25EfficiencyofDuckweedsforDesalinationand

LeibnizCentreforAgriculturalLandscapeResearch(ZALF)EfficiencyofDuckweedsforDesalinationandTreatmentofAgriculturalDrainageWaterinDetentionPondsM.Sc.MohieEldeenOmar(Egypt)-PhDScholarshipSupervisors:Dr.DagmarBalla(ZALF),Prof.M.Barjenbruch,Prof.R.Hinkelmann(TUBerlin)Mai2009Fig.1:SchemeofagriculturaldrainagesystemwithproposeddetentionpondsDetentionPondSubsurfaceDrainOpenDrainBranchDrainCollectorDrainMainDrainIrrigationCanalforReuseIrrigationCanalforReuseFig.1:SchemeofagriculturaldrainagesystemwithproposeddetentionpondsDetentionPondSubsurfaceDrainOpenDrainBranchDrainCollectorDrainMainDrainIrrigationCanalforReuseIrrigationCanalforReuseSubsurfaceDrainOpenDrainBranchDrainCollectorDrainMainDrainIrrigationCanalforReuseIrrigationCanalforReuseMethodology●UsingstandardizedLemnatest(OECD,2002)underlaboratoryconditionsinclimatechambersfortestingcriticalsaltconcentrations●Experimentsinoutdoorcontainerschargedwithdrainagewaterundernaturalconditionsforestimatingtheuptakefunction●HydrodynamicmodellingofdetentionpondsbysoftwarepackageTELEMACusingexistingdetentionpondconstructions(seeposterSteidletal.)ResultsLemnatestLemnatestisusedtodeterminetherelationshipbetweensalinityandgrowthrateofL.minoraswellasdesalinationandsalinityeffectonnutrientremovaloversevendays.Growthassessmentisbasedonfrondnumberanddryweight.Frondsarethesingleleaf-likestructuresofduckweeds.EC50,theconcentrationcaused50%ofgrowthinhibition,lowestobservedeffectconcentration(LOEC)andnoeffectconcentration(NOEC)aredetermined(OECD,2002).100)(%×−=CTCbRGRRGRRGRI%Ib–inhibitiongrowthpercentofdrymassfordifferentNaClconcentrationsRGRc–relativegrowthrateforcontrolRGRT–realtivegrowthratefortreatmentgroupsLemnatest-100-500501001502002502,63,13,6Log10ofNaClconcentrationI(%)ofdrybiomass-40-200204060802,52,7533,253,53,7544,25LOG10NaClconcentrationsNO3Removal%-200-150-100-5005010001234LOG10NaClconcentrationsCaRemoval(%)-40-200204060802,52,62,72,82,93LOG10NaClconcentrationsCaRemoval(%)●Duckweed`sgrowthisinhibitedsignificantly(p0.05)byNaClincrease,however,duckweedshowspromotedgrowthuptosalinityconcentrationof1.3g/l●Duckweedremovedupto25%ofinitialsalinity.●Thenitrateremovaldecreasesstrongly(p0.01)withsalinityincrease,buttheremovalisnotaffected(p0.05)bysalinityincreaseupto1.3g/l.●Calciumremovaldecreaseswithsalinityincreasesignificantly(p0.05).750100012501500175020002250250020.5.0830.5.089.6.0819.6.0829.6.089.7.0819.7.08Saltmassincontainers(g/d)012345678910Saltmassofprecipipitation(g/d)PrecipTank(1)Tank(2)-30-20-100102030405020.05.200825.05.200830.05.200804.06.200809.06.200814.06.200819.06.200824.06.200829.06.200804.07.200809.07.200814.07.200819.07.200824.07.2008Removalrate(g/d)050100150200250Cumulativeremoval(g/d)Tank(1)Tank(2)CumulativeinTank(1)CumulativeinTank(2)90011001300150017001900210029.7.083.8.088.8.0813.8.0818.8.0823.8.0828.8.082.9.087.9.08Saltmassincontainers(g/d)012345678910Saltmassofprecipitation(g/d)PrecipTank(1)Tank(2)-50-30-101030507029.07.200803.08.200808.08.200813.08.200818.08.200823.08.200828.08.200802.09.200807.09.2008Removalrate(g/d)050100150200250300350Cumulativeremoval(g/d)Tank(1)Tank(2)CumulativeinTank(1)CumulativeinTank(2)●Duckweedsgrowwelleitherinnormalorsalinewaterwithobservablelessgrowthinsalinewater.Adaptiontohighsalinitytakesplacewithlongertime.●Duckweedsaccumulatesaltsintissuesandsubsequentlyremoveswatersalinity.●TheaccumulationofNt,P,andNO3-Nintheduckweedtissuesdecreaseaslongaswatersalinityincrease.Outdoorcontainerswithactualdrainagewater67cm380cm80cmRainfall75cmRulerV=1750LRainfallguage67cm380cm80cmRainfall75cmRulerV=1750L67cm380cm80cmRainfall75cmRulerV=1750L67cm380cm80cmRainfall75cmRulerV=1750LRainfallguage)*()*(JCPAdtCVdPS−=¾SaltbalanceincontainerV–watervolumeincontainer,m3t–time(d)Cs–saltconcentrationofwater(g/m3)A–surfacearea(m2)P–precipitationrate(m/d)J–removalrate(g/d)¾Saltandnutrientsinduckweedtissuesbycentrifugationandanalysationofcationsandanionsafter6weeksTheresearchisfundedbyBMBF,IPSWaTProgrammesupportedbyTUBerlin,andZALF-Verbundprojekt3.2WasserverfügbarkeitundGewässerqualitätOutdoorcontainerswithactualdrainagewaterFig.1Duckweed(Lemnaminor,Spirudelapolyrhiza)Background●Detentionpondsareaneffectivemethodforreducingdrainagewatermatterconcentrations●Solidsanddissolvedmatteraresettled,accumulatedandtransformedbybiotaandchemicalprocesses●Inaridzonessalinizationplaysakeyroleinusageofwaterforagriculturalneeds•Biologicaluptakeofsaltandnutrientsbybiomasscouldenhancewaterpurification•Duckweeds(Fig.1)arefastgrowing,aquaticfree-floatingmacrophytesrangingintheworldfromtropictoarticzone.Theyhaveproventheirefficiencyforremovalofnutrients●Detentionpondscouldbeintegratedindrainagesystems,asshowninFigure2Scopeofresearch●Provingdesaliniationfunctionofduckweeds●Investigationoftheinfluenceofhighsalinity(NaCl,10g/l)onduckweed`sgrowthandnutrientelimination•Estimationoftheuptakefunctionindependenceontimeandtemperature•Optimizingthepondconstructionwithrespecttohydraulicefficiency,saltremovalefficiencyandminimizingwaterlosses●Developingtransferfunctionsforaridcondi