山地城市封閉水體氮磷敏感點識別方法研究
發(fā)布時間：2018-08-30 11:49
【摘要】：湖泊的富營養(yǎng)化問題是全球關注的湖泊熱點問題之一,而水體中氮磷的含量則是影響富營養(yǎng)化程度的主要因素。山地城市封閉水體除具有流動性差、水生態(tài)系統(tǒng)簡單、水環(huán)境容量小等特點,還具有水位深、受風生流擾動較小、存在溫躍層以及密度流等特點。水深、溫度以及水流條件等因素,均對氮磷在水體中的分布具有重要的影響作用。論文以位于山地城市重慶的龍景湖為研究對象,詳細調查了龍景湖的區(qū)域概況并評價了龍景湖水質及富營養(yǎng)化現狀,探究了山地城市封閉水體中總氮、總磷濃度與水深的響應關系,并通過EFDC水環(huán)境模型對龍景湖總氮、總磷分布特征進行了模擬,分析找出了龍景湖氮磷敏感點位置,建立了氮磷敏感點識別方法。主要研究結論如下:①根據龍景湖水動力條件等因素,將龍景湖分為A、B、C、D、E五個區(qū)域。基于三年來對龍景湖的實測水質數據,對龍景湖水質現狀以及富營養(yǎng)化現狀進行了分析。A、B、C區(qū)總磷濃度在0.05mg/L~0.23mg/L之間變化,其中10月份至次年2月份,總磷濃度均在0.1mg/L以上。D、E區(qū)總磷含量在秋冬超過了0.1mg/L的標準�？偟緼、B、C區(qū)相對穩(wěn)定,僅2月份出現超標現象。D區(qū)總氮含量10月至2月存在超標現象,而E區(qū)總氮含量則非常高,全年有一半的時間總氮濃度高于1.5mg/L。龍景湖全年平均TLI指數為57.69,處于輕度富營養(yǎng)化狀態(tài),其中6、7、9以及2月處于中度富營養(yǎng)化狀態(tài),平均TLI指數為63.68。②對龍景湖A、B、C、D、E五個分區(qū)中氮磷濃度與水深的響應特性進行了研究。不同分區(qū)、不同采樣時間以及不同水質指標之間,響應關系均存在差異。其中,8月15日和9月4日龍景湖區(qū)域B中水深與總磷含量的擬合曲線擬合優(yōu)度值最高,分別達到0.997和0.992,響應關系最為明顯。這可能是由于不同分區(qū)水流環(huán)境不同、湖泊底泥類型存在差異、氣溫變化、風速風向改變、污染物在水中的主要存在形態(tài)以及物質擴散系數等因素造成的。③在對擴散原理充分認識的基礎上,基于費克定律擴散方程以及Mike-Chang擴散系數經驗方程等科學定律和經驗方程式,推導出污染物濃度與水溫以及水深之間的關系方程式C_A=y_2e~z/(y_1T)+x_2,并運用MATLAB(matrixlaboratory)矩陣實驗室進行二元非線性擬合,計算出該關系式中的未知系數,分別得到總氮、總磷的具體方程形式,其中總氮方程的擬合優(yōu)度為0.714,平均相對誤差為12.96%,總磷方程的擬合優(yōu)度為0.662,平均相對誤差為23.16%。對龍景湖中總氮濃度以及總磷濃度隨水深的變化情況的具體計算,表明總氮與總磷含量均隨水深的增加而上升。并且,在自然環(huán)境下,垂向溫度變化對總氮、總磷濃度變化影響十分微小。④通過EFDC(Environmental Fluid Dynamics Code)水環(huán)境模型,構建龍景湖的水動力、水質模型。為研究龍景湖在無外來污染源進入的情況下,總氮以及總磷在龍景湖水動力條件、底泥吸釋等湖體自身因素影響下的分布特征,在建立模型的過程中,污染物的輸入量被設置為0。模型結果表明,在龍景湖自身水流條件等因素的作用下,總磷最易集聚的區(qū)域為D區(qū),秋冬總氮積聚的區(qū)域為D區(qū),而春夏則為E區(qū)。⑤通過對龍景湖氮、磷垂向分布情況以及空間分布情況的模擬,分析指出龍景湖中對湖體氮、磷濃度上升最為敏感的點。就總氮而言,具有一定的季節(jié)性。秋冬季節(jié),對湖體總氮濃度上升表現得最為敏感的點為區(qū)域D的A10取樣點,而春夏季節(jié)對水中總氮濃度上升最為敏感的點為E區(qū)域的A08點。總磷全年分布較為穩(wěn)定,對湖體中總磷濃度升高最為敏感的點為區(qū)域D的A09以及A10點。取樣點垂向上總氮、總磷濃度敏感性則以水深為依據,水深越深,總氮、總磷越容易富集。
[Abstract]:The eutrophication of lakes is one of the hotspots in the world, and the content of nitrogen and phosphorus in the water body is the main factor affecting the degree of eutrophication. The distribution of nitrogen and phosphorus in the water body is affected by water depth, temperature and flow conditions. The Longjing Lake, located in the mountainous city of Chongqing, is investigated in detail, and the water quality and eutrophication status of Longjing Lake are evaluated. The response relationship between total nitrogen and total phosphorus concentration and water depth in closed water body was studied. The distribution characteristics of total nitrogen and total phosphorus in Longjing Lake were simulated by EFDC water environment model. The location of nitrogen and phosphorus sensitive points in Longjing Lake was analyzed and identified, and the identification method of nitrogen and phosphorus sensitive points was established. The lake is divided into five regions: A, B, C, D and E. Based on the measured water quality data in the past three years, the water quality and eutrophication status of Longjing Lake are analyzed. Total nitrogen content in area A, B and C was relatively stable, but exceeded the standard only in February. Total nitrogen content in area D exceeded the standard from October to February, while total nitrogen content in area E was very high. The annual average TLI index of Longjing Lake was 57.69, which was slightly eutrophic in June, July, September and February. The average TLI index was 63.68. The goodness-of-fit value of the fitting curve was the highest, reaching 0.997 and 0.992 respectively, and the response was the most obvious. This may be due to the different water flow environment, different types of Lake sediment, changes in temperature, wind speed and direction, the main forms of pollutants in the water and the diffusion coefficient of substances. On the basis of full understanding of diffusion principle, the equation C_A=y_2e~z/(y_1T)+x_2 of the relationship between pollutant concentration and water temperature and water depth is deduced based on the diffusion equation of Fick's law and Mike-Chang's empirical equation of diffusion coefficient. The binary non-linear equation is carried out by using MATLAB (matrix laboratory) matrix laboratory. The unknown coefficients in the equation were calculated, and the specific equations of total nitrogen and total phosphorus were obtained. The goodness of fit of the equation was 0.714, the average relative error was 12.96%, the goodness of fit of the equation was 0.662, and the average relative error was 23.16%. The calculation shows that the total nitrogen and total phosphorus content increase with the increase of water depth, and the vertical temperature has little effect on the total nitrogen and total phosphorus concentration in natural environment. The distribution characteristics of total nitrogen and phosphorus under the influence of hydrodynamic conditions and sediment suction and release in Longjing Lake were studied. In the process of establishing the model, the input of pollutants was set to 0. The vertical distribution and spatial distribution of nitrogen and phosphorus in Longjing Lake were simulated. It was pointed out that the most sensitive point to the increase of nitrogen and phosphorus concentration in Longjing Lake was the point where the concentration of nitrogen and phosphorus in the lake increased. As far as total nitrogen was concerned, it had a certain seasonality. The most sensitive point is A10 sampling point of region D, and A08 sampling point of region E is most sensitive to the increase of total nitrogen concentration in spring and summer. According to the deeper water depth, total nitrogen and total phosphorus are more easily enriched.
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X524
本文編號：2212980
[Abstract]:The eutrophication of lakes is one of the hotspots in the world, and the content of nitrogen and phosphorus in the water body is the main factor affecting the degree of eutrophication. The distribution of nitrogen and phosphorus in the water body is affected by water depth, temperature and flow conditions. The Longjing Lake, located in the mountainous city of Chongqing, is investigated in detail, and the water quality and eutrophication status of Longjing Lake are evaluated. The response relationship between total nitrogen and total phosphorus concentration and water depth in closed water body was studied. The distribution characteristics of total nitrogen and total phosphorus in Longjing Lake were simulated by EFDC water environment model. The location of nitrogen and phosphorus sensitive points in Longjing Lake was analyzed and identified, and the identification method of nitrogen and phosphorus sensitive points was established. The lake is divided into five regions: A, B, C, D and E. Based on the measured water quality data in the past three years, the water quality and eutrophication status of Longjing Lake are analyzed. Total nitrogen content in area A, B and C was relatively stable, but exceeded the standard only in February. Total nitrogen content in area D exceeded the standard from October to February, while total nitrogen content in area E was very high. The annual average TLI index of Longjing Lake was 57.69, which was slightly eutrophic in June, July, September and February. The average TLI index was 63.68. The goodness-of-fit value of the fitting curve was the highest, reaching 0.997 and 0.992 respectively, and the response was the most obvious. This may be due to the different water flow environment, different types of Lake sediment, changes in temperature, wind speed and direction, the main forms of pollutants in the water and the diffusion coefficient of substances. On the basis of full understanding of diffusion principle, the equation C_A=y_2e~z/(y_1T)+x_2 of the relationship between pollutant concentration and water temperature and water depth is deduced based on the diffusion equation of Fick's law and Mike-Chang's empirical equation of diffusion coefficient. The binary non-linear equation is carried out by using MATLAB (matrix laboratory) matrix laboratory. The unknown coefficients in the equation were calculated, and the specific equations of total nitrogen and total phosphorus were obtained. The goodness of fit of the equation was 0.714, the average relative error was 12.96%, the goodness of fit of the equation was 0.662, and the average relative error was 23.16%. The calculation shows that the total nitrogen and total phosphorus content increase with the increase of water depth, and the vertical temperature has little effect on the total nitrogen and total phosphorus concentration in natural environment. The distribution characteristics of total nitrogen and phosphorus under the influence of hydrodynamic conditions and sediment suction and release in Longjing Lake were studied. In the process of establishing the model, the input of pollutants was set to 0. The vertical distribution and spatial distribution of nitrogen and phosphorus in Longjing Lake were simulated. It was pointed out that the most sensitive point to the increase of nitrogen and phosphorus concentration in Longjing Lake was the point where the concentration of nitrogen and phosphorus in the lake increased. As far as total nitrogen was concerned, it had a certain seasonality. The most sensitive point is A10 sampling point of region D, and A08 sampling point of region E is most sensitive to the increase of total nitrogen concentration in spring and summer. According to the deeper water depth, total nitrogen and total phosphorus are more easily enriched.
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X524
【參考文獻】
相關期刊論文 前1條
1 孫學成,鄧曉龍,張彩香,潘娟琴;WASP6系統(tǒng)在三峽庫區(qū)水質仿真中的應用[J];三峽大學學報(自然科學版);2003年02期
，本文編號：2212980
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