WELCOMEWELCOME

Sewage Treatment

Method of Treatment-Aerobic, Anaerobic.

• Aerobic-Sewage treatment in the presence of Oxygen-

MBBR, SBR-where aerators/blowers are installed-MBBR, SBR-where aerators/blowers are installed-

generally no smell during treatment.

• Anaerobic-Sewage treatment in the absence of

Oxygen-UASB-No aerators/blowers are required-foul

smell during treatment.

Aerobic Treatment

• Continuous pumping of Oxygen is required to maintaintreatment process. The aerators/blowers have to beoperated continuously.

• The plants required to run through DG Sets in caseElectric supply not available.

• Once supply of Oxygen stopped due to non functioning ofaerators, the stabilization process interrupted and requirere-stabilization which may take much more time.

• Hence independent feeders required to ensure assuredelectric supply.

Necessity of Aeration

• For tanks up to depth of 0.50 m, the aeration takes place in anatural way.

• If the depth of tank exceeds 0.50 m, aeration system is requiredto supply oxygen to bacteria. If the aeration system is notoperated for such depths, it will indicate that the sewageoperated for such depths, it will indicate that the sewagetreatment is not done satisfactorily and desired parameters willnot be achieved in any case.

• Even during flow over the launders and weirs, the aeration ofsewage takes place.

VARIOUS SEWAGE TRAETMENT

TECHNOLOGIES

• Oxidation Pond

• Moving Bed Biofilm Reactor (MBBR)

• Sequential Batch Reactor (SBR)

• Upflow Anaerobic Sludge Blanket Reactor

(UASB)

Moving Bed Biofilm Reactor (MBBR)

The STP is said to be running successfully, if:-

• The bio film layer shall accumulate on the bio media.

• The flocs should generate in Clarifier.

• The smell of sludge should not be foul.

• When starting the plant initially, the air blowers should be

operated for passing the air through diffusers and run

continuously, otherwise the desired parameters will not be

achieved.

• Fill both aeration tanks to the normal operating sewage

depth, thus allowing the aeration equipment to operate at

maximum efficiency.

Moving Bed Biofilm Reactor (MBBR)

• Using all of the aeration tanks will provide the

longest possible aeration time.

• The effluent end of the aeration tank should

have a dissolved oxygen level of at least 1.0

mg/L. DO in the aeration tank should bemg/L. DO in the aeration tank should be

checked every two hours. Generally the DO is

approx. above 4 in aerated sewage.

• The COD reduction in treated sewage Vs. raw

sewage cannot be less than BOD reduction.

Sequential Batch Reactor (SBR)

• The first is to make certain that all mechanical, electrical and controlequipment is operating properly.

• The purpose of Fill-React operation is to add substrate (rawsewage) to the reactor. The addition of substrate or filling iscontrolled by a timer to a set time period. The filling operation isalso controlled by level transmitter to limit filling volume uptomaximum level. Usually, SBR tanks are designed to take flow asmaximum level. Usually, SBR tanks are designed to take flow asit comes into STP with all variations from peak flow to minimumflow without necessiating any equalization tank.

• The Settling process is controlled by time and is usually fixedbetween 30 minutes to an hour so that the sludge blanketremains below the withdrawal mechanism during the nextphase.

• The purpose of Decantation is to remove the clarified, treatedwater from the reactor.

Sequential Batch Reactor (SBR)

• When starting the plant initially, the diffuser should be

operated first and run continuously, otherwise the desired

parameters will not be achieved.

• The precaution needed is to make sure that power supply is

available continuously. If power supply fails, immediately

bring the genset on-line.

• COD to BOD ratio indicates the biodegradabitity of the• COD to BOD ratio indicates the biodegradabitity of the

sewage. Normally, sewage will have COD to BOD ratio

between 1.5 to 2. If the ratio is more than 2, entry of

industrial effluents into sewer network is a possibility.

• The daily tests shall be COD, TSS, pH, Dissolve oxygen,

Ammonia and dissolved phosphate. BOD can be a weekly

test.

IMPORTANT ASPECTS IN ACTIVATED SLUDGE PLANT

• Oxygen is required in aeration tanks;

- Low DO in influent sewage

- Influent sewage may become septic

• Operational variables in aeration tanks

- Rate of flow of sewage- Rate of flow of sewage

- Air supply

- MLSS

- Aeration period

- DO in aeration tank and settling tank

- Rate of sludge return and sludge condition

Problem of foaming

• Foaming in aeration compartment in first week of start be tackled with water hose using fresh water with lawn sprinkler

• It will diminish when sufficient mixed liquor solids It will diminish when sufficient mixed liquor solids are obtained

• Do not waste sludge until desired level of MLSS obtained

Upflow Anaerobic Sludge Blanket Reactor

(UASB)

• The Up flow Anaerobic Sludge Blanket reactor (UASB) maintains ahigh concentration of biomass through formation of highly settleablemicrobial aggregates. The sewage flows upwards through a layer ofsludge.

• The sludge in the UASB is tested for pH, volatile fatty acids (VFA),alkalinity, COD and SS. If the pH reduces while VFA increases, thesewage should not be allowed into the UASB until the pH and VFAsewage should not be allowed into the UASB until the pH and VFAstabilise.

• The reactor may need to be emptied completely once in five years,while any floating material (scum) accumulated inside the gascollector channels may have to be removed every two years to ensurefree flow of gas.

• All V-notches must be cleaned in order to maintain the uniformwithdrawal of UASB effluent coming out of each V-notch. The irregularflow from each V-notch results in the escape of more solids washout.Similarly, blocking of the V-notches of the effluent gutters will lead touneven distribution of sewage in the reactor.

Upflow Anaerobic Sludge Blanket Reactor (UASB)

• The regular maintenance involves cleaning of V-notches

with a broom three times a day and removing sludge with

a brush or with a water jet once a day.

• The feeder pipes should be checked regularly for

clogging. Flexible iron rods can be used for this purpose.

• The gas collectors should be checked for leakage.

Leakage is easily detected by applying soap solution toLeakage is easily detected by applying soap solution to

the piping. This should be done on a regular basis. If the

gas collectors are leaking, the valve at the end of one

bay in the gas leak should be first closed and then

repaired as soon as possible.

• The risk of the corrosion of dual fuel engine parts, as

biogas contains H2S, can be minimised if biogas can be

scrubbed before using it as fuel for dual fuel gas engines.

Visual Test

• The final effluent shall be clear and free from suspended

particles.

• Flocs do exists in the clarifier.

• A film exist on the MBBR Media.

• Sludge is produced daily.• Sludge is produced daily.

• No odour or smell in the final effluent.

• No odour in sludge.

Recommended Plant Control Tests on a Daily basis in a typical STP

Recommended Plant Control Tests on a weekly basis in a typical STP

Recommended Plant Control Tests on a Monthly to Biannual basis in a typical STP

How to check DO in aeration Tank

The presence of DO in aeration tank requires the

elaborate procedure of using a meter operated

electronically and keeping the probes well cleaned

at all times. This is not always possible. Moreover,

typical plant control requires an answer to thetypical plant control requires an answer to the

question of whether residual DO is present or

absent in the secondary clarifier overflow. This can

be easily carried out in the field as follows:

1. Take a 10 ml well washed test tube.

2. Hold it gently against the weir overflow

sideways.

How to check DO in aeration Tank

3. Allow the sewage to fill the tube and overflow for a few minutes.

4. Gently take the tube and pour out about 2 ml.

5. Add few drops of manganous sulphate solution.

6. Add a few drops of potassium iodide solution.6. Add a few drops of potassium iodide solution.

7. Close the top with the thumb and invert a fewtimes.

8. Allow to stand for a few minutes.

9. If there is a yellow precipitate, DO is present.

10. If there is a white precipitate, there is no DO.

• With help of electronic instrument

• Online sensors are required to be provided

BOD Versus COD graph and its Interpretation

In respect of BOD test, a graph of BOD versus

COD for the raw, primary treated, secondary

treated and outfall sewage should be prepared

every week and the daily COD readings used toevery week and the daily COD readings used to

interpret the BOD values.

Water (Prevention and Control of

Pollution) Act, 1974

• Section 24-Relate to prohibition of discharge of sewage

into water body, stream, well or on land.

• Section 25-Restricts the discharge of sewage without• Section 25-Restricts the discharge of sewage without

previous consent of HSPCB.

• Section 27-Relate to powers of HSPCB to grant or to

refuse the consent.

• Section 28-Relate to appeal against the orders for

refusal of the consent by HSPCB.

Water (Prevention and Control of

Pollution) Act, 1974

• Section 33-Empower the HSPCB to give directions regarding

closures, disconnection of electricity or water etc. to any

authority.

• Section-43-Relate to punishment for violation of Section-24• Section-43-Relate to punishment for violation of Section-24

with imprisonment for a term from 1.5 Years to 6 Years with

fine.

• Section 44-Relate to punishment for violation of Section-25

with imprisonment for a term from 2 Years to 6 Years with

fine.

Water (Prevention and Control of

Pollution) Act, 1974

• Section 47 & 48- Defines the Responsibility of theofficers liable to be punished-Incharge or responsibleperson to the company for the conduct.

• The Hon’ble High Court in COCP No. 1149 of 2013 ismonitoring the grant of consent under by HSPCB underSection-25 of the Water Act, 1974.

• All E.Es shall apply for consent under Section-25 ofWater Act, 1974 to HSPCB.

Provision of PWD Code Estimate and Project

(Chapter-10)

• Necessity, Survey and Investigation, Rough CostEstimate.

• Estimate shall include report/ necessity,specifications, quantities and rates.

• Administrative approval.

• Detailed estimates-Complete details based ondrawings and calculation, quantity of various itemsof works, rates, specifications method ofconstruction.

Provision of PWD Code

Estimates and Projects (Chapter-10)

Detailed estimates may also include:-

• Constructions of access road, additional cost due to

unusual site conditions, contingencies, quality

control, land development, instrumentation, service

re-location, cost payable to Forest Department/re-location, cost payable to Forest Department/

Railways/ B&R/NHAI, rehabilitation and re-

settlement, Department charges, dewatering, site

office, Hutment for workmen, shed for stores etc.

Contracts and Work Orders

(Chapter-13)

Steps for Procurement/ Allotment of work.

• Preparation of tender (bid) documents;

• Approval of tender documents by the tender• Approval of tender documents by the tender

accepting authority;

• Issue of notice of pre-qualification (if required);

• Receipt of pre-qualification applications and their

evaluation;

• Approval of pre-qualification;

Contracts and Work Orders

(Chapter-13)

Contd….

• Issue of notice inviting tenders;

• Pre-bid conference (if specified), issue of minutes and clarifications, and addendum to ITB and clarifications, and addendum to ITB (Instructions to Bidders), if necessary;

• Receipt of tenders;

• Scrutiny of tenders and their evaluation;

Contracts and Work Orders

(Chapter-13)

Contd….

• Negotiation (only where warranted);

• Acceptance (or rejection) of tender;• Acceptance (or rejection) of tender;

• Award/ allotment of work.

• Ordered to commence; and

• Deposit of Performance Security (if specified).

WHAT IS DNIT

• DRAFT NOTICE INVITING TENDER (DNIT)

• AFTER APPROVAL OF DNIT FROM THE COMPETENT

AUTHORITY IT BECOMES NOTICE INVITING TENDER (NIT)

Approved NIT shall consists of :-

• Index.

• Abbreviations.

• Press Notice for NIT.• Press Notice for NIT.

• Eligibility criteria.• Tender Form.

• Deposit & Release of Security and Performance Guarantee

• CSR (Contract Schedule of Rates).• Technical Specifications.

• Qualification criteria for staff deployed at STP for O&M

• Payment Schedule• Issue of Completion Certificate

• Drawings and layout Plans of all structures and equipments.

ELIGIBILITY CRITERIA FOR STPs

A) UPTO 3 MLD CAPACITYOpen to all the agencies/ contractors enlisted with PHED for the amount of NIT.

B) ABOVE 3 MLD CAPACITYOpen to the agencies enlisted upto DNIT cost with Department/Board/Corporation of Central Govt. , any State Govt., fulfilling the following criteria.:-a) Average Annual financial turnover during the last 3 years, ending 31st March of the

previous financial year, should be at least 30% of the DNIT cost.

b) Experience of having successfully completed similar works during last 7 years b) Experience of having successfully completed similar works during last 7 years ending last day of month previous to the one in which applications are invited should be either of the following:-

i) Three similar completed works coasting not less than the amount equal to 40% of the DNIT cost or 40% of the capacity of the Plant.

orii) Two similar completed works coasting not less than the amount equal to

50% of the DNIT cost or 50% of the capacity of the Plant.or

iii) One similar completed works coasting not less than the amount equal to 80% of the DNIT cost or 80% of the capacity of the Plant.

Note: Similar completed works is defined as the works of construction of Sewage Treatment Plants / Effluent Treatment Plants (other than package unit) with biological treatment process in the Govt. / Semi Govt. / Private Sector with documentary proof.

DEPOSIT OF SECURITY AND PERFORMANCE

GUARANTEE

S.

No.

Description SECURITY DEPOSIT

FOR DNIT COST UPTO

3 CRORE

EMD, PERFORMANCE

SECURITY FOR DNIT

COST MORE 3 CRORE

i) EMD 2% at time of

submission of bid

document

2% at time of submission

of bid document

ii) Performance

guarantee

3% within 30 days from

allotment but before

1% within 30 days from

allotment but beforeguarantee allotment but before

commencement of work

allotment but before

commencement of work

iii) Security deduction 5% from each running

bill

2% from each running bill

iv) If performance

guarantee not

submitted then

deduction from 1st

running bill

3% of agreement

amount + 5% security

deduction of running bill

1% of agreement amount

+ 2% security deduction of

running bill

RELEASE OF SECURITY AND PERFORMANCE GUARANTEE

Release of Retention money :

• 50% of the total security deposited and deducted (i.e out of 10% or 5% asapplicable & deducted above) shall be released after 3 months of finalpayment of the work excluding Operation and Maintenance part andremaining 50% will be released against Bank Guarantee (BG) ofequivalent amount on completion of defect liability period of one year.This Bank Guarantee shall be submitted in five parts which will beThis Bank Guarantee shall be submitted in five parts which will bereleased in the following manner:-

• i) 1st Bank Guarantee of 5% will be released after one year ofsatisfactory completion of O&M period after defect liability period.

• ii) 2nd Bank Guarantee of 5% will be released after two years ofsatisfactory completion of O&M period.

• iii) 3rd Bank Guarantee of 10% will be released after three years ofsatisfactory completion of O&M period.

• iv) 4th Bank Guarantee of 10% will be released after four years ofsatisfactory completion of O&M period.

• v) 5th Bank Guarantee of 20% will be released after five years ofsatisfactory completion of O&M period.

PAYMENT SCHEDULE

• FOR STPs BASED ON SBR TECHNOLOGY

S. No.

Unit Percentage

1 After approval of design and drawings 1%

2 Civil Works 29%

3 Mechanical Works 45%3 Mechanical Works 45%

4 Electrical Works 15%

5 After completion and satisfactory testing,commissioning of main pumping station/sewage treatment plant upto the satisfaction ofEngineer in charge after trial run period

10%

Total 100%Cont…..

PAYMENT SCHEDULE

• FOR STPs BASED ON MBBR TECHNOLOGY

S.No Unit Percentage

1 After approval of design and drawings 1%

2 Civil Work for MPS 20%

3 Civil Work for STP 40%

4 Supply installation and testing of MBBR media,

electrical, mechanical equipments and instrumentation

29%

electrical, mechanical equipments and instrumentation

a)70% of the cost of the above items will be paid after

receiving at site.

b)20% after installation.

c)Balance amount after commissioning of the job

5 After completion and satisfactory testing,

commissioning of main pumping station/ sewagetreatment plant upto the satisfaction of Engineer in

charge after trial run period

10%

Total 100%

Secured Advance - 75% of the cost of

imperishable material with formal agreement under

which Govt. Secures a lien on the materials and is

safeguarded against losses with proper watch and

safe custody. The certificate to the effect shall besafe custody. The certificate to the effect shall be

made not below the rank of SDE, who shall bepersonally responsible.

Mobilization Advance-5% of the contractvalue or as specified for works costing morethan Rs. 5.00 Crores against unconditionaland irrevocable bank guarantees equivalentto the amount of advances paid from time toto the amount of advances paid from time totime at the interest rates specified in thetender document

DOCUMENTATION AT SITE

• Photocopy of NIT.

• Approved Drawings of all civil structures (including X-sections, L-sections, layout plan etc.)

• Test register regarding cube compressive strength test,slump test of concrete, sieve analysis of fine and coarseaggregates, Vicat apparatus test for cement, etc.

• Cement consumption register.• Cement consumption register.

• Details of material to be arranged by contractor as peragreement, material arranged and material to be issuedby the department from reserve stock.

• JE/SDEs are required to maintain diary having technicalspecifications of all civil/ electrical/ mechanical works tobe executed at site.

Cont….

DOCUMENTATION AT SITE

• To maintain the record of activities to be executed(either independent or parallel activities) at site w.r.t.time period of project, to ensure the work insystematic manner (application of PERT/ CPM).

• In case of O&M, the record of material issued to thecontractor, i.e., Diesel, chemicals etc. & qualification

and no. of staff employed.and no. of staff employed.

• Log book for operation of pumps.

• Site order book.

• Proper arrangement for storage of cement, all material.

• Site office during construction.

TECHNICAL SPECIFICATIONS

• Civil Works

– All the civil works shall be executed as per the PWD specifications /National Building Code.

– Ordinary portland Cement shall be used in all concrete/ plaster/ pointing works

– The design mix concrete obtained from design mix plant shall be asfollows:-

(i) Water bearing structure including roof - M35

(ii) Other structural concrete - M30

Note:- If the site of quarry of coarse/ fine aggregates changes, the ratio of weights ofNote:- If the site of quarry of coarse/ fine aggregates changes, the ratio of weights ofcement / sand/ stone aggregates will vary and sampling for design mix must bedone again to avoid deviation in strength of concrete.

The water/cement ratio shall also be worked out accordingly.

– The concrete thickness and the concrete cover of reinforcement of dry andwetted surfaces etc. shall be according to the IS Codes.

– All RCC structures shall be coated with chemical resistant material.

– Any material not covered in any PWD specifications shall comply with the latestrelevant Indian Standards with approval of Engineer-in-charge of work.

CONT…..

TECHNICAL SPECIFICATIONS

• Civil Works

– Plinth protection work shall be done for all the civilstructures, i.e., building, reactor units, collecting tank etc. asper provisions.

– During construction sampling, preparation of testspecimens, curing and testing of concrete shall beconducted in accordance with relevant IS codes.conducted in accordance with relevant IS codes.

– In case sample fails, no payment shall be made fordismantling of structure and contractor at his own expensesshall make embedded fixtures and reinforcement ofadjoining damaged structures during dismantling work.

– Curing -Special care be given for curing the concrete..

TECHNICAL SPECIFICATIONS

Mechanical Works

Sewage Pumping Machinery:-

– Submersible Non clog Pumping Machinery shall beused in pumping sewage.

– The impellers of the pump shall be of 4 vanes withsolid handling capacity to pass the soft solids ofsolid handling capacity to pass the soft solids ofminimum 100mm diameter. The material ofimpeller shall be of Stainless Steel (SS) CF8M.

– The RPM of the pump shall be 1450.

– The pump shall consist of guide rail, duck footbend, lifting chains with shackles.

TECHNICAL SPECIFICATIONS

Motor:-

– The Motor shall be squirrel cage type 3 phase induction, 415Volt.

– The motor winding shall be suitable for star-delta/ autotransformer starter.

– The motor shall be designed for minimum 10 starts per– The motor shall be designed for minimum 10 starts perhour.

Piping:-

– The entire piping for distribution of air in reactor shall beof SS – 3o4 material.

– All inter connecting pipes & channels shall be designedhydro logically for peak flow.

TECHNICAL SPECIFICATIONS

Electrical Devices:-

• Control Panel consisting of:-

– VCB/ MCCB/ OCB

– Ampere meter

– Volt meter,

– Electronic motor protection overload relay– Electronic motor protection overload relay

– Contactors

– Solid connections

Cont…

TECHNICAL SPECIFICATIONS

• Transformer:-

– G.O. Switch

– ACB (upto 500 KVA)

– VCB (above 500 KVA)

– HT Metering Panel

• Earthing :-

– Copper plate Earthing for HT Panel, LT Panel and 5 Nos. forTransformer (2-Neutral, 2-Body, 1-Lighting)

– GI pipe Earthing for each LT Panel, HT Panel, Motors,Transformer & G.O. Switch

QUALIFICATION CRITERIA OF THE STAFF DEPLOYED AT STPs

FOR O&M

SNol Personnel Minimum

Experience

Main Task of the Personnel

1. Plant Manager (Diploma in Civil/Environmental Science Engineering or B.Sc. Chemistry )

3 years Co-ordination of activities for satisfactoryperformance of the STP and reporting to theEngineer-in-Charge and responsible for theproper functioning & maintenance, datacollection of STP

2. Operators (ITI) 3 years Responsible for overall operation for STP2. Operators (ITI) 3 years Responsible for overall operation for STP

3. Electrician (ITI) 3 years Responsible for overall operation for electricalequipments

4. Fitter (ITI) 3 years Responsible for overall operation forMechanical Equipments

5. Sweeper/Casual labour/ Sewerman

Literate Responsible for keeping STP premises clean,cleaning of sewer lines and also they will assistoperators in day to day activities

6. Security guard cum Gardener

Literate To maintain the garden / landscaping of theplant and for security.

ISSUE OF COMPLETION CERTIFICATE OF STPs

• As per the provisions of the PWD code, the works allotted

to contractual agencies are required to be physically

completed within assigned time frame. The Physical

Completion of the work becomes more important when the

trial run, defect liability period

• To notify date of the Physical Completion of work after due

inspection before start of trial run period and will inform toinspection before start of trial run period and will inform to

the concerned contractual agency, concerned SE and

Head Office.

• To notify the date of Completion of trial run period and copy

thereof shall be forwarded to all concerned i.e. contractual

agency, concerned SE and Head Office.

ISSUE OF COMPLETION CERTIFICATE OF STPs

• The notification regarding trial run shall be issued only after

the ensuring that developed infrastructure meet the

requirements and objectives of the contract agreement,

otherwise it shall be extended and the contractor shall not be

paid for this extension in the trial run period, beyond the time

period of trial run specified in the contract agreement.period of trial run specified in the contract agreement.

• Similarly, the date of completion of defects liability period

shall be notified under intimation to all the concerned. In case

any defect is observed during defects liability period, the

same shall be dealt as per the provisions of Clause-16.24 of

PWD Code.

• The Engineer-in-Charge may take help of 3rd party

inspection who shall only be a member of the Committee

headed by Engineer-in-Charge himself

OPERATION AND MAINTENANCE

OF SEWAGE TREATMENT

PLANTS

Units in Sewage Treatment Plants

Main Pumping Station

1. Coarse Screen Chamber

2. Wet well/ collecting tank2. Wet well/ collecting tank

3. Pumping Machinery

Sewage Treatment Plant (STP)

• Receiving Chamber.

• Fine screen.

• Grit Channel.

• Proportional weir

• Distribution Channel

• Reactors.• Reactors.

• Compressors & VFD.

• Clarifier.

• Treated Effluent Channel/Chlorination tank

• Sludge Sump.

• Sludge Drying Bed/ Centrifuges.

• Instruments-Do Meter, level meters, flow meters etc.

Screening Chamber

• Regular Cleaning

• Disposal of Screenings• Disposal of Screenings

• Washing of Bar Screens

Wet Well / Collecting Tank

• Washing sludge layer from walls using water jet

• Desilting of wet well once a year

Pumping Machinery

• (4W + 1S) sets of 0.625 Average Discharge Capacity (Peak /4).

• To run the machinery in a way so as to have free fall from invert ofsewer.

• Mostly 2 or 3 pump sets are out of order.• Mostly 2 or 3 pump sets are out of order.

• Guide Wire/ Guide Rail should in working condition.

• Minimum one pump be operated during night hours so that sewersare empty in morning.

• Should be scoured minimum once in a week.

• Fine Screens should be kept clean of all obstructions. If

the screen are of mat type, its operation should be

Receiving Chamber & Fine Screens

the screen are of mat type, its operation should be

adjusted such that a mat is always on the screen.

Grit Channel

• (1W + 1S) grit channels for peak flow.

• Should be used one at a time, alternatively every day.

• Should be cleaned every day.

• Proper & efficient removal of silt in grit channel will improve

the functioning of treatment.

Proportional Weir

• Must be Calibrated so as to show the quantity of flow.

• Flow be recorded every hour. In SBR Plants the Flow• Flow be recorded every hour. In SBR Plants the Flow

recording graphs are recorded in SCADA PC.

Distribution Channel

• Must be cleaned every day.• Must be cleaned every day.

Reactors /SBR

• 4 in nos. (2 in parallel & 2 in series).

• The walls, walkway and the railing to be washed daily

using water jet.using water jet.

• The problem of foam can be solved using water jet .

• Reactors should be desludged every day to maintain

proper MLSS

Compressors and VFD and DO meter

• (2W +1S) compressors.

• 2 compressors should continue running till desired D.O. level is

achieved.

• Generally compressors and VFD are found out of order.

• Most of the times, the compressors are found not working with the

excuse of power cut.

• At least one compressor should be in operation every time in case of

power cut also (with the help of D. G. set).

Clarifier

• The treated water flow should be uniform over the

entire length of the launder. It would ensure aeration

also.

• There should be no scum over the surface.

• Bridge should be kept running.

• Sludge should be continuously removed.

• Launders should be kept clean.

Sludge Sump & Sludge Drying Beds

• Sludge from the sump be regularly pumped out.

• Generally the Sludge Drying Beds are empty without

any sludge shows that plant is not running.any sludge shows that plant is not running.

• Dried sludge cakes be removed regularly from Sludge

Drying Beds.

Maintenance Scheduling

• Maintenance of each equipment is done as the

recommendations of manufacturer.

• A History card is maintained for each equipment so

that record is maintained on equipment performance

and maintenance.and maintenance.

• Good housekeeping is an important aspect of plant

operation.

O & M STAFF

• The staff employed is not in conformity with the agreement.

• The name, designation and the shift (morning/ evening/ night) of

the staff be put up in the control room.the staff be put up in the control room.

• The problem of poor performance can solved if trained &

qualified staff is deployed.

Laboratory Tests

• BOD (Bio-Chemical Oxygen Demand) - should be <10 mg/l) or

as per design of STP.

• TSS (Total Suspended Solids) – should be <10 mg/l.

• COD (Chemical Oxygen Demand) should be <100 mg/l.

• Oil and grease <10 mg/l.

General observations

• M. S. parts are not epoxy painted regularly and are

rusted.

• Screens and grit channels are not cleaned.

• Both Grit channels are run simultaneously where as it

should be one running & to be used alternatively

every day.

• Pumps are not run in proportion to the discharge

received.

• No pumps are run from 10:00 P.M. to 4:00 A.M.

• Sludge is not removed from reactors & clarifier.

• Dried sludge cakes are not removed from Sludge

Drying Beds.

• General maintenance of the lawns etc. is very poor.

General observations ….Contd….

• The sitting room & the toilet are not in good condition.

• D.G. set is not operated in case of power failure.

• O & M staff is not as per the norms i.e. qualification

and experience.

• Industrial effluent is being received at the Sewage

Treatment Plants for which no correspondence being

made with Haryana State Pollution Control Board.

• Consent to operate has not been obtained from

Haryana State Pollution Control Board.

• Samples are not being tested in laboratory daily.

• Samples are not being got tested regularly from some

reputed laboratory.

Discrepancies observed in construction of STPs

• Stairs/ Steps not fitted in any of the chambers/ reactors/ sumpetc.

• V- notch weir plates not fitted around the launders.

• Circular S.S. peripheral wall not provided in the clarifier.

• Scum removal arrangement not made in the clarifier.

• Proportional weir has not been calibrated.

• Scour valves not provided in receiving chambers.• Scour valves not provided in receiving chambers.

• Arrangement for proper disposal of screens & grits not made.

• Level of outlet channel is such like that water remains stagnantin the launders.

• VFD and DO meter have not been installed.

Discrepancies observed in construction of STPs

• Chemical protection on the RCC not done

• SS pipes not checked

• Cement store not constructed

• Site office not constructed

• Railing not provided as per agreement• Railing not provided as per agreement

• Sample test register not maintained

• No planned execution

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