25-Efficiency-of-Duckweeds-for-Desalination-and

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(p<0.05)byNaClin