Mixed digestion process for producing biogas through synergistic fermentation of sludge, fruits and vegetables

Abstract

The invention belongs to the field of biological fermentation, and particularly relates to a mixed digestion process for producing biogas through synergistic fermentation of sludge, fruits and vegetables. The method comprises the following steps: crushing fruit and vegetable waste to 1mm, and uniformly mixing the crushed fruit and vegetable waste with residual sludge to obtain a fermentation substrate; adding an inoculum into the fermentation substrate, and performing uniform mixing to obtain a fermentation system; adding calcium carbonate particles into the fermentation system; and adding water to dilute until the content of volatile solids in the fermentation system is 4%, and performing fermentation at 35-37 DEG C. The invention provides an environment-friendly gas production process ofsynergistic anaerobic digestion which is specially used for producing biogas by fermenting residual sludge and fruit and vegetable wastes. The process is simple to operate, the system configuration process is simple, the requirements on environment and cost are low, and the effect is remarkable and stable. According to the method provided by the invention, residual sludge and fruit and vegetablewastes are recycled by utilizing a biological method, the reaction conditions are mild, and large-scale and industrialized production is facilitated.

Description

Technical field [0001] The invention belongs to the field of biological fermentation, and specifically relates to a mixed digestion process for synergistic fermentation of sludge and fruits and vegetables to produce biogas. Background technique [0002] With the construction and operation of a large number of urban sewage treatment plants, the output of surplus sludge has increased substantially in recent years, and sludge, which is the main by-product of sewage treatment, has become a new pollution problem. Excess sludge refers to the sediment in the primary sedimentation tank of the sewage treatment plant in the sewage treatment process of the municipal sewage treatment plant and the mixture of by-products produced in the secondary and tertiary sewage treatment processes, including solid particles such as mud, sand and fibers in the sewage Its condensed flocs contain various colloids, organic matter, heavy metals, pathogenic bacteria, parasite eggs, viruses and other toxic and ...

AI Technical Summary

Problems solved by technology

The lower C / N is easy to cause the accumulation of ammonia gas in the anaerobic digestion tank, which has a certain toxic effect on microorganisms and seriously restricts the gas production during the digestion process.

However, if fruit and vegetable waste is used as the only fermentation substrate for anaerobic digestion, there is a problem that the fruit and vegetable waste will be rapidly acidified in the early stage, and the pH value in the fermentation system will quickly drop to the point where methane bacteria cannot grow, eventually leading to anaerobic digestion. The system is not working properly