Method used for processing biogas slurry via boilogical filter combination filtering

Abstract

The invention provides a method used for processing biogas slurry via boilogical filter combination filtering. According to the method, a cylindrical filtering container is adopted; coarse maize straw is taken as a first stage column filling material, fine maize straw is taken as a second stage column filling material, and walnut sand is taken as a third stage column filling material; a first stage column, a second stage column, and a third stage column are connected successively; and biogas slurry is subjected to three stage series filtering. The biogas slurry filtering method is simple and convenient in operation; biogas residue is abundant in nitrogen nutrition, and is retained in filtering materials along with sludge after filtering so that carbon nitrogen ratio of the filtering materials is reduced; after filtering, biogas slurry low in suspension content can be used for subsequent liquid organic fertilizer preparation via membrane concentration, and can be used for composting process of spent filtering materials so as to obtain organic fertilizers; and environmental benefit and economic benefit are excellent.

Description

technical field [0001] The invention belongs to the technical field of resource utilization of waste, and in particular relates to a method for treating biogas slurry by combining biological filter materials. Background technique [0002] As a way of efficient utilization of biomass energy, biogas engineering can not only remove harmful substances in waste through anaerobic fermentation, but also generate clean biogas energy. However, biogas engineering also discharges a large amount of biogas slurry. It is rich in nutrient elements, and direct discharge will cause serious environmental pollution. In foreign countries, biogas slurry is generally used as fertilizer and recharged to farmland after simple treatment. The use of biogas slurry in my country generally includes: crop seed soaking, pest control, feed additives, crop hydroponics, and farmland irrigation as fertilizer. The use of biogas slurry in other methods except irrigation is relatively small, and the scale of bio...

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Problems solved by technology

However, the concentration of suspended solids in the biogas slurry is too high, which will affect the efficiency of membrane passing and pollute and block the filter membrane. Therefore, the biogas slurry needs to be pretreated to remove suspended solids. Currently, the filter materials for biogas slurry pretreatment are mostly coarse sand, fine sand, quartz sand, Inorganic filter materials such as volcanic rock need to be replaced or backwashed regularly, and a large amount of wastewater will be generated during backwashing. There are existing reports about using only corn stalks as filter materials, but single-stage filtration cannot take into account the processing capacity well, and the processing capacity buffers poor sex

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