Evaluation on Performance and Backwashing Effect of Filter Media for Treatment of Nonpoint Pollution

Abstract

The stormwater is a typical urban non-point source. About 80% of pollutants in stormwater are present in particulate phase and attached to particles transported in suspension, with under 100 µm particle size. Therefore, various pollutants are associated with particles, it has been suggested that the removal of SS is critical for the treatment of a wide range of stormwater pollutants. This study has been carried out to evaluate the applicability of three filter media and backwashing effect for treatment of stormwater micro-particle pollutants. Upflow type column filter was used for to treat micro particles. Three filter materials were selected for this study: PP, Ball type fiber media, and Ceramic media. SEM image analysis was performed to view of three media surface structure. As the results of PP, Ball, Ceramic media filtration, the mean removal efficiency of SS were 80.5%, 78.4%, 80.0%, respectively. The range of mean particles size, D_Mean for influent and effluent were 12.35~42.32 µm and 1.58~31.16 µm, respectively. Based on SS load mass balance, the results of filter recovery rate for PP, Ball, Ceramic media were 95.0%, 92.0%, 89.7%, respectively. Key words: Stormwater, Filter media, Backwashing effect, SEM