藻-菌单一及共生系统对海水养殖尾水的净化作用

为探索高效可行的海水养殖尾水处理技术,在净化尾水污染物的同时达到微藻生物量积累,本文对比了普通小球藻(Chlorellavulgaris)和芽孢杆菌(Bacillusspp.)在游离和固定形态下,单一和共生系统的细胞生长及其对尾水中氨氮(NH_4~+-N),正磷酸盐(PO_4~(3–)-P),总磷(TP),化学需氧量(COD_(Mn))的去除效果。实验结果表明:游离状态下,藻–菌共生系统促进小球藻细胞生长及尾水中PO_4~(3–)-P和COD_(Mn)的去除。固定态藻–菌共生系统对NH4~+-N, PO43–-P和TP的处理效果优于单一固定态小球藻和单一固定态芽孢杆菌。对比实验设计的所有处理(游离或固定态下的单一藻、单一菌、藻–菌共生),藻–菌共固定系统的处理效果相对最优,对NH_4~+-N, PO_4~(3–)-P, TP和COD_(Mn)的去除率分别达到96.57%, 98.62%, 89.89%和39.09%,出水NH_4~+-N, PO_4~(3–)-P分别达到中国《渔业水质标准》和《海水养殖水排放要求》二级标准, COD_(Mn)达到《污水综合排放标准》二级标准。

Purification of mariculture wastewater by utilizing single and symbiotic systems of microalgae-bacteria treatment technology

To explore an efficient and feasible treatment technology of mariculture wastewater, with a win-win strategy of achieving the remediation of mariculture wastewater, and also accumulating microalgae biomass, this study investigated two modes of aquaculture wastewater bioremediation (i.e., free-state mode and immobilized mode) with monoculture and symbiotic systems of the microalgae Chlorella vulgaris and bacteria Bacillus spp. The cell growth and removal of wastewater nutrients, such as ammonium (NH₄⁺-N), phosphate (PO₄^3--P), total phosphate (T_P), and chemistry oxygen demand (COD_Mn) were tested. Under the free-state mode, microalgae-bacteria symbiosis significantly increased the dry cell weight of C. vulgaris and promoted the removal of PO₄^3--P and COD_Mn Under immobilized conditions, the co-immobilization of C. vulgaris and Bacillus spp. enhanced the removal efficiency of NH₄⁺-N, PO₄^3--P, and T_P as compared with that of the monoculture treatment in the same mode, and both nutrient uptake capabilities of microalgae and bacteria were mutually enhanced. Overall, the highest removal efficiency of NH₄⁺-N, PO₄^3--P, T_P, and COD_Mn of 96.57%, 98.62%, 89.89%, and 39.09%, respectively, was achieved under the bioremediation of co-immobilization of C. vulgaris and Bacillus spp. The concentration of NH₄⁺-N and PO₄^3--P in effluent reached the national second-level standards of "Water Quality Standards for Fisheries" and "Drainage Standard for Sea Water Mariculture," whereas the value of COD_Mn met the second-level of "Integrated Wastewater Discharge Standard." These results showed that the monitored effluent indexes met the national seawater quality standards and the concept of combining mariculture wastewater treatment with the microalgae-bacteria symbiosis is feasible under indoor laboratory conditions. It also showed that higher purification efficiency can be achieved by co-immobilized microalgae-bacteria symbiosis. In the future, the selection of immobilized materials, the tolerance of microalgae-bacteria symbiosis to high salinity in seawater, and the separation methods of microorganisms from the effluent should be investigated.