Post on 10-Apr-2018
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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
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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
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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
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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
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Where does the water comeWhere does the water comefrom? from?
surface waters (lakes, rivers, and reservoirs) groundwater (wells).
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Minerals ( Iron ,Manganese & Sulphur)Minerals ( Iron ,Manganese & Sulphur)
ManMan--made chemical pollutants includingmade chemical pollutants including
fertilizersfertilizers
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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
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DesalinationDesalination-- Process of removing salt Process of removing salt from waterfrom water
DisinfectionDisinfection-- for killing bacteriafor killing bacteria
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Raw Water
Storage
Mixing FlocculationSedimentation
Filtration
Clear Well
Distribution
Ozonation
Surface Water Treatment Plant Surface Water Treatment Plant
Coagulant, pH AdjustmentDisinfectant (Cl2, NaOCl)
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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.
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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:
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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.
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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.
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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)
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Schematic diagram for treatment Schematic diagram for treatment
processes for drinking waterprocesses for drinking water
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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
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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
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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
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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
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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
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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.
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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
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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.
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Process flow diagram for a sewageProcess flow diagram for a sewage
treatment plant treatment plant
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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).
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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.
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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
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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.
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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.
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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
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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
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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 )
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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
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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