Study On The Anaerobic Digestion Performance And Pretreatment Technology Of Vinegar Residue

Vinegar residue was main waste which produced in vinegar production process. In China, about180～220million tons per year of vinegar residue is produced. Serious environmental problems have been created by this waste because of its high acidity. Traditional treatment methods such as incineration, landfilling, and open discharge, are still the main ways for the management of this waste in China. These methods often lead to the pollution of groundwater, land, and air. Anaerobic digestion technology applied in the processing of vinegar residue, which coudle be able to achieve the effective reduction of vinegar residue, and able to convert the organic matter contained in the vinegar residue into biogas. Good environmental and economic benefit could be obtained by these technology.The main characteristics of vinegar residues were analysised in this paper.The85%VS and more than70%lignocellulosics contents was detected in the vinegar residue. Based on the TBMP calculated equation and the elements analysis results, the TBMP of vinegar residue was accouted as473.34mL·gVS-1Bio-chemical methane potential of vinegar residue and the infllunece of different F/I ratios on biogas production was determined in this research. Good performance of vinegar residue in biogas production was observed. After60days digestion, the maximum cumulative methane yield of242.69mL·gVS-1produced from vinegar residue was obtained. Higher F/I ratio could lead to the cumulation of VFA in the digester which caused the lower methane yield at the end of digestion.Based on the batch test, CSTR reactor was used in this research in order to determine the performance of vinegar residue in semi-continuous digestion. The influence of slurry reflux on semi-continuous degestion was also observed in this research. The results showed that the slurry reflux could effectively maitain the pH value of influent which highly increased the buffer capacity of anaerobic digestion system. The highest volume biogas yield was1.08mL·L-1in this research (OLR=2.5gVS·L-1·d-1, HRT=40d and slurry reflux ratio=40%). After digestion, the solid content in the effluent was disposed in pyrolysis process. After the pyrolysis process,70%of solid content was decreased.Considering the higher lignocellulosics contents, the vinegar residue was pretreated with NaOH and ammonia before digestion. Fourier transforms infrared spectroscopy, X-ray diffraction, and scanning electron microscopes were used to investigate the changes of vinegar residue after pretreatment. The highest biogas yield was obtained at10%NaOH pretreated sample which was31.4%higher than that of the non-pretreated sample. The lignin in the vinegar residue was partly degradated after10%NaOH pretreatment. Swelling effects was observed in the SEM analysis of NaOH pretreated vingar residue. Non crystal form change was observed in this study.