Effect of Combined Plant-Rope Ecological Floating Beds on Improvement of Eutrophic Water Quality

Recently,lakeeutrophicationhasbecomeaseriousconcernanditscausesandcontrolshaveattractedgrowingattentionworldwide.Intheexperimentsdescribedhere,wehaveusedIpomoeaaquaticaasanexperimentalplantforusewithecologicalfloatingbeds.Threekindsofcombinedecologicalfloatingbedsystemswereconstructedbyhangingtwokindsofrope(hempandPST)belowthebeds,andtheireffectivenessforimprovingwaterqualitywasinvestigated.Theresultsshowedthattheplantecologicalfloatingbed,plant-PST-ropecombinedbed,andplant-hemp-ropecombinedbedprovidedsignificantremovaleffectsonTN,NH4+-N,TPandDIP.Removalefficiencieswere39.09%,49.46%and60.43%,44%55%,67.79%and70.05%,63.68%,54.72%and71.70%,and53.70%,50.62%and64.20%,respectively.Theplant-hemp-ropecombinedfloatingbedhadespeciallyhighNandPremovalrates.Inthethreekindsofecologicalfloatingbeds,thecontributionsofplantabsorptiontoNandPremovalwere36.13%and71.85%,32.15%and87.07%,27.11%and74.34%,respectively.ThissuggestedthatforNremovalinthesystem,plantuptakeaccountedforarelativelysmallportionoftotalabsorption,andthatdenitrificationbymicroorganismsmightplayamoreimportantrole.However,plantuptaketooktheleadingroleinPremovalinallthreekindsoffloatingbeds.Therefore,thecombinedecologicalfloatingbedhavingbothropesandplantswasaneffectivewayforimprovingthequalityofeutrophicwater.