Experimental study and simulation of water quality purification of urban surface runoff using non-vegetated bioswales

• Multiple bioswale cells with different media and structures are designed.
• The influencing of important factors on the purification effects of bioswales are studied.
• The models between bioswale pollutant removal rate and its factors are established.

Road runoff pollutants are widely recognized as major causes of receiving water pollution. Bioswale serves as an effective storm-water natural purification and disposal technology, which presents important practical value in controlling runoff pollution and stormwater utilization. Multiple bioswale cells with different media are designed and built. Artificial stormwater is synthesized on the basis of the investigated and measured data on the surface runoff pollution in Northwest China, which is used to study the purification effect of bioswale on runoff pollutants from four aspects. Results show that different factors significantly affect water purification process. The removal rate of nitrogen decreases with the increase of inflow concentration for most of media; however, which is contrary for phosphorus and mostly greater than 90%. Blast furnace slag has the best removal of nitrogen, phosphorus and heavy mental Zn under low inflow concentration. The correlation models between the purification effects of total nitrogen, total phosphorus and COD and their influencing factors are established using the multivariate regression method. The Nash–Suttcliffe simulation efficiency coefficients of the models are greater than 0.6.