过滤对污水—微藻培养体系中氮磷去除的影响研究

Effect of Filtration on Removal of Nutrients from Wastewater by Cultivation of Chlorella Vulgaris

本文通过比较污水和过滤污水中培养小球藻对微藻基本指标和污水中氮磷的去除效果,研究过滤对污水-微藻培养体系的影响。研究结果显示,微藻生物量在污水和过滤污水中分别在8 d和10 d达到最大值,分别为6.4×106和10.3×106个/mL。相比较于污水,过滤污水中的pH、藻密度和叶绿素a均较高,但在污水和过滤污水中基本都呈现相同的先增加后减小的趋势。污水中溶解氧变化趋势与藻密度一致,过滤污水中较高水平溶解氧维持时间更长。小球藻生长对污水和过滤污水中氨氮去除效果明显,但硝态氮的变化趋势有所不同。污水中总氮和总磷在15d从开始的9.74和1.39 mg/L分别降低到最低值3.44和0.15 mg/L。过滤污水中的总氮在21 d从开始的9.52 mg/L降低到了最低值2.66 mg/L,而总磷在12 d从开始的1.39 mg/L降低到了最小值0.03 mg/L。微藻生长对污水和过滤污水中TP的去除效果要好于TN。污水中氮磷在达到最低值后普遍呈不同程度增加趋势,这可能是由于微藻生物量在达到极大值后开始衰亡,释放胞内物质。对污水进行过滤可显著提高微藻生物量,但对污水中氮磷去除无明显差异。

The removal of pollutants in wastewater and filtered wastewater by cultivation of Chlorella vulgaris was carried out in this study. The highest biomass values were observed at 8 d and 10 d in wastewater and filtered wastewater, being 6.4×10^6 and 10.3×10^6 n/mL, respectively. Medium pH, biomass, and chlorophyll a all exhibited an increasing and then decreasing trend with cultivation time. The variation of medium DO was consistent with that of microalgal biomass, but higher DO remained for a longer time in filtered wastewater than that in wastewater. Growth of microalgae both posed a significant effect on the removal of ammonium in wastewater and filtered wastewater, but variation of nitrate shown a different trend. Nitrate concentration was significantly enhanced in filtered wastewater after cultivation of microalgae due to oxidation of ammonium, and then began to decrease after 12 d, while that in wastewater increased to 2.1 mg/L, and kept a stable level, but continued to increase after 15 d. TN and TP in wastewater were both reduced from 9.74 and 1.39 mg/L to 3.44 and 0.15 at 15 d, respectively. TN in filtered wastewater was reduced from 9.52 mg/L to 2.66 mg/L at 21 d, while TP was reduced from 1.39 mg/L to 0.03 mg/L at 12 d. In a whole, microalgae cultivation in wastewater and filtered wastewater both posed a higher removal of TP than that of TN.TN and TP in wastewater and filtered wastewater both began to show an increasing trend after being highest values, which might be attributed to the release of intracellular organic matter after decay of microalgae. Filtration on wastewater obviously enhanced the microalgal biomass, but posed no significant effect on removal of N and P in wastewater.