Industrial Effluent Treatment by Modern Techniques.ppt

Effluent Treatment Plant or ETP is one type of waste water treatment method which is particularly designed to purify industrial wastewater for its reuse and its aim is to release safe water to the environment from the harmful effect caused by the effluent. Helping achieve a greener society.

1. Industrial Effluent Treatment by
Modern Techniques

2. Introduction
•TheEffluenttreatmentplants(ETP)areusedfortheremoval
ofhighamountsoforganiccompounds,debris,dirt,grit,
pollution,toxic,non-toxicmaterialsandpolymersetc.from
industrialeffluent.
•AnyIndustrialEffluentTreatmentPlant(ETP)mustbe
studiedforthepossibilityofthe”3R”principle,theyare
Reduce,RecycleandReuse.

3. What is an ETP
•ETP (Effluent Treatment Plant) is a process design for treating the industrial waste water for its
reuse or safe disposal to the environment
•Influent: Untreated industrial waste water.
•Effluent: Treated industrial waste water.
•Sludge: Solid part separated from waste water by ETP.

4. Chemical Unit Processes:
•Those processes used for the treatment of waste water in which
change is brought about by means of or through chemical reaction
are known as “Chemical unit processes”.
•Various chemical unit processes:
Chemical precipitation
Adsorption
Disinfection
Dechlorination
Other chemical applications

5. Biological Unit Processes:
•Those processes used for the treatment of waste water in which Reduction
or Removal of impurities is brought by microorganisms is called “Biological
unit processes”.
•Classification of biological process for waste water treatment :
•Processes according to Operational Conditions
•Aerobic Process
•Anaerobic Process
•Facultative Process
•Anoxic Process
•Processes according to Microbial Maintenance in the system
•Suspended growth process
•Attached growth or fixed film Process

6. These are the Common methods of
treatment of Industrial Wastes
•Neutralization cum Equalization
•COD/BODRatio
•Chemical Coagulation and Precipitation
•Settling Treatment
•Segregation
•Monitoring of ET P
•Oxidation and Reduction
•Disinfection
•Adsorption by Activated Carbon
•Stripping
•Thermal Processes
•Tertiary Treatment of Sewage
•Removal of Color
•Disposal of Solid Wastes

7. Neutralization cum Equalization
•Acidiceffluentsofoneprocessandalkalineeffluentsofanother
processcanbecombinedforNeutralization.Byneutralization
thepHoftheeffluentwillbebroughtintherangeof6to
9.NeutralizationmaybeachievedinthesameEqualization
tank.
•pHmustbeintherangeof6to8.5formostofthebiological
treatmentprocessestofunctionefficiently.
Acid + Base = Salt +Water
Bases employed are: Slaked lime, Caustic Soda, NaOH
Soda Ash Na2C03
Acids employed are: H2S04, HCI or CO2.

8. COD/BODRatio
•IfCOD/BODRatiois2orlessi.emorethanabout0.5,
BiologicaltreatmentmethodsWillbeeconomical.
•IfCOD/BODratioisveryhigh,Biologicaltreatmentissuitable
onlyiftheChemicalPrecipitationmethodsarefirstemployed.
•Oncethenon-biodegradables(COD)areremoved,the
COD/BODratiodecreasesandifitis<2,Biologicaltreatment
methodslikeTricklingFilters,ActivatedSludgeProcess,
Oxidationpondsetc.maybeemployed.

9. Chemical Coagulation and Precipitation
•Coagulationareusedtoseparatethesuspendedsolidsportion
fromthewater.Suspendedparticlesvaryinsource,charge,
particlesize,shape,anddensity....Coagulationoccursin
successivesteps,allowingparticlecollisionandgrowthoffloc.
•Chemicalprecipitationinwaterandwastewatertreatmentis
thechangeinformofmaterialsdissolvedinwaterintosolid
particles.Chemicalprecipitationisusedtoremoveionic
constituentsfromwaterbytheadditionofcounter-ionsto
reducethesolubility.

10. Settling Treatment
•Thegoalofsettlingprocessistheexpulsionofsettleable
organicandinorganicsolidsbysedimentation,andtheremoval
ofmaterialsthatwillfloat(scumorrubbish)byskimming.
•Thesewageshouldfirstbesubjectedtosettlingprocessfor
removalofScreeningslikewood,paperandplasticsquanders
andskimmingstooilandgrease.
•EvacuationoftoxicsubstanceslikeChromium,Cadmium,
Cyanide,Arsenicetc.,isessentialbeforesendingthe
wastewaterforbiologicaltreatment.
•AlmostalltoxicsubstanceslikeArsenic,Selenium,Cadmium,
Nickeletc.,canberemovedbyAlkalineChlorination(i.e.
ChlorinationatpH>10)orActivatedCarbon.

11. Segregation
•segregationistheseparatingandsortingofwastetofacilitate
recycling....Forexample,acompanywhosortsitscardboard
packaging,glasscontainers,metalwasteandwoodwastewillsave
aconsiderableamountofwastethensendingamixedmaterialskip
forrecycling.
•Streamswithtoxicsubstancesandhighconcentrationsofa
particularpollutantlikeCyanideandChromium.BODandpHshould
betreatedseparately.Separationofwastewaterstreamsofdifferent
qualitiesisknownas‘Segregation’orSeparation’.CoolingTower
blowdownsthatarelargeinquantityandhavenomajorpollutantsin
themshouldbetreatedseparately,theyaresegregatedfromothers.
Similarly,smallstreamwithhighconcentrationofapollutantshould
notbemixedwithothers.

12. Monitoring of ETP
•TheEffluentTreatmentPlantneedsaconstantmonitoring.
ConstantwatchontheOperationofBiologicaltreatment
processisessential.Beforestartinganybiologicalmethod,the
wastewatermustbemadefreefromtoxicsubstanceslikeAs,
Hg,Chlorineetc.pHmustbeintherangeof6.5to8.5by
addingsuitableneutralizingagents.

13. Oxidation and Reduction
•Hazardoussubsatncesareconvertedtoharmlessorlesstoxic/
hazardousforms.

14. Disinfection
•Boiling,KMnO
4,UVRays,BromineandIodine,Excesslimeare
aportionofthedisinfectantsutilizedwhileChlorinationisthe
mostutilizedtechniqueforsterillization.Disinfectionregularly
includestheinjectionofachlorinesolutionattheheadendofa
chlorinecontactbasin.Thechlorinedosagedependsuponthe
ofthewastewateranddifferentfactors,butdosagesof5to15
mg/larecommon.

15. Adsorption by Activated Carbon
•Adsorptionisasurfacephenomenoninwhichthepollutantsto
beremovedortakenontothesurfaceoftheadsorbent.
Efficiencyofadsorbentincreaseswithavailabilityofsurface
areapergramofadsorbent.NormalCarbonhasasurfaceare
of0.001m
2
/gramwhileActivatedcarbonhasasurfaceareaof
morethan1000m
2
/gram.MolecularSievesalsoarepossible
alternativestotreatmentofeffluentswithtoxicsubstancesbut
theefficiencyismoreonlyiftheeffluentisfreefromprimary
pollutantslikeclay,MLSSandTDS.

16. Advance Demineralization Techniques
•Itislike
EvaporationandDistillation
IonExchange
ReverseOsmosis
Freezing.

17. Stripping
•Gasesdissolvedineffluentcanberemovedbystrippingor
desorption.Effluent,ifsprinkledorsprayedintoatmospherein
theformofdropletsthroughnozzles,gasesaredeabsorbed
andtemperatureofeffluentalsodecreasesduetoescapeof
steam.

18. Thermal Processes
•Thermalprocessesi.e.byIncinerationattemperaturesof800
0
C
oraboveofC,H,O,S,N,HeavyMetalsforthermaldestruction
ofhazardouswastes-organicaswellasinorganic.

19. Tertiary Treatment of Sewage:
•AftertheSecondaryClarifier,anOxidationPondisalways
recommendedasitgivesatertiarytreatmenttothewastewater
andgivesitapolishingnature.AStabilizationPondusingAlgae
isaverylowcosttreatmentmethodandisveryefficientalsoin
theremovalofBOD.DesignOrganicloadingsashighas300kg
BOD/ha/dayanddetentionperiodsof10to15days,givesupto
90%ofremovalofBOD,ifproperlymaintained.Anaerobic
PondsmaybeusedifBODis>2000mg/l.AnaerobicPond
with3monthsdetentiontimeand5mdepthremoves60%of
BOD/COD.Alsothishasnomaintenancecostsatall.

20. Removal of Color
•IronimpartsredorreddishbrowncolortoWaterwhileManganese
impartsblackcolortowater.ZincgivesOpalescence,awhitishcolor
towaterwhilesomedissolvedorganicsetc.,causeothercolorsand
odorstowater.MostofIron’Manganeseandassociatedcolorand
odorcanberemovedbyChlorination,inthefinalstages.Further
removalofcolorandodor,asatertiarytreatmentisdonebyusing
ActivatedCarbon,ActivatedSilicaorMolecularSieves.Activated
CarbonatapHOf3removes90%ofcolor,whichisthemaintrouble
shootingparameterinaTannery.TextileorPaperandPulpIndustry.
Consumeracceptancewillbemoreandpublicuproarwillbeless
oncethecolorisremovedeffectivelyascolorisacommonman’s
indexof-pollution.Coagulation,Flocculation,Carbonadsorptionand
Chlorinationarethecommonruethodsadoptedforremovalofcolor.

21. Disposal of Solid Wastes
•MostofthetoxicsubstancesarepresentinthePrecipitatesor
thesolidwastes,whichareconsideredhazardousandhence
aretakenawaybythelocalPollutionControlBoardonceina
year.Thesolidwastesaretobestoredinwatertightstorage
tanksduringthisperiodandneednotbefurthertreated