浑河流域沈阳段氨氮污染源核算及水质模拟分析

为研究氨氮污染源的排放情况,根据排污系数法核算了沈阳市浑河流域2015年各类点源、面源污染物情况,并利用QUAL2K模型对该流域氨氮进行模拟,得到氨氮在不同水期的变化趋势。结果表明,浑河沈阳段氨氮2015年入河总量为3 840.1t,氨氮主要来自农村非点源污染(占氨氮入河总量约92%,其中包括畜禽养殖污染67%、农业灌溉20%、农村生活污水4%),点源污染物占比仅8%;另外流域所包含两条河流浑河干流、蒲河支流的氨氮入河量分别为1 774.0、2 066.1t,且均以畜禽养殖污染为主。QUAL2K模型对氨氮的模拟结果与不同水期实测值相对误差在4%~20%之间,氨氮模拟浓度整体水平为枯水期>平水期>丰水期,其中浑河干流中游氨氮污染最为严重,枯水期氨氮浓度最大值3.6mg/L,为丰水期的12倍;而蒲河支流中下游污染情况较为复杂,在不同水期均存在超标风险。

Analysis of Ammonia Nitrogen Sources and Water Quality Simulation in Hunhe River Basin of Shenyang City

To study the discharge of ammonia and nitrogen pollution sources, all kinds of point source and non-point source pollutants in 2015 in Hunhe river basin, Shenyang City were calculated with the method of discharge coefficient. QUAL2K model was used to simulate ammonia nitrogen and obtain the variation trend in different water periods. The results show that the total amount of ammonia nitrogen flow into this basin in 2015 is 3 840.1 t, and 92% of it is from the rural non-point source pollution (including the livestock and poultry farming pollution 67%, agricultural irrigation 20%, and rural domestic sewage 4%), while the point source pollutants are just 8%. Besides, both mainly polluted by livestock and poultry farming pollution, the amount of ammonia nitrogen flow into Hunhe trunk stream and Puhe branch river are 1 774.0 t and 2 066.1 t, respectively. As for the stimulation result by QUAL2K model, the relative errors between the simulation and the measured values in different water periods are in the range of 4% and 20%. The simulated values of ammonia nitrogen in the dry period are higher than that in the normal period, and that in the normal period is higher than the moist period. The ammonia nitrogen pollution is the most serious in the dry period at the middle reaches of Hunhe trunk stream, and the maximum concentration in this period is 3.6 mg/L, and it is 12 times higher than that in the moist period. The middle and lower reaches of Puhe branch river are polluted in a complex way, with the risk of exceeding the standard limited values in all water periods.