Method for separating and concentrating nitrogen, phosphorus and potassium from biogas slurry by electrodialysis

Abstract

The invention discloses a method for separating and concentrating nitrogen, phosphorus and potassium from biogas slurry by electrodialysis, relates to the technical field of waste resource utilization, and can realize separation and concentration of nutrients such as nitrogen, phosphorus and potassium in the biogas slurry so as to facilitate promotion of high-valued utilization of nutrient resources in the biogas slurry. The method for separating and concentrating nitrogen, phosphorus and potassium from biogas slurry by utilizing electrodialysis comprises the following steps: pretreating the biogas slurry by adopting a sand filtration and ultrafiltration combined process, removing suspended and colloidal particles, and carrying out solid-liquid separation; and concentrating the filtered biogas slurry through an electrodialysis system, so as to keep the contents of nitrogen, phosphorus and potassium in the biogas slurry 25% or more. The method is mainly applied to biogas slurry treatment.

Description

technical field [0001] The invention relates to the technical field of utilization of waste resources, in particular to a method for separating and concentrating nitrogen, phosphorus and potassium from biogas liquid by electrodialysis. Background technique [0002] At present, biogas (biogas) is a clean and renewable energy, which is listed as the main renewable energy in my country for key development. [0003] Specifically, biogas slurry is the product of anaerobic fermentation of biogas, which is rich in nutrients such as nitrogen, phosphorus, and potassium. It is an excellent liquid organic fertilizer with strong quick-acting nutrient capacity and high nutrient availability. It can be used for soaking seeds, Foliar spraying, farmland irrigation, hydroponic vegetables and feeding pigs and fish, etc. Among them, the direct use of farmland fertilizer is the most important utilization method of biogas slurry. [0004] However, the operation of the biogas digester will conti...

AI Technical Summary

Problems solved by technology

[0004] 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 threats and great waste of nutrient resources; on the other hand, compared with traditional commercial fertilizers, the nitrogen, phosphorus and potassium nutrients in biogas slurry have disadvantages such as low nutrient concentration, large storage volume and high transportation costs, which are not conducive to centralized collection and cross-regional utilization , restricting the recycling of nutrient resources in the biogas slurry