The Optimal Test And Research On Nitrogen And Phosphorus Removal In Operating UCT Process

In this paper, it explored the contradictions and problems of nitrogen and phosphorus removal simultaneously on carbon source in municipal wastewater treatment. The processes about UCT was studied and improved on different influent ways for the research on the removal of nitrogen and phosphorus simultaneously. Also it analyzed the relationship between input distribution ratio and the process operating parameters, such as the dissolved oxygen concentration,the recycling ratio. At the same time, it discussed the focus factors on enhancing the removal of nitrogen and phosphorus from the utilization of carbon sources.The actual water quality about supernatant influent:CODcr 208-412 mg/L, BOD5 98-228 mg/L, TN 20.1-49.8 mg/L, TP 2.5-7 mg/L, the average of BOD5/TN was 3.4, BOD5/TP was 31.And the tests fell into three parts following:1.The processes about UCT was tested and analyzed on one influent point,two influent points and three influent points. The results showed it had better removal of nitrogen and phosphorus simultaneously on two and three inlets than it on one under the same conditions.The main reasons were that two inlets could offer more carbon source for the nitrogen and phosphorus removal,bringing with the more radical denitrification, providing supportive conditions for cutting the anaerobic hydraulic retention time.Setting the internal recirculating ratio 200%, the external recirculating ratio 100%, the state which had a influent distribution ratio of 7:3 achieved a higher total-phosphorus removal up to 83%,in excess 10% of the state in distribution of 5:5, which has a slight advantage about 4% than the former in total-nitrogen removal.The state of three inlets enhanced the nitrogen and phosphorus removal simultaneously by improving the carbon use proportion in removing nitrogen and phosphorus with a TN removal of 78% and a TP removal of 88%. 2.The UCT process with three inlets on impacting factors on both distribution and recycling ratios was tested and analyzed.The results demonstrated it could get the points between recycling and input closer definitely in order to improve the utilization ratio in nitrogen and phosphorus removal, saving carbon resource from the other kinds of heterotrophic bacterium which had no abilities in removing nitrogen and phosphorus from the wastewater. The influent distribution could be set by the test on certain recycling ratio according to certain water quality.3.The tests were operated on different dissolved oxygen concentration by testing the UCT process with two inlets.The results showed that, in distribution on 7:3 and 5:5,the DO in aerobic zone could be sustained respectively in 1.0-1.8mg/L and 1.8-2.5mg/L in order to keep high removal efficiency with lower power consumption and less carbon resource companied with a certain degree of denitrifying phosphorus situation.