THE PATTERNS OF HAZARDOUS ORGANIC WASTE DESTRUCTION WITH OBTAINING OF ENERGY IN THE INSTALLATIONS MODELING LANDFILL SITES
Hovorukha V, Havryliuk O, Tashyrev O.
D.K. Zabolotny Institute of Microbiology and Virology of the NAS of Ukraine,
Department of extremophilic microorganism’s biology
е-mail: vira-govorukha@ukr.net
More than 1 billion tons of food waste is dumped in the world annually. The constant growth of solid waste landfills indicates the absence of effective methods of their treatment. Further ignoring of the problem will cause the poisoning and destruction of natural ecosystems. The decomposition of organic waste is a priority issue. Moreover, it is a constantly renewable source of CH4.
The goal was to study the patterns of the destruction of organic waste by methane fermentation in installations modeling landfills and to increase its efficiency.
Plexiglass containers (0.2×0.2×0.9 m) were used. Typical household waste was loaded modeling the landfill waste. To compare the efficiency of waste destruction the process taking place in landfill without optimization was modeled in the variant 1. The variant 2 involved the study of the fermentation with the methanogenic microbial community and periodic regulation of the pH of the liquid phase. In the variant 3, the efficiency influenced by methanogens, optimization of waste particle size and regular maintenance of the pH optimum was investigated.
The absence of regulation caused the suppression. The accumulation of toxic exometabolites (pH = 4.8-5.2), lack of mass transfer and regulation shifted the metabolism to the inhibition of CH4 synthesis. The duration of fermentation T = 69 days, the yield of hydrogen VH2 = 5 L/kg of waste, the traces of CH4 were observed, the coefficient of waste destruction Kd = 5. The results of waste fermentation in the variants 2 and 3 showed the need to maintain the pH = 6.0-7.0 to achieve maximum efficiency of waste destruction, as well as H2 synthesis on the first stage and CH4 obtaining on the second. In the variant 2, with irregular pH regulation, the T = 103 days, the VH2 = 20 L/kg of waste, and the VСH4 = 16 L/kg of waste, the Kd = 11. Waste grinding, mass transfer and regular pH optimization provided the efficiency increase. Thus, after 14 days the Kd reached 20 and the VH2 = 27 L/kg of waste, the VСH4 = 12 L/kg of waste.
Thus, it is necessary to optimize the fermentation in landfills. This increases the efficiency of waste destruction that will reduce landfills and provide CH4 and H2 synthesis.