基于实地监测的新型粒状海绵介质土的性能研究

Performance of innovative granular sponge city growing media based on field monitoring

海绵城市设施种植层的介质土对径流调控、污染物去除和植物生长有重要影响.在实际降雨情形下,对新型粒状海绵城市介质土进行径流控制与污染物去除效果进行实地监测分析.结果表明:新型粒状海绵城市介质土的平均渗透率最低为500 mm/h,且污染物去除效果良好,固体悬浮物去除率均达80%以上,主要出水水质指标(总磷、总氮、氨氮和化学需氧量)符合地表水环境质量Ⅲ类水标准.常绿灌木、落叶灌木和宿根地被等中国华南地区本土植物在新型介质土中均生长良好.新型粒状海绵城市介质土的经济成本核算需因地制宜,总体成本是传统介质土的1/3~3/4.与传统海绵介质土相比,新型粒状海绵城市介质土成本低廉,具有更好的渗透性和污染物去除效果,且后期运行维护便利,可广泛应用于没有重金属污染的地区,有望在一定程度上取代传统海绵城市介质土.

The growing media in the planting layer of sponge city facilities has an important influence on stormwater runoff control,pollutant removal and plant growth.This study consists of field tests that include the continuous monitoring to evaluate the performance of runoff control and pollutant removal of the innovative granular sponge city growing media during wet season.The results show that the lowest average permeability of innovative granular sponge city growing mediais 500 mm·h-1,and the pollutant removal effect is good,the removal rate of solid suspended solids is more than 80%,and the main effluent quality indexes(total nitrogen,TN;total phosphorus,TP;ammonia,NH 3-N;chemical oxygen demand,COD)sampled from the outflow of the testing bioretention cells show that the water quality of discharged runoff meets the Class-Ⅲindices of the Environmental quality standards for surface water(GB 3838—2002).Combination of local landscape plants such as evergreen shrubs,deciduous shrubs,perennial ground cover and other native plants in South China all grow well during the field tests.The overall life-cycle cost of this new type of growing media also needs to be further verified by different projects in different climate regions,generally it is 1/3-3/4 of that of traditional media.In summary,compared with the traditional sponge city media,the innovative granular sponge city growing media has better permeability and pollutantremoval effect,low cost,and convenient operationand maintenancein the later stage.It can be widely applied in areas without heavy metal pollution,and is expected to replace the traditional media to a certain extent.