Tangpu reservoir is plain regional water supply special water of Shaoxing and Shangyu,not only protect the safety of drinking water of 300 million people,to improve the living environment,and also made great contributions to local social and economic development.The water quality of Tangpu reservoir is overall good except TN and TP,has more sediment content,and contains large quantities of pollutants.Pollutants in sediment is nitrogen and phosphorus pollutants within the sources of pollution.This paper takes Tangpu reservoir as an example,the general rules about the release of contamination in sediment were obtained.The results obtained in the study might provide scientific references for the research of the water quality safety.The main conclusions of this study are:1.By analyzing the distributed relationship of the contaminants between sediment contaminants and overlying water to detect the pollutions of sediment contaminants and vertical water in Tangpu reservoir,the results showed that the variation of the sediment contaminants kept consistent with overlying water.Affected by releasing of sediment contaminants,the contents of nitrogen and phosphorus in overlying water were almost always higher than the average content of each layer of the water and the maximum contents of the total nitrogen and ammonia nitrogen were 1.30 times,16.71 times and 3.65 times,respectively,which indicated that the pollutions in water largely came from the release of sediment contaminants.And researching the seasonal distribution of the contaminants in water,results showed that the season with higher temperature,the higher pollutions,and the maximum contents of the total nitrogen and ammonia nitrogen could attain 2.96mg/L,0.43mg/L and 0.1mg/L,respectively.2.By conducting static simulating experiment with the on-site sediment of Tangpu reservoir,the respective impacts of dissolved oxygen,temperature and disturbance on the law of nitrogen and phosphorous release from sediment is analyzed and the experimental results are summarized.Total nitrogen,total phosphorus and ammonia nitrogen were correlated linearly with dissolved oxygen,temperature and disturbance.From different fitting equations under different conditions the influence law were also analyzed:(1)The larger the dissolved oxygen content,the smaller of the release quantity of nitrogen and phosphorus;(2)The higher the temperature,the faster the release rate and the greater the release quantity;(3)The higher the disturbance intensity,the greater the pollutant concentration when the equilibrium.The research results and the measured water quality showed the same change law.3.Aiming at three factors:disturbance,DO,temperature.Design of three factors and three levels orthogonal experiment,and there are nine kinds of working condition.The correlations between three factors and the release of total nitrogen,total phosphorus,ammonia nitrogen in the sediment were analyzed.The biggest influence to nitrogen and phosphorus is DO.The correlation coefficients most between 0.5-0.8,Up to 0.853,more points show a high correlation and moderate correlation.Effect of temperature on the release of nitrogen and phosphorus in sediment most show a low correlation or weak correlation.The correlation coefficient most under 0.5.Varying degrees of influence of different environmental factors in different locations,this result provides a master environmental factors for controlling release of nitrogen and phosphorus in sediment in different locations in the Tangpu reservoir.4.The effects of different temperature and DO were optimized with response surface methodology(RSM).Establish the regression model of response variables,analyze the response relationship between pollutants and effecting factors to release a quantity to a minimum.The experimental results show that the best release condition is:temperature is 9.87 ℃ and DO is 7.93mg/L.The most unfavorable conditions for release is:temperature is 19.64 ℃ and DO is 1.12 mg/L.This conclusion is validated is reliable through the experiments.5.Response surface model combined with actual situation in Tangpu reservoir.The actual temperature and dissolved oxygen in overlying water reservoir in spring,summer,autumn and winter was combined with the model to predict the reservoir sediment release in different seasons,the results have good consistency with the water quality of reservoir under the same conditions.Estimate the release quantity with a year in the worst case of total nitrogen,total phosphorus and ammonia nitrogen respectively were 51.28t、9.14t、26.60t,were 9.23%,74.66%and 81.80%of the total water pollutants.Under the optimum conditions respectively were 15.78t,2.88t,7.65t and were 2.84%,23.52%,23.53%of the total water pollutants. |