Electrochemical removal and recovery of ammonia and phosphates from blackwater and wetland passed blackwater

Abstract

Removal of nutrients from blackwater is essential before discharge into the water bodies to avoid harmful anthropological or environmental manifestations. In the present study, two membrane-divided electrochemical cells in series were employed for simultaneous removal of ammoniacal nitrogen (TAN) and orthophosphates (TP) from blackwater and wetland-treated blackwater. The parameters optimized were hydraulic retention time, flowrate, and current density. The highest TAN and TP removal achieved for blackwater at 16 Am−2 was 63 ± 2% & 39 ± 2%. TAN and TP recovery was 88 ± 0.1% and 60 ± 10%. TAN and TP removal rates were 78.07 and 12.7 g m-2d-1, while the recovery rates were 68.44 and 7.56 g m−2 d-1. The energy consumption was 5.4 ± 0.1 WhL-1. The treatment and nutrient recovery process was demonstrated in the long-term (7 days) to estimate the scalability and field applicability. The recovery solution post long-term experiment showed a low concentration of nutrients. Simultaneously, the anionic membrane showed ion transferability losses and physical damage limiting the scale-up and field application.