Basic Experimental Study On Water Reuse Through Bacterial Film Process

Increasing amount and low reuse rate of domestic sewage with increasing year,and short supply of urban water due to water resource shortage were becoming very serious problems.To solve these problems,we chose domestic sewage as processing object and build the experimental installation of anaerobic-aerobic.Three sewage reuse experiment were carried out,which included bio-contact oxidation,anaerobic filter and anaerobic-aerobic.The feasibility of sewage reuse through bacterial film process was discussed in order to find the impact factors of the experimental installation and best operating parameters.According to the features of domestic sewage, the thesis designed reasonable biological contact oxidation pond and anaerobic biological filter as laboratory equipments, and mainly investigated the changes of COD, ammonia nitrogen, total phosphorus and turbidity in the water after aerobic, anaerobic and anaerobic-aerobic treatment, also analysed operating element of temperature, way of aeration, amount of oygenation and stirring rate on the impact of water quality,and got the best operating condition of high efficiency of the equipments.The results showed that the decreasing rate of COD, ammonia nitrogen, total phosphorus and turbidity were proportional to the temperature increase in the bio-contact oxidation experiment. Temperature rise is beneficial to the bio-contact oxidation. Among the experimental temperature range of10℃-30℃,30℃is the best temperature,at which the laboratory equipments got the best pollutantion removal rate. In addition, the continuous aeration is the best way of aeration for removing COD, ammonia nitrogen, turbidity, and intermittent aeration was useful for the removal of total phosphorus in sewage. Stirring rate has different effect on different pollutantions, there is no clear regularity. Improve the amount of oygenation is advantageous to pollutantions removal.In the early experiment of anaerobic filter, content of COD and ammonia nitrogen got down, and removal of total phosphorus and turbidity takes a long time. Compared with bio-contact oxidation, anaerobic biological filter had a better removal rate of total phosphorus and a poor removal rate of ammonia nitrogen and turbidity.According to the experiment results,the thesis proved that different kinds of domestic sewage after treatment could meet the standards of reusing sewage,which were water quality after (CJ/T95-2000) and the water quality of domestic sewage in the People’s Republic (CJ25.1-89).That proved the feasibility of reusing sewage of the thesis and provided necessary experimental basis for the further development of a practical and efficient system of small-scale water reuse.