Investigating the Fast Anaerobic Digestion of Urban Waste and the Efficiency of Biogas Production in Combination with Animal Waste (Case Study: Qazvin Urban Waste)

Abstract

The process of anaerobic digestion and biogas production, like other biochemical reactions, is affected by various physical and chemical factors. This research was carried out with the aim of increasing the rate of biogas production, reducing the feed retention time in the digester, and increasing the amount of biogas production, by investigating the effect of co-digestion of urban solid organic waste with cow waste by anaerobic digestion method. For this purpose, 52 samples of mixed municipal waste (during the year 2021, once a week and one sample each time) were prepared from the waste transfer station of Qazvin city, And in order to investigate the effect of manure on the studied variables, 50 kg of fresh manure was collected from a cattle farm located in the region. After preparing the samples, a laboratory bioreactor was used to perform the experiments. The biogas production process was carried out in two stages. In the first stage, urban waste materials were used, and in the second stage, a combination of urban waste materials and animal manure was used. The results showed that with the use of animal manure in the initial feed and keeping other variables constant, the retention time has decreased by 6 days compared to the first stage. Also, taking into account the cumulative amount of biogas production, it was found that in stage 1 and 2, 140.89 and 230 lit.kg^-1 VS of biogas were produced during the digestion period, respectively. Therefore, the efficiency of biogas production has increased by 38%.