Envi Sanitation (Waste Water Treatment)Slide 1

8/8/2019 Envi Sanitation (Waste Water Treatment)Slide 1

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ENVIRONMENTAL SANITATIONENVIRONMENTAL SANITATION

Involves controlling theInvolves controlling the aspects of Wasteaspects of WasteManagement Management that may lead tothat may lead to

transmission of diseasestransmission of diseases Included in the term waste management Included in the term waste management

areare

WATERWATER SOLID WASTESOLID WASTE

INDUSTRIAL WASTEINDUSTRIAL WASTE



Environmental sanitation also covers the topic of Environmental sanitation also covers the topic of POLLUTIONPOLLUTION

According to WHO (World Health Organization) According to WHO (World Health Organization)there are three areas that must be reviewed inthere are three areas that must be reviewed inorder for environmental sanitation to beorder for environmental sanitation to beeffectiveeffective

Water SupplyWater Supply SanitationSanitation

Hygiene EducationHygiene Education



Sources Of WaterSources Of Water

Water supply can play a huge part inWater supply can play a huge part inpollution and spread of diseasepollution and spread of disease

The common sources of water includesThe common sources of water includes1)RAIN WATER1)RAIN WATER

2)SURFACE WATER2)SURFACE WATER

3)GROUND WATER (Wells and Springs)3)GROUND WATER (Wells and Springs)Ground water can be the least threateningGround water can be the least threatening

of all potable waterof all potable water



Rain water and Surface waterRain water and Surface water are oftenare oftenconsidered theconsidered the least potableleast potable and in need of and in need of

water treatment before human consumptionwater treatment before human consumption The most The most threatening source of water is surfacethreatening source of water is surface

water.water. If waste is not disposed off properly it If waste is not disposed off properly it can mix with water on the ground that may becan mix with water on the ground that may be

collected for drinking and cookingcollected for drinking and cooking Contamination can be caused by human wasteContamination can be caused by human waste

and household trashand household trash



Where does the water comeWhere does the water comefrom? from?

surface waters (lakes, rivers, and reservoirs) groundwater (wells).



Consumption of tainted water can lead to newConsumption of tainted water can lead to newdisease outbreaks and spread of current disease outbreaks and spread of current

outbreaksoutbreaks When factories or businesses dispose off When factories or businesses dispose off chemical and physical wastes in the ways that chemical and physical wastes in the ways that directly affect the water supply it is oftendirectly affect the water supply it is oftenreferred to asreferred to as industrial pollutionindustrial pollution

Dumping site may be away, but drainage andDumping site may be away, but drainage andrainfall may cause waste to mix with waterrainfall may cause waste to mix with watersupplysupply



When proper water treatment methodsWhen proper water treatment methodsand waste disposal methods are followedand waste disposal methods are followed

disease and pollution can be reduceddisease and pollution can be reduced



Factors affecting the per captiaFactors affecting the per captia

demand (l/hr/day) of water supplydemand (l/hr/day) of water supply Size of the citySize of the city ------------ small citiessmall cities consumption lessconsumption less

large townslarge towns------ huge quantity of water are required for maintaining healthyhuge quantity of water are required for maintaining healthyand clean environment and clean environment------------commercial and industrial activitiescommercial and industrial activities ----------airaircooled housescooled houses

Climatic conditionsClimatic conditions ------ hotter and dry placeshotter and dry places------consumption more, (bathing,consumption more, (bathing,sprinkling in lawns garden, air conditioning)sprinkling in lawns garden, air conditioning) Economic status of the consumersEconomic status of the consumers------ rich and upper classrich and upper class------ consumptionconsumption

more, middle classmore, middle class--------average consumption, poor slumsaverage consumption, poor slums -------- lowlowconsumptionconsumption

Industrial and commercial activitiesIndustrial and commercial activities ------ more consumptionmore consumption Quality of water suppliesQuality of water supplies

Based on the distribution systemBased on the distribution system supply for the whole daysupply for the whole day or for the peakor for the peakperiod during morning and eveningperiod during morning and evening

Cost of waterCost of water



Characteristics of drinking waterCharacteristics of drinking water

Physical ,chemical and biological characteristicsPhysical ,chemical and biological characteristics

PHYSICALPHYSICAL ------ 1) Turbidity1) Turbidity --------muddy appearancemuddy appearance

of waterof water------------due to the presence of suspendeddue to the presence of suspendedmatters like clay silt etc. Permissible valuematters like clay silt etc. Permissible value-------- 55to 10ppmto 10ppm

2)Taste & Odor2)Taste & Odor

3)Temperature3)Temperature potable water desired temppotable water desired temp 101000CC



Chemical characteristicsChemical characteristics

Suspended solidsSuspended solids

Acidity Acidity------ presence of mineral acidspresence of mineral acids

Alkalinity Alkalinity ------ carbonates and bicarbonatescarbonates and bicarbonatesof calcium and magnesiumof calcium and magnesium

pHpH permissiblepermissible ------ 6.6 to 8.5(close to 7)6.6 to 8.5(close to 7)

higher pHhigher pH ------ problem during chlorinationproblem during chlorination

low pHlow pH ------ corrosion in pipecorrosion in pipe



Hardness of waterHardness of water -------- temporary andtemporary andpermanent hardnesspermanent hardness

Temporary hardnessTemporary hardness or carbonate hardnessor carbonate hardness ------Its caused by the carbonate and bicarbonates of Its caused by the carbonate and bicarbonates of calcium and magnesiumcalcium and magnesium

Permanent or non carbonate hardnessPermanent or non carbonate hardness ItsIts

caused by the sulphates, chlorides and nitratescaused by the sulphates, chlorides and nitratesof calcium and magnesiumof calcium and magnesium



Permissible hardness for public waterPermissible hardness for public watersupplies normally ranges between 75 tosupplies normally ranges between 75 to

115 mg/l or ppm (14.25 mg/l is equivalent 115 mg/l or ppm (14.25 mg/l is equivalent to one degree of hardness)to one degree of hardness)

hardnesshardness----------75 ppm75 ppm----soft watersoft water

hardnesshardness----------200ppm200ppm----hard waterhard waterdesirabledesirable-------------- 7575 115 ppm115 ppm



Chloride content Chloride content ------ present in the water in thepresent in the water in theform of sodium chloridesform of sodium chlorides------------ due to pollutiondue to pollution

from industries, sea water, domestic sewagefrom industries, sea water, domestic sewagePermissible chloride content not greater thanPermissible chloride content not greater than

250ppm for public water supplies250ppm for public water supplies

Metals and other chemical substancesMetals and other chemical substances leadlead

,arsenic Hg,arsenic Hg------permissible amount zeropermissible amount zero

Dissolved gasesDissolved gases HH22S, OS, O22 etcetc





WATER TREATMENTWATER TREATMENT

Water treatment describes those processes usedWater treatment describes those processes usedto make water more acceptable for a desiredto make water more acceptable for a desired

end useend use These can include use as drinking water,These can include use as drinking water,

Industrial processes, medical uses etc.Industrial processes, medical uses etc.

The goal of all water treatment processes is toThe goal of all water treatment processes is to

remove the existingremove the existing contaminantscontaminants in water or toin water or toreduce the concentrationreduce the concentration of contaminants soof contaminants sothat water becomes fit for its desired end usethat water becomes fit for its desired end use



Water Treatment ProcessesWater Treatment Processes

Processes involved in treating the water forProcesses involved in treating the water fordrinking purpose may be solid separation usingdrinking purpose may be solid separation using

physical processesphysical processes such assuch as settling and filtrationsettling and filtrationandand

chemical processeschemical processes such assuch as disinfectiondisinfection andandcoagulationcoagulation

Biological processesBiological processes involved in the treatment of involved in the treatment of waste water includeswaste water includes Aerated lagoons, Activated Aerated lagoons, Activatedsludge or slow sand filterssludge or slow sand filters



POTABLE WATER PURIFICATIONPOTABLE WATER PURIFICATION

Water purification is the removal of contaminants fromWater purification is the removal of contaminants fromuntreated water, that is pure enough for its intendeduntreated water, that is pure enough for its intendeduse, most commonly human consumptionuse, most commonly human consumption

SubstancesSubstances removed during the processes of drinkingremoved during the processes of drinkingwater treatment includewater treatment include

Suspended solidsSuspended solids BacteriaBacteria

Algae Algae Viruses Viruses FungiFungi



Minerals ( Iron ,Manganese & Sulphur)Minerals ( Iron ,Manganese & Sulphur)

ManMan--made chemical pollutants includingmade chemical pollutants including

fertilizersfertilizers



Processes For Drinking WaterProcesses For Drinking Water

Combination of the following processes is usedCombination of the following processes is usedfor the municipal waste water treatment for the municipal waste water treatment

worldwideworldwide PrePre--chlorinationchlorination-- for algae control and arrestingfor algae control and arresting

any biological growthany biological growth

Aeration Aeration--along with prealong with pre--chlorination for thechlorination for the

removal of dissolved iron and manganeseremoval of dissolved iron and manganese

CoagulationCoagulation--for flocculationfor flocculation





DesalinationDesalination-- Process of removing salt Process of removing salt from waterfrom water

DisinfectionDisinfection-- for killing bacteriafor killing bacteria



Raw Water

Storage

Mixing FlocculationSedimentation

Filtration

Clear Well

Distribution

Ozonation

Surface Water Treatment Plant Surface Water Treatment Plant

Coagulant, pH AdjustmentDisinfectant (Cl2, NaOCl)



Water Treatment Water Treatment

W ater treatment transforms raw surface and groundwater into safe drinking water.

W ater treatment involves two major processes:

physical removal of solids and chemical disinfection.

COAGULATION:

WATER TOWARDS

SEDIMENTATION

C oagulation removes dirt and other particles suspended in water.

alum and other chemicals are added to water to form tiny sticky

particles called ´flocµ which attract the dirt particles. T he combined

weight of the dirt and the alums (floc) becomes heavy enough to sink

to the bottom during sedimentation.



Water Treatment Water Treatment WATER F ROM

COAGULATION

WATER TOWARDS

F ILTRATION

Coagu l a t a rti l f a ll, g r av it , t r ough a t r i

a ttli g t ank and accumu l a t a t t he o tt om o f t he

t ank , c l ea ri ng t he a t e r o f much o f t he o li d deb ri

and c l ea r a t e r moves t o filtr a ti on .

SEDIMENTATION:



Water Treatment Water Treatment FILTRATION, DISINFECTION & STORAGE:

F ILTRATION : T he water passes through filters, some

made of layers of sand, and charcoal that help

remove smaller particles.

DISIN F ECTION : A small amount of chlorine

is added or some other disinfection

method is used to kill microorganisms

that may be in the water.

STORAGE : W ater is placed in a

closed tank or reservoir

for disinfection to take

pace. T he water then

flows through pipes to

home and business in the

community

WATER

F ROM

SEDIMENTATI

ON



Water Disinfection Water Disinfection

Purpose of disinfection:

T o make D rinking water free of any disease causing

bacteria and microbes.

Methods of disinfection:

T here are 3 mainly used disinfection methods at

large scale.

CHLORINATION

OZONATION

ULTRAVIOLET RADIATION



CHLORINAT ION CHLORINAT ION

C hlorine is the most common cost-effective means

of disinfecting water

T he addition of a small amount of chlorine is highly

effective against most bacteria, viruses, and

protozoa.

But cysts (durable seed-like stages) formed by

parasitic protozoa such as C ryptosporidium and

G iardia can survive chlorine .

C hlorine is applied to water in one of three forms:

elemental chlorine (chlorine gas), hypochlorite

solution (bleach), or dry calcium hypochlorite. All

three forms produce free chlorine in water



Types of ChlorinationTypes of Chlorination

Depending on the quantity of chlorineDepending on the quantity of chlorineadded or the stage at which it is added oradded or the stage at which it is added orthe results of chlorinationthe results of chlorination

PLAIN CHLORINATIONPLAIN CHLORINATIONPRE CHLORINATIONPRE CHLORINATION

POST CHLORINATIONPOST CHLORINATION

DOUBLE CHLORINATIONDOUBLE CHLORINATION

SUPER CHLORINATIONSUPER CHLORINATION

DECHLORINATIONDECHLORINATION



PLAIN CHLORINATIONPLAIN CHLORINATION

Raw water fed to the distribution systemRaw water fed to the distribution systemafter chlorine treatment alone.after chlorine treatment alone.

Removes organic matter, bacteria and color.Removes organic matter, bacteria and color. For water relatively free from suspendedFor water relatively free from suspended

matter (turbidity < 20matter (turbidity < 20--30 mg/L)30 mg/L)

Used in emergencies alsoUsed in emergencies also

Dosage chlorine range from 0.5Dosage chlorine range from 0.5--1.0mg/lit 1.0mg/lit may be required to give the residual chlorinemay be required to give the residual chlorinein range of 0.1in range of 0.1--0.2mg/lit 0.2mg/lit



PRE CHLORINATIONPRE CHLORINATION The application of chlorine to raw waterThe application of chlorine to raw water

before any other treatment to improve thebefore any other treatment to improve thecoagulation & to remove the taste, odor, &coagulation & to remove the taste, odor, &

colorcolor Reduces load on filtersReduces load on filters

Chlorine dosage adjusted to get 0.1Chlorine dosage adjusted to get 0.1--0.50.5

mg/L of residual chlorine. Normal dosage 5mg/L of residual chlorine. Normal dosage 5 --10 mg/L10 mg/L

Always followed by post chlorination Always followed by post chlorination



POST CHLORINATIONPOST CHLORINATION

Application of chlorine to treated water Application of chlorine to treated waterafter all the other treatment.after all the other treatment.

After filtration and before water enters After filtration and before water entersdistribution systemdistribution system

Disinfection,Disinfection, prevents recontaminationprevents recontamination

Dosage chlorine range from 0.25Dosage chlorine range from 0.25--5.0mg/lit 5.0mg/lit in order to obtain the combine residualin order to obtain the combine residualchlorine in range of 0.1chlorine in range of 0.1--0.2mg/lit 0.2mg/lit

Contact periodContact period 20 minutes20 minutes



Double ChlorinationDouble Chlorination

Chlorination twiceChlorination twice

Involves both pre and post chlorinationInvolves both pre and post chlorination

Used when water is highly turbid andUsed when water is highly turbid andcontaminatedcontaminated



Super ChlorinationSuper Chlorination

Addition of excessive amount of chlorine Addition of excessive amount of chlorine(5(5 15 mg/L to give 115 mg/L to give 1 2 mg/L of 2 mg/L of

residual beyond break point residual beyond break point Special cases of highly polluted water orSpecial cases of highly polluted water or

during epidemicsduring epidemics

Additional doses may be used Additional doses may be used



DechlorinationDechlorination

Removing chlorine from waterRemoving chlorine from water

Used when super chlorination is doneUsed when super chlorination is done

To give a chlorine residual of 0.1To give a chlorine residual of 0.1 0.20.2mg/Lmg/L

Sulphur dioxide gasSulphur dioxide gas

Sodium thiosulphateSodium thiosulphate

Sodium sulphateSodium sulphate



OZONAT ION OZONAT ION

OZONE is S trongest oxidant/disinfectant available.

M ore effective against microbes than chlorination.

But, costly and difficult to monitor and control under

different condition.

Ozonation process:

O zone (o3) is generated on-site

at water treatment facilities by passing dry oxygen or air

through a system of high voltage

electrodes.



U LT RAVIOLE T RAD IAT ION U LT RAVIOLE T RAD IAT ION

N ow a days emerging technology

made UV radiation to find a place

in both household and large scale

drinking water disinfection.

How is UV light generated?

U ltraviolet light is most typically generated

from a low pressure or a medium pressure lamp

generating UV light.



There isThere is no unique solutionno unique solution (selection of (selection of processes) for any type of waterprocesses) for any type of water

Also it is difficult to standardize the solution in Also it is difficult to standardize the solution inthe form of water from different sourcesthe form of water from different sources

Treatability methodsTreatability methods for each source of water infor each source of water indifferent seasons has to be carried out todifferent seasons has to be carried out toapproach appropriate processes .The aboveapproach appropriate processes .The abovementioned technologies are well developed andmentioned technologies are well developed andgeneralized designs are available which are usedgeneralized designs are available which are usedby many water utilities (public or private)by many water utilities (public or private)



Schematic diagram for treatment Schematic diagram for treatment

processes for drinking waterprocesses for drinking water



Characteristics of domestic sewageCharacteristics of domestic sewage

Design of a sewage treatment works depends onDesign of a sewage treatment works depends onthe quantity and quality of the waste to bethe quantity and quality of the waste to betreatedtreated

The following are the important characteristicsThe following are the important characteristics Organic MatterOrganic Matter-- Most important pollutingMost important polluting

component of sewagecomponent of sewage Composed of proteins, carbohydrates and fatsComposed of proteins, carbohydrates and fats

Measured in terms of BOD and CODMeasured in terms of BOD and COD Biological stabilization of organic matter leads toBiological stabilization of organic matter leads to

depletion of oxygen in water bodiesdepletion of oxygen in water bodies



Nitrogen And PhosphorousNitrogen And Phosphorous-- Important pollutingImportant pollutingconstituent of sewageconstituent of sewage

Role inRole in algal growth and eutrophicationalgal growth and eutrophication of lakesof lakes

Nitrogen present in domestic sewage is in theNitrogen present in domestic sewage is in theform of form of proteinaceous matter ureaproteinaceous matter urea (Organic(OrganicNitrogen)Nitrogen)

Its decomposition by bacteria readily changesIts decomposition by bacteria readily changes

intointo Ammonia Ammonia In Aerobic environments ammonia nitrogen isIn Aerobic environments ammonia nitrogen isoxidized into Nitrates and Nitritesoxidized into Nitrates and Nitrites



Nitrates can be used by algae to formNitrates can be used by algae to formplant proteinsplant proteins

Nitrogen is commonly measured asNitrogen is commonly measured as TKNTKN(Organic +ammoniacal)(Organic +ammoniacal)

Also measured in the form of Also measured in the form of nitrates andnitrates and

nitritesnitrites



PhosphorousPhosphorous present in the form of present in the form of orthophosphate, polyphosphate andorthophosphate, polyphosphate and

organic phosphate formsorganic phosphate forms Organically bound phosphorous is of littleOrganically bound phosphorous is of little

importance in domestic sewageimportance in domestic sewage

PolyphosphatePolyphosphate form undergo hydrolysis toform undergo hydrolysis torevert in to orthophosphate formsrevert in to orthophosphate forms



Suspended SolidsSuspended Solids represents therepresents the fraction of fraction of total solidstotal solids that can be settled gravitationallythat can be settled gravitationally

Can be classified intoCan be classified into organic (volatileorganic (volatile) and) andinorganic (fixed) fractionsinorganic (fixed) fractions

Organic matter present in the form of Organic matter present in the form of settelablesettelableandand non settelablenon settelable (dissolved or colloidal form)(dissolved or colloidal form)

If suspended solids in sewage is dischargedIf suspended solids in sewage is dischargeduntreated into streams it untreated into streams it leads to sludgeleads to sludgedeposits and subsequently anaerobic conditionsdeposits and subsequently anaerobic conditions



Dissolved OxygenDissolved Oxygen

Bacterial parameter (fecal coli form)Bacterial parameter (fecal coli form)

Presence of coliform organisms is taken asPresence of coliform organisms is taken asan indication of presence of pathogenican indication of presence of pathogenicorganisms and absence of coliformorganisms and absence of coliform

organism is taken as an indication that organism is taken as an indication that water is free from disease producingwater is free from disease producingorganisms.organisms.



SEWAGE TREATMENT (Primary,SEWAGE TREATMENT (Primary,

Secondary)Secondary) Sewage treatmentSewage treatment, or, or domestic domestic

wastewater treatmentwastewater treatment, is the process of , is the process of removingremoving contaminantscontaminants fromfrom wastewaterwastewater andand

household sewage, bothhousehold sewage, both runoff runoff ((effluentseffluents) and) anddomestic. It includes physical, chemical, anddomestic. It includes physical, chemical, andbiological processes to remove physical,biological processes to remove physical,chemical and biological contaminants. Itschemical and biological contaminants. Itsobjective is to produce a waste stream (orobjective is to produce a waste stream (or

treatedtreated effluent effluent ) and a solid waste or) and a solid waste or sludgesludgesuitable for discharge or reuse back into thesuitable for discharge or reuse back into theenvironment environment



Origins of sewageOrigins of sewage

Sewage is created by residential, commercial,Sewage is created by residential, commercial,institutional and industrial establishments whichinstitutional and industrial establishments whichincludesincludes

Household wasteHousehold waste

Liquid from bathrooms ,toilets, showers,Liquid from bathrooms ,toilets, showers,kitchens, sinks via sewerskitchens, sinks via sewers

Contaminants includes soil ,sediments, heavyContaminants includes soil ,sediments, heavymetals, organic compounds, oil grease, animalmetals, organic compounds, oil grease, animalwastes etc.wastes etc.



Process flow diagram for a sewageProcess flow diagram for a sewage

treatment plant treatment plant



Pretreatment Pretreatment

Equalization and neutralization tanksEqualization and neutralization tanks equalization tank for dilutingequalization tank for dilutingpolluted effluent & is a rapid mix ,flocculation chamberpolluted effluent & is a rapid mix ,flocculation chamber

Neutralization tanksNeutralization tanks for pH adjustment by adding suitablefor pH adjustment by adding suitable

chemicalschemicals Pretreatment then carried out in various stages throughPretreatment then carried out in various stages through screens,screens,

grit chamber, skimming tank ,the primary sedimentation tanks etc.grit chamber, skimming tank ,the primary sedimentation tanks etc. PrePre--treatment removes materials that can be easily collected fromtreatment removes materials that can be easily collected from

the raw wastewater before they damage or clog the pumps andthe raw wastewater before they damage or clog the pumps andskimmers of primary treatment clarifiers (trash, tree limbs, leaves,skimmers of primary treatment clarifiers (trash, tree limbs, leaves,

etc).etc).



ScreeningScreening-- so as to trap and remove the floatingso as to trap and remove the floatingmatter, such as pieces of cloth, paper, wood,matter, such as pieces of cloth, paper, wood,kitchen refuse etc. present in sewage. Thesekitchen refuse etc. present in sewage. Thesefloating materials, if not removed will chock thefloating materials, if not removed will chock thepipes or adversely affect the working of thepipes or adversely affect the working of thesewage pumps. Thus the main idea of providingsewage pumps. Thus the main idea of providingscreens is to protect the pumps and otherscreens is to protect the pumps and other

equipments from the possible damages due theequipments from the possible damages due thefloating matter of the sewage. It should befloating matter of the sewage. It should beplaced before the grit chambers.placed before the grit chambers.



Grit ChamberGrit Chamber removes heavy settelableremoves heavy settelableinorganic solids such as sand, grit andinorganic solids such as sand, grit and

stones, ash, egg shellsstones, ash, egg shells Skimming tankSkimming tank ------ fats, waxes, fatty acids,fats, waxes, fatty acids,

soaps, mineral and vegetable oils present soaps, mineral and vegetable oils present

in oil are collectively called as oil andin oil are collectively called as oil andgrease. Compressed air is sent throughgrease. Compressed air is sent throughthe bottom of tank for effective removalthe bottom of tank for effective removal



Primary Treatment Primary Treatment

Sedimentation tanksSedimentation tanks are designed to separate solidsare designed to separate solidsfrom liquids under gravity and remove suspendedfrom liquids under gravity and remove suspendedsettleable solids about 60%.settleable solids about 60%.

In the primary sedimentation stage, sewage flowsIn the primary sedimentation stage, sewage flowsthrough large tanks, commonly calledthrough large tanks, commonly called "primary clarifiers""primary clarifiers"or "primary sedimentation tanks".or "primary sedimentation tanks". The tanks are used toThe tanks are used tosettle sludge while grease and oils rise to the surfacesettle sludge while grease and oils rise to the surfaceand are skimmed off. Primary settling tanks are usuallyand are skimmed off. Primary settling tanks are usually

equipped with mechanically driven scrapers that equipped with mechanically driven scrapers that continually drive the collected sludge towards a hoppercontinually drive the collected sludge towards a hopperin the base of the tank where it is pumped to sludgein the base of the tank where it is pumped to sludgetreatment facilities.treatment facilities.



Secondary treatment Secondary treatment

Is designed substantially to degrade the biologicalIs designed substantially to degrade the biologicalcontent of the sewage which are derived from foodcontent of the sewage which are derived from foodwaste, human waste, soaps, detergents.waste, human waste, soaps, detergents.

Usually useUsually use biological processesbiological processes Bacterias and protozoa consume biodegradable organicBacterias and protozoa consume biodegradable organic

wastes and converts to flocswastes and converts to flocs

Some of the treatment processes includesSome of the treatment processes includes Aerobic Aerobic,Anaerobic decomposition, Activated sludge treatment,,Anaerobic decomposition, Activated sludge treatment,Trickling filter treatment, rotating biological contactors,Trickling filter treatment, rotating biological contactors,Oxidation Ponds etc.Oxidation Ponds etc.



Decomposition of sewageDecomposition of sewage Sewage contains bacteria and organic matterSewage contains bacteria and organic matter

Organic matter serves as food for bacteriaOrganic matter serves as food for bacteria

During decomposition gases escape and solidsDuring decomposition gases escape and solids

settle easilysettle easily The decomposition in the presence of dissolvedThe decomposition in the presence of dissolved

oxygen is termed asoxygen is termed as Aerobic decomposition Aerobic decomposition

Decomposition in the absence of dissolvedDecomposition in the absence of dissolvedoxygen is termedoxygen is termed as Anaerobic decompositionas Anaerobic decomposition



Aerobic & Anaerobic decomposition Aerobic & Anaerobic decomposition

Decomposition in theDecomposition in thepresence of dissolvedpresence of dissolved

OxygenOxygen

Decomposition in theDecomposition in theabsence of dissolvedabsence of dissolved

oxygenoxygenCaused by aerobicCaused by aerobicbacteriasbacterias

Caused by anaerobicCaused by anaerobicbacteriasbacterias

End products are COEnd products are CO22 &&

HH22OO

End products areEnd products areCHCH44,H,H22S & NHS & NH33

End products are stableEnd products are stable are unstable and requireare unstable and requirefurther treatment further treatment

No offensive odor or foulNo offensive odor or foul Bad odor generatedBad odor generated



No offensive odor or foulNo offensive odor or foulgases generatedgases generated

Bad odor generatedBad odor generated

Few hours of detentionFew hours of detentiontime requiredtime required Detention time extendsDetention time extendsup to 30 days or moreup to 30 days or more

More complete reactionMore complete reaction Incomplete reactionIncomplete reaction

Measured from dissolvedMeasured from dissolvedoxygen utilization or BODoxygen utilization or BODsatisfiedsatisfied

Measured from gasMeasured from gasproduction and remainingproduction and remainingvolatile organicsvolatile organics

Energy consumingEnergy consuming

process (bulk of theprocess (bulk of theenergy in the form of cellenergy in the form of cellmass & heat )mass & heat )

Energy yielding processEnergy yielding process

(large part of energy(large part of energyappear in the form of endappear in the form of endproducts and hence cellproducts and hence cellproduction is low )production is low )



Treatment units includeTreatment units include

trickling filter, activatedtrickling filter, activatedsludge process, oxidationsludge process, oxidationpond etc.pond etc.

Treatment units includeTreatment units include

anaerobic septic tank,anaerobic septic tank,anaerobic lagoons etcanaerobic lagoons etc



Factors to be considered for settingFactors to be considered for setting

up ETPup ETP Waste water flow rateWaste water flow rate

Influent soluble substrate concentrationInfluent soluble substrate concentration

Total suspended solidsTotal suspended solids Sedimentation retention timeSedimentation retention time

Maximum rate of soluble substrate utilizationMaximum rate of soluble substrate utilization

Fraction of biomass that remains as cell debrisFraction of biomass that remains as cell debris Daily sludge productionDaily sludge production

Oxygen requirement Oxygen requirement

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Envi Sanitation (Waste Water Treatment)Slide 1