Laboratory evaluation of heavy metal removal from stormwater runoff by pervious concrete pavement containing seashell and oil palm kernel shell

One of the major issues related with impermeable surfaces such as impervious concrete pavement in urban area is the collecting of rain as stormwater runoff, which then moves harmful natural and man-made pollutant into the natural water bodies such as lakes, streams, rivers, etc. This study investigated the effect of pervious concrete containing palm oil kernel shell and seashell on removing dissolved heavy metals contaminants from stormwater runoff. Therefore, mixtures were made, which replaced 6.3-9.5 mm limestone with 25 and 50% of 6.3-9.5 mm and 4.75-6.3 mm of both shells. The specimens were cured in a fog room and void content were tested. Specimens with same void content (23%) are selected to reduce experimental variability from differing void content. Pervious concrete cylinders were loaded in the laboratory with collected stormwater runoff, and concentrations, volumes of influent and effluent evaluated. Ten consecutive storm events of 200 mL in 20 min of rain are simulated to test heavy metal removal performance. The range of heavy metal removal for pervious concrete mixture containing seashell was 37 and 93% which was higher than that of control mixture (39-73%). However, the rate of heavy metal removal for specimens incorporating kernel shell was between 14 and 63% which was lower than that of control mixture. The results showed that the waste materials can be considered as one of the sustainable runoff purification methods, respecting their effective heavy metal removal rate in runoff, as well as the reasonably low cost and consumption when used on the pervious concrete pavement.