Research On Volatile Fatty Acid Production From Anaerobic Fermentation Of Vegetable And Kitchen Wastes

Recently with the development of society, the amount of vegetable wastes and kitchen wastes has rapidly increased by year and year. More and more scholars have paid attention to look for a method which is economical and environmentally friendly to deal with the organic wastes. The disposal of the vegetable wastes and kitchen wastes can be used by the method of anaerobic fermentation to produce volatile fatty acid (VFA). TheVFA can be used as a carbon source in the biological nutrient removal (BNR) process of wastewater treatment. This study has focused on the process of anaerobic fermentation with the feedstock of cabbage wastes and kitchen wastes. The following conclusions were obtained:Firstly, the effect of feedstock proportion on the anaerobic fermentation of cabbage wastes was studied using batch experiments at temperature of 35℃.The results showed that the VFA production from anaerobic fermentation which used potatoes as feedstock were suitable for carbon source in the BNR process.Secondly, the effect of the heat pretreatment on anaerobic fermentation of kitchen wastes was investigated. The results showed that the heat pretreatment of feedstock and seed sludge can enhance the anaerobic fermentation of the kitchen wastes. At temperature 35℃,the VFA production was higher than that of 45℃ and 55℃.Thirdly, the effect of pH on the anaerobic fermentation of kitchen wastes was studied at temperature of 35℃.The results showed that when controlled the pH was controlled at 5,7 or 10, the VFA production was higher than pH without controlled. When pH was at 7, the VFA production and VFA compositions were suitable as the carbon source for the denitrification in the BNR process.Lastly, the effect of organic loading rate (OLR) on the fermentation was investigated. The pH, temperature and hydraulic retention time (HRT) were set at 7.0,35℃ and 5d, respectively. The results showed that the VFA production increased with the OLR increasing. But if the OLR was too high, it would cause the failure of the reactor system.