A study on the Reuse of Purified Wastewater for Agriculture

日本正在积极开展农村污水处理项目。另一方面，我们担心缺水。思考农村污水处理，我们可以理解为污水处理厂的建设在某种意义上就是水的再生利用厂的建设。污泥是污水处理厂污水净化过程中产生的产物。但是，污泥是人们讨厌的危险和麻烦的事情。在古代，农民把粪便用于农业。但是，由于生产化学肥料，人类粪便不受欢迎，也不受重视。因此，它导致了许多地方的环境问题。回顾农田，由于停止向农田供应有机质，仅使用化肥，农田失去了肥力。在此基础上，开展了净化后的污水回用解决水资源短缺问题和污泥堆肥作为有机肥培肥土壤的研究。研究结果表明：（1）净化后的污水可作为灌溉用水，相当于饮用水;（2）污泥堆肥可作为有机肥料，具有较高的利用价值。这并不是说在回用前必须对回用水和污泥是否符合环保标准进行严格的检查。

In Japan, the rural sewerage projects are being actively carried out. On the other hand, it is afraid that we are running short of water. Thinking of the rural sewerage treatment, we can understand that the construction of sewage plant is the construction of recycling plant of water in a sense. The sludge is always produced as the results of purification of sewage in the plant. But, the sludge is hated as dangerous and troublesome matters by people. In the old time, night soil was used by farmer for agriculture. But, as the chemical fertilizers are being produced, human manure is disliked and is not paid attention to. Therefore, it leads to environmental problems in many places. Reviewing agricultural field, as supply of organic matter to agricultural fields was stopped and only the chemical fertilizer were used, the field has lost the fertility. Then we started the study to reuse the purified wastewater to solve the shortage of water, and to use the composted sludge as organic fertilizer to enrich soil. It is concluded from our study that (1) the purified wastewater can be recycled as irrigation water equivalent to drinking water, (2) the composted sludge used and valued high as organic fertilizer. It is not to say that the exact check has to be done if both of the recycled water and sludge meet the environmental standard or not before their reusing.