Study On Water-dropping Aeration And Plug-flow Biological Contact Oxidation

Traditional aerobic biological treatment technology need consume huge energy, while water-dropping aeration utilizes potential exchange to realize aeration. Compared with bubble aeration and paddlewheel aeration, water-dropping aeration possesses several advantages such as simple structure, low cost, less energy consumption, which has been used in eliminating manganese in groundwater. In wastewater treatment, water-dropping aeration can adapt the terrain in hilly and mountain area, reduce the project and operation cost, so it is worth studying as a method of aeration.Biological contact oxidation is a typical aerobic biological method, which belongs to a kind of bio-film process and has been widely used in municipal wastewater and industrial wastewater treatment. This paper studies on the effect of water-dropping aeration factors and the plug-flow biological contact oxidation in order to find out the impact to domestic sewage and polluted river. One of the most important factors whether the process can work is the DO concentration. The DO concentration in water is a critical index, which is a condition of maintaining the ecological balance and decomposing organic compounds. Through optimizing water-dropping height, decreasing tank depth and increasing reflux, DO concentration is enhanced. The result shows: under the experimental condition, the optimal water-dropping height is 1.0m; rational flowing load is 0.14L/m·s and with temperature enhancing, the effect of aeration improves.Experimental water simulates Dalian Malan river in summer and the quality of raw water is as follows: CODcr 160mg/L,NH3-N 16mg/L. The experiment shows: rational ratio of reflux is 3:1, the removal of CODcr and NH3-N increases along the reactor and the pollutants decreases significantly in the former part. The CODcr concentration of effluent is lower than 60mg/L and TOC is about between 20mg/L and 30mg/L. The removal rate of both is about 60%; The NH3-N concentration of effluent is around 10mg/L and the removal is above 30%; the TN is around 12mg/L and the removal rate is nearly 20%. In the experiment, combined filler is replaced by elastic filler and the investigation shows that the pollutant removal rate is almost the same.In order to investigating the stability of the reactor, the higher influent concentration is to enhance the volume load. The result shows that short-time impact has not obvious effect to pollutant removal rate. Prolonging the time of impact, the needed recovered time correspondingly prolongs, so long-time impact does harm to operation. Simulated rain of quadruple influent flow scours for 2h and the removal rate of CODcr and NH3-N doesn't change obviously. The study of the result shows that water-dropping aeration and plug-flow biological contact oxidation process is suitable for domestic sewage treatment in combined drainage ditch or polluted river channel. The higher pollutant removal rate displays that the combined process is a promising process.