关键词: 沼渣, 牛粪, 生物质飞灰, 堆肥, 好氧发酵, 生物炭

Abstract: In order to improve the problems of low phosphorus and low potassium content in biogas residue and cow dung compost, biomass fly ash was added to compost heap, and the physical and chemical characteristics of compost heap were analyzed. The fly ash supplemental levels of 8%, 12%, 20% and 25% were selected, and the changes of water content, electrical conductivity, total carbon, total nitrogen, total phosphorus and total potassium were recorded every 10 days according to the quartering method, and the effects of fly ash supplemental levels on biogas residue and cow dung composting were analyzed and studied. The results showed that when the addition of fly ash increased from 8% to 25%, the moisture content of the compost increased, but when the addition amount exceeded 12%, it had little effect on the moisture content, which was maintained at about 58% in the end; the existence of alkali metals and other substances in the fly ash neutralized the acid produced in the aerobic fermentation process, increased the pH value of the heap, and also increased the conductivity of the compost improved the fermentation environment of the compost; the biochar and potassium in the fly ash increased the total carbon and total potassium content of the compost. After 60 days of decomposing, the total carbon content of the compost increased by 37.37% to 47.81%, the maximum value of total potassium content reached 35.74 g/kg, but the effect on total nitrogen and total phosphorus content was not obvious. However, excessive fly ash addition would inhibit the growth of microorganisms, thereby reducing the fermentation rate and product quality.

Key words: biogas residue, cow dung, biomass fly ash, mixed composting, aerobic fermentation, biochar