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)

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