Study On Dealing With Domestic Sewage Of Small Town By Dorp-aeration Bio-contact

Recently, China has laid great stress on the development of small town since the 10th and 11th "five-year plan" period. Especially in the days when we fully focus on the construction of a new socialist countryside, the construction of small town has become the most important task. Meanwhile, because of the fast construction and development speed, and the traditional development concepts stressing on construction but neglecting protection, there are a lot of problems existing, among which the pollution of water is the most serious. In the 11th "five-year plan" period, a principle to construct a resource-saving and friendly environment-treating society has been presented, which emphasizes on preventing pollution, protecting the environment from the source, and changing the state in which governing always comes after or at the same time as polluting occuring. Therefore, it has become emergent to work at sewage treatment in small town when county economy and small town are fast developed.This experiment focuses on the drop-aeration oxidation process to deal with domestic wastewater. Taking the characteristic of small town sewage into consideration, this experiment chooses the low-concentration domestic wastewater for research. It also explores the resistance ability of bio-contact to shock loading by changing water flow volume and water quality. Effects for sewage treatment resulting from the changing of water temperature, height of dropping water, wastewater flow volume, different ways of water-inputting, changing of HRT and intermittent operation are investigated during the experiment. The following conclusions are achieved through analysis: 1. The drop-aeration oxidation device can get a best result of inflating oxygen when the temperature is 16℃high and a best result of sewage treating when the temperature is 21℃high. It can also get a best result of inflating oxygen and sewage treating when the height of dropping water is 50cm and the wastewater flow volume is 0.35L/s(the thickness of water membrane is 0.64mm). Under the same condition, it can get a better result of sewage treating to adopt inner water-inputting than to adopt outer water-inputting. When HRT is 3h, the device has a rate of eliminating COD and BOD about 60%. During the intermittent operation experiment, there can be a stable operation state when the system has an intermittence of 15days.2. Through the experiment of drop-aeration oxidation process to deal with low-concentration domestic wastewater and the comparison of different aeration ways in economic and technological aspects, it can be illustrated that it is feasible to treat low-concentration domestic wastewater by drop-aeration oxidation process, which can be used as an independent treating biotechnology. Drop-aeration process can greatly cut down the cost of construction and operation in sewage treatment plant. Combined with the characteristic of bio-contact resistance to shock loading, they are of great practical value in small town sewage treating. Therefore, the process of drop-aeration oxidation has a prospective future and it is worth further exploring and popularizing.