不同排水体制对内秦淮河污染负荷的比较分析

排水体制和管网系统是城市基础设施建设的重要组成部分,不同排水体制对流域水环境污染存在明显差异.理论计算结果表明,在秦淮河流域分流制条件下,全年COD、NH3-N平均入河总量分别为1 057.2 t、15.9 t,其中51.0％、48.4％来源于中雨径流雨水;合流制条件下,全年COD、NH3-N平均入河总量分别为1 517.6 t、29.9t,其中82.2％、74.9％来源于大雨污水溢流.负荷比较分析结果表明,不同排水体制在3种雨型条件下,各河段NH3-N负荷无明显差异,主要表现在中雨COD负荷不同.中雨时,分流制雨水中COD负荷约是合流制溢流污水的2～3倍;而大雨时,合流制溢流污水与分流制径流雨水负荷相近.总之,分流制雨水径流污染不容忽视,合流制溢流污水污染应结合降雨强度及其他因素综合考虑.

Comparative Analysis of Different Drainage Systems for Pollution Load of Internal Qinhuai River

The drainage system and network system is an important part of urban infrastructure construction,it exists obvious difference from different drainage system in water environmental pollution of river basin.Theoretical calculation shows that in Qinhuai River,under the separate system,the total annual average COD and NH3-N into the river were 1 057.2 t,15.9 t,respectively,and 51.0％,48.4％ comes from runoff of moderate rain; Under the combined system,the total annual average COD and NH3-N into the river were 1 517.6 t,29.9 t,respectively,and 82.2％,74.9％ comes from the sewage overflow under heavy rain.Comparative analysis shows that there is no obvious difference was found between each section of NH3-N load under the different drainage system and three kinds of rain type ; mainly the different of COD load in the moderate rain ; the COD load of rain under the separate system is about 2-3 times as the combined sewage overflow; and in the heavy rain; the NH3-N,COD load of these two systems are similar.In a word,we should not ignore the rainwater pollution of separate system,and take the rainfall intensity and other factors into account for the overflow sewage pollution confluence system.