Wang Dong-bo, Zhang Zi-yun, Li Xiao-ming, Zheng Wei, Ding Yan, Yang Bo, Yang Qi, Zeng Tian-jing, Cao Jian-bin, Yue Xiu, Shen Ting-ting, Zeng Guang-ming, Deng Jiu-hua, He Xun
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China.
Water Sci Technol. 2010;61(11):2881-8. doi: 10.2166/wst.2010.180.
Intermittent sand filters (ISFs) are effective and economical in treating wastewater, but they are easy to clog up. To explore a feasible and simple method to alleviate clogging, two pilot-scale ISFs were constructed, one of which contained earthworms and the other did not. During the operation, the effects of earthworms on the hydraulic behaviour of ISFs were investigated. The results showed that both ISFs exhibited good performance in wastewater treatment. However, they showed different hydraulic characteristics although operated at the same organic loading rate (approximately 300 g m(-2) d(-1)). The ISF without earthworms clogged only after 53 d operation, and was partially recovered after 7 d resting, but after that, clogging occurred again, and more rapidly than the initial clogging event (40 d). However, water on the medium surface of the ISF with earthworms was not observed during the whole experiments. In addition, 11-13% of effective porosity and 0.015-0.026 cm s(-1) of infiltration rate were measured in the upper 20 cm of the ISF at the end of the experiments. The facts demonstrated that earthworms played a positive role in alleviating clogging and earthworms fed filter could alleviate surface clogging effectively.
间歇砂滤池（ISFs）在处理废水方面既有效又经济，但它们很容易堵塞。为了探索一种可行且简单的方法来缓解堵塞问题，构建了两个中试规模的间歇砂滤池，其中一个装有蚯蚓，另一个没有。在运行过程中，研究了蚯蚓对间歇砂滤池水力行为的影响。结果表明，两个间歇砂滤池在废水处理方面均表现出良好的性能。然而，尽管它们在相同的有机负荷率（约300 g m(-2) d(-1)）下运行，但却表现出不同的水力特性。没有蚯蚓的间歇砂滤池仅运行53天后就堵塞了，休息7天后部分恢复，但之后又再次堵塞，而且比初始堵塞事件更快（40天）。然而，在整个实验过程中，未观察到装有蚯蚓的间歇砂滤池介质表面有水。此外，在实验结束时，在装有蚯蚓的间歇砂滤池上部20 cm处测得有效孔隙率为11 - 13%，渗透速率为0.015 - 0.026 cm s(-1)。这些事实表明，蚯蚓在缓解堵塞方面起到了积极作用，且装有蚯蚓的滤池能够有效缓解表面堵塞。
