2 (table) defines for the first phase 2018

Volume 3, Section 2, 3.2.4.3.3 defines for the first phase 2013 and the second phase 2020








In addition, Volume 3, Section 2, 3.2.4.2.1.1 table,

Please refer to response on Question no. 2.

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No Question Answer160,000 PE for second phase instead of 180,000 PE.

Please clarify clearly, which item of the plan has to be designed and constructed for which input data (phase)

75

Volume 3, Section 1, Chapter 3.1.5.2.6 defines the sources of bad odour to be covered. Please state clearly, if the implementation of a biofilter unit (exhaust air treatment) is an obligatory requirement.

No, nowhere in the tender document is such requirement specified.

76

Volume 3, Section 2, Chapter 3.2.4.2.1.2 defines that the screen room has to be considered as Ex-zone Ex 1. Please confirm, that Ex-Zone Ex 1 is obligatory for the installations (mechanical, Electrical) and not depending on any protective measures.

Ex-Zone Ex 1 is obligatory for the installations Mechanical and Electrical.

77

In our opinion, submersible pumps are not adequate for grease pumping (Volume 3, Section 2, Chapter 3.2.4.2.1.4). Please confirm, that the choice of type of grit pumps is up to the Tenderer’s decision.

It is confirmed, choice of type of grit pumps is up to the Tenderer’s decision - Volume 3, Section 1, 3.1.5.4.2.

78

In accordance to Volume 3, Section 2, Chapter 3.2.4.2.1.5, please confirm that two separate primary sludge pumping stations (one for each tank) including each three dry mounted eccentric sludge pumps (total 6) are obligatory (ref. Is made to Volume 3, Section 2, Chapter 3.2.4.2.1.5 in addition).

Choice of type and number of pumps is up to the Tenderer’s decision - Volume 3, Section 1, 3.1.5.4.2.

79

Accordance to Volume 3, Section 2, Chapter 3.2.4.2.2.6 and Volume 3, Section 2, Chapter 3.2.5.2.2.6, it is obligatory to implement one inductive flow meter for each sludge feeding pipe (from SSTs) and one inductive flow meter each for the excess and the return sludge pressure pipe (total: 4 inductive flow meters) Please confirm.

Choice of type and number of inductive flow meter for sludge lines is up to the Tenderer’s decision - Volume 3, Section 1, 3.1.5.4.2, to correspond to a well defined control philosophy.

80

Please confirm that the re-use of an existing sludge thickener as a lost shuttering (Volume 3, Section 2, Chapter 3.2.4.3.1.1) is not an obligatory requirement.

It is not specified as obligatory requirement –

Volume 3, Section 1, 3.1.5.4.2


81

Please confirm, that in accordance to Volume 3, Section 1, Chapter 3.1.2.2, clause 2, the demolition of all existing structures is an obligatory requirement.

In accordance to Volume 3, Section 1, Chapter 3.1.2.2, clause 2, the demolition of all existing structures is an obligatory requirement in accordance to Vol 3 sec 3 article 3.3.2.2.

82Please state clearly, if any existing structure has to be kept in operation during the construction of the new plant.

In accordance to Volume 3, Section 1, the Contractor is obliged to ensure discharge of the incoming sewerage flows in the recipient during all of his Works till commissioning.

83 Please confirm that the P-percipitation is a part of An effluent value of 2 mg (total P) and a

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the main proposal and that Volume 3, Section 2, Chapter 3.2.5.2.2.2, ...”optional” is not correct. Please confirm that for the main proposal, an effluent value of 2 mg (total P) and a storage capacity of 3 months at 100% load is obligatory.

storage capacity of 3 months at 100% load is obligatory -Volume 3, Section 2, Chapter 3.2.5.2.2.2, and therefore, P-percipitation is a part of the main proposal.


84

Employer’s requirement shows no process technological requirements in view of the sludge drying beds. Please state clearly, if there are any requirements (and if yes, state the requirements).

Please refer to response on Question no. 59.

85 Will the existing transformer station be in operation during construction phase?

Yes it will be.

86In one moment the existing pole mounted transformer station will be removed from the site location. Please advice where and how?

The action will be conducted by the Electrical supply company and the pole will be relocated at the boundary of the WWTP location.

87Please indicate from where the new transformer station will be supplied. Who will provide the high voltage power supply cable?

Please refer to Volume 4, item 2.16. and related requirements in Volume 3, Section 5.

88Who will provide the technical conditions from local Power Authority, necessary for connection to the supply public network?

The connection to the power supply public network shall be performed by the local Power Authority.

89Who will cover expenses for the above mentioned activities? (Questions from 85 to 88).

With exception of activities under question no. 87 which are to be covered by the Contractor, the activities under questions 85, 86 and 88 will be coordinated and covered by the Beneficiary.

90

Volume 2, Sec 3, special conditions, Art 44.1. states that the payment will be executed in EUR. In case a bidder (or consortium leader) is domestic – Serbian – company who issues invoices in local currency how that payment will be performed. Is project 100% VAT exempted.

In accordance with Article 44.1 of the SC all payments will be processed in Euro. Therefore the invoices should be issued in Euro.

In accordance with Article 4 of the Contract Form: “VAT and other taxes shall not be paid on the funds originating from EU funds.”

91 Volume 3, Sec 1, General requirements, Art 3.1.5.3.4 states: Power Supply. At the WWTP a transformer is available and the overall power supply and capacity is not adequate for the future CWWTP, Delivery, installation and commissioning of the new transformers, including connections to the public network and the site network are to be included in the Contractors scope of works. In accordance with the usual practice HV connection and transformer station (up to the meeting point) is performed by the power company. The financing is by beneficiary through payment of power connection duty in value corresponding to the needed electric power (kW). As duty is not subject of IPA financing so that part is not covered. Please

Both paragraphs of the question are correct and defining limits are correctly stated. Also it is correct that IPA funds can not be used for financing taxes and duties which will be, in this case, covered by the Beneficiary directly to the Power Supply Company.

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No Question Answerexplain where are the limits of the scope to be covered by the Contractor i.e. which works have to be done by contractor and which by power company (Elektrovojvodina) from the duty money.

92

Volume 3, Sec 2, Process and design requirement, Art 3.2.4.3.3.1 that mechanical dewatering up to 22-28 dry solid should be offered as an option. Can bidder offer as an additional option a system up to 90% of the dry solid with total sludge neutralisation that have successfully operating references.

No alternative solutions to the optional units are to be submitted.

93

Volume 3, Sec 2, Process and design requirement, Art 3.2.4.2.1. Tender request two lines with coarse screens – fine screens – grit + grease removal.

Should the design of each line be for 50% of the flow, or each should be for 100% i.e. is redundancy required?

Can bidder instead proposed solution offer mechanical compact units (2) instead fine screen – grit +grease removal line.

The design of each line should be for more than 100% maximum dry weather flow, storm weather flow is defined in the table of Art 3.2.4.2.1.4 Volume 3, Sec 2.

Mechanical compact units are considered alternative solution to the specified process requirements and will not be accepted.

94

Volume 3, Sec 2, Process and design requirement, Art 3.2.4.2.2.1 states: The AST shall be completed and incorporated in the existing, longitudinal secondary clarifiers. Therefore the existing basins shall be rehabilitated.

From the site visit, dimensions of the existing tanks an their lay out vs lay-out from the tender proposal are not matching for the request. Please explain?

What is the Contractor’s scope of work re existing plant?

The existing basins do not need to be rehabilitated.


95 According to Volume 3, Section 1, 3.1.2.9, first clause, it is understood that the plant units required for the main proposal and all optional units have to placed on the plot of the existing treatment plant. The neighbour plot, which is under process of acquisition, is to be considered for the future extension only.

Volume 3, Section 1, 3.1.5.1.1 states, that the sludge drying beds, all optional units and all extension units shall be planned at the extension plot (under the process of acquisition).

Please confirm clause Volume 3, Section 1, 3.1.5.1.1 as it is not possible to place all required plant units (under provision, that \all Employer’s requirements are followed, which is a basic requirement) for the main proposal and all optional units on the plot of the existing plant because it is

It is confirmed, the Tenderer should prepare his proposal in accordance to Volume 3, Section 1, 3.1.5.1.1, i.e.the sludge drying beds and the optional items can be planned (designed) on the indicated additional plot.

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No Question Answernot large enough.

96

Many items of the preliminary design presented within the tender documents do not confirm with the Employer’s Requirements (e.g. sludge storage area is missing, coarse screens are not covered, retention time of grit removal is not kept, etc.). Therefore, please confirm clearly, that Employer’s Requirements take precedence in view of the preliminary design presented within the tender documents.

The Employer’s Requirements in Vol 3 have absolute precedence in view of the preliminary design drawings of Vol 5, as they are specified as indicative only.


97

According to Volume 3, Section 1, 3.1.5.3.1 and Volume 3, Section 4, price schedule 3.4. the tertiary treatment is defined as “optionally”.

Please confirm, that reaching the effluent limits defined within the Volume 3, Section 2, 3.2.2.5, page 8 of 63, table effluent standards, limit values for WWTP discharge to “less sensitive area” is an obligatory requirement for the main proposal and not optional (i.e. effluent values for Ptot (2 mg/l) and Ntot (15 mg/l)). As a consequence, the tertiary treatment (i.e. P-precipitation agent storage tanks) has to be realised in parts even for the main offer.

P-precipitation is required in accordance to Volume 3, Section 2, 3.2.2.5 for insuring the required Ptot (2mg/l) in the effluent. For tertiary treatment (optional), Volume 4, Schedule 3.4 considers biological reduction of P&N concentrations for sensitive areas effluent.

98

Please give us additional explanation regarding the filling of Form 4.6.9. in case that there is no institution in Bulgaria which can issue a document which confirms the information declared by us that there is no effective decision that our affairs are to be managed by the courts or equivalent.

Please confirm that it is enough we to confirm this with Declaration.

Where no such document or certificate is issued in the country concerned, it may be replaced by a sworn/solemn statement made by the interested party before a judicial or administrative authority, a notary or a qualified professional body in its country of origin or provenance.Please refer to article 2.3.3 of the PRAG.

99 Please confirm that in accordance with the technical and professional capacity of the Tenderer, the Employer’s requirement as per Art 16.3 from the Tender procurement are acceptable for the Employer to be met by:

1. The Tenderer’s experience as Prime contractor in the implementation of one project for design, reconstruction, upgrade and extension (additional line) with capacity of 90 000 e.p. of Waste Water Treatment Plant, valued over 6 500 000 EUR;

2. The Tenderer’s experience as a Partner in Joint Venture – Prime Contractor in the implementation of a project for Design and Construction of WWTP for 100 000 e.p, valued over 14 000 000 EUR.

The Tenderer’s experience as per both projects can

All tenderers must comply with the requirements specified in the published Procurement notice (namely article 16) and in Volume 1, Section 1, ITT, and also with Article 12.

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No Question Answerbe proved with references, issued by the Employers and Taking –Over Certificates or similar document, in accordance with local legislation.

100

Electrical supply from the public network: we need to receive Area map where is shown the public network around the future CWWTP and the proposed point of connection.

This was indicated to the participants on the site meeting.

101

We assume that the Transformer Station wil be with only one incoming feeder 20 kV from the Public network – Yes or No?

Yes.

102

In Price Schedule No 3.3 The Power Generator is an optional item but in Volume III, section 5, page 6 Emergency Power Generator is required. What is right?

As per Volume 4, schedule 3.3 The Power Generator is optional item for the Gas Utilization optional system specified in Vol 3 sec 3.

The emergency power generator of Vol 3 sec 5 is separate item for save guarding of the WWTP operation during power cuts, as all emergency generators are for.

103

We assume that in Price Schedule 2.16 – Transformer station and Medium Voltage building we have to include all HV cabling for Power Supply from the Public network. Yes or no?

No. Please refer to the responses given on the questions 85-89 and 91.

104

Outdoor lighting – in which Price schedule to be included?

In the Volume 4, Price Schedule 2.24 item 2.24.3.

105

We need to receive the basic Climate conditions for the Area – ambient temperature, humidity, wind, rain, etc.

Any climate information for the area can be obtained by the tenderers from the relevant authorities of the Republic of Serbia

106

Telephone Systems – in which price schedule to be included? Connections with the public telephone network and the internal telephone system in CWWTP?

In the Volume 4, Price Schedule 2.18.4.

107

Fire Alarm System – we assume that this item will be included in Electrical and SCADA works – sub-position x.x.3. Yes or No?

In the Volume 4, Price Schedule 2.18.4.

108

It is obligatory during the site visit on August 26th representatives of the Local Power Supply Company and the Local telephone Company to attend this meeting and some questions arisen to be clarified with them.

Answers to any questions raised by Tenderers in writing are addressed in the clarifications to the Tender Dossier

109

What about the Internet access to CWWTP? Not subject of the tender.

110

According to Item 3.5.5 – (Each LV Process Distribution shall be segmented into sections according to the number of connected incoming feeders (minimum = 2). The LV Process Distributions receive power from the respective LV

The tender should propose distribution control system as per Volume 3, Section 5, chapter 3.5.6.1.

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No Question AnswerMain Distribution so we assume that the second incoming feeder will be as a reserve connection from the LV main Distribution. Yes or No?

111

Earthing and Lightning installations: In Item 3.5.2.3.14 is written: (Depending on the ground conditions, either galvanised steel strip 30x3.5 with a zink coating of 00 g/m2 or high-grade steel (W 1.4301/ANSI 304) with rounded edges shall be used as earth electrodes.

In Item 3.5.13 is written: (The earthing networks shall be obtained by the connection of cooper earthing conductors with a suitable cross-section and copper earthing electrodes with the diameter of Ø= 20 mm ma length of 1,5m).

What kind of earthing electrodes to be used?

The earthing electrodes should be proposed in accordance to Volume 3, Section 5, item 3.5.13.


112

In Item 3.1.2.5 a Security System is required. Could you please specify?

It is envisaged to provide standard security fire alarm system for the WWTP units as per 3.5.12.1. Volume 3 sec 5.

113

The tender documents do not show any recommendation about treated water disinfection. According to EN and others regonized technical standard it is obligatory during epidemiological situation and using of treated water as technical water. In this case is the contractor required to provide disinfecting units of treated water?

No. Disinfection is not part of the tender.

114

In developing our proposal we need a surveying layout of the site of the WWTP including the point of discharge of treated water. Where we can see this surveying layout?

The topographic surveys data are available within the Preliminary Design documentation as per Article 7 Vol 1 ITT.

115

In developing our proposal we need a layout with trails of:

- Axes road;

- Incoming collectors;

- Incoming water supply;

- Existing incoming power supply;

- Existing telephone line and

- Gas supply pipe line

Please send as addi6tionally this layout.

The data are available within the Preliminary Design documentation as per Article 7 Vol 1 information to tender.

Please see Corrigendum no. 1 to the Tender Dossier for the layout on the existing utilities.

116

Please clarify is the construction of axes road, incoming water supply, power supply, telephone line and gas supply pipe line are in Contractors scope of work. If these works are the responsibility of the contractor where to be listed prices for their implementation.

Please see response to Question no. 55

Gas supply is not required and therefore not specified.

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117

The TD are not required a landscaping safety belt as recommended EN. Is it necessary for contractors to provide this protection landscaping safety belt?

Please consider Article 3.3.25.2. Vol 3 Sec 1 and Volume 4, Schedule 1.1.4.

118

What is the necessity of using sulphate resistant concrete and what are the chemical properties of soil and groundwater at the site of WWTP?

The fluid environment where the water retaining structures are to be constructed and especially operated are dictating the necessity of sulphate resistant cement.

The soil condition data are available within the Preliminary Design documentation as per Article 7 Vol 1 ITT

119

Referring to Volume III, Section 2, Page 6 – The Tender requires that the Contractor should ensure an operational gravitational bypass channel from the Inlet works to the recipient. According to Tender document drawings – Hydraulic profile (upstream and downstream boundary conditions) and our knowledge of local site, it seems that this is not possible without affecting the hydraulic flow conditions in the trunk sewer DN1200 i.e. pressure flow (surcharge flow conditions). Please confirm the Tender requirements in respect to this issue. Is the Contractor allowed to offer an alternative solution in order to avoid the above situation and include the existing facilities like the trunk sewer, existing pumping station and existing effluent discharge pipeline?

The tenderer is asked for to propose a competitive solution which will be fully functional and operational as per the defined requirements in Volume 3, Section 2, page 6.

120

Sludge concept: Tender Basic Design requires thickening of primary sludge (Gravity Thickener) but no thickening or treatment of excess sludge. Both are pumped to drying beds. We have following concerns:

a) Unstabilised primary sludge will cause major odour problems due to biologic activity.

b) It will be a big amount of un-dewatered sludge (DS excess sludge max 1%, primary sludge max 4%) to be handled on sludge drying beds. 300/250 days storage are required in the Tender (Vol. III Sec 2, page 48), resulting in big areas!

c) It is difficult to reach the required sludge parameters (30-35% DS) and to handle the dried sludge.

We would suggest having Primary Settling as and optioning and to include thickening and mechanical sludge dewatering of excess sludge n basic solution and everything else included in the Option.

Primary and secondary sludge are to be collected in separate gravity thickeners and treated as per the defined optional units in relation to Vol 3. Sec 2. Article 3.2.3.


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No Question AnswerPlease clarify your opinion to this suggestion.

121

Activated Sludge Tank (AST)

“The AST shall be completed and incorporated in the existing, longitudinal secondary clarifiers. Therefore, the existing basins shall be rehabilitated....” Please confirm the possibility or / and necessity to utilise existing structures on the site.

No utilisation of any existing structures is required.


122

If some structures can not be used, is it necessary to completely demolish them?

Yes, per Volume 3, Section 1.

123

As specified in Vol 3, “The Contractor’s shall not only adopt the process solutions used in the conceptual design but also shall also incorporate the required number of units and/or equipment as shown in the conceptual design. For example, if for a screening 2 mechanical and 1 manual screens are shown, then Contractor’s design must include this arrangement..Similarly, if the 2 tanks are shown, then a replacement by one larger tank will not be acceptable. Is it allowed to replace the shown number of units by more units?

The number of units shown on the drawings and specified in Volume 3 are minimum number of units.


124

Odour control – ventilation – is it necessary to put the air filters with the specified ventilated premises?

No odour air filters are required only bowers protection filters as per Vol 3 Sec 4.

125

I would be grateful if you could provide us clarification regarding a technology question: would the activated sludge process with preliminary clarification and endogenous deniftrification be eliminated as an alternative technology solution or we are allowed to create our Tender Bid on such a solution?

Please see response to Question no. 46.

126

Is it allowed for Legal Entities, Subsidiaries of such Legal Entities or any other directly or indirectly connected Legal Entities to participate in subject tender in case that any or all A.M. Entities were involved in preparation of designing documents based on which building permit for Waste water treatment and sewerage collection project Veliki Backi Kanal / Kula and Vrbas Municipalitites Central Wate Water Treatment Plant (CWWTP), specified in tender documents and instructions to tenderer, has been issued by Serbian Authorities, with respect that their participation could not ensure participation on equal terms of all tenderers.

Please refer to Article 2.3.6 of PRAG on unfair competition and conflict of interest.

127

In case that Natural Persons which were involved in preparation of designing documents based on which building permit for Waste water treatment and sewerage collection project Veliki Backi Kanal –


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No Question AnswerKula and Vrbas municipalities Central Waste Water Treatment Plant (CWWTP), specified in tender documents and instructions to tenderer, has been issued by Serbian Authorities are currently employed in Legal Entities which desire to participate in subject tender, is such involvement going to be legal obstacle for such Legal Entity to participate in subject tender having in mind possible advantage due to fact that they had much more time for preparation for submitting the offer as well as much more information considering the subject project.

128

I am representative of a company who is interested in participating in the tender for the reconstruction of the Grand Canal of Backa . on 08/26/2010 I was to attend a meeting in Vrbas, but because of severe damage to the vehicle was prevented and could not attend the meeting.

I turned office of MISP to get information about the topic of the meeting and who attended, and they told me to contact you for any additional questions.

Today I got a notice from MISP that the presence on a meeting is a condition for final selection artist. Please understand the reasons for my absence at the meeting and allow the company equal participation in the tender even though I not attended a meeting of 26/08/2010/ due to force majeure.

Please see Article 6 of the Volume 1, Section 1 ITT.

129

Is it possible that deadline for tender submission can be postponed in order that all tenderers have additional time to prepare the tender?

The deadline for submission of tenders remains as stipulated in Article 19 of the Procurement Notice.

130

If the Tenderer is submitting the tender as member of Joint Venture, should the Tender Guarantee be in the name of Joint Venture or it can be in the name of leader of Joint Venture.?

Tender guarantee should be provided in accordance to Article 15 of the Volume 1, Section 1 and can be in the name of a JV or a leader of the JV.

131

During the site visit it was mentioned that all costs related to connection to utilities, electricity, portable water, telephone will be covered by the beneficiary.

a) Could you please confirm the above?

b) If yes, does this include the connection to utilities for consumption during construction?

i. Yes

ii. No

132

Given that our consortium is made by a French construction company and Serbian Civil Works company, we do not posses and Electrical Engineer with a license as per the Planning and Construction Act of the Republic of Serbia, although we have electrical engineers with the required skills and

Please be referred to the answer to Question 69.

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No Question Answeryears of experience. Could you please confirm that you will accept a tender that, instead of the attached license for the Electrical engineer, will have attached with undertaking that, in case the Tender is awarded to our consortium, an electrical engineer with the required license will be hired for the Works?

133

In Volume 1, Section 4, Form 4.6.11, “Process performance Guarantee” in the table “Effluent standards for Wastewater Treatment Plant”, the guarantee for Nitrogen is requested as Ammoniacal Nitrogen “NH4-N”. Moreover on this table there is not requested a guarantee on COD.

a) Please confirm that the guarantee for nitrogen should be given as Total Nitrogen “Ntot” according to the Volume 3, Section 2, 3.2.2.6 “Effluent Standard and Treatment Efficiencies” and also according to the requirements of the Commission Directive 98/15/EEC.

b) Please confirm that a guarantee on COD should be given according to Volume 3, Section 2, 3.2.2.6 “Effluent Standard and Treatment Efficiencies” and also according to the requirements of the Commission Directive 98/15/EEC.

iii. It is confirmed that Total Nitrogen “Ntot” according to the Volume 3, Section 2, 3.2.2.6

iv. It is confirmed that COD should be given according to Volume 3, Section 2, 3.2.2.6


134

Concerning the optional Price Schedule 3.4 “Tertiary Treatment extension of Biology Lines”, since this option is for extension of biology lines only, we understand that this option should be designed for design horizon 120,000 PE, and for guarantees Ntot = 10 mg/l and Ptot= 1mg/l. Please confirm.

Confirmed.

135

In the event of tenders submitted by an un-incorporated JV / Consortium (Informal JV /Consortium which has no legal personality), please confirm whether each JV/ Consortium members, for any payment due under each interim payment certificate, can separately invoice the Contracting Authority for their respective scope of work and receive directly the corresponding payment? If no such separate payments can be made to each JV /Consortium member, please confirm that each application for interim payment certificate (payment request) will be raised by the lead member, and will be accompanied by each member corresponding invoice (for their respective scope), in charge however, and in line with the Tender dossier and General Conditions, for the Contracting Authority

Requests for payments shall be complemented by invoices issued only by the appointed leader of the JV/Consortium.

Payments under the Contract will be processed to a single account given in Financial Identification Form (Form 4.5), Volume 1, Section 4.

These issues related to the JV/Consortium shall be agreed by the partners in the Consortium Agreement.

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No Question Answerto make the due payment the lead member (to the bank account specified in the Contract).

136

Regarding the electrical scope:

a) Please clarify the number of Medium Voltage supply feeders and the rated voltage.

b) Please clarify if the diesel generator should backup the entire treatment station or only the vital consumers.

c) Please confirm that the Medium Voltage Switchgear is included in the Contractor’s scope.

v. Tenderer should provide his own design solution in relation to Volume 3, Section 5 requirements.

vi. It should cover only operation of vital consumers as it is the emergency power supplier as per the response to Question 102.

Yes, confirmed as per Vol 3. Sec 5.

137

Please provide unit prices for the consumables below in order to calculate the “performance ratios for treatment plant” and the “Cost of all maintenance, materials, services and supply” requested in Vol 1, Section 4, Form 4.6.10 Technical Solution:

- Ferric Chloride

- Electricity

- Cationic polymer for sludge

Ferric Chloride – 1,50 €/kg

Electricity – 0,10 €/kWh

Cationic polymer for sludge – 6,00 €/kg


138

Regarding the optional quick lime adding, as per Volume 3, Section 2, 3.2.4.3.3.2, please confirm that the price for this option should be included together with the price of dewatering in Price Schedule No 3.0 “Mechanical Sludge Dewatering and pipelines”.

Tenderer should separately price the overall costs for the unit as per Volume 3, Section 2, 3.2.4.3.3.2 in an additional schedule number 3.0.a.


139

In Volume III, Section 1, Article 3.1.5.4.6, (page 45), paragraph f., there is a request to provide free overflows in tanks and chambers. Please indicate the tanks and chambers where the overflows shall be provided.

Tenderer should propose solution as requested in 3, Section 2, 3.2.4.3.3.2, paragraph f for all relevant principal units of his design.

140

In Volume V, Drawings, drawing number 2 does not have a scale indicated.

Please provide the scale of the abovementioned plan or the topographical drawing of the site where the plant will be constructed, in order to be able to know the available space and the position of the existing works.

Unfortunately the drawing is not in scale.

141

Please specify the invert level of the ND1200 inlet pipe and the type of water inlet (gravitational or under pressure).

The invert level of ND1200 inlet pipe is -3.74m from the ground level and water inlet is gravitational.

The existing installations condition data are available within the Preliminary Design

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No Question Answer

documentation as per Article 7 Vol 1 ITT.

142

In Volume III, Section 2, Article 3.2.3.1 (page 10) in the biological wastewater treatment is mentioned an intermediate pumping which is not described in Particular Process and Design Requirements and in P&ld.

Please precise if in case gravitational flow can be achieved without intermediate pumping, such an intermediate pumping station is mandatory to be designed in the tenderer’s proposal.

According to Volume III, Section 2, Article 3.2.3.1, no intermediated pumping station should be considered.

143

In Volume III, Section 2, Article 3.2.4.2.1.2 (page 17) in table, is requested 1 conveyor per coarse / fine screen line.

In Volume III Section 4, Article 3.4.9.11 (page 82) first paragraph, is asked for screw conveyors for both types of screens (coarse and fine).

In Volume V, Drawings, drawing no. 4, the coarse screenings are discharge into a manual operated skip (~ 1 m3), while the fine screening from the 2 (two) automated fine screeners are discharged via 2 (two) conveyors (1 per fine screen) into a container.

Please specify what type of screenings discharge it is acceptable for coarse screens and for fine screens?

As per Volume III, Section 2, Article 3.2.4.2.1.2 each coarse screen should have one conveyer only and in according to Volume III Section 4, Article 3.4.9.11 each fine screen should have screw conveyers.

144

In Volume III, Section 2, Article 3.2.4.3.1.2 the solution proposed for excess sludge thickening is a gravity pre-thickener just with a storage role, while in Volume III, Section 4, Article 3.4.16.2 is presented a drum sieve concentrator as solution for excess sludge thickening.

In Volume III, Section 2, Article 3.2.4.3.1.2 (page 39) in the table is mentioned a final dry solids content ± 2.5% for the thickened excess sludge by using gravity pre-thickener.

In Volume III, Section 4, Article 3.4.16.2 (page 127) for the same dry solids output content of thickened excess sludge is mentioned 6-8% by using sieve concentrator and in Article 3.4.16.4 (page 131) is mentioned also 6-8%, by using decanter centrifuge.

Please specify what equipment from the two above should be used for the new plant, and the corresponding output dry solids content of excess thickened sludge to be considered.

Tenderer should price and bid for solution as specified Volume III, Section 2, Article 3.2.4.3.1.2. All the other suggested solutions for sludge thickening should be defined and priced as optional.

Please refer to Corrigendum no. 1 on the sludge disposal solution.

145

In Volume III, Section 2, Article 3.2.4.3.2.2 (page 44) is described a secondary sludge thickener for the digested sludge.

As per Volume 4, Schedule 3, this unit is optional.

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No Question AnswerPlease specify if this equipment is mandatory to be designed for the sludge treatment.

146

In Volume III, Section 2, Article 3.2.4.3.3.1 (page 45) in the table is mentioned a final dry solids content for the dewatered sludge of 22-28%.

In Volume III, Section 4, Article 3.4.16.3 (page 128) is mentioned 18-25% by using belt presses and at Article 3.4.16.4 (page 130) is mentioned 20-35% by using decanter centrifuge.

Please specify what is the output dry solids content range of dewatered sludge requested.

The output dry solids content range of the dewatered sludge is as per the specified values in Volume 3, Section 2 and 4 depending on the proposed dewatering equipment by the Tenderer.

147

For many of equipment described in Volume III, Section 4, at paragraph Elelctrical Equipment, (for instance 3.4.10.5) it is a reference to comply with the requirements set out in Volume H of these Tender documents.

All references to Volume H should be read as Volume 3 Section 5.


148

In Volume III, Section 1, Article 3.1.5.4.3 paragraph 2, is mentioned that bill of quantities for MEICA equipment should be in accordance to Schedules of Particulars.\

Please indicate where the Schedules of Particulars can be found?

MEICA related schedule of particulars should be read in conjunction with requirements specified in Volume 3, Section 4 and Section 5.

149

As the vast majority of D&B contracts provide that the contractor’s liability shall not exceed the amount of the Contract Price, please confirm that such a condition shall apply to the present Contract.

The question is not clear enough. Contractor’s liability conditions are set by the published tender documents.

150

Please confirm that the Contractor shall not be liable for any indirect loss or consequential loss under this Contract.

Contractor’s liability conditions are set as per published tender documents.

151

Please confirm that the delay penalties specified on Volume 2, Section 2, General Conditions and Volume 2, Section 3, Special Conditions shall be the sole and exclusive remedy for delays, notwithstanding under provisions in the Contract.

Penalties and damages are dealt with by Special and General Conditions of contract. especially as per Article 63 of the General conditions of contract.

152

Referring to Articles 13.3 and 13.4 of ITT (Vol.1, Section 1), The Tenderers must quote all components of the overall price exclusive of taxes and customs and import duties, which shall be quoted separately. Aligned with the schedule of prices (Vol. 4) and with The Contract Form (Vol. 2, Section 1), please confirm the aforementioned “taxes and customs and import duties” include Serbian VAT.

Article 4 of The Contract Form (Vol 2, Section 1), though not paid on EU funds, VAT shall be paid in compliance with the binding regulations, national

“taxes and customs and import duties” do include Serbian VAT.

Exemption applies to VAT and also to custom taxes and duties.

VAT payment is exempted under this contract. The procedure will be communicated to the contractor.

Exemption also applies to import VAT for goods/equipments to be imported to Serbia.

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No Question Answerlaw and international agreements concerning the execution of the program. Referring however to article 44 of Special Conditions of Contract (Vol. 2, Section 6), “the payment to the Contractor (.../...) shall be made by the contracting authority (.../...) with all required document including VAT exemption certificate”.

- Please confirm whether any such (Serbian) VAT exemption is indeed expected to apply under the Contract. If YES, under which conditions & procedures?

- Please confirm whether any such exemption also applies to Import VAT for goods/equipments to be imported to Serbia for the Contract execution? Please confirm whether any further Customs duties and import taxes exemptions are likely to apply for goods/equipments to be imported in Serbia for the Contract execution?

- If no VAT exemption applies, please clarify which competent body/authority will pay the (Serbian) VAT due under the Contract to the Contractor, since we understand VAT (and other taxes) shall not be paid on the funds originating from EU funds. Same question for import duties and import taxes, in the event no exemption applies.

153

On Vol4, page 14 there is Price Schedule No 3.0 Mechanical Sludge Dewatering and pipelines. However on the Grand Summary table (vol 4, page 5) there is no dedicated line for Price Schedule 3.0.

Please confirm that the value of Price Schedule 3.0 should be included in the “OPTIONAL ITEMS” of GRAND SUMMARY, and therefore dedicated price line should be added in GRAND SUMMARY table.

Please see Corrigendum no. 1 to the Tender Dossier where correction is agreed.

154

On Vol 4, page 14 there is Price Schedule No 4.0 Dayworks and at its last line it is stated “Total to be carried to SUMMARY. Moreover on Vol 4, page 4 Dayworks – Preamble it is stipulated that “... the extended total for daywork shall be carried forward as a Provisional Sum to Summary Price Schedule.

However on the Grand Summary table (Vol 4, page 5) there is no dedicated line for Price Schedule 4.0 Dayworks.

Please confirm that the value of Price Schedule 4.0 should be included in the “GRAND TOTAL TO BE CARRIED TO LETTER OF TENDER”, and therefore a dedicated price line should be added in

No need to carry the sums to Grand Summary table and therefore to the Letter of Tender.


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No Question AnswerGRAND SUMMARY table.

155

On Vol 2, Section 3 Special Conditions Article 61.7 it is stipulated that : “In addition, the Contractors should have provided for additional period of Defect Liability activities as required according Serbian Laws and regulations”. Please give details for the additional Defects Liability activities and specify the corresponding Serbian law and regulation.

Please refer to Article 222 of the Planning and Construction Law and to the Decision on minimal guaranteed periods for specific facilities.

156

On Vol 2, Section 3 Special Conditions article 58.3 and Volume 1 Section 4, Form 4.6.11, it is stated that “once the tests on completion have been completed to the satisfaction of the Supervisor, the Contractor shall operate and maintain the Plant in accordance with the operation and maintenance manuals for a trial period of approx. 1 month.”

- We understand that, since the Trial Operation will start after the successful completion of Tests on Completion, the Trial Operation will take place after the Provisional Acceptance and therefore that this period is not included in the Period of Implementation of Tasks (24 months) but included in the Defects liability period (12 months). Please confirm

Please confirm that approx. 1 month means 30 calendar days.

Yes, it is confirmed.

157

Vol III, Section 2, page 11/63 it is written that sludge concept shall consider sludge thickening and sludge dewatering on drying beds. But from drawings attached to the tender documentation there is no place for sludge drying beds and also on P&I diagram there is no sludge drying beds. Please clarify if the sludge drying beds are obligatory to construct? Where is foreseen place for sludge drying beds and how primary sludge and excess biological sludge surplus should be transported to the sludge drying beds?


158

The excess sludge pre-thickening is optional? If the optional sludge line will not be constructed, where we have to foresee to pump excess sludge from sludge pumping station and what kind of treatment is required for excess sludge?


The excess sludge should be thickened in a sludge thickening bed at 2,5% dry solids and disposed on drying beds for 20 days.

159

Is it necessary that screening from the coarse screen fall down to the belt or screw conveyor or is it allowed to just drop directly into the container?


16 Vol III, Section 2, page 18/63 it is written that the Please see response to Question no. 76.

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No Question Answer

0

operation room is zone EX-1. Does that mean that all electric devices must have explosion proof motors? Usually screening room is not subject of EX treatment.

161

Vol III, section 2, page 15/63, due to different statement regarding design phases please clarify whether final stage is 2020 or 2030 (fe, on page 15/63 the first phase is stated 2020, while on the page 16/63 the first phase is stated 2013.

Please see response on Question no. 2.

162

Regarding the referenced tender, we would like to know: Concerning IIT Sec1 - 12.2 - 3) Technical and professional capacity, is it possible to meet the necessary conditions with WWTP projects having values independent of P.E. above 60,000 or is it necessary to fulfil both requirements together in the same projects

No. In order to meet the conditions, previous projects shall have a value above 10,000,000 and 6,000,000 EUR and shall be similar in nature and complexity. This means that these projects included design and construction works for waste water treatment plants and mechanical and biological treatment process for above 60,000 P.E.

163

We have noticed the call for proposals for the project in reference, it is mentioned that there was an obligatory site visit. Later it is stated that 'tenderers who want to participate' should announce their interest before 22.7.2010.

Does this mean that tenderers can also participate in the tender without having participated at the meeting yesterday?

Please see Article 6 of the Volume 1, Section 1 ITT.

164

About existing items: Is it mandatory the use of the existing items in the design, such as, the existing intermediate pump station, thickener and secondary longitudinal clarifiers?

No.


165

About raw water: Could you confirm if raw water coming to the new WWTP is pumped or does it come by gravity? We have not seen any element at the inlet to prevent damage to the coarse screens due to big materials entering the plant through the inlet collector. This type of design without any catchment for big materials is common when raw water comes from pumping station but when water comes by gravity a gross pit to catch them is necessary. Please, confirm.


The specified requirements in Volume 3 sections 1 and 2 shall be followed completely as they are developed by experts familiar with the incoming sewerage quality.

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