| As one of the five largest freshwater lakes in China, Taihu Lake is the source of water supply for Wuxi, Changzhou and so on. Since the 1980's, the water quality had been worse year by year, and now it was at light eutrophication level. There's little effcet in its treatment in 20 years. Taking the water system in Yixing City as the research area, this paper analysised its water contamination features and confirm the key pollution factor and its sources. On the other hand, the feasible ecological remediation approach was also discussed. For phosphorus removal, the optimal work on the former research of the Al/Ca/Fe composite metal oxides adsorbent was employed, in order to make it can be better applied to the actual work and finally achieve the goal of pollution control. The specific research content are as follows:(1)Collecting the data of Lanshan Mouth situation of WQSSN in 2012-2014. The analysis results show that The Taihu lake basin water quality decline year by year, until the end of the study, water quality is given priority to with IV class, basic accounting for 60% of the year, I class dropped to 0, II class does not exceed 6%. In addition, there are three large water quality fluctuation in each year, followed by the late January to the early February, July to August, late October to early November, which matches with the Ponds clearing, temperatures rising and Agricultural return flow.(2)Monitoring and analyzing water quality index like COD, TN, TP, The nitrate nitrogen, etc.. The results show that TP, TN and The ammonia nitrogen are the key pollution factors, but the development trend varies because of different of the river. Although COD has not to exceed bid, but the value of Pi is to converge with 1, which close to the surface of the value of class III water quality standard, and also has a rising trend, so it's still the key pollution factor.(3)The investigation result shows that agricultural non-point source pollution is greater than the point source pollution. This paper takes XIjiu as an example, a feasible ecological engineering is put forward, Constructing or renovating plants filter belt which fill the adsorption material in the region of the engineering conditions allowed, to replace the existing stone and upright revetment, aiming to prevent the diffusion of pollutants before entering the main channel by using biological/ecological method, thus controlling the N, P in water pollutants.(4)In the aspect of water quality, for phosphorus removal, this topic on the former research of the Al/Ca/Fe composite metal oxides adsorbent performance tuning, The results show that keeping the sintering temperature stays at 1150 ?, reducing the granularity of Al2O3 and Ascending temperature to 1220 ?, reducing particle size of bentonite could make the adsorbent adsorption capacity and strength are improved to varying degrees. Results show that when the sintering temperature was 1150 ?, alumina particle size is less than 125 microns, the adsorbent adsorption capacity is 36.99 mg P/g, mass loss rate is 8%;When the sintering temperature was 1220 ?, bentonite clay particle size is less than 98 microns, the adsorbent adsorption capacity of 37.09 mg P/g, mass loss rate was 12%, compared with the original adsorbent which adsorption capacity was 34.71 mg P/g, mass loss rate of 16% has a certain improvement. |
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