upgradation for 345 kld effluent treatment plant at m/s...

700 KLD Sewage Treatment Plant at D. Y. Patil Educational Academy, Ambi, Pune

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CHAPTER – 1

INTRODUCTION


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INTRODUCTION

DYPCOE, AMBI, an institution established in 2009 aspires to be a world class institution in the

future. The institute offers graduate programs in four disciplines. The courses focus on all round

growth while exploring the latest developments in science and technology. With state of the art

facilities, experienced faculty members and a homely hostel, DYPCOE, AMBI is the technical

institute being sought after.

This engineering college has been approved by All India Council for Technical Education, New

Delhi and the Government of Maharashtra. All its courses are affiliated to Savitribai Phule Pune

University. Here highly qualified and experienced staffs are guiding the student who will be

making impact on global market.

The campus provides separate hostel facilities for boys and girls. Considering all these facts

management decided to place a STP at institute. With considering performance of Aqua care

Water Solutions in market they awarded STP work to their team.


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CHAPTER – 2

BASIC OF DESIGN


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BASIS OF DESIGN

The Design basis for STP including Biological treatment with Diffused aeration system and

Filtration system etc is given below:

CHARACTERISTICS OF INLET RAW SEWAGE

Sr. No Parameter Unit Concentrations

1. Flow m3/day 700

2. pH - 6 - 8

3. O & G mg/l < 50

4. Total Suspended Solids (TSS) mg/l 600 to 800

5. Biochemical Oxygen Demand (BOD) 5 day mg/l 200 to 300

6. Chemical Oxygen Demand (COD) mg/l 500 to 600

7. Total Dissolved Solids (TDS) mg/l < 1000

Source : D. Y. Patil College of Engineering, Ambi

NOTES:

1. The Basis of design is as per the details given by client.

2. The outlet COD value depends on the presence of Inlet COD.

. TREATED SEWAGE QUALITY

The desired Treated Sewage characteristics after UF are as mentioned below:

Sr. No Parameter Unit MPCB standards

1. Flow m3/day 700

2. pH - 6.5 to 8.5

3. O & G mg/l < 10

4. Total Suspended Solids (TSS) mg/l < 30

5. Biochemical Oxygen Demand (BOD) 5 day mg/l <30

6. Chemical Oxygen Demand (COD) mg/l < 100

7. Total Dissolved Solids (TDS) mg/l < 1000

Source : D. Y. Patil College of Engineering, Ambi

1) The outlet value of BOD and COD in the treated Sewage will be downstream of the ACF


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CHAPTER – 3

DETAILS OF STP UNITS


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DETAILS OF STP UNITS

Sr.

No. Unit / Equipment Details

1. Bar Screen Chamber

No. of chambers : 1 No

Dimensions : 2.0 m x 1.0 m x 2.0 m SWD

2. Oil & Grease Chamber


Quantity : 1 No

3. MBBR Tank

No. of tanks : 1 No


4. Settling Tank

No. of tanks : 1 No


5. Filter Feed Tank

No. of Tanks : 1 No


6. Sludge Holding Tank

No. of Tanks : 1 No


7. Treated Water Tank

No. of Tanks : 1 No

Dimensions : 10.0 m x 5m x 4 m SWD


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CHAPTER – 4

EQUIPMENTS AND INSTRUMENTS

LIST


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EQUIPMENTS AND INSTRUMENTS LIST

4.1 LIST OF EQUIPMENTS:

SN DESCRIPTION CAPACITY/ SIZE QTY MOC MAKE

1. Air Blowers 450 m3/hr @ 0.5kg/cm2 2 CI Blowvacc

2. Air Diffuser System 63mm dia x 2m Length Lot PP S. Cogen

3. Return Sludge Pump 30 m3/hr @ 10m WC 2 CI Kirloskar

4. MBBR Media Dia 22 mm x 16 mm Ht Lot PP Marvellous

5. Tube settler Media 4.9 m x 6.0 m Lot PP Marvellous

6. Hypo Dosing Tank 100 Lit 1 PVC Local

7. Filter Feed Pumps 35 m3/hr @ 25m WC 2 CI Kirloskar

8. Pressure Sand Filter 1600mm Dia x 1800 mm Ht 1 MSEP Aqua care

9. Activated Carbon Filter 1600 mm Dia x 1800 mm Ht 1 MSEP Aqua care

10. Filter Press Feed Pump 2.0 m3/hr @ 50m WC 2 CI Roto

11. Filter Press 600 mm x 600 mm x 24 Plates 1 -- Pharmatech

4.2 LIST OF INSTRUMENTS

SR NO.

DESCRIPTION CAPACITY/ SIZE QTY MOC MAKE

1 Control Panel NA 1 - Xmetric

2 UV 35 m3/hr 1 SS Sukrut

3 Water Meter Electromagnetic Type

1 -- Utkarsh


9

CHAPTER – 5

TREATMENT METHODOLOGY FOR

STP


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TREATMENT METHODOLOGY FOR STP

The methodology adopted for the treatment of the Sewage consists of the following:

A) Primary Treatment

B) Biological Treatment

C) Tertiary Treatment

D) Sludge dewatering system

5.1 Primary Treatment Units:

Bar Screen Chamber

Oil & Grease Tank

5.2 Biological Treatment Units:

Aeration tank

Air Blowers

MBBR Media

Settling Tank

Tube Settler Media

Sludge Recycle Pumps

5.3 Tertiary Treatment Units:

Filter Feed Tank

Hypo Dosing System

Filter feed pumps

Pressure Sand Filter

Activated Carbon Filter

UV

5.4 Sludge Dewatering System Unit:

Sludge Holding Tank

Filter Press feed pumps

Filter Press


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CHAPTER – 6

OVERVIEW OF OPERATION


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OVERVIEW OF OPERATION

STP to be operated as follows:

6.1 Primary Treatment:-

Sewage produced in Institute will be passed to Aeration Tank Via Bar Screen Chamber and Oil &

Grease Trap Tanks. In Bar Screen floating material will be trapped. In oil & grease tank oil will be

separated. These tanks are designed as like septic tank which helps to trap floating oil and

material.

6.2 Biological Treatment System:-

The Sewage from passed through screening chamber and oil & grease trap will passed to aeration

tank for further process. In This stage, Sewage will be treated by MBBR process. In MBBR

wastewater containing organic matter is aerated in an aeration basin in which micro-organisms

attached to media metabolize the suspended and soluble organic matter. Part of organic matter

is synthesized into new cells and part is oxidized to CO2 and water to derive energy. In this

system the new cells formed in the reaction are removed from the liquid stream in the form of a

flocculent sludge in settling tanks. A part of this settled biomass, described as activated sludge is

returned to the aeration tank and the remaining forms waste or excess sludge. Biological

Treatment includes following,

Aeration Tank

Air Blowers

Air Diffusers

MBBR Media

Settling Tank

Tube settler Media

Sludge Recycle Pumps

Aeration tank is equipped with Air Blowers to aerate sewage. This Aerated Sewage will be sent to

Settling Tank for solid – liquid separation. Sludge from this Tank will be recycled back to Aeration

Tank to maintain MLSS (Mixed Liquor Suspended Solids) level. Overflow from Settling Tank will be

sent to Filter Feed Tank. The treated water parameters will be far better than Sewage parameters

specified by MPCB.


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Return sludge pumps will be used for recirculation of sludge from Settling Tank to Aeration Tank.

Overflow from Settling Tank will be sent to Filter Feed tank for further process. Excess Sludge

from settling tank will be sent to Sludge holding tank for further separation.

6.3 Tertiary Treatment System

Biologically treated sewage from Settling Tank will be collected in Filter Feed Tank. In this tank,

treated water will be disinfected by sodium hypochlorite. From filter feed tank treated and

disinfected water will be pumped by Filter feed pump to Pressure Sand Filter and then Activated

Carbon Filter for removal of traces of solids and colour removal etc. After Activated Carbon Filter

treated sewage will be passed through UV. UV will achieve more ultra-disinfection level. This final

treated Sewage will be then collected in Treated water tank from where it will be reused.

6.4 Sludge dewatering and disposal:

Excess/waste activated sludge from the Settling Tank shall be collected in sludge holding tank.

In this tank air grid is provided for missing of sludge with water during filter press treatment.

Filter Press feed pumps helps to pump out thickened sludge to filter press. Filter press is

equipped with smaller micron bags/clothes. These clothes help to retain sludge on it and

allow water to pass through it. This clear water will pass back for further treatment. Sludge

gathered over clothes removed and filled into bags for using it as a fertilizer.

6.5 CHECK LIST

Check for the direction of rotation of Pumps. Refer manufacturer manual.

Check the current drawn by Pumps periodically. Record all current readings & it shall be checked

against rated current

Ensure that motor fan is running smoothly.

Check & tighten the bolts/ gland of the pumps, bolts of the motors/agitators, base frames frequently.

Remove air lock from the pumps.

Check for the maintenance of pumps, Jet etc is carried out as per manufacturer’s guidelines.

Take care for dry running of pumps. It should not be happened.


14

CHAPTER – 7

IMPORTANT INSTRUCTIONS

FOR STP


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IMPORTANT INSTRUCTIONS FOR STP

Daily monitoring of flow & Sewage quality for parameters such as pH, TSS, TDS, COD, BOD, MLSS,

DO. To monitor the performance of the plant; Logging daily operations of equipment, monitoring

of hourly pH values, flow rates, lubrication schedule, etc is important.

7.1 Aeration Tank :

DO in the Aeration Tank to be maintained in the range of 1.0 – 2.0 mg/lit.

Jet Aerator should run continuously to achieve uniform mixing & DO levels.

7.2 Calculation of various process parameters:

7.2.1 F/M Ratio (Food to microorganism ratio):

BOD to be removed (mg/lit) x Flow (m3/day) F/M ratio = Volume of Aeration tank (m3) x MLSS (mg/lit)

7.2.2 Sludge Volume Index (SVI)

It is an indicator of settling characteristics of biomass. It varies from 50 to 150.

SR.NO SVI Characteristics of sludge

1. < 50 Excellent settleability of sludge.

2. < 100 Appreciable settleability of sludge

3. > 150 Poor settlement of sludge.

7.2.3 Sludge wastage:

Normal sludge wastage basis for 1st stage Aeration (Extended Aeration system): 0.10 % of

total Kg. BOD removed. However the same to be confirmed with the available MLSS in

the Aeration tanks.


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7.2.4 Nutrient Addition:

In case of nutrient deficiency in the Sewage namely for Phosphorus & Nitrogen, these

requirements can be supplemented by addition of DAP & Urea. The addition of nutrient is

done normally on the basis of BOD ratio which is

For Aeration: BOD : N : P = 100 : 5 : 1

The addition of nutrients, DAP & Urea is dependent on the BOD load and the presence of

Nitrogen & Phosphorus in the Sewage. The calculation is explained as below;

For eg, Assume the concentration of ammonical nitrogen & phosphates as 40 & 89 mg/lit.

Addition of nutrients to be added in the following ratio, BOD : N : P = 100 : 5 : 1.

Requirement of DAP & Urea works out to be:

Flow : 3000 m3/day.

BOD of primary treated Sewage : 675 mg/lit.

BOD in kgs / day : 2250 kgs

Ammonical Nitrogen : 40 mg/lit. i.e 24 kgs / day

Phosphates : 89 mg/lit. i.e 54 kgs /day

14 kgs of P required x 130 (Mol.wt of DAP) DAP required = 30 (Mol.wt of Phosphorus)

= 60 kgs / day – 54 kgs /day (present in the Sewage)

= 6 kgs /day

70 kgs of N required x 60.14 (Mol.wt of Urea) Urea required = 14.0 (Mol.wt of Nitrogen)

= 300 kgs / day – 24 kgs/ day (present in the Sewage)

= 276 kgs /day

However, these requirements are to be periodically checked by monitoring the concentrations of

Ammonical nitrogen and phosphates and calculating the requirements from the above formulae.


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CHAPTER – 8

RECORD KEEPING


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RECORD KEEPING

This operation manual includes formats for various aspects of record keeping. They are;

1. Daily Analysis Record sheet.

2. Daily Operational Log sheet of STP.

3. Monthly Analysis Record sheet.

8.1 DAILY ANALYSIS RECORD SHEET

OF

SEWAGE TREATMENT PLANT AT D. Y. PATIL COLLEGE OF ENGINEERING, AMBI, PUNE

Date:

SEWAGE CHARACTERISTICS:

SR

NO

SAMPLE

pH

TSS

mg/lit

TDS

mg/lit

COD

mg/lit

BOD

mg/lit

O&G

mg/lit

DO

mg/lit

Hardness

mg/lit

1. Raw Sewage

2. Filter Feed Tank

3. Treated Water Tank


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8.2 AERATION TANK CHARACTERISTICS (BIOLOGICAL CHARACTERISTICS)

Sr. No. Parameters AERATION TANK Unit

1. MLSS mg/lit

2. MLVSS mg/lit

3. Sludge Volume Index --

4. Dissolved Oxygen mg/lit

Total Sewage flow: m3/day

Chemist’s Signature: Remarks:

In-charge Signature:


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8.3 MONTHLY ANALYSIS RECORD

OF

SEWAGE TREATMENT PLANT AT D. Y. PATIL COLLEGE OF ENGINEERING

RAW SEWAGE

Date

pH

TSS

TDS

COD

BOD

O & G

HARDNESS

Amm.

N2

FILTER FEED TANK

Date

pH

TSS

TDS

COD

BOD

O & G

HARDNESS

Amm.

N2

FINAL OUTLET AFTER ACF

Date

pH

TSS

TDS

COD

BOD

O & G

HARDNESS

Amm.

N2


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SEWAGE TREATMENT PLANT AT D. Y. PATIL COLLEGE OF ENGINEERING

8.4 CHEMICAL STOCK REPORT FOR THE MONTH OF _________________

DATE DAP UREA

Stock Used Bal. Stock Used Bal.

Plant Incharge Signature:______________


22

CHAPTER – 9

GENERAL PRECAUTIONS AND

TROUBLE SHOOTING PROBLEMS &

ITS REMEDIAL MEASURES


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GENERAL PRECAUTION & TROUBLE SHOOTING PROBLEMS & ITS

REMEDIAL MEASURES

9.1 AEROBIC TREATMENT:

For proper operation of biological treatment it is necessary that pH should not be highly

acidic or highly alkaline. Normally pH should be within 6.5 & 8.0.

For uniform loading the equalized Sewage is to be pumped at a constant rate.

The biological action for reducing organic load requires activated sludge. Therefore it is

necessary to add activated sludge from any of the existing sewage treatment plant or using

cow dung.

Qualitative shock loads must be avoided in case of biological treatment. In case it receives

any shock loads and the microbial culture dies out, and fresh sludge needs to be added. This

qualitative shock load can occur in case of sudden change in the process, presence of high

chlorides, high TDS, heavy metals etc. In that case, these need to be eliminated separately.

Microbial activity is measured by the amount of MLSS present in the Aeration tank. MLSS

should be maintained around 3500 – 4000 mg/lit.

When sludge exceeds than required, it is necessary to drain it on sludge drying beds.

Lastly but not the least, in case of power failure, the air jet and the sludge recycle pumps

should be run continuously on DG sets.

There must be sufficient aeration to maintain a dissolved oxygen concentration of at least

two mg/L at all times throughout the aeration tanks.

Dissolved oxygen should be present at all times in the treated wastewater in the final settling

tanks.

Activated sludge must be returned continuously from the final settling tanks to the aeration

tanks.

Optimum rate of returning activated sludge will vary with each installation and with different

load factors. In general, it will range from 20 to 40 percent of the influent wastewater flow

for diffused air and 10 to 40 percent for mechanical aeration units.

A sludge volume index of about 100 and a sludge age of three to fifteen days are normal for

most plants. When the optimum sludge volume index is established for a plant, it should be

maintained within a reasonably narrow range. A substantial increase in SVI is a warning of

trouble ahead.


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The suspended solids content in the aeration tanks may partially be controlled by the amount

of sludge returned to them. All sludge in excess of that needed in the aeration tanks must be

removed from the system. It should be removed in small amounts continuously or at

frequent intervals rather than in large amounts at any one time.

Sludge held too long in the final settling tank will become septic, lose its activity and deplete

the necessary dissolved oxygen content in the the tank.

Periodic or sudden organic overloads that may result from large amounts of sludge digester

overflow to the primary tanks or from doses of industrial wastes having an excessive BOD or

containing toxic chemicals will usually cause operating difficulties. Whenever possible,

overloading should be minimized by controlling the discharge or by pretreatment of such

deleterious wastes.

The basic indicator of normal plant operation is the quality of the plant Sewage.

Failure of plant efficiency may be due to either of the two most common problems

encountered in the operation of an activated sludge plant, namely, rising sludge and bulking

sludge.

9.2 SECONDARY CLARIFICATION :

For an activated sludge process to achieve optimum plant efficiency the clarification unit

must effectively separate the biological solids from the mix liquor. If these solids are not

separated properly and removed from the clarifier in a relatively short period of time,

operating problems will result, causing an increased load on the receiving waters and a

decline in plant efficiency. The most important function of the final clarifier is to maintain the

wastewater quality produced by the preceding processes.

Operational Problems with Secondary Clarifiers:

The operator must keep in mind that many operating problems in the final clarifier can be

associated with operating problems in the preceding processes, i.e. mainly the aeration

system.

1. Floating Solids: This is commonly referred to as “clumping”, “ashing” or “rising sludge”.

Floating solids are usually due to a high sludge age (too many solids in system) or too long of

a solids detention time in the final clarifier.

Remedies:

1. Decrease solids inventory (increase wasting rate)

2. Remove solids from final clarifier quicker


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3. Check for any dead spots in clarifier where solids are not being collected and removed.

A heavy accumulation of solids on the surface of a clarifier may be alleviated by spraying the

surface with a high pressure hose to knock the solids down.

2. Solids Losses Over Sewage Weirs: Excessive solids losses in the final clarifier can be the result

of hydraulic overload or due to the type and characteristics of the biological solids present.

Straggler Floc is indicative of a young sludge which tends to settle slowly. This type of floc

consists of light, fluffy, buoyant particles. This situation can be intensified by short-circuiting

and hydraulic overloads.

Remedies:

1. Increase solids inventory by decreasing the wasting rate to produce an older sludge which

tends to settle faster.

2. Check clarifier for short-circuiting.

3. Calculate detention time and check for hydraulic overloading.

3. Pin Floc: Pin Floc is indicative of an older sludge which tends to settle too fast, leaving many

fine suspended particles in the supernatant and a turbid Sewage. The sludge particles are

usually darker, heavier and more granular in appearance.

Remedies:

1. Increase sludge wasting rate to decrease solids inventory.

2. Check for short-circuiting and hydraulic overload.

4. Fouling of Weirs: An accumulation of solids and/or on the weir surfaces can cause short-

circuiting within the tank, creating excessive velocity currents that pull solids over the Sewage

weirs.

Remedies:

1. A thorough scrubbing of weir surfaces to remove solids build-up.

2. Strong chlorine solutions applied to the weirs is also effective.

3. Plugging of Withdrawal Ports is usually caused by too high of a solids concentration in the

return sludge.

Remedy:

1. Withdraw sludge faster and/or more frequently.

5. Rising Sludge: Unlike bulking the problem of rising sludge is only seen in the final settling

tank and has definite operational causes and it can be corrected through an understanding of

the system and defined management practices.


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The biological oxidation of a wastewater has been described as a two-phase reaction where

organic carbon oxidation occurs first and is usually followed by the biological oxidation of

ammonia or nitrification. Wastewaters having organic, carbon containing compounds always

contain ammonia. Generally, prolonged aeration or organic under loading of a biological

wastewater treatment plant can result in a condition where oxidation of most of the organic

matter occurs (that is, carbon is converted to carbon dioxide) and nitrification follows. This

process of nitrification involves the conversion of ammonia, nitrogen and organic nitrogen to

nitrate nitrogen. The nitrates that are formed in the aeration tank then flow into the final

settling tank where quiescent settling and solids removal will take place. If the dissolved

oxygen levels are sufficiently low in the settling tank and there is some organic matter

available, denitrificaton will take place.

Rising sludge is caused by denitrification in which nitrites and nitrates in the wastewater are

reduced to nitrogen gas. Denitrification occurs in the sludge layer in the secondary clarifier

when conditions become anaerobic or nearly anaerobic. As the nitrogen gas accumulates, the

sludge mass becomes buoyant and rises or floats to the surface. Rising sludge can easily be

differentiated from a bulking sludge by noting the presence of small gas bubbles attached to

the floating solids and by microscopic examination. This problem can be overcome by

increasing the removal rate of the sludge, by regulation of the flows (loading) and monitoring

of the dissolved oxygen levels in the final settling tank. In this case, DO needs to be checked.

In case it exceeds 4.0 mg/lit, the air Jet are to be shut for some time.

6. Filamentous Bulking: Generally, non-flocculent or non-settling microbial growth is the result

of either suppressing the normal wastewater treatment bacteria or promoting conditions

favorable to filamentous microorganisms, such as fungi or actinomycetes which cannot be

settled readily.

The presence of filamentous microorganisms to the point where they interfere with settling

is called bulking. This condition may be seen in the aeration tanks of activated sludge

processes and is sometimes accompanied by frothing. The solids do not settle in the final

settling tank and a homogeneous blanket of solids will pour out over the Sewage weirs,

especially during diurnal peak flow variations. Filamentous bulking can be recognized through

a microscopic examination of the mix liquor and observing the presence of these

microorganisms in the flocculent material that does not settle. Under filamentous bulking

conditions the presence of filaments is obvious and the filaments can be seen preventing

more normal looking flocs from coming together.


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The conditions associated with filamentous bulking are not always well understood, but have

been associated with high organic loadings, pH changes, low pH wastewaters, inputs of

industrial wastes, low dissolved oxygen levels, seasonal variations, septic primaries, and an

improper balance between carbon, nitrogen and phosphorous in the waste. The problem of

bulking is not easy to deal with since its causes cannot always be identified. However, a

careful review of the operating records with respect to pH, loading, and aeration tank DO,

MLSS, etc. is always useful in attempting to develop relationships between poor operating

conditions and bulking. Careful records and trending as well as a close control over operating

conditions and a knowledge of inputs into the wastewater system is useful. When bulking of

activated sludge is caused by overloading, prechlorination to reduce the load on the aeration

process has been tried with some success. Prechlorination of the influent to produce a

residual of about 0.1 mg/L in the primary tank Sewage is used. Prechlorination of the primary

tank influent is particularly useful in controlling septicity. Chlorination of the return activated

sludge can control filamentous bulking. The point of application should be where the return

sludge will be in contact with the chlorine solution for about one minute before the sludge is

mixed with the aerator influent. The chlorine dose is varied according to the variations in the

sludge volume index and may be estimated as follows:

SVI x F x W x 8.34 x 106 = pounds of chlorine per day

Where;

SVI = Sludge Volume Index

F = Return sludge rate in million gallons per day

W = Suspended solids in return sludge in mg/L

Chlorine dosages can better be determined by trial and error. In general, chlorination of a

bulking sludge will reduce the sludge volume index, thus the dose is reduced daily until

bulking is corrected. In some plants intermittent chlorination will maintain a low sludge

volume index, and in others continuous chlorination of the return sludge has proven more

satisfactory. Generally, when chlorination of the return sludge is started, the turbidity of the

plant Sewage will increase, but after a few days of operation the turbidity will again decrease

to that of normal conditions.

Extensive wasting of the biological sludge to reduce the filamentous organisms also has

proven to be somewhat effective in alternating a bulking situation.

The operator must realize that these measures are only temporary steps to alleviate bulking

and that the problem may reappear if the cause is not identified and corrected.


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CHAPTER – 10

DRAWINGS

upgradation for 345 kld effluent treatment plant at m/s...

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