引黄济青调水沿程氮污染物的迁移转化研究

2011年4—6月在引黄济青工程输水沿程11个采样点进行4次取样,分析氮污染物的迁移转化。结果表明,总氮在沿程呈下降的趋势,但不同月份存在差别;硝酸盐氮是氮污染物的主要存在形式,与总氮呈正相关;氨氮和亚硝酸盐氮质量浓度较低,沿程有一定波动,但变化较小。沉砂池对硝酸盐氮有一定的去除作用,但对总氮的作用在不同月份存在差异。农业面源污染、植物残体分解、泥沙沉积作用、植物同化作用、微生物作用等因素会影响引黄济青沿程氮污染物质量浓度变化。

Nitrogen migration and transformation along the water diversion project route from Yellow River to Qingdao City

The water demand risk is increasing in many developing countries,especially in China.Inter-basin water transfers are designed by artificially conveying water to locations where people need it.To abate the jeopardy of water shortage in Qingdao city,the project of water diversion from Yellow River to Qingdao was started in 1989.In this study,water samplings were carried out four times from 11 sampling sites along the project route from April to June in 2011,and the migration and transformation of nitrogen pollutants in water transfer process were studied.The results of our investigation indicated that the range of total nitrogen concentration was 2.30-5.60 mg/L in water transfer process.Total nitrogen concentration exhibited a downward trend along the project route,and the largest amplitude reduction was 1.18 mg/L.Nitrate nitrogen,which is the major form of nitrogen pollution,showed notable positive correlation with total nitrogen and exhibiting a downward trend along the project route.The concentration of ammonia and nitrite nitrogen was lower in source water.In the water transfer process,the range of ammonia concentration was 0.03-0.37 mg/L and nitrite nitrogen concentration was lower than 0.23 mg/L.Both concentrations are fluctuated slightly along the project route.The grit chamber of the project has a certain effect on the removal of nitrate nitrogen.However,its effect on total nitrogen was quite different in different months.Several factors including agricultural non-point source pollution,decomposition of plant residues,deposition of sediment,the assimilation of plants and microorganisms etc.affected the concentration changes of nitrogen-pollutants in the water transfer process and their behaviors were quite different in different water sampling times.