半连续及连续培养小球藻减排沼液及CO2

采用半连续或连续模式培养小球藻,考察小球藻减排沼液和CO2的能力。结果表明:在半连续培养模式中,当更新率为30%时,沼液中的N、P质量浓度可分别稳定在16～18和0.4～0.6 mg/L,达到污水二级排放标准;提高更新率到40%以上,3 d后微藻生物量及其对沼液中N、P的吸收达到动态平衡,但N、P去除率未达到污水直接排放标准;在连续培养模式中,分别选用20%及30%的日更新率,7 L规模12 d后沼液中的总氮(TN)仍高达55.64 mg/L。说明大规模培养条件下的光限制是微藻法减排沼液的主要制约因素。

Reduction of biogas slurry and CO2 by Chlorella vulgaris in semi-continuous and continuous cultures

Chlorella vulgaris was cultivated by semi-continuous and continuous mode to reduce the emissions of both biogas slurry and CO2.In semi-continuous cultivation mode,when the renewal rate was 30%,nitrogen and phosphorus contents in the biogas slurry were stable at 16 to 18 mg/L and 0.4 to 0.6 mg/L,respectively,which met the secondary sewage discharge regulations.While the renewal rate increased to higher than 40%,a dynamic equilibrium was obtained between the microalgae biomass and its absorption of nitrogen and phosphorus in the biogas slurry after three days,but the removal rates of nitrogen and phosphorus did not meet the direct sewage discharge standard.Effects of chlorella vulgaris on the removal of nitrogen and phosphorus in the biogas slurry were investigated in a columnar photobioreactor by selecting the daily renewal rates at 20% and 30% in continuous mode.The results exhibited that the total nitrogen amount in the biogas slurry remained at 55.64 mg/L after 12 days on the 7 L scale.Emission reduction of biogas slurry employing the microalgae method was primarily restricted by the light limitation during the large-scale cultivation.