基于固着藻类反应器的生态沟渠构建

为使池塘循环水养殖系统中人工湿地出水更加满足养殖水质要求,在长×宽×深为150m×0.5m×0.6m的养殖池塘排水沟内借助固着藻类反应器原理设计构建了生态沟渠,研究了生态沟渠对人工湿地出水溶氧恢复状况及深度净化效果。研究结果显示,人工湿地出水溶氧经过生态沟渠后显著提高至4.41～7.91mg/L,pH值显著提高(P﹤0.05)。在150m长度范围内,生态沟渠水中溶氧量随着沟渠长度的增加呈线性增加的趋势(P﹤0.05)。生态沟渠对人工湿地出水中NH4+-N、IMn和PO43--P等具有进一步去除效果,去除率分别达19.46%、13.38%和31.09%,对总大肠菌群的去除率范围在12.5%～78.13%。上述结果表明基于固着藻类反应器的生态沟渠能使人工湿地出水溶氧低的状况得到改善,N、P等物质得到进一步去除,可以作为与人工湿地配套的水回用系统。

太湖水/沉积物界面固着藻类的时空分布特征

2004年6月至2005年4月分别选取太湖湖泊的草型、藻型及过渡型区域为研究对象,对不同类型湖泊水/沉积物界面中固着藻类的分布情况进行了调查。结果表明:在种群分布上,硅藻门(53.85%)和绿藻门(34.62%)最多,其次是蓝藻门(7.69%),而裸藻门(3.84%)相对较少,各采样点的优势种主要集中在硅藻门;在季节分布上,夏季和秋季种类和数量较多,冬季最少;在空间分布上,草型湖泊在全年(6月份除外)的藻种类和密度居多,过渡型湖泊次之,藻型湖泊最低(11、12月份除外)。另外,在藻型湖泊(站点3)中发现了越冬的微囊藻。根据各种藻类对水体生态环境的响应情况,在太湖中不同区域筛选出不同的生态敏感指示藻类。

Construction of an Ecological Ditch Based on Periphyton Reactor

[Objective] This study aimed to make the effluent of constructed wetlands in a pond recirculating aquaculture system satisfy aquaculture requirements. [Method] A 150 m long, 0.5 m wide and 0.6 m deep ecological ditch was constructed on the basis of the periphyton reactor theory, to investigate the reoxygenation and deep purification effect of the ecological ditch on the effluent of constructed wetlands. [Result] Experimental results showed that the level of dissolved oxygen （DO） in the effluent of constructed wetlands increased to a range of 4.41-7.91 mg/L and pH val- ue increased significantly by flowing though the ecological ditch （P〈0.05）. DO level in the water of ecological ditch increased linearly with the increasing length of the ecological ditch within the range of 150 m （P〈0.05）. The ecological ditch showed further removal effect on NH4＋-N, IMn and PO4^3 -P in the effluent of the constructed wetlands, with the removal rate of 19.46%, 13.38% and 31.09%, respectively. The total coliform group was also eliminated with the removal rate ranging between 12.5% and 78.13%. [Conclusion] The ecological ditch based on periphyton reactor could improve DO level and further reduce N and P contents in the effluent of the constructed wetlands, which could be used as a matching water-reuse system of constructed wetlands. Key words Water quality; Purification; Dissolved oxygen; Periphyton; Pond aquaculture

河蟹的稻田养殖技术

河蟹学名中华绒螯蟹,又名毛蟹、田蟹等,是在半咸水中繁殖在淡水中生活的生物,稻田环境适宜其生长栖息。河蟹食性杂,稻田中的浮游生物、固着藻类、杂草、小动物等都是河蟹的天然饵料。我市在1996年开始引进稻田养蟹技术,取得了成功。实践证明,稻蟹并作,互利共生,可使粮食增产5—15％,每667平方米稻田当年可养成10—30只/公斤的上市规格蟹30公斤以上,蟹稻共生模式具有显著的社会、经济和生态效益。