The disappearance of bromuconazole fungicide in domestic waste anaerobic fermentation

Abstract

Abstract A previous study recommended observing degradation of bromuconazole in waste anaerobic fermentation. This research, therefore, was carried out to study the disappearance of bromuconazole in waste anaerobic fermentation. Bromuconazole is a fungicide which is effective against Ascomycetes, Basidiomycetes and fungi imperfecti in cereals, grapes, top fruits and vegetables. It is also effective against Alternaria and Fusarium sp. In this study, one-month old refuse added with bromuconazole was anaerobically incubated in the 500 ml bottles at 30°C with no shaking in the dark room. Bromuconazole with total concentration of 200 mg/L was added in day 0 and 31. As a control, a bottle with refuse and bromuconazole at concentration of 200 mg/L was autoclaved and incubated at the same condition. High-performance Liquid Chromatography with UV detector and a 100 RP18 5µm Lichrosphere column was used to determine bromuconazole concentration. Methane content was determined by Gas Chromatography method equipped with a flame ionization detector and a metal column packed with 5% neopentyl glycol sebacate and 1% H3PO4 on Chromosorb W-AW (mesh 80-100). The disappearance of bromuconazole in anaerobic enrichments can be observed from mass balance determination after incubation for 225 days. The result showed that there was no change in bromuconazole mass balance. Bromuconazole was mostly adsorbed by the refuse. Bromuconazole inhibited the production of methane (99.58 mM), less than that of the control bottle with no added bromuconazole (121.78 mM). This phenomenon indicated the persistence of bromuconazole and its toxicity against methanogen bacterial activity. The presence of bromuconazole in the anaerobic process caused the refuse to be imperfectly fermented and so the production of methane was inhibited and volatile fatty acids were accumulated. Accumulation of the volatile fatty acids may cause further pollution in aquatic environment around the landfills site.