A study of the distribution and composition of pollutants in snow collected from streets and a treatment system for recycling snow in winter cities

Abstract

In winter, cold cities have a severe shortage of water resources. Snow is a potential water resource, and the effective classification and recycling of snow is, therefore, significant for addressing the sustainable utilization of urban water resources in cities during the winter months. In this study, the water quality and pollutant composition of snow collected along a transect across a typical street were analyzed to develop an on-site treatment technique based on the classification of snow water. The levels of suspended substances, COD, salt, ammonia, and oil in snow from urban streets were relatively high. The salinity, conductivity, and chloride levels were also high due to the application of a snow-melting agent. Twenty-nine major pollutants were identified, and the oily substances were dominated by hexadecane accompanied by toxic substances such as BTEX and naphthalene. Snow can adsorb and receive pollutants from the streets, while becoming a carrier for pollutants. The underground space below city streets is proposed for establishing a snow-melting system. The snow meltwater may be directly discharged into double subsurface tanks if the concentration of suspended substances is less than 200 mg/L. A V-type filtering tank may be used if the concentration of suspended substances is greater than 200 mg/L. This method, which integrates city planning and municipal technology, accomplishes both the recycling and utilization of snow water, as well as the on-site treatment of pollutants.