不同氮磷比条件下绿球藻对猪场污水的净化效率

采用添加NaH_2PO_4的方法调节猪场污水中氮磷比(N∶P)分别为8∶1、16∶1、32∶1和64∶1,以未添加NaH_2PO_4的污水为对照(氮磷比为532∶1),探讨一株耐污绿球藻(Chlorococcum sp.)在不同氮磷比污水中的生长性能及其对猪场污水(初始氨氮浓度为291.31 mg·L~(-1))的净化效果.结果表明:经过12 d的培养,绿球藻(接种密度为400×104cells·m L~(-1))在N∶P为64∶1的污水中生长最好,且对污水中氨态氮和总氮的去除效果最佳,细胞密度和生物量分别为3393×104cells·m L~(-1)和0.49 g·L~(-1),对氨态氮和总氮的去除率分别为74.94%和48.78%,显著高于对照组,氨态氮浓度降低到73.01 mg·L~(-1),总氮浓度降低到148.96 mg·L~(-1).培养期间各试验组污水中硝态氮浓度均升高.培养12 d后,N∶P为64∶1组污水中总磷浓度降低为3.07 mg·L~(-1),去除率为71.86%.综上,绿球藻在N∶P为64∶1的污水中生长性能及其对污水中氨态氮和总氮的去除效果均最佳,可使污水中的氨态氮和总磷浓度基本达到相关排放标准.

Purification efficiency of swine wastewater by Chlorococcum sp. with different N:P ratios

The present study was conducted to investigate the growth and purification efficiency of swine wastewater (initial ammonia nitrogen content of 291.31 mg·L^-1) by microalgae Chlorococcum sp. under different N/P (8:1, 16:1, 32:1 and 64:1), mediated by supplementation of NaH₂PO₄.After 12 days'' cultivation, Chlorococcum sp. (inoculated 400×10⁴ cells·mL^-1) cultured in swine wastewater with N:P of 64:1 obtained the highest growth with the maximum cell density of 3393×10⁴ cells·mL^-1 and biomass concentration of 0.49 g·L^-1. The concentrations of ammonia nitrogen and total nitrogen decreased to 73.01 mg·L^-1 and 148.96 mg·L^-1, respectively, with removal rates of 74.94% and 48.78%, respectively, which were significantly higher than those of the control. However, the nitrate concentration in all treatments increased during the cultivation. Also, the concentration of total phosphorus in the group with N:P of 64:1 decreased to 3.07 mg·L^-1 with removal rate of 71.86% after 12 days'' cultivation. In summary, Chlorococcum sp. displayed the best growth performance and efficient purification of ammonia and total nitrogen in swine wastewater under N:P ratio of 64:1, and the contents of ammonia nitrogen and total nitrogen in the swine wastewater would generally reach the discharge standards after purification.