Removal of nitrate and ammonium ions from livestock wastewater by hybrid systems composed of zero-valent iron and adsorbents

Abstract

The feasibility of hybrid systems for simultaneous removal of nitrate (NO) and ammonium ions (NH) from livestock wastewater was examined in batch experiments. As a part of efforts to remove nitrate and ammonium simultaneously, Fe0 and adsorbents including coconut-based granular activated carbon (GAC), sepiolite and filtralite were used. Various parameters such as adsorbent dosages and temperature were studied. Removal of NO increased with increase in temperature. Maximum NO removal (85.3%) was observed for the Fe0–filtralite hybrid system at 45 °C for a 24 h reaction time. Increase in GAC and sepiolite dosages had significant (P<0.01) effect on the NH removal efficiency, which was primarily due to the net negative surface charge of the adsorbents. The efficiency of hybrid systems for the removal of NO was in the order of filtralite>sepiolite>GAC, and the order of the removal of NH was GAC>sepiolite>filtralite. The results of the present study suggest that the use of hybrid systems could be a promising innovative technology for achieving simultaneous removal of NO and NH from livestock wastewater.