Method for separating and concentrating nutrient from biogas slurry by utilizing selective electrodialysis

Abstract

The invention relates to a method for separating and concentrating nutrient from biogas slurry by utilizing selective electrodialysis and belongs to the field of water pollution control and resource regeneration. The method comprises the following steps: adopting a pre-treating method for removing suspension and colloid particles in the biogas slurry; performing solid-liquid separation; pumping supernate into an electrodialysis system with an anion-cation selective exchanging film, separating and concentrating PO4<3->, NH4<+> and K<+>; after separating and concentrating, acquiring a concentrated solution containing PO4<3-> as a polar solution 1 and the concentrated solution containing NH4<+> and K<+> as a polar solution 2 acquired by a selective electrodialysis system. The method for separating and concentrating nutrient from biogas slurry by utilizing selective electrodialysis provided by the invention can establish a basis for recycling phosphorus of biogas slurry or concentrating nitrogen phosphorus and potassium nutrient and acquiring high-value commodity fertilizer, is beneficial to the increasing of the use ratio of the biogas slurry, is capable of boosting the high-value utilization of the biogas slurry resource and has positive significance in sustainable development of ecological environment.

Description

technical field [0001] The invention belongs to the field of water pollution control and resource regeneration, in particular to a method for separating and concentrating nutrients from biogas slurry by selective electrodialysis. Background technique [0002] In recent years, the rapid development of large-scale livestock and poultry breeding has produced a large amount of livestock and poultry manure, which has also brought enormous pressure to the environment. Biogas fermentation technology is an effective method for treating and utilizing livestock and poultry manure. The biogas produced by it is a cheap and clean energy with high utilization value. With the support of the state and governments at all levels, the development of my country's biogas technology level and scale has advanced by leaps and bounds, and remarkable results have been achieved. By the end of 2011, there were 72,700 biogas projects nationwide, including 4,631 large-scale biogas projects (with a singl...

AI Technical Summary

Problems solved by technology

However, the operation of the biogas digester will continuously discharge biogas slurry, which is far more than the one-time consumption of the fertilization rules of surrounding farmland crops. A large amount of biogas slurry is stored around the biogas digester and cannot be digested, which has become a problem affecting the normal operation of the biogas project and is also a problem for the environment. Potential threat and great waste of nutrient resources

On the other hand, the nutrient NH in biogas slurry 4 + -N 200-800 mg / L, PO 4 3- -P30-120 mg / L, K + 80-500mg / L, compared with traditional commercial fertilizers, it has the disadvantages of low nutrient concentration, large storage volume and high transportation cost, and also has peculiar smell, which is not conducive to centralized collection and cross-regional utilization, and restricts the recycling of nutrient resources in biogas slurry

Images