乙醇废水培养浮萍及其沼气发酵利用

Research on the Duckweed Cultivation in Alcohol Wastewater and Energy Utilization

利用乙醇废水氧化塘出水培养校内湖泊淡水浮萍(青萍),确定了最适稀释倍数为10倍。149 g/m2(湿重)初始接种密度下获得了浮萍最大相对生长率(RGR)9.11%,以干重计的蛋白质质量分数为28.50%;不同接种密度浮萍对培养废水中总氮(TN)、总磷(TP)、氨氮(NH4+-N)和化学需氧量(COD)的去除效果相差不大,去除率分别为46%~49%、70%~79%、78%~82%和35%~38%。浮萍厌氧消化结果表明:其具有单独生产沼气的能力;将其与剩余污泥混合厌氧消化,通过底物互补的优势,缩短了产甲烷酸化期,提高了厌氧消化产气能力,其累积产气量实际值为2 963 mL,比计算值2 669 mL提高了11%;且混合厌氧消化提高了产生气体的甲烷纯度,由浮萍组的50.29%提高到混合组的56.93%.

The freshwater duckweed(Lemna minor)from the campus lake is cultured in the alcohol waste water(oxidation pond effluent).The optimum dilution ratio of alcohol waste water is 10 times.The maximum Relative Growth Rate(RGR)and protein content are 9.11%and 28.50%,respectively when the initial seeding density is 149 g/m2(wet weight);The removal efficiencies of TN,TP,NH4+-N and COD of alcohol wastewater are similar under different seeding density.They are 46%~49%,70%~79%,78%~82%and 35%~38%respectively after culturing the duckweed for 8 days.The results show that duckweed has the ability to produce methane individually by the anaerobic digestion process;Methane-producing acidification period is shortened and the gas production capacity is improved for the advantages of complementary substrate by mixing the duckweed with excess sludge.The actual value of cumulative gas production is 2 963 mL,which is 11%higher than calculated value of 2669 mL;In addition,methane purity is improved,from 50.29%of duckweed group to 56.93%of mixed group.