Influence of regulative materials on aerobic composting of biogas residues

As to the high moisture capacity and the harmful substance after anaerobic fermentation in the regulative materials, we conducted the test about the modification of biogas residues' aerobic composting, taking rice straw, wheat straw, carbonized powder of straw and urea as regulative materials, and biogas residues will be added once or several times. The results showed that: rice straw helps to the degradation of organic substance; wheat straw is helpful to the regulation of water, degradation of cellulose and decrease of nitrogen loss; carbonized powder of straw is helpful to the degradation of lignin and phosphorus fixation. Compared with the biogas residues added once, multiple additions with small amount is more helpful to nutrient loss and the degradation of organic substance and cellulose.

I. Introduction

Biogas fertilizer (biogas slurry and biogas residue) is a high-quality organic fertilizer, in addition to rich in nitrogen, phosphorus, potassium elements, but also containing boron, copper, iron, manganese, calcium, zinc, etc. trace elements which play an important role on crops, and a large number of organic matter, amino acids, vitamins, etc^[1]~[2]. _o Biogas residue from a pool of biogas digesters still remained a small amount of harmful substances, and high water content. It is not easy to transport and storage, then it can only be consumed locally, while the capacity of organic fertilizer of farmland around medium-sized biogas project is limited, it results that biogas fertilizer become the secondary source of contamination. Hence, it is considerably significant for the commercialization of biogas fertilizer and the reduction of environmental pollution, if the appropriate conditioning material is used for the modification of biogas residue aerobic compost. Bhamidimarri S.M.R[3] found that sawdust is the ideal bulking agent by comparing the effect of straw, sawdust, peat, peanut shell and rice bran on pig manure compost, the sawdust has a strong moisture absorption and retention capacity of adsorption of NH₃, and increases the porosity of the pile material to meet the O₂ demand for microbial activity, reduces the odor and NH3 volatilization loss as well.