Quality Change of Aerobic Fermentation Process of Kitchen Waste，Agricultural Waste and Cow Manure

Using cow manure as main raw material, kitchen waste, corn stalk, vegetable waste, and vegetable waste fermentation sieve residue as auxiliary materials for mixing, a self-made fermentation reactor was used for forced aeration aerobic fermentation to compare impact of different excipients on quality change and composting effect of dairy manure fermentation process．A total of 6 treatments were set up in experiment: CK was cow manure, T₁ was cow manure+sieve residue, T₂ was cow manure+kitchen waste, T₃ was cow manure+kitchen waste+sieve residue, T₄ was cow manure+vegetable waste, T₅ was cow manure+corn stalk．Results showed that duration of high temperature period above 55 °C for CK, T₁, T₄, and T₅ reached 5 days, meeting requirements of aerobic fermentation for number of days of high temperature period, while T₂ and T₃ were less than 5 days, of which T₃ did not reach a high temperature above 55 °C, and average temperature of T₅ during high temperature period was 62.8 °C．After fermentation finished, water content loss rate of material was from 27.08% to 47.39%, and T₄ treatment had the highest loss rate．The pH range was from 8.15 to 8.84, and only the pH of CK and T₃ treatments was less than 8.5．Organic matter loss rate ranges from 9.19% to 17.28%, with T₅ being the highest．Total nitrogen, total phosphorus, and total potassium of each treatment were higher than initial content, and T₁ and T₄ could significantly improve total nutrient content of material．Contents of heavy metals As, Pb, and Cd after fermentation were lower than those before fermentation, while contents of Hg and Cr were on the contrary．Especially, attention should be paid to excessive Cr content after fermentation of cow manure．Mixed fermentation of cow manure and corn straw/vegetable waste could effectively improve quality of compost．