This experiment was conducted by employing immobilized microorganisms (I) on ceramics and Myrio-phyllum aquaticum (M) and unloaded ceramsite (UC) to purify aquaculture wastewater in the lab. Different nitro-gen forms removed from aquaculture wastewater and the dynamic distribution of four groups of bacteria involved in nitrogen cycling, ammonifiers (AB), nitrosobacteria (NOB), nitrifiers (NB) and denitrifiers (DB), were evalu-ated. Our results revealed that the removal efficiency of nitrogen and chemical oxygen demand (CODMn) per-formed by the combined treatment (I+M) was significantly higher than when used separately (P<0.05). By the end of day 15, the nitrite and ammonium removal rate by the I+M treatment reached 50.83% and 62.38 %, respectively, significantly higher than I (39.55% and 51.17%) or M (40.78% and 53.31%) separately (P<0.05). At the end of the experiment, CODMn removal by the I+M treatment was significantly higher (67.23%) than that of treatment I (48.23%) or M (33.35%) (P<0.05); the nitrate removal rate (88.74%) was also significantly higher than I (67.85%), but there was a significant difference between I+M and M (P<0.05). In addition, four groups of bacteria on the roots surface increased in certain extent compared with treatment M, and during the last period four groups of bacteria on the ceramic surfaces showed an overall downward trend, e.g. AB in treatment I+M were 1.8~2.6 mag-nitudes lower than in treatment I. Principal response curve analysis (PRC) showed that turbidity, NO− -N, TN con-3 tribute great to total difference, during the early and middle stages of this experiment the combined treatment was more efficient at removing nitrogen than treatment I or M, but the overall differences between I and UC decreased greatly in the later stage with differences between I+M and I becoming small. This purifying method has some drawbacks and therefore requires further optimization to ensure its effects are long lasting.% 在实验室条件下,以固定化菌种枯草芽孢杆菌(Bacillus megaterium)、弯曲芽孢杆菌(B. flexus)和大型水生植物粉绿狐尾藻(Myriophyllum aquaticum)为实验材料,研究微生物与水生植物两者单独或联合作用等不同处理模式对水体不同形态氮素的去除效果及氨化细菌(AB)、亚硝化细菌(NOB)、硝化细菌(NB)和反硝化细菌(DB)4类氮循环细菌的动态分布情况,实验阶段为25 d.结果表明,与固定化微生物(I)、粉绿狐尾藻(M)分别单独作用相比,两者联合作用(I+M)对水体氮素和 CODMn 的去除效果显著.比较实验前15天, I+M 对养殖废水亚硝态氮( NO−-N)和2铵态氮( NH+-N)的去除率分别达50.83%和62.38%,显著高于 I(39.55%和51.17%)与 M(40.78%和53.31%)(P<40.05).实验结束时, I+M 水体 CODMn 的去除率达67.23%,显著高于 I(48.23%)与 M(33.35%)分别单独作用(P<0.05)；I+M 对养殖废水硝态氮( NO−-N)的去除率高达88.74%,显著高于 I(67.85%)(P<0.05),但与 M 无显著差异.另外,3 I+M 植物根系表面4类氮循环细菌的数量相比 M 组均有不同程度的增加,而载体表面的4类氮循环细菌数量实验后期整体呈现下降趋势,其中 I+M 载体表面 AB 数量始终比 I 低1.8~2.6个数量级.主响应曲线分析(PRC)表明,水体浊度、NO−-N、TN 等对造成组间差异的贡献较大,实验前中期 I+M 组对养殖废水的净化效果强于两者分别单3独作用,但实验末期 I 组与 UC 组间的总体差异大幅度减小,且 I+M 与 M 的差异很小.结论认为,利用固定化微生物与粉绿狐尾藻联合处理循环养殖废水能有效提高对养殖水体NO−-N、2 NH+-N、CODMn 等的去除效果,从而减4轻氨氮和亚硝态氮等物质对养殖生物的毒害,使得养殖生物能维持正常的物质代谢,但在实际工厂化养殖生产中应综合考虑养殖废水的水质状况、固定化菌种组分及其生理生化特性、植物种类及搭配等因素,使反应器的设计更加科学以确保系统稳定、高效、持久地运行.本研究旨在为构建高效、稳定的养殖废水生态净化模式提供科学依据.
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