Sodium persulfate and potassium permanganate inhibit methanogens and methanogenesis in stored liquid dairy manure
Habtewold, J., Gordon, R., Voroney, P., Sokolov, V., VanderZaag, A., Wagner-Riddle, C., Dunfield, K. (2018). Sodium persulfate and potassium permanganate inhibit methanogens and methanogenesis in stored liquid dairy manure. Journal of Environmental Quality, [online] 47(4), 786-794. http://dx.doi.org/10.2134/jeq2018.01.0054
Plain language summary
Stored liquid dairy manure has a large potential to produce methane (CH4) emissions and mitigation strategies are required to reduce these emissions. This study investigates three chemical additives (sodium persulfate, potassium permanganate and sodium hypochlorite) to evaluate their impacts on microbial communities and CH4 production. Laboratory analysis was used to determine quantities of different microorganisms on days 0, 60 and 120. CH4/CO2 ratios in the space above manure was used to evaluate methane production. Results showed that sodium persulfate and potassium permanganate reduced CH4/CO2 ratios and negatively impacted the growth of methane producing microorganisms, suggesting that these additives could reduce CH4 production. Sodium hypochlorite on its own did not limit methane producing microorganism growth or CH4/CO2 ratios. Sodium persulfate and potassium permanaganate may offer alternative options to reduce CH4 emissions from stored liquid dairy manure but further studies are required to assess the impacts on the environment and characteristics of the treated manure.
Stored liquid dairy manure is a hotspot for methane (CH4) emission, thus effective mitigation strategies are required. We assessed sodium persulfate (Na2S2O8), potassium permanganate (KMnO4), and sodium hypochlorite (NaOCl) for impacts on the abundance of microbial communities and CH4 production in liquid dairy manure. Liquid dairy manure treated with different rates (1, 3, 6, and 9 g or mL L-1 slurry) of these chemicals or their combinations were incubated under anoxic conditions at 22.5 ± 1.3°C for 120 d. Untreated and sodium 2-bromoethanesulfonate (BES)- treated manures were included as negative and positive controls, respectively, whereas sulfuric acid (H2SO4)-treated manure was used as a reference. Quantitative real-time polymerase chain reaction was used to quantify the abundances of bacteria and methanogens on Days 0, 60, and 120. Headspace CH4/CO2 ratios were used as a proxy to determine CH4 production. Unlike bacterial abundance, methanogen abundance and CH4/CO2 ratios varied with treatments. Addition of 1 to 9 g L-1 slurry of Na2S2O8 and KMnO4 reduced methanogen abundance (up to ~28%) and peak CH4/CO2 ratios (up to 92-fold). Except at the lowest rate, chemical combinations also reduced the abundance of methanogens (up to ~17%) and CH4/CO2 ratios (up to ninefold), although no impacts were observed when 3% NaOCl was used alone. With slurry acidification, the ratios reduced up to twofold, whereas methanogen abundance was unaffected. Results suggest that Na2S2O8 and KMnO4 may offer alternative options to reduce CH4 emission from stored liquid dairy manure, but this warrants further assessment at larger scales for environmental impacts and characteristics of the treated manure.