Treatment of cellar rainwater by multi-dimensional electrode electro-flocculation/submerged ultrafiltration

Abstract

Rainwater cellars collect and store rainwater to make full use of water resources and improve the problem of drinking water shortages. The treatment of rainwater cellars is therefore of great significance. In this study, we tested the performance of the multi-dimensional electrode electroflocculation/submerged ultrafiltration process on the removal of ammonia nitrogen, total phosphorus (TP), chemical oxygen demand (CODMn ), and UV254 from cellar rainwater. The effects of plate spacing, current density, activated carbon dosage, and electro-flocculation time were analyzed. The integration of the submerged ultrafiltration and electro-flocculation/submerged ultrafiltration processes was found to promote cellar rainwater quality. The removal rates of ammonia nitrogen, TP, CODMn, and UV254 using the combined processes were 53.17%, 90.81%, 59.55%, and 37.67% respectively, corresponding to an optimal plate spacing of 10 mm, current density of 18.51 A/m2, activated carbon dosage of 60 mg/L, and electro-flocculation time of 15 min. The energy consumption to remove pollutants using the multi-dimensional electrode electrocoagulation process was 0.215 KWh/g, which verifies that the process effectively purifies cellar rainwater.