Enhanced coagulation for removal of dissolved organic nitrogen in water: A review.

Wastewater treatment plants (WWTPs) meeting strict nutrient discharge regulations typically effectively remove inorganic nitrogen, leaving dissolved organic nitrogen (DON) as the main component of total nitrogen in the effluent. DON in treated effluent from both WWTPs and drinking water treatment plants (DWTPs) has the potential to induce eutrophication and contribute to the formation of nitrogenous disinfection byproducts (N-DBP). While numerous studies have investigated DON in different water sources, a limited number of studies have focused on its removal through enhanced coagulation.

Understanding the influence of dissolved organic nitrogen characteristics on enhanced coagulation performance for water reuse.

With the recent focus on using advanced water treatment processes for water reuse, interest is growing for utilizing enhanced coagulation to remove dissolved chemical species. Up to 85% of the nitrogen in wastewater effluent is made up of dissolved organic nitrogen (DON), but there is a knowledge gap regarding its removal during coagulation, which can be influenced by DON characteristics. To address this issue, tertiary-treated wastewater samples were analyzed before and after coagulation with polyaluminum chloride and ferric chloride.

Pilot-scale demonstration of dissolved organic nitrogen removal from an advanced water reclamation facility using enhanced coagulation.

Most wastewater treatment facilities that satisfy stricter discharge restrictions for nutrients, remove dissolved inorganic nitrogen (DIN) species efficiently, leaving dissolved organic nitrogen (DON) to be present at a higher proportion (up to 85 %) of total nitrogen (TN) in the effluent. Discharged DON promotes algae growth in receiving water bodies and is a growing concern in effluent potable reuse applications considering its potential to form hazardous nitrogenous disinfection byproducts (N-DBPs). Enhanced coagulation is an established process in the advanced water treatment train for most potable reuse applications.