Production process for producing organic fertilizer through concentrating biogas slurry by using multistage membrane separation technology

Abstract

The invention discloses a production process for producing an organic fertilizer through concentrating biogas slurry by using a multistage membrane separation technology; the production process comprises the following steps: a, pretreatment: carrying out pretreatment of biogas slurry after anaerobic fermentation through precipitation, aerobic fermentation, solid-liquid separation, primary filtration, homogeneous curing adjustment, deep precipitation, fine filtration and biological bacteria inhibition; b, multistage membrane separation before concentration: carrying out microfiltration membrane separation and ultrafiltration membrane separation of the biogas slurry after fine filtration and biological bacteria inhibition; c, multistage membrane concentration: carrying out multistage membrane concentration of the biogas slurry penetrated fluid obtained by ultrafiltration membrane separation through nanofiltration membrane concentration, reverse osmosis membrane concentration and concentration membrane protection; d, blending: adding large, medium and trace elements and other nutritional ingredients and functional components into the intercepted concentrate obtained by nanofiltration and reverse osmosis membrane separation, blending to obtain a liquid organic fertilizer, and sub-packaging; and e, product packaging. The production process has the advantages of flexible structure, advanced equipment and scientific process layout, can meet resource comprehensive utilization development of biogas slurry of all large and medium sized biogas projects.

Description

[0001] Technical field: [0002] The invention relates to the technical field of concentrating biogas slurry to manufacture organic fertilizer, in particular to a production process for concentrating biogas slurry to manufacture organic fertilizer by utilizing multi-stage membrane separation technology. [0003] Background technique: [0004] Biogas slurry is a liquid-phase residue formed after anaerobic fermentation to produce biogas of various organic matters such as livestock and poultry manure and crop straw, which is generally brown liquid. In recent years, with the increase in the number of large-scale farms in my country and the continuous improvement of the degree of intensification, the environmental problems caused by livestock and poultry manure have become increasingly serious. According to statistics, as of 2007, the total discharge of livestock and poultry manure was over 3 billion tons, and the total COD discharge was more than 77 million tons, which was more tha...

AI Technical Summary

Problems solved by technology

[0007] 1) The pretreatment process before membrane separation is complicated, with large investment and high operating cost;

[0008] 2) Membrane separation process, due to a single membrane type, the nutrients in the biogas slurry cannot be fully intercepted, and the concentration efficiency is low;

[0010] 4) Membrane fouling and membrane clogging are difficult to eradicate, and the recovery of membrane flux depends on periodic cleaning by adding chemicals, which is not conducive to the use of concentrated liquid as fertilizer;

[0011] 5) The service life of the membrane module is short, and the membrane is changed frequently, which not only affects the production efficiency but also increases the operating cost;

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