Abstract: Batch experiments were conducted to study the effect of lipase pretreatment on the hydrolysis of kitchen oil and its anaerobic digestion performance. First, take the exam
We investigated the effects of enzyme dosage, water oil ratio, pH, and temperature on the hydrolysis of kitchen oils and fats, and determined them through response surface analysis
Preprocessing conditions; Based on the anaerobic digestion experiment of kitchen wastewater (containing oil) under pretreatment conditions, the important impact of pretreatment on the anaerobic digestion of kitchen wastewater was analyzed. The results showed that the pretreatment conditions for kitchen oil were as follows: enzyme dosage mass fraction of 1.15%, water oil mass ratio of 0.9, pH 8.0, temperature of 42.5 ℃. The predicted hydrolysis rate was 86.6%, and the repeated experiment hydrolysis rate was (88.1 ± 2.2)%, which was close to the predicted value. This indicates that the response surface model can well predict the effects of the above four reaction conditions on hydrolysis. The study on lipase pretreatment and anaerobic digestion of actual kitchen wastewater found that the cumulative methane production of the enzyme group was 572.12 mL/g · COD, which was 55.10% and 14.56% higher than that of the kitchen wastewater group (368.86 mL/g · COD) and the oily wastewater group (499.47 mL/g · COD), respectively. This indicates that fats in kitchen wastewater have great potential for methane production, and lipase pretreatment can significantly improve the methane production efficiency of fats. A comparative analysis was conducted on the pH, volatile fatty acids (VFAs), and dehydrogenase activity of anaerobic reaction processes under different pretreatment conditions, and it was found that enzymatic pretreatment had a relatively small impact on the system pH; Its impact on VFAs and dehydrogenase activity is mainly reflected in the early stage of anaerobic digestion, manifested as a significant increase in VFA and dehydrogenase activity, indicating that pre hydrolysis can ensure substrate supply and improve methane production efficiency in the methane production process.