Preparation method of biogas residue organic fertilizer employing biochar as carrier

Abstract

The invention discloses a preparation method of biogas residue organic fertilizer employing biochar as a carrier. The preparation method includes following steps: performing a solid-liquid separating process to a biogas residue, mixing the biogas residue with minced straw, stirring the biogas residue and the straw uniformly, adding plant ash or calcium oxide to carry out a secondary fermenting process to obtain a fermented product of the biogas residue, mixing the fermented product of the biogas residue with biochar, adding a binding agent, and performing a granulating and dring process to obtain biogas residue-biochar organic fertilizer. The biogas residue organic fertilizer, without addition of any chemical fertilizer, is a pure organic fertilizer. By means of the biogas residue organic fertilizer, yield and quality of crops can be increased and a negative influence of the fertilizer to environment can be reduced. In addition, the biogas residue organic fertilizer is beneficial to improvement of soil and continuous utilization of land. The biochar is prepared by employing water hyacinth and is used as the carrier of the fertilizer so that a problem of application of the water hyacinth can be solved. By means of the straw as an auxiliary material for fermentation, a large amount of agricultural wastes can be digested. Furthermore, on the basis that the biochar has a carbon-sequestration effect, greenhouse gas emission can be reduced. Development and utilization of the biogas residue organic fertilizer are beneficial to alleviation of greenhouse effect.

Description

technical field [0001] The invention belongs to the technical field of agricultural fertilizers, in particular to a method for preparing biogas residue organic fertilizer with biochar as a carrier. Background technique [0002] Since the reform and opening up, the output of agricultural products in my country has increased greatly, and the contribution of chemical fertilizers is indispensable. However, with the accumulation of time, the side effects of chemical fertilizers have become increasingly prominent: chemical fertilizers cause soil compaction, affect soil air permeability, and reduce soil productivity after long-term application; the impact of chemical fertilizer residues on the environment is immeasurable, for example, nitrogen fertilizers will pollute in the form of nitrate for a long time Groundwater, excess nitrogen, phosphorus, and potassium fertilizers enter the water body with rainfall runoff, causing eutrophication of the water body. In addition, with the im...

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Problems solved by technology

[0006] Chinese patent document CN101774848A aims at the problems of difficult dehydration and solidification of biogas residues and high energy consumption of mechanical dehydration and drying, and proposes a process of using shallow ponds to naturally solidify and air-dry. Moisture and physical property requirements for granulation; however, the proposed shallow pool natural curing and air-drying process requires 5-6 months of curing time, and the efficiency of this secondary fermentation method is not high, which may make the fermentation incomplete

In order to increase production, many biogas residue fertilizer processes have adopted the method of adding chemical fertilizers, such as Chinese patent document CN101229982A (a method of utilizing biogas residue to produce organic compound fertilizer) and CN101774848A (biogas residue organic fertilizer and its preparation method) ; while this results in high yields in the short term, it has a negative effect on the soil in the long run

And, for the production of high-quality green food, the biogas residue fertilizer added with chemical fertilizer is still not suitable

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