Stormwater Treatment Using Membranes: A Feasibility Investigation

Urban stormwater commonly contains many pollutants. This has threatened the ecological health of receiving waters as well as stormwater reuse safety. In this context, an effective treatment of urban stormwater is essential. This study undertook a feasibility investigation on using membranes to remove heavy metals from urban stormwater. Two of the most commonly used membranes in the field of water treatment, namely flat ceramic membrane and organic flat membrane, were selected. The research outcomes showed both membranes had the potential to treat urban stormwater. In the case of real stormwater in low influent velocity, the removal percentages were 77.48% (Zn), 64.33% (Cu), 98.04% (Pb), 74.45% (Ni), 56.96% (Cr), and 49.81% (Cd) for flat ceramic membranes and 81.76% (Zn), 77.69% (Cu), 98.13% (Pb), 81.49% (Ni), 59.62% (Cr), and 68.55% (Cd) for organic flat membranes. In high influent velocity, they were 78.66%, 67.74%, 97.02%, 60.84%, 49.05%, and 78.06% for flat ceramic membranes and 74.35%, 66.70%, 96.94%, 61.19%, 48.79%, and 88.00% for organic flat membranes. However, the influence of membrane types on treatment performance was secondary to rainfall characteristics and pollutant forms. It was noted that the heavy metal removal percentages had lower variability for events with high rainfall intensity while both membranes indicated a significant preference on treating particulate pollutants by interception mechanisms. The results also highlighted that using membrane technology to treat stormwater might have a relatively low cost due to low membrane fouling. This reduced the cost of replacement and maintenance. These research outcomes provided an effective stormwater treatment approach and can provide improved stormwater quality, ensuring its reuse safety.