Upgradation for 345 KLD Effluent Treatment Plant at M/s...
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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
Dimensions : 7.7 m x 2.0 m x 2.0 m SWD
Quantity : 1 No
3. MBBR Tank
No. of tanks : 1 No
Dimensions : 12.0 m x 10.0 m x 4.5 m SWD
4. Settling Tank
No. of tanks : 1 No
Dimensions : 6.0 m x 6.0 m x 4.3 m SWD
5. Filter Feed Tank
No. of Tanks : 1 No
Dimensions : 10.0 m x 6.0 m x 4.1 m SWD
6. Sludge Holding Tank
No. of Tanks : 1 No
Dimensions : 6.0 m x 3.7 m x 4.5 m SWD
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
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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.
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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
700 KLD Sewage Treatment Plant at D. Y. Patil Educational Academy, Ambi, Pune
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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:______________
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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