Method for treating biogas slurry

Abstract

The invention provides a method for treating biogas slurry, which comprises the following steps: introducing biogas slurry into an aerobic bioreactor, treating under the action of aerobic activated sludge to obtain aerobic effluent, wherein the inoculation amount of the aerobic activated sludge is 10-14 g / L, the hydraulic retention time is 1-3 days, the dissolved oxygen concentration is 3.8-4.2 mg / L, and the aeration rate is 0.4-2.0 L / min. The pH of the aerobic effluent treated according to specific parameters is reduced, the SS and turbidity removal rate of the effluent is maximum, the content of various nutrient elements is highest, and the removal rate effect of organic matters is optimal. The aerobic effluent is separated through an ultrafiltration membrane, so that SS and turbidity inthe biogas slurry can be further reduced, the separated effluent is concentrated through a reverse osmosis membrane, so that the content of various nutrient elements and humic acid in the RO concentrated solution can be effectively increased, and meanwhile, the concentration of heavy metal ions in the RO concentrated solution cannot be increased. The obtained RO permeate liquid can be directly discharged after reaching the standards. The method provided by the invention effectively combines biogas slurry resource recovery and up-to-standard discharge, and has a wide application prospect.

Description

technical field [0001] The invention belongs to the field of biogas slurry recycling, and in particular relates to a method for treating biogas slurry. Background technique [0002] With the rapid development of my country's animal husbandry, while ensuring the growing demand for animal products, a large amount of livestock manure and sewage have also been produced, and the pollution of livestock and poultry manure has become increasingly prominent. At present, the annual production of livestock and poultry manure in the country is about 3.8 billion tons, which is the most important livestock and poultry farming waste. According to statistics, the chemical oxygen demand (COD) emitted by my country's livestock and poultry breeding industry in 2010 was 12.6826 million tons, accounting for 42% of the country's total, accounting for 96% of the total emissions from agricultural sources; total nitrogen (TN) and total phosphorus (TP ) emissions were 1,024,800 tons and 160,400 tons,...

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Problems solved by technology

[0005] The literature "Effects of Biogas Slurry on Soil Quality and Yield and Quality of Chinese Cabbage, Huang Jieying, etc." used biogas slurry fermented from large-scale livestock and poultry breeding manure sewage as organic fertilizer, and found that the application of biogas slurry can increase the yield of Chinese cabbage and promote the growth of Chinese cabbage. The absorption of mineral elements can increase the content of Vc and soluble sugar in pakchoi. However, the contents of Cr, Zn and Cd in the soil and pakchoi after the application of biogas slurry all exceed the standard, indicating that the heavy metals in the biogas slurry will cause differences in soil and plant systems. Accumulate to a certain extent, thus creating certain environmental pressure, even endangering human health

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