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

• Published in: Aerosol and Air Quality Research 2019-11, Vol.19 (11), p.2490-2501
• Main Authors: Huang, Kuo-Lin, Liu, Chou-Ching, Lee, Chia-Wei, Ma, Chen-Yao, Lin, Ting-Chun, Tsai, Jen-Hsiung, Chen, Shui-Jen
• Format: Article
• Language: English
• ISSN: 1680-8584; 2071-1409
• DOI: 10.4209/aaqr.2019.09.0486

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.