Post on 19-Nov-2021
Journal of Research in Engineering and Applied Sciences
JREAS, Vol. 1, Issue 03, July 2016141
GREYWATERTREATMENTANDMANAGEMENT:THEPOTENTIALOFGREYWATERSYSTEMSTOAIDSUSTAINABLEWATERMANAGEMENT
1 2 3 4Y.DChintanwar ,ParasBatra ,VikashKumar ,RushabhGour ,5 6 7SumantChorey ,NikhilYeole ,RavikantKumar
1 2,3,4,5,6,7Asst.Professor, StudentsDepartmentofCivilEngineering,
PriyardarshiniJ.L.CollegeofEngineering,Nagpur,440009,Maharashtra,India.
Abstract
Accordingtothestatisticsabout71%oftheEarth'ssurfaceiswatercoveredandtheoceansholdabout96.5%oftheearth'swaterandrest is theconsideredas freshwaterorportablewater .Wateruses intheworldhas increasedatapaceexceedingourpopulationgrowth,withdevelopingcountriesusingmorewater than therestof theworld tomaintainastandardof living.Developingcountriesaredealingwithlimitedexcesstocleanwater,oneofthelargestcontributionstopoorhealth.Fortheproperuseandmaintenanceitisimportantthatwestartmanagingwastewaterinanefficientway.Thewastewaterproducedcanbedividedintotwocategoriesblackwaterandgreywater.Blackwaterisusedtodescribewastewatercontainingfeces,urineandflushwaterfromtoiletsandgreywateriswastewatergeneratedfromhouseholduseslikebathingandwashingclothes.BlackwatertreatmentisdoneonaverylargescaleinIndia,whereasitis30%ofthetotalwastewaterproducedandthegreywateris70%ofthewastewaterproduced.Greywaterisasourceofwastewaterthatcanbetreatedforreusemuchsimplerthancurrentmixedsewageorblackwater.TreatmentofgreywaterwillincreasetheamountofwaterthatcanbereusedforvariouspurposeandthatwilleventuallyhelpthedevelopingcontrarysuchasIndiatofighttherewatercrises.Thispaperpresentinformationongreywateranditstreatmentthatmayhelptomanagethewastewaterefficiently
KeyWords:Greywater,Greywaterreuse
1.Introduction
Aspressures on freshwater resources growaroundthe world and as new sources of supply becomeincreasingly scarce and expensive efforts areunderway to identify new ways of meeting waterneeds. Efforts are taken all over the world to savewaterandefficientlyreusethewastewater,thusgreywatertreatmentanditsreuse isaneffectivewaytofacetheproblemofwatercrisesasitisproducedonalargeandregularbasis.
Grey water, defined slightly differently in differentpartsoftheworld,generallyreferstothewastewatergenerated from household uses like bathing andwashing clothes. This wastewater is distinguishedfrommoreheavilycontaminated“blackwater”fromtoilets.Inmanyutilitysystemsaroundtheworld,greywater is combined with black water in a singledomesticwastewaterstream.Yetgreywatercanbeoffarhigherqualitythanblackwaterbecauseofitslowlevelofcontaminationandhigherpotentialforreuse.Whengreywaterisreusedeitheronsiteornearby,ithasthepotentialtoreducethedemandfornewwatersupply, reduce the energy and carbon footprint ofwaterservices,andmeetawiderangeofsocialand
economicneeds.Inparticular,thereuseofgreywatercanhelpreducedemandformorecostlyhigh-qualitypotablewater
2.SourceandGenerationofgreywater
Statistically70%wastewatergeneratedisgreywaterand30%isblackwater.thesourceofgreywaterarehandbasin,laundrey,kitchenandbathroom.
Fig.1:Pecentagesofgreywaterandblackwaterfromwastewaterproduce(RafatKhalaphallahetal.,2012)
Fig.2:Percentagesofgreywaterresourcesfromhouseholdwastewater(RafatKhalaphallahetal.,2012)
Table1:Distributionofwastewateraccordingtosource,typeandQuantity:
No Sourceofwastewater
Typeofwastewater
Quantity/day/person
1 Toilet Blackwater 3liters
2 Bathing Greywater 20-30liters
3 kitchen Greywater 5-10liters
4 Washingcloths Greywater 15-20liters
5 Animals Greywater 10-15liters
(J.S.LAMBEandR.S.CHOUGULE,IOSRJournalofMechanicalandCivilEngineering)
Table2:Characteristicsofgreywater
PARAMETER UNIT ACEPTABLE RANGE
Ph ---- 6.4 - 8.1
Electrical Conductivity
µmhos/cm 325 –
1140
Suspended Solids
mg/L 40 –
340
Turbidity
NTU
15 –
270
Total Hardness (as CaCO3)
mg/L 15 –
50
Sulphate (as SO4)
mg/L < 0.3-12.9
Ammonia
mg/L 1.0 –
26
Nitrate-N
mg/L 0.1 –
1.0
Total Phosphorous
mg/L 1.0 –
0.8
Sodium(as Na)
mg/L 60 -250
K jeldahl Nitrogen
mg/L 2 -23
BOD
mg/L 45 –
330
Total coliforms
MPN/100ml 0 FOR PER 100 ML
Faecal coliforms MPN/100ml 0 FOR PER 100 ML
E-Coli MPN/100ml 0 FOR PER 100 ML
(NationalEnvironmentalEngineeringResearchInstituteNehruMargetal.,2007)
Collectionandtestingofgreywatersample
Fig.3:ThecollectionofgreywatersamplewasdoneaccordingtoPercentagesofgreywaterresourcesfromhouseholdwastewater (Rafat Khalaphallah et al.,2012)
Methodology
Ph ---- 7.2 6.4- 8.1
Electrical
Conductivity
µmhos/
cm
1998 325– 1140
Suspended
Solids
mg/L 532 40– 340
Turbidity
NTU
340
15–
270
TotalHardness
(asCaCO3)
mg/L
160
15–
50
Sulphate(as
SO4)
mg/L
28
<0.3-12.9
Ammonia
mg/L
2.50
1.0–
26
Nitrate-N
mg/L
0.25
0.1– 1.0
Total
Phosphorous
mg/L
2.380
1.0– 0.8
Sodium(asNa)
mg/L
280
60-250
Kjeldahl
Nitrogen
mg/L
5.48
2-23
BOD
mg/L
400
45–
330
Totalcoliforms
MPN/1
00ml
350000
0FORPER
100ML
Faecal
coliforms
MPN/1
00ml
240000
0FORPER
100ML
E-Coli MPN/1
00ml
130000 0FORPER
100ML
PARAMETER UNIT LABORATERY
RESULT
ACEPTABLE
RANGE
JREAS, Vol. 1, Issue 03, July 2016142
Fig.4 :Treatmentoption forwastewater (NationalEnvironmentalEngineeringResearchInstituteNehruMargetal.,2007)
Outoftheoptionofthetreatmentsystemweselectedthe aerobic process for the treatment of the greywater.The treatmentunitweused consistedof thefollowingunits:
l Storagetank
l Aerationtank
l Flashmixer
l Sedimentationtank
l Filtrationunit
l DisinfectionunitbyUVRays
l Disinfectionunitbychlorination
3.StepsforDesingofGreyWaterTreatmentPlant
1]DesignofFlashMixer
A) Designofsuitableflashmixerfordesignflowof100lpcdfor10000people.
Q =100lpcd
=100×10000
=1000000
QD =1.5×1000000
=1500000lit/day
=1500m3/day
=0.0173m3/sec
B) Designofinletandoutletpipe
Assumingvelocityofflowinpipe
Vf=0.9m/sec
Areaofpipe=Q
V
= 0.0173/0.9
= 0.0192 m2
Diameterofpipe=0.0192×4
p
=0.156m
=1.56cm
=0.6inch
=0.5inch(take)
C)Designofmixingtank
Assuming detention time ( t ) = 60 sec
\ Volume of water in tank (V) = Q × t
= 0.0173 × 60
= 1.038 m3
Assuming depthof water in tank (d) = 1m
Surface area of tank = v
d
= 1.038
1
= 1.038 m2
Assuming LB
= 4.5
A = L x B
1.038 = 4.5B x B
B= 0.48m
L = 2.16m
\
2)DesignRectangularSedimentationTank
A) Designofsuitablerectangularsedimentationtank for design flow of 100 lpcd forpopulationof10000peoples.
SOLUTION:
Q=100lpcd
=100×10-3×10000
Q=1000m3/d
QD=1.5×1000
=1500m3/d
=62.5m3/hr
=0.0173m3/sec
Treatment Options
Anaerobic AerobicAnaerobic -
Aerobic
Upflowanaerobic
sludgeblanketreactor
AnaerobicFilter
Septictank
AnaerobicPonds
Septictank+
Oxidationpond
Filters Oxidationpond
JREAS, Vol. 1, Issue 03, July 2016143
B)Designofinletandoutletpipe
Assuming velocity = 0.3 m/sec
Area of channel =Q
V
= 0.0173
0.3
= 0.0578 m2
Dia. of pipe = 0.0578
×4
p
= 0.27 m
C)Designofsedimentationtank
Assume detention time = 3hr.
Volume of water in tank = 62.5 × 2.5
= 156.25 m3
Surface area of tank = volume
d
= 156.25
2.5
= 62.5 m2
S.O.R. = Q
B ×L
= 62.5
62.5
= 1m3/hr/m2
Assuming ,L
B = 4.5
L = 4.5B
A = L × B
62.5 = 4.5 B2
B= 3.72 m = 37.2 cm
L = 16.77m = 167.7 cm
Assuming sludge depth = 25 % of water depth
\ ds = 0.25 × 2.5
= 0.625 m
Assuming free bored = 0.22 m
Total depth of inlet = 2.5 + 0.5 + 0.22
= 3.22 m
Assuming bottom slope = 1: 100
Total depth at inlet and outlet channel = 3.22 + 1
100 × 16.77
= 3.389 m
Providing the rectangular sedimentation tank of
size 3.72 × 16.77 m
\
\
\
3)DesignofFilterationUnit
Q = 0.0173 m3/sec = 62.5 m3/hr
No. of filter = 62.5
4.69
= 1.68 @ 2 no.
Assuming Rate of Filtration = 3 m3/hr/m2
Area of filtration =
Q
R
=
62.5
3
= 20.83 m2
\ Area of each filter unit =
20.83
2
= 10.41 m2
Assuming L = 1.4 B
A = L × B
A = 1.4 B × B
10.41 = 1.4 B2
B = 2.72 m = 27.2 cm
L = 1.4 × 2.72
= 3.81 m = 38.1 cm
Depth of sand bed = 34421
Rd3 h
d×(100
35 +70)
= 0.335 m @
0.34 m
Henceprovide2no.of filterunithavingsize3.81×2.72mwith0.340mdepthofsandbedoutofwhich1unitisforstandby.
4DesignOfUnderDrainageSystem(U.D.S.)
(Manifold and lateral)
Size of 1 unit = (3.81 × 2.72)
Area of 1 unit = 10.36 m2
Total area (AD) = 0.3 % surface of filter
= 0.3
100× 10.36
= 0.031 m2
JREAS, Vol. 1, Issue 03, July 2016144
Assuming area of lateral (AL) = 2 × AD
= 2× 0.031
AL = 0.062 m2
Assuming Area of Manifold ( A m ) = 2 × AL
= 2 × 0.062
= 0.124 m2
A)Designofmanifold
Area of manifold = π4 × d2
0.124 = π4
× d2
D = 0.397 m
D @ 0.4m
Henceprovidecentralmanifoldofdiameter0.4mparallellengthoffilterunit.
B)Designoflateral
Assuming dia. of lateral = 62.5 mm
Area of one lateral ( A ) = π4
× d2
= π4
×(62.5 × 10-3)2
AL= 3.067 × 10-3 m2
\ Total no. of lateral present in filter = QL
AL
= 0.0173
3.06 ×10 - 3 m2
= 5.65
@ 6 nos.
Check = Always comes even no.
No. of lateral on each side of manifold = 6
2 = 3 no.
Spacing of lateral = L
no .of one size of manifold
= 3.81 ×100
3
Spacing of lateral = 127 cm C/C
Length of lateral = B - d manifold
2
= 2.72- 0.4
2
LL = 1.16 m
Check for length dia. Of lateral = 60d
= 60 × 62.5 × 10-3
= 3.75 m
LL = 1.16 < DL = 3.75
Hence ok
5DesignofAerationTank
Qd = 0.0173 m3 / sec
= 62.5 m3/hr
Assuming Velocity = 0.6 m/sec
Q = A × V
0.0173 = A × 0.6
A = 0.028 m2
But A = π4
× dp 2
0.028 = π4
× dp
dp = 0.188 m
@ 0.2 m
Fig.5
JREAS, Vol. 1, Issue 03, July 2016145
Filtarationunit
The filtration unit consist of various layers ofaggregate.
l The first layer consists of 600 micron fineaggregate.
l The second layer consists of 1.18mm fineaggregatewith activated carbonmixedwith itwhichactasapurifyingagent.
l The third layer consists of 2.36mm fineaggregate.
l The fourth layer consists of 4.75mm coarse aggregate
l The fifth layer consists of 20mm coarseaggregate
l The sixth layer consists of 25mm coarseaggregate.
l Under drainage system is provided below thefiltermediatocollectthefilteredwater.
Whataretheadvantagesofgreywaterreuse?
Greywaterisreusedforawholerangeofapplications:
l Urinalandtoiletflushing
l Irrigation of lawns (college campuses, athleticfields, cemeteries, parks and golf courses,domesticgardens)
l Washingofvehiclesandwindows
l Fireprotection
l Concreteproduction
l Developandpreservewetlands
l Infiltrateintotheground
l Agricultureandviticulturereuse
Grey water reuse can save lot of money which canbeeasilyunderstoodbythefollowingexample:
EconomicsofGreywaterRecycle&ReuseConsideraComplexwith100ResidentialUnits.
Eachunithassay4persons.
Average consumption of Freshwater is@ 100 ltrs/day/person.
HenceTotalFreshwaterrequiredshallbe100x4x100=40000litres/day.
ThecostofMunicipalwaterissay30Rs/1000litres(Itisincreasingdaybyday.
AtChennaiitisalready60Rs/1000litres)
DailyWaterBill=40000x30/1000=Rs.1200/day.
WhichisRs.4,38,000/year.
At60Rs/1000litresthiswillbeRs.8,76,000/year.
Wecansavearound70%ofwastewaterieintheformofgreywatertreatment.
Thereforewecansave70%X1200Rs=840Rs/day
(J. S. LAMBEand R. S. CHOUGULE, IOSR Journal ofMechanicalandCivilEngineering)
Thewatertreatedinthetreatmentunitreducedtheturbidityinthewatersampleby98.99%andrestofthe impurities present in the sample which wereabovethelimit(asmentionedinthetableoftestresulthighlightingtheparameters)weremaintained.
Fig.6
JREAS, Vol. 1, Issue 03, July 2016146
6.Conclusion
Reusingofgreywaterwilldefinitelyhelptosolvetheproblemofwaterdemandintheworld.Thetreatmentsystem can be easily adopted by the developingcountries .SincethereisrapiddevelopmentinIndiaandthereisplanningofdevelopingmanysmartcities,thisconceptofTreatmentandreuseofgreywatercanplayamajorroleinit.ThecountrylikeIndiaandmanysuchcountriesintheworldarefacingandifnotwilldefinitely face theproblemofwatercrises thusourresearch aims to help facing the problem of watercrises.
References
[1] RafatKhalaphallah,“Greywatertreatmentforreusebyslow sand Filtration : study of pathogenicmicroorganisms and phage survival” hal. archives-ouvertes.fr.Submittedon27Sep2012
[2] J. S. LAMBE and R. S. CHOUGULE “ Greywater -TreatmentandReuse”IOSRJournalofMechanicalandCivil Engineering (IOSR-JMCE) ISSN(InternationalStandard Serial Number): 2278-1684, PP(pagenumber):20-26
[3] National Environmental Engineering ResearchInstitute,“GreyWaterReuseinRuralSchoolsGuidanceManual”January2007
[4] ATAGreywaterProjectReportsupportedbytheSmartWater Fund, “ATA Smart Water Grey water Project”November2005
[5] Sara Finley, “Reuse of Domestic Grey water for theIrrigation of Food Crops” Mcgill University, August2008
[6] Barbara Imhof and Joellemuhlemann , “GreyWaterTreatmentonHouseholdLevelinDevelopingCountries–A State if theArtReview” AntoineMorel from theSwissFederalInstituteforEnvironmentalScienceandTechnology(EAWAG)February2005
[7] LucyAllen,JulietChristian-Smith,MeenaPalaniappan,“OverviewofGreywaterReuse:ThePotentialofGreywaterSystemstoAidSustainableWaterManagement” November2010
[8] DesingofwatertreatmentunitsbyDr.A.GBhole
[9] WatersupplyandsanitaryEngineeringbyG.SBirdieandJ.S.Birdie
[10] Website:-www.everwater.com.au
www.greywater.com
[11] IS10500:1991Drinkingwater–Specification
[12] IS10500:2012Drinkingwater–Specification(SecondRevision)
JREAS, Vol. 1, Issue 03, July 2016147