Impact of saline wastewater on the behaviour of aerobic granular sludge (AGS)

Abstract

This study delves into the impact of influent salinity on the efficacy of aerobic granular sludge (AGS) in wastewater treatment. It emphasizes the influence of salinity on vital biological processes like organic elimination, denitrification, nitrification, and phosphate removal while assessing the applicability of AGS technology under varying salinity conditions. The research further examines how salinity shapes microbial diversity and structure within the AGS framework. Utilizing three separate sequential batch reactors with distinct NaCl concentrations (2000, 5000, and 10000) mg/l, the research analyzed aspects such as sludge properties, settling speed, sludge volume index, and the efficiency of COD and NH4-N removal. Findings underscored that increased salinity levels from, (2000 to 10000) mg/l adversely affected AGS operations, resulting clear drop in removal efficiencies: from 94% to 68% for COD, from 91% to 52% for NH4,   from 80% to 20% for TN and caused reducing in settling speeds, granular deterioration,. Moreover, the microbial composition within the AGS was notably influenced by escalated salinity concentrations. This study offers crucial perspectives on the potential challenges of employing AGS technology for saline wastewater treatment and underscores the importance of additional investigations in this domain.