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.