Effect of exchange rate of the medium (water and biodigester effluent) on biomass yield and composition of duckweed

摘要

Duckweedwasgrowninplasticbinsof100litrecapacitywithawatersurfaceareaof0.17m2.Thesourceofnutrientswaseffluentfromabiodigesterchargedwithcattlemanuremixedwithwaterintheratioof9.1%effluent:90.9%water(byvolume).Fiveratesofexchangeofthemediumwerecompared:0,9.1,13.6,18.2and22.7%perday.Thereweresignificantdifferencesinyieldandincontentofdrymatter,crudeprotein(N*6.25),phosphorusandcrudefibreduetomediumexchangerate,thetrendsbeingpositiveforyield(R2=0.99),andcontentofdrymatter(R2=0.95),crudeprotein(R2=0.99)andphosphorus(R2=0.95)andnegativeforcrudefibre(R2=0.62).Itissuggestedthatthebeneficialeffectsofpartialexchangeofthemediumcouldberelatedtothereductionintemperature(from33.2to31.4oC)inthemediumortotheremovalofcompoundspresentinthebiodigestereffluentthatwereinhibitorytogrowth.