Method for preparing concentrated liquid fertilizer by using wastewater containing livestock excrement

Abstract

The invention discloses a method for preparing a concentrated liquid fertilizer by using wastewater containing livestock excrement. The method comprises the following steps: adding acids to immobilize amino and keep fertilizers; adding quicklime to neutralize excessive acids; performing primary fermentation so as to increase the dissolution degree of organic fertilizers; performing solid-liquid separation; performing negative-pressure concentration; and performing secondary fermentation on a concentrated liquid, thereby obtaining a livestock excrement concentrated liquid fertilizer. The method is simple in concentration process, good in operability and low in concentration cost; the solution degree of fertilizer components in the organic liquid fertilizer is high; due to amino immobilization and fertilizer increase of acids, and alcohol for increasing the dissolution degree of livestock excrement in the wastewater, the organic fertilizers can be relatively thoroughly dissolved in the wastewater, the cost of negative pressure concentration is reduced, the alcohol and the water can be both recycled, and the utilization rate of the livestock excrement is effectively increased; and by adopting the method, wastewater containing livestock excrement generated in the on-scale livestock breeding process can be turned into a high-concentration organic fertilizer, so that wastewater treatment in the on-scale livestock breeding process is solved, and harmonious development of agriculture, on-scale livestock breeding and living environments of people is promoted.

Description

Technical field: [0001] The invention relates to the field of poultry manure treatment methods, in particular to a process for producing concentrated liquid fertilizer from livestock and poultry manure. Background technique: [0002] With the development of the aquaculture industry, especially the large-scale livestock and poultry aquaculture industry, the problem of poultry manure disposal has become a key factor restricting the further development of the aquaculture industry. The adverse impact of poultry manure on water, soil and atmospheric environment has attracted much attention. Failure to properly dispose of manure in a timely and effective manner will have a serious impact on environmental sanitation. Some farms that have just been built are facing shutdown due to non-compliance with environmental protection standards. . There are two ways to treat livestock manure, one is composting and the other is incineration. These two treatment methods have high requirements ...

AI Technical Summary

Problems solved by technology

High-temperature rapid drying consumes a lot of energy and has strict requirements on equipment. The investment and cost are large, and the application is not wide. The biological dehydration cycle is long, and it takes at least 7-12 days to complete the dehydration. Therefore, the infrastructure investment is large and the site is also large. Not suitable for large-scale industrial production; the energy consumption of mechanical dehydration is relatively low and the cycle is short, so mechanical dehydration is widely used

In the prior art, although the popular poultry and livestock manure solid-liquid separator has a solid part moisture content lower than 60% after solid-liquid separation, the solid recovery rate of the solid-liquid separator is not high (all lower than 30%). More total nitrogen and total phosphorus run into the aqueous solution, which will cause waste of resources, greatly increase the cost of sewage treatment in the later stage, and aggravate the impact on the environment

In order to solve this problem, flocculants or phosphorus-fixing agents are generally added to absorb organic elements in feces, and then solid-liquid separation operations are performed to obtain solid components for composting, and the liquid is directly discharged. Patents CN102745866A and CN103723906A have reported This method of dehydrating poultry and livestock manure, however, found in use that even if the moisture content of the solid fertilizer obtained by this method can reach the standard, the discharged wastewater is far from reaching the "Discharge Standard of Pollutants for Livestock and Poultry Breeding Industry" (GB18596 -2001) stipulates the maximum allowable daily average discharge standard of water pollutants in the intensive poultry and livestock breeding industry, phosphorus and nitrogen elements are still high, and direct discharge will have a serious impact on water quality