城市雨水径流颗粒物中氮磷赋存特征及其影响因子研究进展

RESEARCH PROGRESS ON FORMS AND INFLUENCING FACTORS OF NITROGEN AND PHOSPHORUS IN PARTICULATE MATTERS IN URBAN STORMWATER RUNOFF

颗粒物是径流雨水中氮磷污染物的主要载体,控制占比较大的颗粒物可有效削减污染负荷。颗粒物携带的氮磷容易受到pH、温度、溶解氧、有机质等外部环境因子影响发生转化。首先总结了径流颗粒物中氮磷的来源,对比分析了地表、管道和水体沉积物中氮磷组分变化特征,发现三类沉积物中,总氮由88%~92%的有机氮和8%~12%的无机氮组成;总磷则由5%~20%的有机磷和80%~95%的无机磷组成。其次归纳了颗粒物在不同场景下的粒径分布,以及不同粒径颗粒物上氮磷污染物主要赋存范围变化,其中粒径在11~150μm区间内的沉积物可贡献雨水径流中20%~50%的颗粒态氮和40%~50%的颗粒态磷。最后分析了颗粒物自身特征(粒径、元素组成、表面形态)、其他环境因子(pH、温度、溶解氧、有机质)和微生物对颗粒物中氮磷赋存的影响,如当水体温度从6.85℃升至29.85℃时,单位质量颗粒物对磷的吸附率提高了12%。研究归纳了颗粒物中氮磷污染物相关研究中存在的不足,可为城市径流氮磷污染精准调控提供借鉴。

Particulate matter is the primary carrier of nitrogen and phosphorus in stormwater runoff,and controlling the particulate matter with large nitrogen and phosphorus content can effectively reduce the total pollution load.Particulate-borne nitrogen and phosphorus are susceptible to transformation influenced by external environmental factors such as pH,temperature,dissolved oxygen,organic matter,and so on.This paper firstly summarizes the sources of nitrogen and phosphorus contained in runoff particulate matter,and comparatively analyzes the characteristics of nitrogen and phosphorus components in surface,pipeline,and water sediment.It was found that in the three types of sediments,total nitrogen was composed of 88%to 92%organic nitrogen and 8%to 12%inorganic nitrogen,while total phosphorus was composed of 5%to 20%organic phosphorus and 80%to 95%inorganic phosphorus.Furthermore,it summarizes the particle size distribution of particulate matter in different scenarios,along with the variations in the main ranges of nitrogen and phosphorus pollutants on particles of different sizes.Sediments within the particle size range of 11 to 150μm contribute 20%to 50%of particulate nitrogen and 40%to 50%of particulate phosphorus in stormwater runoff.An analysis was also conducted on the inherent characteristics of particulate matter(particle size,metal composition,surface morphology),other environmental factors(pH,temperature,dissolved oxygen,organic matter),and the impact of microorganisms on the forms of nitrogen and phosphorus carried by the particulate matter.For example,when water temperature increased from 6.85℃to 29.85℃,the adsorption rate of phosphorus by particulate matter increased by 12%.This article summarizes the shortcomings in the relevant studies on nitrogen and phosphorus pollutants in particulate matter,aiming to provide insights for precise control of nitrogen and phosphorus pollution in urban runoff.