treatment & disposal of waste water

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TREATMENT & DISPOSAL OF TREATMENT & DISPOSAL OF WASTE WATERWASTE WATER

Organized byOrganized by Chemical & Civil Engineering DepartmentChemical & Civil Engineering Department

SVNIT SURATSVNIT SURAT

Time: 11:15 to 12:45 hrsTime: 11:15 to 12:45 hrsFrom 5From 5thth October,2009 October,2009

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TABLE OF CONTENTTABLE OF CONTENT

1.1. BRIEF INTRODUCTION OF HAZIRA INDUSTRIAL BRIEF INTRODUCTION OF HAZIRA INDUSTRIAL BELT INCLUDING KRIBHCO.BELT INCLUDING KRIBHCO.

2.2. WATER & EFFLUENT MANAGEMENT IN WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNITNITROGENEOUS FERTILISER UNIT

3.3. WATER IN TERMS OF MICROBIOLOGYWATER IN TERMS OF MICROBIOLOGY

4.4. INDUSTRIAL LEGAL COMPLIANCES ON WATER USE INDUSTRIAL LEGAL COMPLIANCES ON WATER USE & EFFLUENT DISPOSAL& EFFLUENT DISPOSAL

5.5. SEWAGE TREATMENT PLANTSEWAGE TREATMENT PLANT

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1.1. BRIEF INTRODUCTION OF HAZIRA BRIEF INTRODUCTION OF HAZIRA INDUSTRIAL BELT INCLUDING INDUSTRIAL BELT INCLUDING

KRIBHCO.KRIBHCO.

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The area is called Hazira. This is almost 16 Kms from Surat. About 28 years ago, it was a very small village. Today it is one of the most sought-after destinations for setting up industries.

Surat itself is a fast developing city, but the development in Hazira has been phenomenal. At present, Hazira is home of several major corporate houses, including Reliance, Essar Steel, L&T, NTPC, Kribhco, ONGC, GAIL, IOC, HPCL, BPCL,GSEG and IBP.

Oil and gas major Shell has recently started its LNG terminal at Hazira. Cairn Energy has also started operations here.

Investments worth of billions of rupees have been made in the area in various industries and the amount is likely to go up.

1.1. BRIEF INTRODUCTION OF HAZIRA INDUSTRIAL BELT BRIEF INTRODUCTION OF HAZIRA INDUSTRIAL BELT INCLUDING KRIBHCO.INCLUDING KRIBHCO.

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KRIBHCO PLANTONGC

GAIL

L&T

ESSAR STEEL

NTPCRELIANCE

ESSAR

POWER

SURAT RLY STN

KRIBHCO T/S

GSEG

NORTH

S

WE

TA

PT

I LIN

E

TO

BO

MB

AY

TO

AH

ME

DA

BA

D/D

EL

HI

KRIBHCO RAILWAY SIDING

ADAJAN PATIA

ADAJANVILLAGE

TAPTI RIVER

CHOWK HA

ZIR

A

MAGDALLA

ATHWA LINES

TO DUMASTO

SA

CH

IN

TO

OL

PA

D TO MORA VILLAGE

RING ROAD

SHELL

IOC

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Krishak Bharati Cooperative Krishak Bharati Cooperative LimitedLimited

Hazira Plant - SuratHazira Plant - Surat

Certified forCertified for


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Birth of KRIBHCO: KRIBHCO was KRIBHCO was incorporatedincorporated

on 17on 17thth April, 1980 and was promoted by April, 1980 and was promoted by

government of India, IFFCO, NCDC and agricultural government of India, IFFCO, NCDC and agricultural

co-operatives all over the country. co-operatives all over the country.

Foundation stone was laid by Former Hon’ble Prime Foundation stone was laid by Former Hon’ble Prime

Minister Late Smt. Indira Gandhi on Feb. 5, 1982.Minister Late Smt. Indira Gandhi on Feb. 5, 1982.

KRIBHCO is a Multi-state Co-operative Society under KRIBHCO is a Multi-state Co-operative Society under

the administrative control of Department of the administrative control of Department of

Fertilisers, Government of IndiaFertilisers, Government of India..


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Hazira Fertiliser Plant : : Capital CostCapital Cost

EstimatedEstimated RS. 957 CR.RS. 957 CR.FinalFinal RS. 890 CR.RS. 890 CR.SavingSaving RS. 67 CR (~ 7%)RS. 67 CR (~ 7%)

Plant Capacities Plant Capacities (Re-assessed w.e.f (01.04.2000)(Re-assessed w.e.f (01.04.2000)

AnnualAnnual TechnologyTechnologyAmmonia Ammonia 2 x 1520 MT/Day2 x 1520 MT/Day M W Kellog, USAM W Kellog, USAUrea Urea 4 x 1310 MT/Day 4 x 1310 MT/Day Snamprogetti, ItalySnamprogetti, ItalyPower Power 2 X 15 MW2 X 15 MW Senior Thermal Engg, UK Senior Thermal Engg, UK

(Formerly FWPPL) & BHEL, India(Formerly FWPPL) & BHEL, India

Bio-Fertilisers 400 +150 MT/YrBio-Fertilisers 400 +150 MT/Yr (Surat + Varanasi) (Surat + Varanasi)Argon (Feed Gas) Argon (Feed Gas) 7000 NM3/Hr7000 NM3/Hr Linde KCA, GermanyLinde KCA, GermanyStart of Production : Nov. 1985 Commercial Prodn : March 1, 1986Start of Production : Nov. 1985 Commercial Prodn : March 1, 1986

HAZIRA PLANT SITE*


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2. WATER & 2. WATER & EFFLUENT EFFLUENT

MANAGEMENT IN MANAGEMENT IN NITROGENEOUS NITROGENEOUS

FERTILISER UNIT:FERTILISER UNIT:

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Pollution is an unavoidable part of Industrial growth. Actually it is a by- Pollution is an unavoidable part of Industrial growth. Actually it is a by- product of Industrial development. Even though all efforts are made to product of Industrial development. Even though all efforts are made to control the harmful constituents of effluents, and at the same time control the harmful constituents of effluents, and at the same time improve the plant viability through recovery of more expensive by- improve the plant viability through recovery of more expensive by- products, pollution cannot be totally avoided but it can be minimized by products, pollution cannot be totally avoided but it can be minimized by using antipollution devices.using antipollution devices.

The main importance today in Fertilizer industry all over the world is on The main importance today in Fertilizer industry all over the world is on

R&D to evolve processes which will reduce pollution at the R&D to evolve processes which will reduce pollution at the design design stage itself,stage itself, so that the harmful pollutants can be brought to so that the harmful pollutants can be brought to

acceptable level at acceptable level at a reasonable cost. a reasonable cost. ((

The above challenges are also there on the technologies & The above challenges are also there on the technologies & processes for treatment & disposal of waste water. processes for treatment & disposal of waste water.

(We can generate advance technologies by new advance generation, supported by professors like U, I have confidence on new generation because….. See the slide and U will get answer from the slide.)

2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNIT:2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNIT:

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Rule of Thumb:Rule of Thumb:

It is very very important to know that…..It is very very important to know that…..

2O% reduction in water consumption and/or 2O% reduction in water consumption and/or effluent discharge requires little or no cost.effluent discharge requires little or no cost.

40% saving in water consumption can be 40% saving in water consumption can be achieved at some cost.achieved at some cost.


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6.28

7.27

7.09

6.77 6.72 6.756.69

6.37 6.366.20

6.40

6.60

6.80

7.00

7.20

7.40

2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 2008-09

YEAR

WA

TE

R C

ON

SU

MP

TIO

N IN

MG

D2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNIT:

RAW WATER CONSUMPTION IN MGDRAW WATER CONSUMPTION IN MGD

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INCREASING COOLING TOWER COC FROM 6 TO 8. INCREASING COOLING TOWER COC FROM 6 TO 8. ( we have increased COC by adopting ( we have increased COC by adopting some special chemicals treatment. COC is the ratio of H in circulating water & H in m/up water)some special chemicals treatment. COC is the ratio of H in circulating water & H in m/up water)

Effect:Effect: - Less M/Up water required.- Less M/Up water required.- Less B/D required, Correspondingly less effluent generated.- Less B/D required, Correspondingly less effluent generated.

MAINTAINING OPTIMUM LEVEL OF THE RESERVIORS MAINTAINING OPTIMUM LEVEL OF THE RESERVIORS (The shape of our reservoirs is (The shape of our reservoirs is taper Shape. & due to this at optimum level – we can say at 50% level, the surface area is reduced & correspondingly less taper Shape. & due to this at optimum level – we can say at 50% level, the surface area is reduced & correspondingly less evaporation occurs).evaporation occurs).

Effect:Effect: - Less Evaporation loss.- Less Evaporation loss.

RECOVERY OF SEWAGE TERTIARY TREATED WATER TO COOLING RECOVERY OF SEWAGE TERTIARY TREATED WATER TO COOLING TOWAER MAKE UPTOWAER MAKE UP. . (The consumption of water in T/S & plant is abt 3000 M3 & we recover abt 2500 M3 of (The consumption of water in T/S & plant is abt 3000 M3 & we recover abt 2500 M3 of water from STP & use this treated water as CT M/up)water from STP & use this treated water as CT M/up)

Effect:Effect: - Less M/Up water required.- Less M/Up water required.

ADOPTING SOME MEASURES TO RECOVER RAIN WATER & TO USE IT AS ADOPTING SOME MEASURES TO RECOVER RAIN WATER & TO USE IT AS COOLING WATER MAKEUP. COOLING WATER MAKEUP. ( By adopting rainwater harvesting from roof & terrace area of the plant & ( By adopting rainwater harvesting from roof & terrace area of the plant & T/S) T/S)

Effect:Effect: - Less M/Up water required.- Less M/Up water required.- Less B/D required due to hardness level in rain water is - Less B/D required due to hardness level in rain water is negligible; Correspondingly less effluent generated.negligible; Correspondingly less effluent generated.- Less cooling water treatment chemical required.- Less cooling water treatment chemical required.

REDUCTION IN WATER CONSUMPTION BY:REDUCTION IN WATER CONSUMPTION BY:


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Various Effluent in Nitrogenous Fertilizer Unit:Various Effluent in Nitrogenous Fertilizer Unit:

Oily effluent generation from rotating equipments of all Oily effluent generation from rotating equipments of all plants.plants.

Liquid effluent generated from Cooling Tower blow dawn.Liquid effluent generated from Cooling Tower blow dawn.

Liquid effluent generated from DM Plant.Liquid effluent generated from DM Plant.

liquid effluent generation containing NH3 & UREA from Ammonia & Urea plant.

Sewage effluent generated from Township & Plant.Sewage effluent generated from Township & Plant.

2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS 2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNIT:FERTILISER UNIT:

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Various Effluent in Nitrogenous Fertilizer Unit:Various Effluent in Nitrogenous Fertilizer Unit: WATER PRE TREATMENT PLANT: (The RW is treated in in WPT by coagulant dosing to (The RW is treated in in WPT by coagulant dosing to

remove suspended solids (turbidity) from RW. After clarification in remove suspended solids (turbidity) from RW. After clarification in ClarifiersClarifiers & filtration by& filtration by GSF GSF, the treated water , the treated water is supplied to various plant.)is supplied to various plant.)

– Clarifier Sludge is generated during Raw water treatment process to remove suspended solids. This sludge is sent to sludge settling pond.

– The gravity sand filter B/W water which was earlier pumped to sludge collection pond is now being recycled in the system alongwith raw water for clarification.

Urea trted

Effluent Pond

WPT TrtdSludge settling

pond

Balancing pond

Clarifiersludge

Zero discharge to Creek

WaterPretreatment

PlantSludge

PitGSF B/Wwater

Recycled to clarifier

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Various Effluent in Nitrogenous Fertilizer Unit:Various Effluent in Nitrogenous Fertilizer Unit: Demineralization Plant: (DM plant is for supplying DM water to Stm generation Unit in power plant & Amm (DM plant is for supplying DM water to Stm generation Unit in power plant & Amm

plant. The cations & anions are present in the water is removed by the ion exchange method in Cation exchangers & plant. The cations & anions are present in the water is removed by the ion exchange method in Cation exchangers & Anion exchangers having resin. After exhaustion of the cation exchanger, the unit is regenerated by HCL & similarly Anion exchangers having resin. After exhaustion of the cation exchanger, the unit is regenerated by HCL & similarly anion exchanger is regenerated by NaOH.)anion exchanger is regenerated by NaOH.)

– Acidic and Alkaline effluents are generated during regeneration of various units such as Cation, anion and Mixed bed Exchangers of DM Plant.

– This effluents are collected in neutralization pit. Its pH is adjusted to 6.5 to 8.5 & finally pumped directly to Balancing Pond.

– The rinse water of the Exchangers which was earlier pumped to Balancing pond with treated effluent is now being recycled to system with treated water from WPT.

Urea trted

Effluent Pond


pond

Balancing pond

AcidicEffluent


NeutralizationPit

AlkalineEffluent

CationUnits

AnionUnits

Rinse waterRecycled to FWST

Acid/ caustic dosed if required

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2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS 2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNIT:FERTILISER UNIT:


Ammonia Plants:

B/D

SecondaryReformer

Jacket

Boiler

CondensateStripper

Mixed BedUnit

Acidic/ Alkaline Effluent toNeutralization Pit of DM Plant

Treated Condensate as Boiler Feed Water M/Up

To Cooling Tower

Condensate inlet

Stripped Ammonia, CO2

Bed of SSSlotted Rings

LP Steam

•The Process Condensate from Raw Gas Separator, Synthesis Gas Compr suction drum, Syn. Compr 1st & 2nd stage Separator is treated in the Stripper by LP Steam at a temp. of 295 deg C.

•On coming in contact with LP Steam NH3, CO2 & Mehanol dissolved gases are stripped out.

•Stripper outlet condensate is used as Boiler feed water M/up after passing through Cooler & MB Polisher Unit.

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Various Effluent in Nitrogenous Fertilizer Unit:Various Effluent in Nitrogenous Fertilizer Unit: Cooling Towers:

There are 5 nos of cooling towers to remove heat load of the process plant condensers & heat exchangers. They are operating on Non chromate based cooling water treatment to prevent the system from corrosion, scaling, fouling & microorganisms growth. To maintain circulation CW parameters (hardness, chloride etc) CW B/D is required from the systems. This B/D water is directly pumped to Urea treated Effluent Pond.

Now part of the CW B/D is being used to Lawn & Farm area for Horticulture purpose.

Urea trted

Effluent Pond


pond

Balancing pond


B/D waterCoolingTowers

To Lawn & Farm Area

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Urea Plants:


Urea waste water

ACF

Deep Hydrolysersection

MB inDM Plant

Boiler Feed water M/up

Distillation Tower

Condenser

RefluxAccumulatorDrum

Ammo. + CO2 + H2O Vap

Urea Contaminated Condansate

Ammo. contaminated condensate (Abt 50 ppm)

LP Steam

Re-boiler

Recovery of

Ammo. carbonate Soln to Process

RefluxHS steam

93 ata 500 oC

CW

<5 ppm Urea & Ammonia

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Process: 2 NH3 + CO2 NH4 COO NH2 NH2CONH2 + H2O2 molecule of Ammonia is reacted with CO2 to form an intermediate Ammonium carbamate & it is 2 molecule of Ammonia is reacted with CO2 to form an intermediate Ammonium carbamate & it is

decomposed to UREA and decomposed to UREA and water.water. This water is called This water is called “Process Condensate Water”.“Process Condensate Water”.

During the process of concentration of Urea Solution up to 99.7% in Evaporation section about 2400 M3/day Of Waste water is generated.

Analysis: Ammonia : 4.5 %Urea : 1.0 %CO2 : 2.5 %

The waste water is pumped to upper section of Distillation tower via pre-heater to raise the Temp. This section is operated at at 2.5 ata. Pressure & 120 deg C Temp. Here Ammo. & CO2 are stripped out & remaining Urea contaminated condensate is pumped into Hydrolyser section.

In the Deep Hydrolyser section Urea is decomposed with steam at 93 ata & 500 oC.

NH2CONH2(aq) + H2O 2 NH3(g) + CO2 (g) (Endothermic)The vapour from the Hydrolyser section alongwith vapour from Distillation Tower containing Ammo & CO2 are sent to overhead Condenser. The condensed Ammoniam carbonate solution is recovered & sent to process for Urea production.

The condensate from the Hydrolyser section containing about 50 ppm ammonia is sent to top of the lower part of the Distillation column. Here remaining Ammonia is stripped by vapour & LP steam from reboiler.

The purified water is used as Boiler Feed water M/up after passing through Cooler, ACF & MB Polisher Unit.

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Effluent management:Effluent management:

Cooling Towers B/D water is utilized for horticulture Irrigation purpose. Remaining Cooling Towers B/D water is utilized for horticulture Irrigation purpose. Remaining effluent is sent to guard pond & Balancing pond. Due to vast area of these ponds effluent is sent to guard pond & Balancing pond. Due to vast area of these ponds maximum water is evaporated (160 acres & 4.5 mm evaporation loss)maximum water is evaporated (160 acres & 4.5 mm evaporation loss)

The approximate effluent generated in the plants after adopting reuse & recycle method:The approximate effluent generated in the plants after adopting reuse & recycle method:CT B/D : 3,500 M3 + DM neutralization pit: 150 M3 + WPT: 50 M3CT B/D : 3,500 M3 + DM neutralization pit: 150 M3 + WPT: 50 M3 = 3,700 M3= 3,700 M3CT B/D reuse for Horticulture purpose in Farm & lawn area CT B/D reuse for Horticulture purpose in Farm & lawn area = = 0,800 0,800 M3M3

Effluent Generation Rate isEffluent Generation Rate is 2,900 M3/ 2,900 M3/ DayDay

By Considering 4.5 mm average evaporation rateBy Considering 4.5 mm average evaporation rate

160 x 4047 x 4.5/1000 160 x 4047 x 4.5/1000 == 2,900 M3/day water is evaporated2,900 M3/day water is evaporated. .

Therefore average effluent generation & evaporation Therefore average effluent generation & evaporation rate is equal & resultingrate is equal & resulting NO effluent is sent to estuary. NO effluent is sent to estuary.

Any biodegradable material present in the effluent is naturally degraded in the pond Any biodegradable material present in the effluent is naturally degraded in the pond because due to vast area of the pond, retention time for degradation is infinitive.because due to vast area of the pond, retention time for degradation is infinitive.

.Sewage effluent is treated in sewage treatment plant & recycled to Cooling Tower for cooling water make up purpose.


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3. WATER IN TERMS OF MICROBIOLOGYWATER IN TERMS OF MICROBIOLOGY

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““Water Is a Water Is a Valuable and Valuable and Limited Limited Resource”Resource”


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Imagine,Imagine, we receive a letter of our grand son in we receive a letter of our grand son in THE SWARG!!.THE SWARG!!.

The running year is 2070.The running year is 2070. Read the letter. Read the letter.

&& Decide; Are we eligible to stay in Decide; Are we eligible to stay in THE SWARGTHE SWARG or or

THE NURK!!!!THE NURK!!!!


04/12/2304/12/23 AR BhattAR Bhatt 2626

LETTER WRITTEN IN THE YEAR 2070LETTER WRITTEN IN THE YEAR 2070

www ww w www wWwwwww w w ww w wwwwwwww wwwwwww w w w wwwww ww w w w www wWwwwww w w ww w wwwwwwww wwwwwww w w ww www ww w www wWwwwww w w

ww w wwwwwwww wwwwwww w w w wwwww ww w w w www wWwwwww w w ww w wwwwwwwwWwwwww w w ww w wwwwwwww wwwwwww w w w wwwww ww w w w www wWwwwww w w ww w wwwwwwww wwwwwww w w ww www ww w www wWwwwww w w

ww w wwwwwwww wwwwwww w w w wwwww ww w w w www wWwwwww w w ww w wwwwwwww

LETTER OF MY GRAND SON

LETTER OF MY GRAND SON

04/12/2304/12/23 AR BhattAR Bhatt 2727

Introduction:Introduction:

Water is essential for the well being of all living organisms. Evidence Water is essential for the well being of all living organisms. Evidence indicates that #indicates that #life originated in the primitive ocean approximately 3.5 in the primitive ocean approximately 3.5 billion years ago. The blood in our veins closely approximates the billion years ago. The blood in our veins closely approximates the composition of sea water. composition of sea water.

All microbes live in an aqueous environment. Without water they either All microbes live in an aqueous environment. Without water they either perish or become inactive. The ecology of aquatic environments is perish or become inactive. The ecology of aquatic environments is complex and our understanding of them is limited. Most aquatic complex and our understanding of them is limited. Most aquatic environments are teaming with life. #environments are teaming with life. #Microbes have evolved that can have evolved that can live in saturated salt (sodium chloride) solutions at temperatures from live in saturated salt (sodium chloride) solutions at temperatures from below freezing to >110below freezing to >110ooC; they thrive in waters full of toxic substances C; they thrive in waters full of toxic substances like copper, cyanide, lead, silver, gasoline, oil, benzene, and a plethora like copper, cyanide, lead, silver, gasoline, oil, benzene, and a plethora of other noxious natural and man-made substances. It is a of other noxious natural and man-made substances. It is a NEAR NEAR NATURAL LAWNATURAL LAW that that where liquid water, an energy source and basic where liquid water, an energy source and basic nutrients exist, you will find living microbes. This is why the scientific nutrients exist, you will find living microbes. This is why the scientific community is so interested in finding water on Mars or any other community is so interested in finding water on Mars or any other planet/moon in our solar system.planet/moon in our solar system.


http://www.slic2.wsu.edu:82/hurlbert/micro101/pages/101_prologue.html

http://www.slic2.wsu.edu:82/hurlbert/micro101/pages/Chap4.html

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Water is of vital importance to man for several Water is of vital importance to man for several reasons. First, as with all other life forms, it is reasons. First, as with all other life forms, it is required to required to MAINTAINMAINTAIN human existence. A person human existence. A person may survive for weeks without food, but only a few may survive for weeks without food, but only a few days without water. Water is crucial for the days without water. Water is crucial for the growing of our food and the operation of all our growing of our food and the operation of all our industries.industries.

Many people consider it likely that the next Many people consider it likely that the next

war in the Middle East may be over war in the Middle East may be over WATERWATER and not and not OILOIL..


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The importance of water in our lives is The importance of water in our lives is often overlooked because of its seemingly often overlooked because of its seemingly endless supply. endless supply.

70% of the earth is covered with water, 70% of the earth is covered with water, which is a whole lot of which is a whole lot of WETWET by anyone's by anyone's definition. Surrounded by this plentiful definition. Surrounded by this plentiful supply of moisture it is hard to imagine supply of moisture it is hard to imagine that we could ever be short of water. that we could ever be short of water.


04/12/2304/12/23 AR BhattAR Bhatt 3030

Because of a need for a stable water supply humans always built their Because of a need for a stable water supply humans always built their communities on or near a water supply. However, this has also led to communities on or near a water supply. However, this has also led to an unfortunate tendency to dispose of our wastes in the same place an unfortunate tendency to dispose of our wastes in the same place where we obtain our drinking water. This presented little problem when where we obtain our drinking water. This presented little problem when the population was small and nomadic, for when the stink of a camp the population was small and nomadic, for when the stink of a camp became offensive, our nomadic ancestors picked up and moved the became offensive, our nomadic ancestors picked up and moved the tribe a few miles up or down stream or over the hill to the next stream. tribe a few miles up or down stream or over the hill to the next stream. Mother nature then stepped in and rapidly recycled the few wastes left Mother nature then stepped in and rapidly recycled the few wastes left behind.behind.

With the coming of With the coming of AGRICULTURE, PERMANENT SETTLEMENTS AGRICULTURE, PERMANENT SETTLEMENTS and LARGE POPULATIONSand LARGE POPULATIONS, it became impossible to move people to , it became impossible to move people to a clean habitat; besides someone usually was already there and they a clean habitat; besides someone usually was already there and they generally took serious umbrage when the new arrivals told them to generally took serious umbrage when the new arrivals told them to move on. move on.


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Classification of Effluent parametersClassification of Effluent parameters

1.1. In waste water treatment, the following In waste water treatment, the following category of pollutants are important:category of pollutants are important:

PhysicalPhysical ChemicalChemical BiologicalBiological

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Classification of Effluent parametersClassification of Effluent parameters Physical Parameters:Physical Parameters:

1.1. Pollutant: Pollutant: TemperatureTemperature

Major Source: Industrial waste waterMajor Source: Industrial waste water

Effect:Effect:- - Hot effluent affect the aquatic life.Hot effluent affect the aquatic life.

- Affect Dissolved Oxygen (DO) concentration- Affect Dissolved Oxygen (DO) concentration As the temp. increased, the DO level in the system is decreased. At 0As the temp. increased, the DO level in the system is decreased. At 000C the DO C the DO

level is 14.6 mg/l & at 30level is 14.6 mg/l & at 3000C the DO level is decreased up to 7.54 mg/l.C the DO level is decreased up to 7.54 mg/l.

- Higher algae growth & undesirable plants.- Higher algae growth & undesirable plants. 353500C temp. is the ideal temp for algae growth.C temp. is the ideal temp for algae growth.

- Increase solubility of chemicals- Increase solubility of chemicals

151500 to 37 to 3700C temp. is ideal environment for biological treatment.C temp. is ideal environment for biological treatment.

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2.2. Pollutant: Pollutant: Suspended & dissolved solids:Suspended & dissolved solids:

Major Source: Industrial waste waterMajor Source: Industrial waste waterSuspended & dissolved solids are

– Floating solidsFloating solids-Removed by Screening & Filtration-Removed by Screening & Filtration

– Settleable SolidsSettleable Solids (>10 micron) (>10 micron)

– Suspended solidsSuspended solids (> 1 micron) (> 1 micron)-Removed by sedimentation-Removed by sedimentation

– Non-settable solidsNon-settable solids- - Removed by coagulation & Filtration.Removed by coagulation & Filtration.

– Colloidal solidColloidal solid (1 to 1000 nanometers) (1 to 1000 nanometers)- - Removed by coagulationRemoved by coagulation

– Dissolved Solids (< 1 nanometer)Dissolved Solids (< 1 nanometer)- - Can be removed by Membrane separation system or Resin systemCan be removed by Membrane separation system or Resin system

Effect:Effect: Interrupts with the sunlight required by plants & animals of water body & also create Interrupts with the sunlight required by plants & animals of water body & also create Anaerobic conditions.Anaerobic conditions.

Physical Parameters:Physical Parameters:

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3.3. ColourColourMajor Source: Major Source: Domestic, Industrial waste water & natural decay of Domestic, Industrial waste water & natural decay of

organic Matter organic MatterEffect:Effect: Aesthetics of the water body. Aesthetics of the water body.

4.4. OdourOdourMajor Source: Major Source: Domestic, Industrial wasteDomestic, Industrial wasteEffect: Effect: Not acceptableNot acceptable

-- Measurement by sensory methods or specific odorant Measurement by sensory methods or specific odorant concentration methodconcentration method

- Common odorous compounds are- Common odorous compounds areAmines, Ammonia, Diamines, Hydrogen sulphide etcAmines, Ammonia, Diamines, Hydrogen sulphide etc

Physical Parameters:Physical Parameters:

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Classification of Effluent parametersClassification of Effluent parameters Chemical Parameters:Chemical Parameters:5.5. pH, Acidity, Alkalinity:pH, Acidity, Alkalinity:Major Source:Major Source: Domestic, Industrial wasteDomestic, Industrial wasteAcidity & Alkalinity in the waste water are due to….Acidity & Alkalinity in the waste water are due to….

Mineral acids:Mineral acids: Decrease pH & corrosive to many equipmentsDecrease pH & corrosive to many equipmentsOrganic acids:Organic acids: Contribute to BOD & CODContribute to BOD & CODAlkalinity:Alkalinity: includes Significant ions -OH, CO3 & HCO3 of Ca, Mg, Na or Kincludes Significant ions -OH, CO3 & HCO3 of Ca, Mg, Na or K

Effect:Effect: Affect Dissolved Oxygen (DO) concentrationAffect Dissolved Oxygen (DO) concentration & Aquatic Life& Aquatic Life

6.6. Oil & GreaseOil & Grease ( Includes Fatty acid, Soap oils (Vegetable & mineral and waxes):( Includes Fatty acid, Soap oils (Vegetable & mineral and waxes):

Major Source:Major Source: Domestic, Industrial wasteDomestic, Industrial waste

Effect:Effect: --- --- Form a scum layer at the top of water surface and thus interrupting the sunlight & Air Form a scum layer at the top of water surface and thus interrupting the sunlight & Air mixing.mixing. -- Affects performance of biological treatment system because oil layer protects the -- Affects performance of biological treatment system because oil layer protects the air mixing air mixing from the atmosphere, which is required for the microbial growth. from the atmosphere, which is required for the microbial growth.

7.7. Surfactant:Surfactant:Major Source:Major Source: Domestic, Industrial wasteDomestic, Industrial waste

Effect:Effect: Similar to aboveSimilar to above

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Chemical Parameters:Chemical Parameters:

8.8. Pesticides:Pesticides:Major Source: Major Source: Domestic, Industrial wasteDomestic, Industrial waste

Effect:Effect: Similar to aboveSimilar to above

9.9. Nitrogen & Phosphorous:Nitrogen & Phosphorous:Major Source: Major Source: Domestic, Industrial wasteDomestic, Industrial waste

Effect:Effect: Leads to growth of undesirable weeds & Algae –Leads to growth of undesirable weeds & Algae –because N & P are the major because N & P are the major nutrients required for the microbial growth.nutrients required for the microbial growth.

10.10. Heavy Metals:Heavy Metals:Major Source: Major Source: Industrial wasteIndustrial waste

Effect:Effect: Affect Humans & Aquatic life depending on the type of Metal.Affect Humans & Aquatic life depending on the type of Metal.

11.11. GasesGases (H2S & CH4): (H2S & CH4):Major Source: Major Source: Decomposition of the Organic wasteDecomposition of the Organic waste

Effect: Effect: Odour from water bodies, Create anaerobic Conditions & are forming explosive Odour from water bodies, Create anaerobic Conditions & are forming explosive mixture alsomixture also


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Classification of Effluent parametersClassification of Effluent parameters Biological Parameters:Biological Parameters:12.12. Pathogens:Pathogens:Major Source: Major Source: Domestic sewage waterDomestic sewage water

Effect:Effect: cause water borne diseases such as Cholera, cause water borne diseases such as Cholera, dysentery, typhoid etc.dysentery, typhoid etc.

Any presence of pathogen content indicates need Any presence of pathogen content indicates need for disinfection or sterilization.for disinfection or sterilization.

Measured byMeasured byE-coli countE-coli countMost probable Number (MPN)Most probable Number (MPN)

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Classification of Effluent parametersClassification of Effluent parameters Biological Parameters:Biological Parameters:

Measurement of Org. Contents in Waste water:Measurement of Org. Contents in Waste water:

BOD & COD:BOD & COD: T These are very important measurement factor for calculation point of view in W W treatment. hese are very important measurement factor for calculation point of view in W W treatment.

- Are the measurement of Org. Contents in waste water.- Are the measurement of Org. Contents in waste water.- Organic matter is a combination of C, H, O + N, P.- Organic matter is a combination of C, H, O + N, P.- Some of the matter is biodegradable or non- biodegradable.- Some of the matter is biodegradable or non- biodegradable.- Carbohydrates, proteins, fats, certain toxic chemicals & pesticides are some of them.- Carbohydrates, proteins, fats, certain toxic chemicals & pesticides are some of them.

BOD (Measurement of biodegradable organics + oxidizable nitrogen): The term BOD indicates Amt of dissolved O2 required by micro-organisms (bacteria) to decompose org. matter aerobically (in pre. Of O2) in a 5 days at a temp. of 27OC. Or BOD is the amount of oxygen, microbes use (demand) in five days of eating (digesting) a given quantity of sewage.

- If the BOD level is high in the waste water, then more oxygen will be required to decompose the EBOM (Easily biodegradable Organic Matter - pollution). - Complete Oxidn of org. matter takes more than 20 days.- 70% degradation may be completed within an oxdn period of 3 days.

In natural aeration process of waste water treatment, the decomposition of the biodegradable org. In natural aeration process of waste water treatment, the decomposition of the biodegradable org. matter will take about 20 days. Therefore mechanically air will be provided by surface aerator or matter will take about 20 days. Therefore mechanically air will be provided by surface aerator or diffused aerator system.diffused aerator system.

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COD: (Measurement of both biological active and biologically inert organic matter):

It is a wet oxidn method using strong oxidizing agent such as potassium dichromate in the pre. of silver sulphate as catalyst. COD value includes other oxidizable substances such as sulphides, sulphites, ferrous ion etc.

If BOD/COD Ratio > 5 Easily biodegradable matterBOD/COD Ratio =0.3 to 0.5 Fairly biodegradable matter BOD/COD Ratio < 0.3 Poorly biodegradable matter

This ratio is very very important to chose the process of waste water treatment.

Classification of Effluent parametersClassification of Effluent parameters Biological Parameters:Biological Parameters:

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Classification of Effluent parametersClassification of Effluent parametersUseful parameters:Useful parameters:

These parameters are useful for designing & operating point of view for waste water These parameters are useful for designing & operating point of view for waste water treatment.treatment.

Setteable solids:Setteable solids:Useful for Design & Operation of clarifiers inUseful for Design & Operation of clarifiers in- - Assessing sludge storage requirementsAssessing sludge storage requirements- Scheduling Frequency of sludge disposal- Scheduling Frequency of sludge disposal- Finding out the rate of sludge pumping- Finding out the rate of sludge pumping

Total suspended solids (TSS)Total suspended solids (TSS)– Useful for sizing of primary treatment unitsUseful for sizing of primary treatment units

Total Volatile suspended solids (TVSSTotal Volatile suspended solids (TVSS))– Indicates organic portion of TSSIndicates organic portion of TSS– Useful for choice of sludge disposal methodUseful for choice of sludge disposal method

Dissolved solids (Inorganic)Dissolved solids (Inorganic)- - Higher value makes biological treatment difficultHigher value makes biological treatment difficult- Partial / complete removal by Ion Exchange or Membrane- Partial / complete removal by Ion Exchange or Membrane

ProcessProcess

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Effluent Treatment ObjectiveEffluent Treatment Objective Protect / maintain receiving bodies (river or stream, land or Protect / maintain receiving bodies (river or stream, land or

sea)sea)

To avoid/reduce quantity of toxic chemicals transmitted to To avoid/reduce quantity of toxic chemicals transmitted to living beings.living beings.

To meet regulatory requirementTo meet regulatory requirement

To maintain soil quality To maintain soil quality

To maintain quality of aesthetic environmentTo maintain quality of aesthetic environment

To reuse effluentTo reuse effluent

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4. 4. INDUSTRIAL LEGAL COMPLIANCES ON INDUSTRIAL LEGAL COMPLIANCES ON WATER USE & EFFLUENT DISPOSALWATER USE & EFFLUENT DISPOSAL

Before going to waste water treatment procedure we should Before going to waste water treatment procedure we should know the legal compliances on know the legal compliances on water use & the norms of water use & the norms of effluent disposal for Industrial effluent & domestic sewage effluent disposal for Industrial effluent & domestic sewage effluent.effluent.

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4. Industrial Legal Compliances on Water Use & Effluent Disposal4. Industrial Legal Compliances on Water Use & Effluent Disposal

IntroductionIntroduction

A pre-requisite for industrial development is the abundant A pre-requisite for industrial development is the abundant supply of natural resources. The preservation of natural supply of natural resources. The preservation of natural resources therefore assumes importance for sustainable resources therefore assumes importance for sustainable industrial development. Industries create a demand for industrial development. Industries create a demand for water and a sustainable supply of water is possible only if water and a sustainable supply of water is possible only if they are preserved at their natural regenerative level.they are preserved at their natural regenerative level.

The constant demand and use of water for various The constant demand and use of water for various industrial activities not only creates a supply crunch but industrial activities not only creates a supply crunch but also causes pollution of water sources. Measures must be also causes pollution of water sources. Measures must be taken to reduce the demand for water and for prevention of taken to reduce the demand for water and for prevention of water pollution. Industries must comply with legal water pollution. Industries must comply with legal requirements for water use and effluent disposal in order to requirements for water use and effluent disposal in order to not only have sustainable development but also to stop not only have sustainable development but also to stop degradation of environmental resources.degradation of environmental resources.

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The 1The 1stst act is Water act & the act is for prevention of water bodies by pollution. act is Water act & the act is for prevention of water bodies by pollution. 1.1. Water (Prevention and Control of Pollution) Act, 1974Water (Prevention and Control of Pollution) Act, 1974

(Called as Water Act)(Called as Water Act)

is the first meaningful attempt by India to deal with problem is the first meaningful attempt by India to deal with problem of water pollution at the national level. The statement of of water pollution at the national level. The statement of objects and reasons of the Act states that the problem of objects and reasons of the Act states that the problem of pollution of rivers and streams has assumed considerable pollution of rivers and streams has assumed considerable importance and urgency. It seeks to ensure that the importance and urgency. It seeks to ensure that the domestic and industrial effluents are not allowed to be domestic and industrial effluents are not allowed to be discharged into watercourses without adequate treatment. discharged into watercourses without adequate treatment. The Act establishes Central & State Pollution control The Act establishes Central & State Pollution control Boards, which are to monitor water quality, suggest and Boards, which are to monitor water quality, suggest and implement schemes to improve water quality, advice the implement schemes to improve water quality, advice the respective governments, and even take action against respective governments, and even take action against polluters. polluters.

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Section 24 of the Water Act prohibits use of stream or well Section 24 of the Water Act prohibits use of stream or well for disposal of polluting matter. Section 25(1) (a) envisages for disposal of polluting matter. Section 25(1) (a) envisages a permit system or consent procedure to prevent and a permit system or consent procedure to prevent and control water pollution. Accordingly, a person has to obtain control water pollution. Accordingly, a person has to obtain consent from State Board before taking any step towards consent from State Board before taking any step towards establishing any industry, operation or process, any establishing any industry, operation or process, any treatment and disposal system, or any extension or treatment and disposal system, or any extension or addition to such a system, which might result in the addition to such a system, which might result in the discharge of a sewage or trade effluent into a stream, well discharge of a sewage or trade effluent into a stream, well or sewer or onto land. The State Board may condition its or sewer or onto land. The State Board may condition its consent by specifying the location, the construction and consent by specifying the location, the construction and use of the outlet as well as the nature & composition of use of the outlet as well as the nature & composition of new discharges.new discharges.

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Persons contravening the provisions of sec. 24 shall be punishable Persons contravening the provisions of sec. 24 shall be punishable with imprisonment for a term which shall not be less than one year and with imprisonment for a term which shall not be less than one year and six months but which may extend to six years and with fine. The six months but which may extend to six years and with fine. The contravention of the provisions contained in section 25 is punishable contravention of the provisions contained in section 25 is punishable with imprisonment for term not less than one year and six months, with imprisonment for term not less than one year and six months, which may extend to six years and with fine.which may extend to six years and with fine.

2. The Water Cess (Prevention and Control of Pollution Act, 19772. The Water Cess (Prevention and Control of Pollution Act, 1977 (hereinafter called Water Cess Act)(hereinafter called Water Cess Act) does not provide for the does not provide for the mechanism for the control and prevention of water pollution but has mechanism for the control and prevention of water pollution but has been adopted as a part of economic incentive for controlling pollution been adopted as a part of economic incentive for controlling pollution and to augment the resources of the Central and State Boards for and to augment the resources of the Central and State Boards for effective implementation of the provisions of the Water Act, 1974. The effective implementation of the provisions of the Water Act, 1974. The Water Cess Act empowers the Central Government to levy cess on Water Cess Act empowers the Central Government to levy cess on water consumed by persons carrying on certain industries and by local water consumed by persons carrying on certain industries and by local authorities. Water cess is to be taken from an industry only if falls authorities. Water cess is to be taken from an industry only if falls within the ambit of a “specified industry” as mentioned in Schedule I of within the ambit of a “specified industry” as mentioned in Schedule I of the Act.the Act.

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ParticularsParticulars UnitsUnits IndustrialIndustrial Domestic sewageDomestic sewage

pHpH 6.5 to 8.56.5 to 8.5

Total Suspd, SolidsTotal Suspd, Solids mg/lmg/l 5050 3030

Ammonical Nitrogen (N)Ammonical Nitrogen (N) mg/lmg/l 2525

BOD (5 days at 20BOD (5 days at 20ooC)C) mg/lmg/l 5050 2020

CODCOD mg/lmg/l 150150

Oil & GreaseOil & Grease mg/lmg/l 10 10

Nitrate NitrogenNitrate Nitrogen mg/lmg/l 1010

Phenolic compoundsPhenolic compounds mg/lmg/l 11

TemperatureTemperature ooCC 4040

ColourColour unitsunits 5050

Bio Assay testBio Assay test 90% survival of fish after90% survival of fish after

96 hrs in 100% effluent96 hrs in 100% effluent


Norms of GPCB: Norms of GPCB: Gujarat Pollution Control Board, the government body gives some norms for Gujarat Pollution Control Board, the government body gives some norms for the disposal of the waste water generated during specific process.the disposal of the waste water generated during specific process.

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5 STP TREATMENT5 STP TREATMENT

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The treatment capacity classified as:The treatment capacity classified as:

PLANTPLANT Cum/DayCum/Day

Small sized Plant Small sized Plant < 3,000< 3,000Medium sized plant Medium sized plant 3,000 to 15,000 Large 3,000 to 15,000 Large sized plant sized plant > 15,000 > 15,000 (Particularly Municipal STP)(Particularly Municipal STP)

STP TREATMENTSTP TREATMENT

METHODOLOGIESMETHODOLOGIES

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STP TREATMENTSTP TREATMENT

METHODOLOGIES METHODOLOGIES (Cont.)(Cont.)

Sewage is nothing but:Sewage is nothing but:

Water + Organics + In-organics + Micro-Water + Organics + In-organics + Micro-organismsorganisms

So if you remove organics & microbes first So if you remove organics & microbes first then decide extent of in-organic removal.then decide extent of in-organic removal.

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5. SEWAGE TREAT PLANT5. SEWAGE TREAT PLANT PRINCIPLE OF SEWAGE TREATMENT:PRINCIPLE OF SEWAGE TREATMENT:

““Biological system works on Biochemistry principle - from dis-order Biological system works on Biochemistry principle - from dis-order to order, something against Thermodynamics principle.”to order, something against Thermodynamics principle.”

A sewage treatment plant is nothing more than a A sewage treatment plant is nothing more than a LARGE LARGE MICROBIAL CULTURE FLASKMICROBIAL CULTURE FLASK. When a microbiologist . When a microbiologist inoculates a flask of bacterial medium with a culture the inoculates a flask of bacterial medium with a culture the intent is usually to produce more bacteria. However, it can intent is usually to produce more bacteria. However, it can be be VIEWEDVIEWED IN ANOTHER WAYIN ANOTHER WAY. The purpose could be to . The purpose could be to ""USE UP THE NUTRIENTS IN THE MEDIUMUSE UP THE NUTRIENTS IN THE MEDIUM" by " by #METABOLIZING them. During the growth of microbes in a #METABOLIZING them. During the growth of microbes in a medium, the nutrients are oxidized to produce energy and medium, the nutrients are oxidized to produce energy and new microbes. The result of this process converts most of new microbes. The result of this process converts most of the nutrients to chemicals like carbon dioxide, nitrate, the nutrients to chemicals like carbon dioxide, nitrate, sulfate, phosphate; i.e., mineralssulfate, phosphate; i.e., minerals..

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Raw sewage is rich in organic nutrients such as human excrement, and food and industrial wastes. The purpose of a sewage treatment plant is to provide the optimum conditions for SELECTING & UTILIZING MICROBES to convert EASILY BIODEGRADABLE ORGANIC MATTER (EBOM) to mineral forms like carbon dioxide, nitrate, sulfate, and phosphate. This process is also called MINERALIZATION.

Since microbes grow and utilize nutrients most efficiently under AEROBIC CONDITIONS, sewage treatment plants are designed to provide excess OXYGEN for the microbes.

Finally, there is always some material that can not be easily degraded by microbes which SETTLES OUT at various stages in the treatment process. This material is called SLUDGE and it must also be disposed of as part of the sewage treatment process.

5. SEWAGE TREAT PLANT5. SEWAGE TREAT PLANT

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STP TREATMENT FLOW SCHEMESTP TREATMENT FLOW SCHEME

1.1. Pre/Primary-treatmentPre/Primary-treatment

2.2. Secondary treatmentSecondary treatment

3.3. Tertiary / advance treatmentTertiary / advance treatment

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STP TREATMENT FLOW SCHEMESTP TREATMENT FLOW SCHEME PRE/PRIMARY-TREATMENT:PRE/PRIMARY-TREATMENT:

Main Objectives are:Main Objectives are:- To remove coarse & floating solids, grit, oil &- To remove coarse & floating solids, grit, oil & greasegrease-To equalize flow & load variations-To equalize flow & load variations

Methods:Methods: ScreeningScreening Grit removalGrit removal Neutralization & EqualizationNeutralization & Equalization Pre-mixingPre-mixing Stripping (To remove toxic ingredient like sulphides, free ammonia etc.)Stripping (To remove toxic ingredient like sulphides, free ammonia etc.) Oil & Grease removalOil & Grease removal Nutrient dosingNutrient dosing

Mixing requirements:Mixing requirements:0.015 to 0.025 M3 Air/ M3 Tank Volume/ Minute0.015 to 0.025 M3 Air/ M3 Tank Volume/ Minute

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STP TREATMENT FLOW SCHEMESTP TREATMENT FLOW SCHEME Secondary Treatment:Secondary Treatment:

Main Dominating Objective is:Main Dominating Objective is:- to remove Gross organics/ BOD from the waste - to remove Gross organics/ BOD from the waste

waterwater

Method:Method: Give sufficient air to microorganisms Give sufficient air to microorganisms by by

Surface AerationSurface Aerationoror

Diffused AerationDiffused Aeration

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Tertiary or Advance Treatment system:Tertiary or Advance Treatment system:

Objectives:Objectives:– Reclaiming the waste waterReclaiming the waste water– Additional steps depends on what one would like to Additional steps depends on what one would like to

remove (Residual organics, nutrients, TDS, Hardness, remove (Residual organics, nutrients, TDS, Hardness, Microbs or combination of all)Microbs or combination of all)

Commonly applied system:Commonly applied system:

Horticulture:Horticulture: PSF + Disinfection/ Sterilization PSF + Disinfection/ Sterilization

CT Make-up:CT Make-up: PSF + Disinfection/ Sterilization + PSF + Disinfection/ Sterilization + SofteningSoftening(If the Hardness level is high in (If the Hardness level is high in

the TTW)the TTW)

STP TREATMENT FLOW SCHEMESTP TREATMENT FLOW SCHEME

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Trends in Biological Waste Water Treatment Trends in Biological Waste Water Treatment MethodsMethods

Overview:Overview:We cannot judge correctly the performance of We cannot judge correctly the performance of STP/ETP bySTP/ETP by

- Fulfilling - Fulfilling “Regulatory requirement”.“Regulatory requirement”.

But byBut by- reusing & recycling and even to re-- reusing & recycling and even to re-

charging it to protect local ground water charging it to protect local ground water resources.resources.(In general some industrialist think in a way that- Install STP & Fulfill regulatory requirement by (In general some industrialist think in a way that- Install STP & Fulfill regulatory requirement by

providing Lab. analysis. But the correct way is that – to reuse & recycle the treated water.)providing Lab. analysis. But the correct way is that – to reuse & recycle the treated water.)

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Trends in Biological Waste Water Treatment MethodsTrends in Biological Waste Water Treatment Methods

Pre-requisites for any biological process to work Pre-requisites for any biological process to work properly:properly:

This is v v imp.

pH:pH: 6.5 to 8.5 6.5 to 8.5 (because in this range of pH, we achieved more Microbial growth. On (because in this range of pH, we achieved more Microbial growth. On lower/higher the pH, the useful bacteria required for the W W treatment will die or inactive)lower/higher the pH, the useful bacteria required for the W W treatment will die or inactive)

Temp: 15 to 37 deg. C Temp: 15 to 37 deg. C ( 35 deg C temp is ideal for microbial growth)( 35 deg C temp is ideal for microbial growth)

Nutrient:- Nutrient:- BOD:N:P RatioBOD:N:P Ratio =100:5:1 for aerobic OR=100:5:1 for aerobic OR 100:2.5:0.5 100:2.5:0.5

for anaerobic for anaerobic

Toxics (No presence of Heavy Metal, No presence of Toxic Toxics (No presence of Heavy Metal, No presence of Toxic Organics/In-organics)Organics/In-organics)

No presence of SolventsNo presence of Solvents

Salinity<8,000 mg/L as Cl or TDS<15,000 mg/LSalinity<8,000 mg/L as Cl or TDS<15,000 mg/L

Organic & Hydraulic Load Balance ProperlyOrganic & Hydraulic Load Balance Properly

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Trends in Biological Waste Water Treatment MethodsTrends in Biological Waste Water Treatment MethodsPathway of Organic Degradation:Pathway of Organic Degradation:

In any oxidation reduction process there should be one electron donor & one In any oxidation reduction process there should be one electron donor & one electron acceptor. In the waste water treatment most of the cases waste water electron acceptor. In the waste water treatment most of the cases waste water containing org. matter itself is the ele. donor and ele. acceptor can be either O2 containing org. matter itself is the ele. donor and ele. acceptor can be either O2 or inorganic compound containing O2 like nitrate, sulphate etc. So they can or inorganic compound containing O2 like nitrate, sulphate etc. So they can also get reduced. In some cases Carbonic matter itself can be ele. acceptor. So also get reduced. In some cases Carbonic matter itself can be ele. acceptor. So depending upon the ele acceptor the process can be divided in different depending upon the ele acceptor the process can be divided in different categories.categories.

Aerobic Process: Aerobic Process: O2 is the final electron acceptor & org matter releases the ele. O2 is the final electron acceptor & org matter releases the ele. During the process lot of energy will be released. That will be utilised for the During the process lot of energy will be released. That will be utilised for the metabolic purpose of the cell.metabolic purpose of the cell.(C,H,O,N) + Microbes (C,H,O,N) + Microbes CO2 + H2O + New cells + Energy

Anaerobic Process: Anaerobic Process: Organic matter itself acting as the ele acceptor & get Organic matter itself acting as the ele acceptor & get reduced to methane gas.reduced to methane gas.

Two step processTwo step processStage:1Stage:1(C,H,O,N) + Microbes(C,H,O,N) + Microbes CO2 + H2O + Volatile Acids + New CO2 + H2O + Volatile Acids + New

cells – Energy + H2S + NH3cells – Energy + H2S + NH3Stage:2Stage:2Volatile acids + Microbes Volatile acids + Microbes CH4 + CO2 + Energy + New Cells CH4 + CO2 + Energy + New Cells

(3(3rdrd process is Anoxic process. In this process nitrification & de-nitrification of Ammonia will process is Anoxic process. In this process nitrification & de-nitrification of Ammonia will occurs, where Ammonia is converted to Nitrate & Nitrate is converted to N2 gas by de-occurs, where Ammonia is converted to Nitrate & Nitrate is converted to N2 gas by de-nitrification process)nitrification process)

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TRENDS IN WASTE WATER TREATMENT:TRENDS IN WASTE WATER TREATMENT:

Following technologies are popularly knownFollowing technologies are popularly known

1.1. Activated sludge processActivated sludge process

2.2. Trickling FiltersTrickling Filters

3.3. Rotating Biological Contactors. Sequential Rotating Biological Contactors. Sequential Batch Reactors (SBR)Batch Reactors (SBR)

4.4. Membrane Biological Reactors (MBR)Membrane Biological Reactors (MBR)

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THEORY OF SEWAGE TREATMENTTHEORY OF SEWAGE TREATMENT(Activated sludge process)(Activated sludge process)

The activated sludge process is a biological waste water The activated sludge process is a biological waste water treatment technique in which a mixture of waste water and treatment technique in which a mixture of waste water and biological sludge (micro organism) is agitated and aerated biological sludge (micro organism) is agitated and aerated for a period of time until a large mass of settable solids for a period of time until a large mass of settable solids forms. Then this biological solids are subsequently forms. Then this biological solids are subsequently separated from the waste water and returned to the separated from the waste water and returned to the aeration process as needed. When air is continuously aeration process as needed. When air is continuously injected into the waste water, micro organisms are mixed injected into the waste water, micro organisms are mixed thoroughly with the organic. Micro organisms stimulate thoroughly with the organic. Micro organisms stimulate their growth through use of the organic as food. As the their growth through use of the organic as food. As the micro organism grow and are mixed by agitation of the air, micro organism grow and are mixed by agitation of the air, the individual organism clump together to form an active the individual organism clump together to form an active mass of microbes called "Activated Sludge".mass of microbes called "Activated Sludge".

““In short, the activated sludge is a mixture of In short, the activated sludge is a mixture of suspended solids & microorganisms having high suspended solids & microorganisms having high activities.”activities.”

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STEP -ISTEP -I:: The first stage is the The first stage is the PRE TREATMENTPRE TREATMENT.. In this treatment In this treatment

the raw sewage coming out of the end of the sewage line the raw sewage coming out of the end of the sewage line runs into a large Inlet Chamber. While in this chamber the runs into a large Inlet Chamber. While in this chamber the sewage flow slows down enough, so that heavy materials sewage flow slows down enough, so that heavy materials like sand grit and stones settle out and it passes through like sand grit and stones settle out and it passes through bars or screens which collect large floating debris like cloth, bars or screens which collect large floating debris like cloth, polyethylene bags, sticks, condoms, sanitary napkins etcpolyethylene bags, sticks, condoms, sanitary napkins etc

This type of waste is removed because it can damage the This type of waste is removed because it can damage the sensitive equipment in the sewage treatment plant. sensitive equipment in the sewage treatment plant.

Parshall flume is provided to measure inlet flow. Parshall flume is provided to measure inlet flow. (ultrasonic flow meter)(ultrasonic flow meter)

The The EFFLUENTEFFLUENT flows into the flows into the Aeration Tank.Aeration Tank.

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Step-2: SECONDARY TREATMENTStep-2: SECONDARY TREATMENT

Is the main treatment because here we remove BOD from the W Water. So Environmental Is the main treatment because here we remove BOD from the W Water. So Environmental condition required for microbiological growth in aeration tank is VV imp factor.condition required for microbiological growth in aeration tank is VV imp factor.

Environmental condition required for microbiological growth:Environmental condition required for microbiological growth:

Secondary treatment is a biological treatment. So we should know what are the Secondary treatment is a biological treatment. So we should know what are the environmental condition conducive for microorganisms. So we have to create environmental condition conducive for microorganisms. So we have to create conducive environment for the microorganisms, otherwise our system will not be conducive environment for the microorganisms, otherwise our system will not be performing better. performing better.

Nutrients & Energy:Nutrients & Energy: Any microbiological growth required nutrients & Energy. Any microbiological growth required nutrients & Energy. Nutrients is essential for supplying carbon molecule for creation of the cell. And Nutrients is essential for supplying carbon molecule for creation of the cell. And the required energy will be coming from photosynthesis in the presence of the required energy will be coming from photosynthesis in the presence of sunlight or Oxdn & Redn process. For oxdn & redn process one should be e sunlight or Oxdn & Redn process. For oxdn & redn process one should be e donor & other should be e acceptor. In aerobic system organic matter means donor & other should be e acceptor. In aerobic system organic matter means waste water itself will be e donor. It will be passing through series of cell & finally waste water itself will be e donor. It will be passing through series of cell & finally the e should be accepted by the system. In some cases the e should be accepted by the system. In some cases nutrient nutrient itself will be itself will be accepting the e or some time it will be accepting the e or some time it will be Oxygen.Oxygen.

pH: pH: AtAt Low of 3 & high of 10 pH most of the microorganisms will die. The Low of 3 & high of 10 pH most of the microorganisms will die. The suitable pH for microbial activities in this treatment is from 6.5 to 8.5.suitable pH for microbial activities in this treatment is from 6.5 to 8.5.

Temperature: Temperature: Microbiological activities will be reducing at low & high temp. The Microbiological activities will be reducing at low & high temp. The suitable temp for the microbiological activities in waste water treatments is from suitable temp for the microbiological activities in waste water treatments is from 35 to 37 deg C.35 to 37 deg C.

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Step-2:SECONDARY TREATMENT (CONT.)Step-2:SECONDARY TREATMENT (CONT.)

Aeration Tanks:Aeration Tanks:The main object of this treatment is to reduce the bio-degradable organic matter The main object of this treatment is to reduce the bio-degradable organic matter contributing to BOD and COD. The additional advantage is simultaneous removal of contributing to BOD and COD. The additional advantage is simultaneous removal of suspended solids and colloidal solids.suspended solids and colloidal solids.

Organic matter + Active sludge + DO (Aeration) Stable compounds acceptable Organic matter + Active sludge + DO (Aeration) Stable compounds acceptable to biosphere + increased concentration of biomassto biosphere + increased concentration of biomass

The stable compounds can be CO2, H2O, NO3The stable compounds can be CO2, H2O, NO3-, -, PO4PO4-3-3

Process:Process:

Here effluent is mixed with the tank content having biological mass. Initially the required Here effluent is mixed with the tank content having biological mass. Initially the required quantity of bio-mass is developed by adding sewage/cow dung into the aeration tank. quantity of bio-mass is developed by adding sewage/cow dung into the aeration tank. The micro organisms present in the biomass /sludge is utilized (consumed) the organic The micro organisms present in the biomass /sludge is utilized (consumed) the organic matter as their food and degrade them to simple form of water and carbon dioxide. The matter as their food and degrade them to simple form of water and carbon dioxide. The suspended colloidal solids is converted to liquid form/soluble form which can be utilized suspended colloidal solids is converted to liquid form/soluble form which can be utilized by the micro-organisms. The oxygen required for this process of oxidation is supplied by by the micro-organisms. The oxygen required for this process of oxidation is supplied by the mechanical surface aerators or diffused aerators. To maintain MLSS around 3,000-the mechanical surface aerators or diffused aerators. To maintain MLSS around 3,000-4,000, the required quantity of sludge is recirculated from secondary clarifier, by 4,000, the required quantity of sludge is recirculated from secondary clarifier, by pumping. pumping.

The entire mixture is mixed vigorously by enormous quantities of air. As a result of this The entire mixture is mixed vigorously by enormous quantities of air. As a result of this the microbes rapidly convert (oxidize) most of the the microbes rapidly convert (oxidize) most of the EBOMEBOM to the mineral state and in the to the mineral state and in the process most of the pathogens die. process most of the pathogens die.

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Step-2:SECONDARY TREATMENT (Cont.)Step-2:SECONDARY TREATMENT (Cont.)

Secondary Clarifier:Secondary Clarifier:

Object:Object: The main purpose of this tank is to remove The main purpose of this tank is to remove biological solids from the aerated mixed liquor from the biological solids from the aerated mixed liquor from the aeration tanks.aeration tanks.

Process:Process:

The clarifier tank is a continuous flow basin in which the The clarifier tank is a continuous flow basin in which the aerated mixed effluent is allowed to flow slowly and aerated mixed effluent is allowed to flow slowly and continuously through the central column. During the continuously through the central column. During the course of passing from center to sides, sedimentation of course of passing from center to sides, sedimentation of biologically flocculated solids takes place. The settled biologically flocculated solids takes place. The settled sludge is collected in the sludge pockets from where it is sludge is collected in the sludge pockets from where it is recycled to Aeration Tank to maintain MLSS or is wasted recycled to Aeration Tank to maintain MLSS or is wasted to Sludge drying beds. The clear water from the over flow to Sludge drying beds. The clear water from the over flow weir is collected in the Collection Pit.weir is collected in the Collection Pit.

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Step-3 :TERTIARY TREATMENTStep-3 :TERTIARY TREATMENT DisinfectionDisinfection : :

Sufficient Sufficient CHLORINECHLORINE is added in the collection pit to kill most the is added in the collection pit to kill most the common bacterial pathogens that have survived the previous common bacterial pathogens that have survived the previous treatments.treatments.

Filtration:Filtration:Sand filtration removes much of the residual suspended matter. Sand filtration removes much of the residual suspended matter. Filtration over activated carbon removes residual toxins. Filtration over activated carbon removes residual toxins.

The treated water is thenThe treated water is then- recycled to cooling tower makeup after passing from - recycled to cooling tower makeup after passing from PSF/DMF & further chlorination.PSF/DMF & further chlorination.- used for Horticulture purpose.- used for Horticulture purpose.- released into the environment, usually a nearby - released into the environment, usually a nearby stream, river, lake or the ocean. stream, river, lake or the ocean.

This treatment however, does not kill (This treatment however, does not kill (STERILIZESTERILIZE) all of the pathogens ) all of the pathogens present so it is unwise to frolic in the water around the sewage outfall.present so it is unwise to frolic in the water around the sewage outfall.

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SLUDGE TREATMENT:SLUDGE TREATMENT: Sludge Drying Beds:

Anything that SETTLES OUT and is subsequently collected during the sewage treatment process is called SLUDGE.

Objective: - SDB are provided for dewatering excess sludge by metal & Sand

filter media- The filtrate from the SDB will be taken to aeration tank through

filtrate pit & pumps- The sludge becomes sludge cake on drying under sun light by

means of evaporation.

Unit Description: The bottom of the rectangular SDB is sloping towards the centre with centrally laid open jointed pipe for collecting the filtrate. The filtrate media is of metal layers with a thick sand layer provided above it.

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SLUDGE TREATMENT (Cont.)SLUDGE TREATMENT (Cont.)

Anaerobic Treatment Of sludge:(In this treatment- in fermentation tank we can produce Methane gas from the sludge,)(In this treatment- in fermentation tank we can produce Methane gas from the sludge,)

Fermentation Tank: Sludge treatment involves an ANAEROBIC PROCESS

that converts 50% of the organic sludge mainly into methane gas, and some carbon dioxide. To do this the sludge, a disgusting-looking thick black soup, is pumped into large ENCLOSED tanks. Here it is allowed to FERMENT for several weeks while being gently stirred. During this time anaerobic bacteria convert 50% of the organic matter into methane gas.

More modern sewage plants utilize this methane for useful purposes from running city vehicles to heating buildings.

See the slide and U will get another use/ misuse of the methane gas.See the slide and U will get another use/ misuse of the methane gas.

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SLUDGE TREATMENT (Cont.):SLUDGE TREATMENT (Cont.):

Where to use Sludge????

in many European city the amount of daily dried sludge produced is so huge that it threatens to cover the city or at least a nearby county or two. Disposing of this sludge presents a really interesting challenge; you might even say large cities are "SLUDGE CHALLENGED".

It can be burned (contributing to air pollution), buried into TOXIC LAND FILLS (contributing to ground water pollution) or dumped into the ocean (contributing to their degradation).

If it is safe (no heavy metals, toxic organic chemicals and the pathogens killed) it makes an excellent fertilizer for lawns and farms.

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Common Bacteria in Activated Sludge are:Common Bacteria in Activated Sludge are:

PseudomonasPseudomonas

ZooglocaZoogloca

ArthrobactorArthrobactor

BacillusBacillus

CytophagaCytophaga

AcinetobacterAcinetobacter

NitrosomonasNitrosomonas

Nitrobactor etc.Nitrobactor etc.

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Calculation of BOD load in domestic Sewage:

Water consumption = 150 l/p/d (Lit per person per day)

Per capita BOD= 45 to 55 grm

BOD= 45/150 = 300 mg/lit (in domestic sewage)

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Terms used in biological waste water treatment processTerms used in biological waste water treatment process MLSS (Mixed Liquor Suspended Solids) & MLVSS (Mixed Liquor Volatile

Suspended Solids) :) : – terms are used to express the microbes concentration.terms are used to express the microbes concentration.– MLSS contains microbes mixed with inorganic substance like Clay, silts, fine sands etc.MLSS contains microbes mixed with inorganic substance like Clay, silts, fine sands etc.– Whereas MLVSS measure true microbes concentration.Whereas MLVSS measure true microbes concentration.

Estimation of MLSS: Estimation of MLSS: – The MLSS is determined by filtering the sample through a glass fiber disk. The residue The MLSS is determined by filtering the sample through a glass fiber disk. The residue

retain in the filter is dried to constant weight at 103 deg. Cent in hot air oven.retain in the filter is dried to constant weight at 103 deg. Cent in hot air oven.– MLSS MLSS mg/Lmg/L = (A-B) x 1000 / Sample volume = (A-B) x 1000 / Sample volume mlml

A= Wt of filter paper + dried residue A= Wt of filter paper + dried residue mg mg & B= Wt of filter paper& B= Wt of filter paper mg mg

Estimation of MLVSS:Estimation of MLVSS: – The residue of MLSS is ignited to constant weight at 550 deg Cent. In furnace & The residue of MLSS is ignited to constant weight at 550 deg Cent. In furnace &

calculated as above equation.calculated as above equation.

The estimation gives rough approximation of the The estimation gives rough approximation of the amount of organic matteramount of organic matter present in the solid fraction of present in the solid fraction of the activated sludgethe activated sludge..

In practice, the MLVSS concentration is generally maintained In practice, the MLVSS concentration is generally maintained 80%80% of MLSS for of MLSS for satisfactory performance of waste water treatment plant.satisfactory performance of waste water treatment plant.

– For Example If MLSS Conc. Is 3500 mg/L, then MLSS should maintain 3500 x For Example If MLSS Conc. Is 3500 mg/L, then MLSS should maintain 3500 x 0.8 = 2800 mg/L 0.8 = 2800 mg/L

The MLSS value is used for calcn of design parameters like substrate utilization The MLSS value is used for calcn of design parameters like substrate utilization rate, F/M ratio, solid retention time , recirculation ratio etc.rate, F/M ratio, solid retention time , recirculation ratio etc.

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Terms used in biological waste water treatment processTerms used in biological waste water treatment process

F/M Ratio:F/M Ratio: (Food to Microorganism ratio):– is one of the process controlling parameters as well as design parameters.

– Express as kg BOD applied / Kg of MLVSS per day (I.e. day-1)

– F/M ratio = Influent BOD conc. mg/LX Influent waste water flow rate m3/day

Vol. of aeration Tank m3 X MLVSS mg/L

= Influent BOD conc. mg/L

HRT days X MLVSS mg/L

Because Hydraulic retention = Vol of aeration Tank m3

time HRT days Influent waste water flow rate m3/day

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Example F/M ratioExample F/M ratio An activated sludge process (ASP) receives influent BOD of 300 mg/L An activated sludge process (ASP) receives influent BOD of 300 mg/L

in aeration tank with a flow of 5 MGD. The detention time is 6 hrs and in aeration tank with a flow of 5 MGD. The detention time is 6 hrs and MLSS concentration is 3000 mg/L. Calculate F/M ratio.MLSS concentration is 3000 mg/L. Calculate F/M ratio.

F/M ratio = Influent BOD conc. mg/L

HRT day X MLVSS mg/L

= 300 mg/L

6 /24 day X 2400 mg/L

= 0.5 day-1

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Calculation for 3 MLD Sewage Treatment Plant:

Design flow (Av.): Say 3 MLD (3000 cum/ day) 125 cum/hrPeak flow is 3 times higher than average flow

Inlet BOD conc: Say 150 mg/l (design for 3 timed higher)Outlet BOD: 20 mg/l

F/M ratio: 0.15 MLSS: Say 4,000 mg/l

O2 provided: 2 kg/kg of BOD

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Calculation for 3 MLD Sewage Treatment Plant:

Calculation for Aeration Tank:Volume= BOD kg/day/ (F/M x MLSS kg/cum)

BOD Load = Flowin x BODin = 3000 cum x 150 mg/l = 450 kg/dayVolume of Aeration tank = 450/ (0.15 x 4)= 750 cum

BOD removed = Flow (BODin –BODout)3 MLD (150-20) = 390 Kg/ day

O2 required = 390 x 2 = 780 kg/ day

Air required = 780/24 x 0.232 x 1.2 x 0.6 x 0.3 = 648.5 m3/hr Where 0.232 is the oxygen content in air1.2 is the density of air0.6 is the field correction for diffuser arrangement0.3 is standard oxygen transfer efficiency of offered diffuser

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Typical loading rate for sewage purificationTypical loading rate for sewage purification

Process

Type

MLSS mg/l F/M ratio HRT hrs BOD removal

efficiency%

Conventional 1,500 to 3,000

0.3 to 0.4 4 to 6 85 to 92

Extended Aeration

3,000 to 5,000

0.1 to 0.18 12 to 24 95 to 98

Highly extended Aeration

3,500 to 4,500

0.4 to 0.08 24 to 36 98 to 99.5

Lower F/M ratio means the microbes are in starved condition, the food will be easily assimilated and hence removal efficiency is fast.

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Process controlProcess control MLSS Drops below 2500 ppmMLSS Drops below 2500 ppm

– The drop will not occur suddenly, but will be indicated by a gradual drop The drop will not occur suddenly, but will be indicated by a gradual drop over a period of days. This indicates that bacterial population in the over a period of days. This indicates that bacterial population in the aeration tank is decreasing because ofaeration tank is decreasing because of

– insufficient aeration.insufficient aeration.

– insufficient food insufficient food

– Shock load of pollutantsShock load of pollutants

– Change in pH of effluent (fatal for biological system)Change in pH of effluent (fatal for biological system)

– REMADIAL MEASURES:REMADIAL MEASURES:

– Check the diffuser system

– Increase the volume of return sludge to aeration system. If still MLSS is not increased, add externally cow dung or domestic waste to increase the MLSS level.

– Analyzed influent for ppm ratio of N2, P, C and any toxic material.

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Process controlProcess control Stoppage of effluent flow:Stoppage of effluent flow:

– If for some reason the flow into the aeration tank stops, the aeration If for some reason the flow into the aeration tank stops, the aeration should be continued. And for long stoppage, the activated sludge should be continued. And for long stoppage, the activated sludge system should be kept in ACTIVE condition by adding alternative system should be kept in ACTIVE condition by adding alternative source of organic load. (cow dung)source of organic load. (cow dung)

DO (Dissolved Oxygen) Control:DO (Dissolved Oxygen) Control:– The DO level in the aeration tank should be at about 0.5 to 1.5 mg/L The DO level in the aeration tank should be at about 0.5 to 1.5 mg/L

- to ensure proper oxidation of organic matter by - to ensure proper oxidation of organic matter by microbsmicrobs

- to maintain residual dissolved oxygen- to maintain residual dissolved oxygen

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What is our What is our THRESHOLD THRESHOLD limit for digesting limit for digesting poison??poison??

We all are habituated to drink highly purified mineral water. We all are habituated to drink highly purified mineral water. But what about the water we take for bath, inhale from air, But what about the water we take for bath, inhale from air, use in kitchen & laundry purpose!!!!use in kitchen & laundry purpose!!!!

""Frog in the Frying PanFrog in the Frying Pan". ". If you place a frog in a shallow frying pan, from which he If you place a frog in a shallow frying pan, from which he could easily escape. Slowly turn up the temperature, the could easily escape. Slowly turn up the temperature, the frog will remain in the pan until it eventually frog will remain in the pan until it eventually DIES FROM DIES FROM THE HEATTHE HEAT. The reason he doesn't jump out is that his . The reason he doesn't jump out is that his heat-sensing system doesn't respond to heat-sensing system doesn't respond to ABSOLUTE ABSOLUTE TEMPERATURETEMPERATURE, but only to , but only to incremental changesincremental changes in in temperature larger than a certain amount. So by keeping temperature larger than a certain amount. So by keeping the changes the changes BELOWBELOW this this THRESHOLDTHRESHOLD of detection the of detection the frog never realizes he is being cooked to death.frog never realizes he is being cooked to death.

AT LASTAT LAST

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THANK THANK YOUYOU

for your time and attention.for your time and attention.

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ACTIVATED SLUDGE PROCESSACTIVATED SLUDGE PROCESS::


Sludge DryingBed

SecondaryClarifier

CollectionPit

CL2

COOLING TOWER MAKE UP

PSFDMF

CL2

RAW SEWAGE INLET

Grit

Bar Screen Grit Chambr

InletChamber

AerationTank

AIRActivated

Sludge

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NEXTNEXTEXTRA SLIDEEXTRA SLIDE

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Good morning every body. Thanks to invite me in this one week Good morning every body. Thanks to invite me in this one week short term training program on treatment & disposal of waste water short term training program on treatment & disposal of waste water organized by Chem & Civil dept of SVNIT, Surat. Particularly Dr A.K. organized by Chem & Civil dept of SVNIT, Surat. Particularly Dr A.K. Mungary & Dr Mausmi Chakraborty, Thanks.Mungary & Dr Mausmi Chakraborty, Thanks.

11stst I introduce myself. I am Atul R, Bhatt, My basic qualification is I introduce myself. I am Atul R, Bhatt, My basic qualification is M.Sc in Organic chemistry from School of science, Guj Uni. A’bd. M.Sc in Organic chemistry from School of science, Guj Uni. A’bd. Now I am working in KRIBHCO as a Manager (P) in Offsites Now I am working in KRIBHCO as a Manager (P) in Offsites Department.Department.

The term offsites means the Department which is “Off the sites”. The term offsites means the Department which is “Off the sites”. Because this Dept provides all the Utilities like air, water & Nitrogen Because this Dept provides all the Utilities like air, water & Nitrogen to process plants & treats effluent, generated by urea & ammonia to process plants & treats effluent, generated by urea & ammonia main process plants and power & Product handling plant. main process plants and power & Product handling plant.

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THE VOCABULARY OF WATER MICROBIOLOGY THE VOCABULARY OF WATER MICROBIOLOGY WATER FACTOIDSWATER FACTOIDS POTABLE (CLEAN) WATERPOTABLE (CLEAN) WATER = Water that is free of all = Water that is free of all objectionable objectionable

materialmaterial, including pathogens, tastes, odors, color, minerals, toxins, , including pathogens, tastes, odors, color, minerals, toxins, radioactive material, organisms, oils, gases etc. It can contain high radioactive material, organisms, oils, gases etc. It can contain high concentrations of some minerals (e.g. calcium and magnesium) and concentrations of some minerals (e.g. calcium and magnesium) and gases like carbon dioxide; the key word being gases like carbon dioxide; the key word being OBJECTIONABLEOBJECTIONABLE. . That is, it doesn't have to be toxic or contain pathogens for it to be That is, it doesn't have to be toxic or contain pathogens for it to be non-potablenon-potable. .

FRESH WATERFRESH WATER = non-salt or -sea water. = non-salt or -sea water. POLLUTIONPOLLUTION = Anything that makes water NON-POTABLE (does not = Anything that makes water NON-POTABLE (does not

have to be a poison or pathogen). have to be a poison or pathogen). SEWAGESEWAGE = = The combined community waste or all the GARBAGE that The combined community waste or all the GARBAGE that

mother nature and we dump into the sewers of a community.mother nature and we dump into the sewers of a community.


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SOME HISTORY OF LAVATORIES AND SEWAGE SOME HISTORY OF LAVATORIES AND SEWAGE SYSTEMS:SYSTEMS:

Our ancestors may have been Our ancestors may have been technologically technologically challengedchallenged, but they were not stupid. It was easy to deal , but they were not stupid. It was easy to deal with human waste when all you had to do was step a few with human waste when all you had to do was step a few yards into the woods to answer the call of nature, but as yards into the woods to answer the call of nature, but as towns and the population grew in size, the woods became towns and the population grew in size, the woods became too distant for routine visits. too distant for routine visits.

The first recorded toilets and sewers were built around The first recorded toilets and sewers were built around 3,000 BC in several parts of the world, including the 3,000 BC in several parts of the world, including the Orkney Islands and India/Pakistan. A system of channels Orkney Islands and India/Pakistan. A system of channels on the Orkney Islands drained wastes from toilets in the on the Orkney Islands drained wastes from toilets in the homes into the sea, whereas cities in India/ Pakistan built homes into the sea, whereas cities in India/ Pakistan built open drains 2 ft deep by 7-10 inches wide along major open drains 2 ft deep by 7-10 inches wide along major streets through which the wastes were flushed away; many streets through which the wastes were flushed away; many of these open sewers are still in use today. of these open sewers are still in use today.

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The Romans, being a social people, favored The Romans, being a social people, favored communal toilets that could seat 10 to 20 communal toilets that could seat 10 to 20 people in public lavatories located over people in public lavatories located over flowing water to carry the wastes away. It is flowing water to carry the wastes away. It is reported that they carried out business and reported that they carried out business and politics in these facilities. Perhaps this led to politics in these facilities. Perhaps this led to the idea expressed by many that politics is the idea expressed by many that politics is ""in the toiletin the toilet". ".


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There are TWO major designs of SECONDARY sewage treatment plants (STP).

These are called the ACTIVATED SLUDGE and the TRICKLING FILTER systems. Each of them achieve the SAME EFFICIENCY of treatment, but they use different DESIGNS for doing so.


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43 to 49

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STEPS: TRICKLING FILTER:STEPS: TRICKLING FILTER:

STEP ISTEP I: The first two stages in : The first two stages in BOTHBOTH designs are designs are the the SAMESAME. . The first stage is the The first stage is the PRELIMINARY PRELIMINARY TREATMENTTREATMENT.. In this treatment the raw sewage In this treatment the raw sewage coming out of the end of the sewage line runs into coming out of the end of the sewage line runs into a large tank. While in this tank the sewage flow a large tank. While in this tank the sewage flow slows down enough so that heavy materials like slows down enough so that heavy materials like sand and rock settle out and it passes through sand and rock settle out and it passes through bars or screens which collect large floating debris bars or screens which collect large floating debris like cloth, sticks etc. The like cloth, sticks etc. The EFFLUENTEFFLUENT (any liquid (any liquid that flows OUT of one container and INTO that flows OUT of one container and INTO another) flows into the another) flows into the PRIMARY SETTLING PRIMARY SETTLING TANKTANK. .


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STEPS: TRICKLING FILTER (Cont.) :STEPS: TRICKLING FILTER (Cont.) : STEP IISTEP II: The : The PRIMARY SETTLING TANKPRIMARY SETTLING TANK

is a large tank where the flow of sewage is a large tank where the flow of sewage slows down to the point where slows down to the point where LARGER LARGER PIECES OF ORGANIC MATTERPIECES OF ORGANIC MATTER settle out settle out as as SLUDGESLUDGE. These tanks also contain a . These tanks also contain a skimmer that picks up smaller floating skimmer that picks up smaller floating material, the majority of which are used material, the majority of which are used condoms. We will deal with the sludge later.condoms. We will deal with the sludge later.


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Challenges to Wastewater Challenges to Wastewater ReuseReuse

WWTP

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STEPS: TRICKLING FILTER (Cont.) :STEPS: TRICKLING FILTER (Cont.) :

STEP IIISTEP III: The third step in the process involves the : The third step in the process involves the AEROBIC AEROBIC metabolism of the metabolism of the EBOMEBOM. In the TRICKLING . In the TRICKLING FILTER design this is achieved by spraying the effluent FILTER design this is achieved by spraying the effluent from the primary settling tank over a 4 to 6 foot pile of large from the primary settling tank over a 4 to 6 foot pile of large inert blocks of material such as rocks, cement blocks, inert blocks of material such as rocks, cement blocks, redwood blocks etc. (Fig. 5A & B). The spraying saturates redwood blocks etc. (Fig. 5A & B). The spraying saturates the effluent sewage with oxygen and air circulates between the effluent sewage with oxygen and air circulates between the blocks. The inert blocks become coated with a layer of the blocks. The inert blocks become coated with a layer of microbes that are microbes that are SELECTEDSELECTED because they because they GROW WELLGROW WELL in the sewage (Fig. 5B). This is another example the in the sewage (Fig. 5B). This is another example the evolutionary principle of "#SURVIVAL OF THE FITTEST". evolutionary principle of "#SURVIVAL OF THE FITTEST". These microbes absorb the nutrients from the sewage as it These microbes absorb the nutrients from the sewage as it trickles over them and oxidizes (metabolizes) the EBOM to trickles over them and oxidizes (metabolizes) the EBOM to minerals. Finally the effluent flows into the minerals. Finally the effluent flows into the SECONDARY SECONDARY SETTLING TANKSETTLING TANK (Fig. 6). Also (Fig. 6). Also 99.9%99.9% of the pathogens of the pathogens are killed during this step. are killed during this step.


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STEPS: TRICKLING FILTER (Cont.) :STEPS: TRICKLING FILTER (Cont.) :

STEP IVSTEP IV: The tank's design is similar to that : The tank's design is similar to that of the primary settling tank (Fig 4). Large of the primary settling tank (Fig 4). Large debris, consisting mostly of chunks of debris, consisting mostly of chunks of microbial growth that flakes off the inert microbial growth that flakes off the inert blocks, settles out in this tank as sludge. blocks, settles out in this tank as sludge. The effluent next flows into the The effluent next flows into the CHLORINATION BASINCHLORINATION BASIN. .


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STEPS: ACTIVATED SLUDGE :STEPS: ACTIVATED SLUDGE :

Steps I, II, IV & V are the same as those described for the TRICKLING FILTER Steps I, II, IV & V are the same as those described for the TRICKLING FILTER treatment, only step III is different. The principle behind the activated sludge treatment, only step III is different. The principle behind the activated sludge treatment is the treatment is the ADDITIONADDITION of a microbial inoculum to the effluent from the of a microbial inoculum to the effluent from the primary settling tank composed OF primary settling tank composed OF HUNGRYHUNGRY MICROBESMICROBES that have been that have been SELECTEDSELECTED for their ability to grow vigorously on the sewage nutrients in the for their ability to grow vigorously on the sewage nutrients in the raw sewage. This selection is achieved by raw sewage. This selection is achieved by COLLECTING THE SLUDGECOLLECTING THE SLUDGE from from the secondary settling tank (step IV, Fig. 7) and mixing approximately 10% of it the secondary settling tank (step IV, Fig. 7) and mixing approximately 10% of it with the incoming effluent from the primary settling tank (Fig. 4). This sludge with the incoming effluent from the primary settling tank (Fig. 4). This sludge consists of large gelatinous clumps (consists of large gelatinous clumps (FLOCSFLOCS) of microbes that grow in the ) of microbes that grow in the aeration tanks. When this is done properly the microbes in the sludge are aeration tanks. When this is done properly the microbes in the sludge are healthy, but healthy, but RAVENOUSLY HUNGRYRAVENOUSLY HUNGRY; something like college students after a ; something like college students after a full day of exciting learning. These famished sludge microbes chow down with full day of exciting learning. These famished sludge microbes chow down with unrestrained enthusiasm on the juicy sewage (a sort of microbial beer and unrestrained enthusiasm on the juicy sewage (a sort of microbial beer and pizza meal) to which they are added. The entire mixture is mixed vigorously in pizza meal) to which they are added. The entire mixture is mixed vigorously in large 20 feet deep tanks through which enormous quantities of air are large 20 feet deep tanks through which enormous quantities of air are BUBBLEDBUBBLED; sort of like a ; sort of like a huge fish tankhuge fish tank without the fish. These tanks are called without the fish. These tanks are called AERATION TANKSAERATION TANKS, for obvious reasons. As a result of this the microbes , for obvious reasons. As a result of this the microbes rapidly convert (oxidize) most of the rapidly convert (oxidize) most of the EBOMEBOM to the mineral state and in the to the mineral state and in the process most of the pathogens die. process most of the pathogens die.


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STEPS: ACTIVATED SLUDGE (Cont.):STEPS: ACTIVATED SLUDGE (Cont.):

Design of an aeration tank. The air, under pressure is pumped into the tanks and vigorously mixed with the sewage to insure that the material always remains aerobic. Otherwise the stench would cause the neighbors to burn the place down. On the far left, some of the activated sludge that has settled out in the secondary settling tank is mixed with the fresh, incoming, sewage from the primary settling tank. The activated sludge contains hungry microbes that immediately chow-down on all that yummy fresh sewage--makes your mouth water at the thought doesn't it?


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STEPS: ACTIVATED SLUDGE (Cont.):STEPS: ACTIVATED SLUDGE (Cont.):

STEP VSTEP V: Sufficient : Sufficient CHLORINECHLORINE is added to the is added to the effluent of the secondary settling tank to kill most effluent of the secondary settling tank to kill most the common bacterial pathogens that have the common bacterial pathogens that have survived the previous treatments. The treated survived the previous treatments. The treated effluent is then released into the environment, effluent is then released into the environment, usually a nearby stream, river, lake or the ocean. usually a nearby stream, river, lake or the ocean. This treatment however, does not kill (This treatment however, does not kill (STERILIZESTERILIZE) ) all of the pathogens present so it is unwise to frolic all of the pathogens present so it is unwise to frolic in the water around the sewage outfall. in the water around the sewage outfall.


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SLUDGE TREATMENT:SLUDGE TREATMENT: Anything that Anything that SETTLES OUTSETTLES OUT and is subsequently collected during the sewage treatment process is and is subsequently collected during the sewage treatment process is

called called SLUDGESLUDGE. All of the sludge is collected in one place and treated separately from the rest of the . All of the sludge is collected in one place and treated separately from the rest of the sewage material. Sludge treatment involves an sewage material. Sludge treatment involves an ANAEROBIC PROCESSANAEROBIC PROCESS that converts 50% of the that converts 50% of the organic sludge mainly into methane gas, and some carbon dioxide. To do this the sludge, a disgusting-organic sludge mainly into methane gas, and some carbon dioxide. To do this the sludge, a disgusting-looking thick black soup, is pumped into large looking thick black soup, is pumped into large ENCLOSEDENCLOSED tanks. Here it is allowed to tanks. Here it is allowed to FERMENT FERMENT for for several weeks while being gently stirred. During this time anaerobic bacteria convert 50% of the organic several weeks while being gently stirred. During this time anaerobic bacteria convert 50% of the organic matter into methane gas. matter into methane gas.

Figure 10. Pullman STP dried sludge bed.Figure 10. Pullman STP dried sludge bed. It is about 2 acres in size and approximately 6 feet deep. It is about 2 acres in size and approximately 6 feet deep. Pullman sludge is of excellent quality and is safe to use as a fertilizer on farms. Several farms in the Pullman sludge is of excellent quality and is safe to use as a fertilizer on farms. Several farms in the area request that the undigested sludge be sprayed on their fields. You can usually spot a sewage area request that the undigested sludge be sprayed on their fields. You can usually spot a sewage plant by the presence of one or more large round tanks with a continuous flame burning beside it; this plant by the presence of one or more large round tanks with a continuous flame burning beside it; this flame is kept burning by the continuous production of the flame is kept burning by the continuous production of the METHANEMETHANE gas. More modern sewage plants gas. More modern sewage plants utilize this methane for useful purposes from running city vehicles to heating buildings. utilize this methane for useful purposes from running city vehicles to heating buildings.

At this point 50% of the original sludge's organic material remains At this point 50% of the original sludge's organic material remains UNDIGESTEDUNDIGESTED and must be and must be DISPOSEDDISPOSED of. Usually this sludge, which comes out a very thick black soup, is pumped into shallow of. Usually this sludge, which comes out a very thick black soup, is pumped into shallow excavations in the ground and allowed to dry. Alternatively, if it is safe, it can be pumped onto crop land excavations in the ground and allowed to dry. Alternatively, if it is safe, it can be pumped onto crop land and used as fertilizer. The dried material is called and used as fertilizer. The dried material is called DRIED SLUDGEDRIED SLUDGE (talk about a lack of imagination!). (talk about a lack of imagination!). In Pullman and Moscow this is not a lot of this muck, but in places like L.A., Seattle and New York the In Pullman and Moscow this is not a lot of this muck, but in places like L.A., Seattle and New York the amount of daily dried sludge produced is so huge that it threatens to cover the city or at least a nearby amount of daily dried sludge produced is so huge that it threatens to cover the city or at least a nearby county or two. Disposing of this sludge presents a really interesting challenge; you might even say county or two. Disposing of this sludge presents a really interesting challenge; you might even say large cities are "large cities are "SLUDGESLUDGE CHALLENGEDCHALLENGED". It can be burned (contributing to air pollution), buried into ". It can be burned (contributing to air pollution), buried into TOXIC LAND FILLSTOXIC LAND FILLS (contributing to ground water pollution) or dumped into the ocean (contributing to (contributing to ground water pollution) or dumped into the ocean (contributing to their degradation). If it is safe (no heavy metals, toxic organic chemicals and the pathogens killed) it their degradation). If it is safe (no heavy metals, toxic organic chemicals and the pathogens killed) it makes an excellent fertilizer for lawns and farms. makes an excellent fertilizer for lawns and farms.


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COMPARISON OF THE TWO STPs:COMPARISON OF THE TWO STPs: Both designs are EQUALLY EFFICIENT at removing about 85 to 95% of the input EBOM and both

destroy about 99.9% of the pathogens. Both FINAL EFFLUENTS have the same composition and are rich in mineral nutrients like phosphate, nitrate and sulfate. Their initial and operational costs are however different. Generally, TRICKLING FILTER plants are less expensive to build and to run if land is not EXPENSIVE as they do not require the pumping of large quantities of air into aeration tanks. Conversely, activated sludge systems are more expensive to build and operate. However, the advantage of the activated sludge system is that it can treat LARGER VOLUMES of sewage in a SMALLER SPACE than can TRICKLING FILTER systems and it is more flexible. Activated sludge aeration tanks can be stacked up in buildings whereas TRICKLING FILTER systems can not. Since most land near cities (where the sewage is!) these days is darn near worth its weight in gold, activated sludge systems are replacing TRICKLING FILTER systems. A prime example of that is seen in Moscow where they have installed an activated sludge system to supplement the TRICKLING FILTER system.

Neither of the two secondary treatment plants do the following: They do NOT KILL ALL THE PATHOGENS, particularly certain viruses and protozoan spores that

survive passage through the entire plant. They do NOT DIGEST MANY MAN-MADE ORGANIC CHEMICALS such as pesticides and

herbicides. They do NOT REMOVE TOXIC METALS like cadmium, mercury, and lead. Rather these chemicals,

which usually come from industrial processes, end up in the sludge. It does NOT PRODUCE POTABLE WATER. Any water that comes out of the pipe of a secondary

sewage treatment plant must be further treated before it is safe to drink; (If you saw the movie Water World, the opening scene illustrated the recycling of waste).

They do NOT REMOVE RADIOACTIVE MATERIALS. Treatment may change its chemical form but the radioactivity is a characteristic of an atom.


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NutrientNutrient removal:removal: Wastewater may also contain high levels of nutrients (nitrogen and Wastewater may also contain high levels of nutrients (nitrogen and phosphorus) that in certain forms may be toxic to Aqua culture. It may also phosphorus) that in certain forms may be toxic to Aqua culture. It may also create growth of weed or algae in the receiving environment. Algae can create growth of weed or algae in the receiving environment. Algae can produce toxins, and their death and consumption by bacteria (decay) can produce toxins, and their death and consumption by bacteria (decay) can deplete oxygen in the water and suffocate desirable fish. The removal of deplete oxygen in the water and suffocate desirable fish. The removal of nitrogen and/or phosphorus from wastewater can be achieved either nitrogen and/or phosphorus from wastewater can be achieved either biologically or by chemical precipitation. biologically or by chemical precipitation.

Nitrogen removal is effected through the biological reduction of nitrogen from Nitrogen removal is effected through the biological reduction of nitrogen from the ammonia to nitrate (nitrification), and then from nitrate to nitrogen gas (de-the ammonia to nitrate (nitrification), and then from nitrate to nitrogen gas (de-nitrification), which is released to the atmosphere. nitrification), which is released to the atmosphere.

Phosphorus removal can be effected biologically in a process called enhanced Phosphorus removal can be effected biologically in a process called enhanced biological phosphorus removal. In this process specific bacteria, called biological phosphorus removal. In this process specific bacteria, called Polyphosphate accumulating Organisms, are selectively enriched and Polyphosphate accumulating Organisms, are selectively enriched and accumulate large quantities of phosphorus within their cells. When the biomass accumulate large quantities of phosphorus within their cells. When the biomass enriched in these bacteria is separated from the treated water, the bacterial enriched in these bacteria is separated from the treated water, the bacterial bio-solids have a high fertilizer value. Phosphorus removal can also be bio-solids have a high fertilizer value. Phosphorus removal can also be achieved, usually by chemical precipitation with salts of iron (e.g. ferric achieved, usually by chemical precipitation with salts of iron (e.g. ferric chloride) or aluminum (e.g. alum). The resulting chemical sludge, however, is chloride) or aluminum (e.g. alum). The resulting chemical sludge, however, is difficult to dispose of, and the use of chemicals in the treatment process is difficult to dispose of, and the use of chemicals in the treatment process is expensive and makes operation difficult and often messy. expensive and makes operation difficult and often messy.

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Disinfection Disinfection The purpose of disinfection in the treatment of wastewater is to substantially reduce the number of The purpose of disinfection in the treatment of wastewater is to substantially reduce the number of living organisms in the water to be discharged back into the environment. The effectiveness of living organisms in the water to be discharged back into the environment. The effectiveness of disinfection depends on the quality of the water being treated (e.g., turbitidy, pH, etc.), the type of disinfection depends on the quality of the water being treated (e.g., turbitidy, pH, etc.), the type of disinfection being used, the disinfectant dosage (concentration and time), and other environmental disinfection being used, the disinfectant dosage (concentration and time), and other environmental variables. Turbid water will be treated less successfully since solid matter can shieldorganisms, variables. Turbid water will be treated less successfully since solid matter can shieldorganisms, especially from Ultraviolet light or if contact times are low. Generally, short contact times, low doses especially from Ultraviolet light or if contact times are low. Generally, short contact times, low doses and high flows all militate against effective disinfection. Common methods of disinfection include and high flows all militate against effective disinfection. Common methods of disinfection include ozone, chlorine, or UV light. Chloramine, which is used for drinking water, is not used in waste water ozone, chlorine, or UV light. Chloramine, which is used for drinking water, is not used in waste water treatment because of its persistence. treatment because of its persistence.

Chlorination remains the most common form of wastewater disinfection in due to its low cost and Chlorination remains the most common form of wastewater disinfection in due to its low cost and long-term history of effectiveness. One disadvantage is that chlorination of residual organic material long-term history of effectiveness. One disadvantage is that chlorination of residual organic material can generate chlorinated-organic compounds that may be carcinogenic or harmful to the can generate chlorinated-organic compounds that may be carcinogenic or harmful to the environment. Residual chlorine or chloramines may also be capable of chlorinating organic material environment. Residual chlorine or chloramines may also be capable of chlorinating organic material in the natural aquatic environment. Further, because residual chlorine is toxic to aquatic species, the in the natural aquatic environment. Further, because residual chlorine is toxic to aquatic species, the treated effluent must also be chemically dechlorinated, adding to the complexity and cost of treated effluent must also be chemically dechlorinated, adding to the complexity and cost of treatment. treatment.

Ultraviolet (UV) Light is becoming the most common means of disinfection because of the concerns Ultraviolet (UV) Light is becoming the most common means of disinfection because of the concerns about the impacts of chlorine in chlorinating residual organics in the wastewater and in chlorinating about the impacts of chlorine in chlorinating residual organics in the wastewater and in chlorinating organics in the receiving water. UV radiation is used to damage the genetic structure of bacteria, organics in the receiving water. UV radiation is used to damage the genetic structure of bacteria, viruses, and other pathogens, making them incapable of reproduction. The key disadvantages of UV viruses, and other pathogens, making them incapable of reproduction. The key disadvantages of UV disinfection are the need for frequent lamp maintenance and replacement and the need for a highly disinfection are the need for frequent lamp maintenance and replacement and the need for a highly treated effluent to ensure that the target microorganisms are not shielded from the UV radiation (i.e., treated effluent to ensure that the target microorganisms are not shielded from the UV radiation (i.e., any solids present in the treated effluent may protect microorganisms from the UV light). any solids present in the treated effluent may protect microorganisms from the UV light).

Ozone O3 is generated by passing oxygen O2 through a high voltage potential resulting in a third Ozone O3 is generated by passing oxygen O2 through a high voltage potential resulting in a third oxygen atom becoming attached and forming O3. Ozone is very unstable and reactive and oxidizes oxygen atom becoming attached and forming O3. Ozone is very unstable and reactive and oxidizes most organic material it comes in contact with, thereby destroying many disease-causing most organic material it comes in contact with, thereby destroying many disease-causing microorganisms. Ozone is considered to be safer than chlorine because, unlike chlorine which has to microorganisms. Ozone is considered to be safer than chlorine because, unlike chlorine which has to be stored on site (highly poisonous in the event of an accidental release), ozone is generated onsite be stored on site (highly poisonous in the event of an accidental release), ozone is generated onsite as needed. Ozonation also produces fewer disinfection by-products than chlorination. A as needed. Ozonation also produces fewer disinfection by-products than chlorination. A disadvantage of ozone disinfection is the high cost of the ozone generation equipment and the disadvantage of ozone disinfection is the high cost of the ozone generation equipment and the requirements for highly skilled operators. requirements for highly skilled operators.

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2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER 2. WATER & EFFLUENT MANAGEMENT IN NITROGENEOUS FERTILISER UNIT:UNIT:

Various Effluent in Nitrogenous Fertilizer Unit:Various Effluent in Nitrogenous Fertilizer Unit: Urea Plants:


Oil

skim

mer

Urea trted

Effluent Pond

ChromateSludgesettlingpond


pond

Balancing pond


Urea wastewater

UreaPlant

Distillationtower

Hydrolysersection

MB inDM Plant

Boiler Feed water M/up

Urea UpsetEffluent

Co

lle

cti

on

pit Alkali

dosingAmmo.

StrippingTower

Am

mo

nia

Fix

ing P

itOilyeffluent Oil recovery

treatment & disposal of waste water

Education

ssttaattee ccoo

hazira fertiliser plant

ffiinnaall rrss

ssaavviinngg rrss

birth of kribhco

aasssseesssseedd ww

ww kkeelllloogg

various industries