guidance of Dr MK Sateesh Presented by Sadhana Reddy CONTENT I NTRODUCTION S OURCES FOR WASTE WATER TERMS C OMPOSITION OF DOMESTIC WASTE WATER O VER VIEW OF WASTE WATER TREATMENT ID: 745775
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Slide1
WASTE TREATMENT
Under the
guidance of: Dr. M.K. Sateesh
Presented by:
Sadhana
ReddySlide2
CONTENT
INTRODUCTIONSOURCES FOR WASTE WATER
TERMSCOMPOSITION OF DOMESTIC WASTE WATEROVER VIEW OF WASTE WATER TREATMENTPrimary TreatmentSecondary Treatment:-Activated sludge , Trickling filter & oxidation pond.Tertiary:-Removal of Nutrients , Heavy metals , PathogensSlide3
INTRODUCTION
The term sewage treatment is now a days is replaced by waste water treatment.Sewage treatment is the process of removal of contaminants from waste water.
The treatment is of chemical, physical and biological processTheir are 2 types of waste water based on the out lets-:1.House and Hotel out let.2.Industrial out letSlide4
SOURCES FOR WASTE WATERSlide5Slide6
TERMSBiochemical Oxygen Demand[BOD]:-
It is the amount of dissolved oxygen [DO] consumed by microorganisms for the biochemical oxidation of organic.Chemical Oxygen Demand [COD]:-
It is the amount of oxygen necessary to oxidize the organic carbon completely to CO2’ H2O, and ammonia.Slide7
TYPES OF BOD
(i) Carbonaceous BOD (CBOD)CBOD is the amount of Oxygen used by a mixed population of heterotrophic microorganisms to oxidize organic compounds
Org comp CO2+H2O+NH4+ Bacterial mass Bacterial bio film
Protozoa biomass +CO2
(ii) Nitrogenous Oxygen demand (NOD)
Autotrophic bacteria such as nitrifying bacteria also require oxygen to oxidize NH
4
+
to nitrate. The oxygen demand exerted by
nitrifiers
is called as NOD and also autotrophic BOD
Slide8
COD
Chemical oxygen demand (COD)COD is the amount of oxygen necessary to oxidize the organic carbon completely to CO
2 , water and ammonia.COD is measured via oxidation with potassium dichrome (K2CR2O7) in presence of sulphuric acid & silver is expressed in mg/L.If COD is higher than BOD it means that the amount of organic compounds are high which are not easily bio degraded.
In untreated domestic waste, water COD ranges between 250 to 1000mg/LSlide9
Composition of domestic waste
Domestic waste water is a combination of human and animal excreta (faeces & urine)
and grey water resulting from washing, bathing and cooking. People excrete 100-500g wet weight of faeces & 1& 1.3 L of urine per capita per day.Domestic waste is composed of mainly Proteins 40-60%Carbohydrates 25- 50%Fats & oils 10%Urea derived from urine Slide10
Contd…Even it includes a large number of trace organic compounds that is pesticides , surfactants, phenol & priority pollutants
The latter category comprises non metals (As , SC) metals (Cd, Hg,
Pb) benzene compounds ( benzene , ethyl benzene) & chlorinated compounds Slide11
Overview of waste water treatment
Physical forces as well as chemical & biological process drive the treatment of waste water.
Unit operations :- Treatment methods that rely on physical forces are called unit operations. These includes Screening Sedimentation Filtration or flotation Unit process:- treatment methods that rely on chemical and biological processes are called unit process Slide12
Contd…
Chemical unit consists of 1. Include disinfection
2. adsorption or precipitationBiological unit process involves 1. microbial activity 2. organic matter degradation 3. removal of nutrients Slide13
Contd..Waste water treatment comprises of four steps
Preliminary treatment :- the objective of this operation is to remove debris and coarse materials that may clog equipment's implant.
Primary treatment :- treatment is brought about by physical process such as screening and sedimentation. Slide14
Contd..3
. Secondary treatment:- Biological and chemical are used to treat waste water. Even nutrient removal also generally occurs during secondary treatment.
Biological :- activated sludge, trickling filter, oxidation ponds Chemical :- Disinfection4. Tertiary or advanced treatment:- unit operations and chemical unit process are used to further remove BOD, nutrients, pathogens, parasites and sometimes toxic substancesSlide15Slide16Slide17Slide18
Activated sludge process
Activated sludge is suspended growth process that began in England at the turn of the century.
This process has since been adopted world wide as a secondary biological treatment for domestic waste water.This process consists essentially of an aerobic treatment that oxidises organic matter to CO2, H2O , NH4 & new cell biomassAir is supplied to this process by diffused or mechanical disposed Slide19
Contd…Effluent from primary treatment is pumped into a tank and mixed with bacteria – rich slurry known as activated sludge
Air or oxygen is supplied to encourage the growth of bacteria.
The material then goes to a secondary setting tank where the water is siphoned off the top of the tank & sludge is removed from the bottom.Slide20
Contd..
Food to Microorganism ratio [F/M] :- A portion of the sludge in the clarifier is recycled back to aeration basin & the remainder is wasted to maintain a proper F/M
F/M ratio indicates the organic load into the activated sludge system & expressed in kilogram BOD per kilogram of MLSS per day. =
Q = flow rate no of sewage in million gallons per day
MLSS= Mixed liquor suspended solids (mg/L)
V= Volume of aeration tank (gallons)
Slide21
Activated sludgeSlide22
Major contents of sludge
Bacteria
ZoogleaPseudomonasFlavobacterium AlcaligenesAchromobacterCorynobacterium Acinebacter
Bacillus
Filamentous
Eg
:
Sphaerotilus
Gliding Bacteria
Eg
:-
Beggitoa
Fungi
Geotrichum
Pencillium
Cephalosporium
Cladosporium
Alternaria
Slide23Slide24
Trickling filter
It is the processing unit which will be circular either rectangular tank containing the filter medium.Depth will be approximately 1.0 to 2.5m this surface area is provided for microbial growth.
The filter media used in trickling filters are stone[crushed limestone & granite], ceramic material, treated wood, hard coal or plastic media.Slide25Slide26
Microorganisms found in trickling
BACTERIA
FUNGIALGAEPROTOZOAZoogleaFusariumUlothrixBodoPseudomonasPenicilliumPhormidiumMonasflavobacteriumAspergillusAnacystisColpidiumAhromobacterc
Mucor
Euglena
Vorticella
Alcaligenes
Geotrichum
Chlorella
Amoeba
FB:Sphaerotilus
.
Yeasts
Arcella
N.
communis
, N.
oligotropha
NitrobacterSlide27
Oxidation pond
Here oxygenation is usually achieved by diffusion and by photosynthetic activity of algaeIn the ditches the microorganisms grow as suspended particles.
The water in pond moves in clock wise direction.Temperature is for about 22 CDuration time is 15 hoursArea is of 15 million gallons Slide28Slide29
Removal of nitrogen
Biological oxidation of nitrogen from ammonia to
nitrate[NITRIFICATION]followed by DENITRIFICATION the reduction of nitrate to nitrogen gas.Nitrosomonas (ammonia oxydizing bacterium or AOB) & Nitrospira ( anitire oxidizing bacteria or NOB)The target region of Nitrosomonas
is
Amo
Agene & 16Sr DNA is target region of
Nitrospira
BABE:- Bio augmentation batch enhanced process can be used to augment nitrification in activated sludge operating at sub optional solid retention times Slide30
Different systems
Single sludge system This system comprise a series of aerobic & anaerobic tanks in lieu of single aeration
tank .Slide31
Multi sludge System
Carbonaceous oxidation, nitrification & de nitrification are carried out in three separate systems Methanol or settled sewage can serve as source of carbon for de nitrifierSlide32
Bardenpho Process
The process consists of 2 aerobic & 2 anoxic tanks followed by sludge
setting tank Slide33
Removal of phosphorus
A/O ( Anaerobic/ oxic
) processA/O process consists of anaerobic zone. During anaerobic phase , inorganic phosphorus is released from the cells as a result of polyphosphate hydrolysis. The energy released is used for up taking of BODBardenpho process: This system remove nitrogen as well as phosphorus. University of cape town process (UCT):In this system train of 3 tanks of anaerobic-anoxic-aerobic followed by clarifier.Slide34
UCTSlide35
BY MICROORGANISMSPolyphosphate accumulating organism [PAOs] are selectively enriched and accumulated large quantities of phosphorous with in the cell.
Up to 20% of their cell. Example for PAOs is Gammaproteo
bacteria of genus Acinetobacter ,Microlunatus phospovorus.Polyphosphate hydrolysis organism[PHA]are hydrolysed P.Example: Betaproteo bacteria, Lampropedia spp. Slide36
PAO”s OrganismSlide37
Heavy metal RemovalHeavy metals are the major toxicants found in industrial waste waters.
The affinity of biological solids for heavy metals was found to follow the order:Pb>Cd>Hg>Cr3+>Cr6+>Zn>Ni.
It was reported that biofilm microorganisms were 2 to 600 times resistant to metals than planktonic. Slide38Slide39
Disinfection
Temperature.Effect of pH.
Chlorine It help in inactivation of microorganisms by cell injury.Disruption of cell permeability.Expose to chlorine leads to leakage of proteins,RNA and DNA.Interrupts nutrient transportation, inhibits cell respiration, damages iron sulfur center.Arest enzyme action by accumulation of hydrogen peroxide.Slide40
DisadvantagesChlorination of drinking water is risk for bladder, kidney and colorectal cancers.
The disinfection by products [DBPs] are mutagens or carcinogens and teratogens.Cardiovascular diseases.
Examples of microorganisms- E. coil, Poliovirus,Campylobacter jejuni.Slide41
Chloramination
NH3 + HOCl
NH2Cl + H2O (Monochloramine, pH 8.5)NH2Cl + HOCl NHCl2 + H2O (Dichloroamine, pH 4.5) NHCl2 + HOCl
NCl
3
+ H
2
O
(
Trichloroamine
, pH <4.5)
Examples:-
Bacteria-
E.coil
, Coli forms, Mycobacterium fortuitism,
M.avium
, M. Intracellular , S. tphimurium,
Shigella sonnei
.Viruses- Polio I, Hepatitis A , Coli phage MS2, Rotavirus SA11.
Protozoan
: Cysts-Giardia
muris
Slide42
Chlorine dioxideDestruction of cysts pathogenic protozoa such as
Naegleria gruberi.At pH 9.0 bacteriophage F2 is inactivated by acting up on protein coat
It disturb the protein synthesis in bacterial cell.Examples-Bacillus subtilis spores, K. pneumonia.Slide43
Chlorine dioxideSlide44
OZONE
By passing dried air between electrodes separated by air gap and applying alternating current.The volts used here is from 8000 to 20,000V.
Standard oxidation potential is 2.07eV but for in activation of bacteria it needs 0.10g/L.Example-E. coli-0.001 to 0.2Enteric viruses-0.04 to 0.42.Mycobacterium > Polio virus 1 > Candida parapsilosis > E.coi > Salmonella typhimurium.Slide45Slide46
Process
Free radicals are produced to aqueous media that inactivates microorganisms.DISADVANTAGES
Mutagenic by product is bromate (BrO3 ) carcinogenMore electricity, costly It don’t cause damage to bacterial spore DNA Slide47
U.V LIGHT
@ wavelength of 253.7nm
It damages micro organisms DNA It causes thymine & cytosine dimer which block DNA replication For viruses it damages viral genome, or virus coat Protozoan cysts >bacterial spores>viruses> vegetative bacteria. Slide48
DISADVANTAGES
Difficulty in
determining U.V doseFormation of biofilms on lamp surfaceElectrical problem Slide49
PHOTO INACTIVATION
Solar radiation
Solar radiation @ ≥ 600w/m2 for 5 hours to reduce pathogens Ex:- vibrio cholerae, salomenella. Water in plastic bottle is exposed to sunshine for 7 h to 550C
PhoTODYNAMIC
inactivation
It is also called as photochemical disinfection
It consists of visible or sunlight as energy source, O2 & sensitizer dye such as methyl blue, rose Bengal or eosin
It reduce the poliovirus I for 1.8 log
Here flow will be 50m
3
/h
35min in reduce 4-5 log of microorganisms Slide50
PHOTODYNAMIC INACTIVATERSlide51
PHOTO CATALYTICTitanium dioxide [Tio
2]+Fluorescent or sunlight=photo catalytic. Even it degrades the endotoxin which are released from the cells.Slide52Slide53
REFERENCEShttp:⁄⁄ www.scitrav.com ⁄ wwater
53⁄ water lnk.htm[collection of web pages on activated sludge]
http:⁄⁄ www.epa.gov ⁄enviro ⁄ html⁄icr⁄dbp.htm1[disinfection byproducts from U.S.EPA]http :⁄⁄ www.epa.gov ⁄owm⁄ mtb⁄ U.V.pdf[U.V disinfection]Waste water Microbiology[3rd edition] by GABRIEL BITTON.Environmental Biology for Engineers and Scientists by David A.Vaccari, Peeter F. Strom,Jaes E.AllemanSlide54
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