Release Reductions of Gaseous Ammonia and Nitrogen Oxides from Electrochemical Treatment of Swine Wastewater

Abstract

This study investigates the release of NH 3 and nitrogen oxides (NO x) from wastewater into the air in relation to the variations in NH 3-N, NO 2-N, NO 3-N, and chemical oxygen demand (COD) concentrations in the swine wastewater with/without electrolysis using boron-doped diamond (BDD), PbO 2 , and graphite anodes. The NH 3 concentration in the air right above the swine wastewater without electrolysis increased over time and this increase was greater when the wastewater NH 3-N concentration was higher. Electrolysis could reduce the release of NH 3 from swine wastewater into the air. The NO concentration in the air was greater for the wastewater without electrolysis than for that with electrolysis but an opposite trend was observed for NO 2 , although the corresponding NO x concentrations for the wastewater with and without electrolysis were similar. Roughly, the air NH 3 , NO, NO 2 , or NO x concentrations for using the different anodes in wastewater electrolysis followed the order Nb/BDD >> graphite/BDD > graphite > graphite/PbO 2 ≈ Ti/PbO 2. Although the BDD and graphite anodes showed less formation of nitrite or nitrate than the PbO 2 anodes, the graphite/BDD and graphite anodes had worse performance in NH 3-N or COD electro-degradation than the other tested ones. When the initial concentration of NH 3-N or COD was higher, its specific energy consumption in electrolysis was lower.

Synthesis and characterization of TiO2/hydrochar matrix composites for enhanced ammonia degradation

“…Ammonia stems from various sources, including agricultural activities, 5 wastewater treatment, 6 and landfills. 7 Due to its highly hydrophilic nature, ammonia readily reacts with air pollutants like SO x , NO x , and liquid-phase sulfuric and nitric acids, forming secondary particulate matter such as ammonium salts, accounting for a significant portion of PM 2.5 (20–80%).…”