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Introduction 11. HistoryofBiosandFilter 22. ComponentsofBiosandFilter(BSF) 23. GoodQualityMould 34. SelectionofBSFVersion 45. SelectionofFilterMedia 46. DiffuserPlateandBox 57. IntegrationofHygienetotheBSFProject 58. NeedAssessmentSurvey 69. MobilizationofaCommunity 710. AcceptanceofBSFTechnology 711. SelectionofHouseholdforBSF 712. LocationforInstallation 813. DistributionofWaterContainerwithFilters 914. Pre-treatmentofSourceWater 915. EducationonOperationandMaintenance 916. FollowupVisits 917. KeyPracticesforEnhancementofBSFEffectiveness 1018. KeyOperatingParameterstoBeConsidered 1019. ReplicationofBSFTechnology 1020. Conclusions 11

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Recent systematic review of water, sanitation andhygiene interventions suggest that the beneficialeffect of improving household water quality atthe point of use (PoU) in the reduction of therisk for diarrheal disease had been previouslyunderestimated.

Anuptodatereviewestimatesa30-40%reductionindiarrhealdiseasebyimprovinghouseholddrinkingwater quality at the PoU, making such treatmentmore effective than improvement at the source,whichreducesdiarrhealdiseasesby25%.

ThegoalofPoUhouseholdwatertreatmentandsafestoragetechnologiesistoempowerpeoplewithnoaccesstosafedrinkingwatertoimprovewaterqualitybytreatingandstoringitsafelyathome.Thebiosandfilter (BSF) is an emerging PoU water treatmenttechnologythatiscurrentlybeingimplementedandpromotedinternationally.

Laboratory studies have examined biosand filter(BSF)performance,includingitsabilitytoreducethedifferent classes of microorganisms. These studiesshowreductionsrangingfrom90%to99%forfaecalcoliform (including E.coli), approximately 90% forviruses and approximately 99.9% for protozoaparasites.

DACAAR is committed to roll out the biosandhouseholdwater treatment technology throughoutthe country and therefore, piloted and evaluatedthree projects in three different regions, namelyEast,NorthandNorth-Eastduring2010-2011. Thekeyfindingsareasfollows:

1. By thetimeof the study, theaverage lengthoftimethatBSFshadbeeninusewas10months.Thestudiesfoundthat96%ofuserswereusingthe filters consistently for their drinking waterand food preparation. The remaining 4% hadstoppedusingtheirfilter.Basedonwaterqualityanalysis the filters were effective in removing94%ofthefaecalbacteriaand96%ofturbidity.

2. Anaverageof50litresofwaterwasfilteredeachday.Allusersfeltthatthefiltersprovidedenoughwaterforthehouseholds.100%oftheregularusersreported better taste, better smell, and betterappearance.Whenaskedabouttheirperceptionoftheirfamilyhealth,100%statedithadimproved.

3. All of the respondents said that they liked thefiltermostly because “it cleans thewater” and“ithelpsourhealth”.Overall,theperceptionsoffamilies using the filterswere strongly positive,with 100% saying that they had recommendedtheBSFtoothers.Whenaskediftheythoughtthefiltersavedthemmoney,100%ofthehouseholdreported that they thought that it had savedmoneywithcommentssuchas;“didn’tgetsick,didn’tgotodoctor,anddidn’tspendmoneyonpurchasingmedicinesordrugs”.

BasedonourexperiencefromBSFprojectevaluations,experience of our field staff implementing the BSFprojects for more than three years, and Centrefor Affordable Water and Sanitation Technologies(CAWST) resources and action researches, weidentified the following best practices regardingbiosand filter manufacturing, utilization andsustainableuse.

Introduction1

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The biosand filter (BSF) is an adaptation of thetraditional slow sand filter but the biosand filter issmallerandadaptedfor intermittentuse,making itsuitable forhouseholds.Thefiltercontainercanbemadeofconcreteorplasticand isfilledwith layersofspeciallyselectedandpreparedsandandgravel.

FollowingarecomponentsoftheconcretemadeBSF:1. Lid:Tightlyfittinglidpreventscontaminationand

unwantedpests.2. Diffuser: Prevents disturbing the filtration sand

layer and protects the bio-layer when water ispouredintothefilter.

3. Filtration Sand Layer: Removes pathogens andsuspendedsolids.

4. Outlet Tube: Requiredtoconductwaterfromthebasetotheoutsideofthefilter.

5. Filter Body: Holdsthesandandgravellayers.6. Separating Gravel Layer: Supports thefiltration

sandandpreventsitfromgoingintothedrainagelayerandoutlettube.

7. Drainage Gravel Layer: Supports the separatinggravel layer and helps water to flow into theoutlettube.

. 8 Biolayer: The biolayer is the top layer of sandwhereverysmallmicrobes live.Youcannot seethem-theyaretoosmall.Theyeatthepathogensinthewaterthatmakeyousick.

. 9 Standing water:Whenthewaterstopsflowing,thereshouldbe5cmofwaterontopofthesand.Thiskeepsthebiolayerwet.Thebiolayerwilldieif itdries.But if there ismuchmore than5 cmofwater,aircannotgetthroughandthebiolayerwilldie.

. 10 Reservoir: The top of the filter wherewater ispoured in is called the reservoir. The reservoircanholdabout12litres,oronebucketofwater.

2. Components of Biosand Filter (BSF)2

Dr. David Manz developed the household biosandfilter(BSF)inthe1990sattheUniversityofCalgary,Canada. Dr Manz has trained many organizationson the design, construction, installation, operationand maintenance of the BSF. He also co-foundedCAWSTin2001toprovidetheprofessionalservices

needed for the humanitarian distribution of thefilter in developing countries. As of June 2012,CAWST estimates that over 400,000 BSFs havebeenimplementedinover50countriesaroundtheworld.DACAARand severalotherNGOshavebeenimplementingBSFprojectsinAfghanistansince2009.

1. History of Biosand Filter1

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Good quality moulds are vital to produce goodquality biosand filter (BSF) boxes. Initially, it wasdifficult tobuildqualitymoulds inAfghanistanthusitwasdecidedtotrainanumberofmetalsmithsinproductionofqualitymoulds.

Itisessentialtoconductmultiplesupervisoryvisitsbytechnicalstafftothemouldconstructionsiteinordertoprovideinstructionsandsupervisionwhilemouldconstruction is on-going. Many of the problemsnotedduringtheproductionofconcretefilterboxescanbeattributedtobadmouldconstruction.

The interiormouldboxmustbesquareso that thethicknessofalltheconcretefilterwallsareconsistent.Weldsonanysurfacethatcontactsconcretemustbeground down for smoothness. This is particularlyimportantfortheedgesoftheinnerandoutermould

toavoidbreakageoffiltersduringde-moulding.

The mould should be oiled (with edible, foodgrade oil such as vegetable oil) for storage so thatitdoesn’t rust,andmustbestored indoors.Beforepouringconcreteintoamould,theouterandinnermoulds should be cleaned from the concrete leftover particles from previous production and thenoiled.Cleaningupandoilingisimportantinordertoavoidconcreteadhesiontothemouldandtoavoidbreakage of the concrete filterwhile removing thehardenedfilterfromthemould.

The construction, installation, operation andmaintenance of biosand filter (BSF) need to becarriedoutaccordingtotheinstructionsprovidedintheCAWSTBiosandFilterManual-Version10.

3. Good Quality Mould

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Basedonstudiesconductedondifferentversionofbiosandfilters(BSF),version10isrecommendedasitismoreeffectiveinbacterialremovalthanprevious

versions.Thedesignoftheversion10BSFisincludedinCAWSTBSFtrainingmanualavailableatDACAARWETCentreandCAWSTwebsite(www.cawst.org).

Amixtureofsandgrainsizesisrequiredfortheproperfunctioning of the filter. The first option is to usecrushedrockorquarrysandasfiltrationsandsinceit has lower chances of being contaminated withpathogensororganicmaterialandhaslessuniformsizeofthegrainsaswell.

Crushed rock or quarry sand may be difficult tolocateandmoreexpensive.However, it iscritical inproviding the best water quality and is worth theextra time, effort and cost. Other options includesandfromhigherbanksofariver(thathasnotbeeninthewater),followedbysandfoundintheriverbeditself.Thelastoptionisbeachsand.

Both river and beach sand are usually well sortedanddonothaveagoodvarietyofgrain sizes fromveryfine to largegrains, therefore it is best tousecrushed rock. River sand is usually contaminatedwith pathogens (from human and animal excreta)and contains organic material (e.g. leaves, sticks).

Puttingcontaminated sand in theBSFmayactuallyresult inevenworsewaterqualitythantheoriginalsourcewaterused.Thishappensbecausetheorganicmatterisafoodsourceforpathogensandhelpsthemtogrowandmultiplyinthefilteruntilallofthefoodisconsumed.

When river sand is selected as the only sourcenearby,thenwashingandcarefullyremovingorganicmaterials is a must. When river sand is used asfiltrationsanditneedstobedisinfectedbychlorineorplacingitinthesun.

Beachsandusuallycontainssalt,organicmaterialandothercontaminantsthatwilldissolveintothefilteredwater.Flushbeachsandwithfreshwatertoremovethesalt,disinfectthesandtokillthepathogensandthenremovetheorganicmaterial.Dryingthewashedfiltration sand under the sunshinewill also kill thepathogens.

4. Selection of BSF Version

5. Selection of Filter Media

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The purpose of the diffuser is to prevent anydisturbanceofthesandsurfaceandbio-layerwhenwater isaddedat the topof thefilter.Thediffuserisessentialforthecorrectoperationofthefiltersothat pathogens do not penetrate far into the sandbedanddonotdisturbthebio-layer.

Thereareseveraltypesofdiffusersthatcanbebuilt,eachwith its own advantages and limitations. Theonethatyouchoosetobuildwilldependonyourskilllevel,thetoolsandmaterialsthatareavailable,andthepreferenceoftheuser.

BSFprojectevaluationsrevealthatinsomecasesthediffuser plateswere rusted, tilted and bent due tothepoorqualityofthesheetmetal(inotherwords30 gauge galvanized sheet metal was not used).Likewise, inother caseswhere thequalityof sheetmetal was good the bio-layers were still disturbed

duetowatertravellingfromthegapalongthewallsofthefilters.Therefore,itisrecommendedthatnogapsmustbeleftbetweentheedgesofdiffuserplateandwallsofthefilter.

Anotherrecommendationistousethemetaldiffuserbox design instead of diffuser plate as it does notletwater to traveldown thewallsof thefilteranddisturbthebio-layer.

Inusingmetaldiffuserbox, it isalsorecommendedtomakethelidfromgalvanizedsheetmetalinsteadofwood.Thislidwillfitnicelyovertheentirefilter,includingthemetalflapsofthediffuserboxthatwillhangoffthetopedgeofthefilter.Theholes inthediffuserplatehaveabearingon thedisturbanceofthetoplayer,bigholesarenotgoodandfewholesarenotcorrecteither.

Integration of hygiene education with the biosandfilter(BSF)projectisvitalforeffectiveworkingofthefilterandsafetyoffilteredwater.Therecruitmentoffemale staff for hygiene promotion is more logicalastheycancontactdirectlywiththeuserswhoaremostlywomenandgirls.Theydon’tneedpermissiontoenterthehouseasopposedtomalestaffwhowillneedpermissionforentrytoahouseholdduetotheconservativeAfghanculture.Therefore,femalestaff

willbeabletoundertakemorefollowupvisitsandconductmorehygienepromotionsessions.

Providingsafewatertoafamilythatdoesnotknowhowtohandle,storeandutilizeit,willnotbeeffectiveand will be a waste of money and time spent ontheprovisionof safedrinkingwater.Therefore, theintegrationof hygiene educationmandatory to thesuccessfulimplementationofaBSFproject.

6. Diffuser Plate and Box

7. Integration of Hygiene to the BSF Project

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Prior to the implementation of biosand filter (BSF)projects a need assessment survey is crucial toidentifythemostneedycommunities,whichinturnhelpinthesustainabilityoftheBSFprojects.ContactwithRuralRehabilitationDirectorate,NGOsexistingin the province and Community DevelopmentCouncilscanhelpinthisregard.

So thefirst step is to senda siteengineerandBSFtechnician to identify those communities whichdonothaveaccess tosafewater,buthaveenoughsources of surface water such as stream, canals,rivers, or pond. Further criteria for selection of acommunityforaBSFprojectare:

• Noaccesstosafewateratall;• Permanentaccesstoabundantsourcewater;• StrongcommitmentforutilizationofBSF;• Nopossibilitiesforboreholeduetodeeperwater

tablei.e.morethan60meters;• Hardgroundstrata;• Undergroundwatersalinity;• Watertablelessthansixmeters;• Scattered families which can’t fulfil the criteria

forconstructionofawaterpointsand;• Openwellordugwell;

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Proper mobilization of intended community is keyto successful and sustainable implementation ofa biosand filter (BSF) project. Community hygienepromoters can do it through different approachessuchasmeetingwithcommunityeldersduringneedassessmentsurveys,briefingsessiononimportance

andutilizationofBSF,andinintroductorymeetingwithwomen.Itisrecommendedtousevisualeducationalmaterials forallmeetingswithcommunity inordertopresenttheBSFanditsimportanceinaneffectivemanner.

Introductionofbiosandfilter(BSF)ashouseholdwatertreatment technology is easyandwell acceptedbyruralcommunitiesinAfghanistan,asthetechnologyis understood. In demonstration projects, users of

BSF recommended the technology to others, theywere100%satisfiedwithfiltersandtherewasahighdemand for this technology during demonstrationsofthefilterinneighbouringcommunitiesaswell.

Oncecommunitiesareidentifiedinneedassessmentsurvey for the biosand filter (BSF) projectimplementation, it’s time to select households forBSFdistributionandinstallation.

AgaintheSiteEngineertogetherwithBSFtechniciangotocommunitiesandgatherthecommunityeldersin a guest roomor in a public gathering place andbriefthemontheimportanceofandprocedureforthedistributionand installationofthefilterstothehouseholds.

Site Engineer and BSF technician explain to thecommunities that this is a demonstration projectand we will allocate xx number of filters to yourcommunityaswecan’tcovertheentirecommunity,firstpriorityshouldbegivento:

• ThosewithstrongcommitmentforutilizationofBSF

• Womenheadedfamilies;• Poorfamilies;• Familieswithdisabilities;and• Familieswithnoaccesstosafewatersourcesat

householdornearby.

The staff will then ask the community elders tonominatehouseholdsthatfulfiltheaforementionedcriteria forBSF forfinal selectionthenextday.Thefollowingday,nominationsarediscussforselection,and ifnoagreementcanbe reachedanalternativevillage can be selected that follows the criteria forBSFdistributionandinstallation.

9. Mobilization of a Community

10. Acceptance of BSF Technology

11. Selection of Household for BSF

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It is important to determine a good location forthebiosandfilter (BSF).Placingthefilter insidethehouse (room or kitchen) is important not only forfiltereffectiveness,butalso for the convenienceofthe users and avoiding filters from freezing due tocoldwinters inmost parts of Afghanistan inwhichcasethecontentofthefiltercanfreeze,resultinginmalfunction and even cracking of the filters. If theuserscanaccess thefiltereasily, theywillbemorelikely touseandmaintain it.Oncefilledwithsand,thefiltershouldnotbemovedandshouldbeplacedinfollowingrecommendedplaces:

• Inaprotectedlocationawayfromsunlight,wind,rain,animals,andchildren;

• Preferably inside the house (room or kitchen)on levelgroundofconcreteorwoodenplatetoavoidthefilterfromslidingtooneside,bendingortiltingduringoperation;

• Near the food preparation or kitchen area(dependingonthespaceandlayoutofthehouse)

• Whereitwillbeusedandmaintainedeasily• Where there’s adequate room for carrying and

pouringbucketsofwaterintothefilter,aswellasstoringthefilteredwater.

12. Location for Installation

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Properoperationandmaintenanceofafilterisvitalfor enhancement of filter effectiveness. Therefore,educationonoperationandmaintenanceshouldbecarriedoutperiodically andatdifferenttimes suchas,duringinstallationoffilterathousehold,hygienepromotionsessionsandfollowupvisits.

Women’s role in operation and maintenance isobvious as they are the main users of the filters,therefore the femalehygieneprompter should pay

more attention in educating women and girls intheoperationandmaintenanceofBSFduring theirhygienepromotionsessionsandfollowupvisits.

It is to be mentioned that the hygiene promotersshouldbeproperlytrainedonbiosandfilteratbothaspects, theoretical and practical. But the moreimportant component they should focus on is theoperation and maintenance component as theyteachthiscomponentdirectlytotheusers.

15. Education on Operation and Maintenance

It is essential to conduct follow-up visits with theuserstoensureproperuseandmaintenanceofthefilters. There should be a series of follow up visitswithahousehold,oneduringthefirsttwoweeksofuseandothervisitsduringtheprojectlifetime.

Thesefollowupvisitsbyhygienepromotersshouldbeconductedat least threetimes in the lifeof theproject. BSFtechnicianshouldalsoconductfollow-upvisitsinthebeginningandmiddleoftheproject.

16. Follow up Visits

SincemanyBSFusersmakeuseofturbidwaterfromrivers,ponds, streamsandcanals as sourcewater,this can clog the BSF and decrease the flow rateveryquickly.Toavoidaforementionedsituation,itisimportanttocollectsourcewaterinadrumorinabigcontainerandlettheparticlessettleatthebottomofthevesselforsometime(couldtakehoursoraday)beforepouringintothefilter.

Anotherwaytodecreasetheturbidityofthesourcewaterandprevent thecloggingoffilter is strainingwhichinvolvesputtingapermeableclothonthetopofthefilteratthetimeofpouringwaterin.Aclothiseffectivewhenlargerparticlesandorganicmaterialsarefoundinthewatercollected.

14. Pre-treatment of Source Water

Distributionofsafewaterstoragecontainertogetherwithfilterisimportantasitwillhelppeopletokeeptheirfilteredwaterfromrecontamination.Ifresourcesareavailable,twocontainers(20litreseach)shouldbedistributedtoeachhousehold,onetobeusedforcollectionofsourcewaterandtheotherforstorage

of filteredwater. The containers should be narrowmouthedandpreferablyatapatbottomtogetthedrinking water from. Evaluations done by DACAARshowthatfilteredwaterwasre-contaminatedwhenimproperstoragecontainerwasused.

13. Distribution of Water Container with Filters13

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OnewaytoreplicatethetechnologyistoinvolvethesmallentrepreneurandBSFtechnicianfromtheverybeginning of the project implementation. This willencouragethemtostarttheirsmallbusinessesintheirowncommunities.ItmakessensetoequipthemwithatleasttwoqualitymouldsandaBSFtoolkit.

ProductionofpoorqualityBSFandprovisionofpoorqualitymediaforthefiltersbylocalentrepreneursaresomeofthechallengestobedealtwith.OnewaytotackletheseistoassignanexperiencedBSFtechniciantoworkcloselywiththeentrepreneursandpayseveralsurprisevisitsduringtheirproductionandinstallationuntilsatisfiedwiththequalityoftheirwork.

19. Replication of BSF Technology

• Install filter inside the house (kitchen or otherroom)

• Goodquality sheetmetal fordiffuserplateandbox

• Integration of hygiene promotion with BSFprojects

• Properoperationandmaintenance• Notlettingthefiltertodryout

• Collectwaterfromonesourcealways• Pre-treatmentofthesourcewater• Strainingofthesourcewater• Separatecontainerforcollectionandstorageof

water• NospoutandpipeattachedtotheBSFoutletpipe• Nodisplacementofthefilter

17. Key Practices for Enhancement of BSF Effectiveness

•Watersource– Notverydirty(turbiditynotgreaterthan50NTU)– Samesource(ifpossible)

•Developingthebio-layer– Maytakeupto30daystogrow– Notvisible

•Flowrate– Controlledbysandsize-sievingandwashing– 0.6litres/minuteorslower(V9)– 0.4litres/minuteorslower(V10)

•Pauseperiod– Microorganismsconsumepathogens– Usefilterdailyatleastonceforthebest efficiency– Uptofourtimesperday– Minimumpauseperiodfor1hour, maximumof48hours

•Waterdepth– Tooshallow–bio-layerdriesout– Toodeep–insufficientoxygenforbio-layer– Waterlevelof5cmabovethesandduring thepauseperiod

•Oxygenlevel– Duringthepauseperiodthestandingwatershouldnotbemorethan6cmtoletoxygen fromtheairdiffusethroughthestanding watertothebio-layer.

•Filteredwaterquality– 90-99%pathogenremovalefficiency– Disinfectionrecommended

•Maintenance– Sandbecomescloggedwithdirtovertime– Dothe‘swirl&dump’whentheflowrateis tooslow

18. Key Operating Parameters to Be Considered

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The biosand filter for single household can be agood solution for families who especially collectsurface water from rivers, kandas, other surfacewatersourcesandshallowwells.Thefilterhasmanyadvantagesandisawatertreatmenttechnologythatcanbe effectively usedby consumers for acquiringsafedrinkingwaterathome,providedthattheyhavea dedicated container that is narrow mouthed inordertostorefiltereddrinkingwaterandpreventre-contamination.

Thefiltermustbemaintainedproperlyforthelocalcircumstances. Hygiene education and training intakingcareofthesandfilterisessential.Theladiesofthehouseholdwillbethemostappropriatetargetgroup to maintain the filters. It is also importantto take care that the pouring of thewater is donewithoutdisturbingtheplateandsandtoplayer(bio-layer).

In order to prevent water from passing betweentheedgesofthediffuserandwallsofthefilter it isrecommendedthatnogapsmustbeleftbetweenthetwo. Another recommendation is to use themetaldiffuserboxdesigninsteadofdiffuserplateasitdoesnotletwatertotraveldownthewallsofthefilteranddisturbthebio-layer.Inusingmetaldiffuserbox,itisalsorecommendedtomakethelidfromgalvanizedsheetmetalinsteadofwood.

The quality of the filter will have an effect on theconsumer, so the production must be checked.Trainingofartisansintheproductionofthefilteronitsownwillnotbesufficienttoguaranteethatgoodfunctionalboxesareproducedandcanbeused.Theselection of sand and the training aspectwill haveto go alongwith the production and selling of thebiosandfilters.Theamountofholes in thediffuserplate is another important point as too big holes(morethen3mmdiameter)andtoofewholes(lessthen36holes)willdisturbthebiolayer.

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Formorepleasevisitourwebsitewww.dacaar.org

DACAAR MAIN OFFICE KABULPaikob-e-NaswarWazirabad

POBox208,Kabul,Afghanistan

Phone:(+93)(0)202201750(+93)(0)202200330Mobile:(+93)(0)797011022E-mail:dacaar@dacaar.org

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Phone:+4533735000E-mail:copenhagen@dacaar.org