| After classification of domestic waste,kitchen waste is classified separately and becomes a usable resource.Anaerobic biogas used to generate electricity or purification and integration into the natural gas pipeline network is one of the main ways to use kitchen waste as a resource.The utilization of biogas residue is the bottleneck for the full quantitative utilization of kitchen resources.Kitchen waste anaerobic digestion residue contains a huge amount of organic matter,and many mineral salts as well.Mixed compost of biogas residue and green waste is an alternative technology path.This paper systematically carried out the experimental research of mixed kitchen waste anaerobic digestion residue and green waste aerobic composting.The main content and results are as follows.The experiment analyzed the components of kitchen waste anaerobic digestion residue and green waste.The results showed that the properties of biogas residue from laboratory anaerobic fermentation were similar to those of industrialized biogas residue,whose organic matter content was 44.6%～51.4%,water content was 75.1%～80.6%,carbon-nitrogen ratio(C/N)was11.8:1～14.8:1,total nitrogen was 2.12%～3.02%,total phosphorus was 1.01%～1.22%,and total potassium was 4.33%～4.64%.The organic matter content of greening waste from three sources of street sweeping,wetland mowing and garden season-changing was similar,ranging from72.4% to 81.6%.The moisture content of the three was quite different,respectively 6.0±0.7%,12.2±1.0% and 7.9±0.7%,and the difference in carbon to nitrogen ratio was also more significant,respectively 52.8:1～58.8:1,34.2:1～39.2:1 and 74.1:1～79.7:1.Mixed kitchen waste anaerobic digestion residue and street sweeping green waste for composting test.Compared the effects of the C/N of the mixture,the height of the pile and the pile-turning frequency.The results of 27 sets of experiments on 3 level conditions of 3 variables showed that: while the mass ratio of biogas residue and street sweeping green waste was 2.3:1(C/N is about 25:1),the height of the pile is 30 cm,and the pile turned 3 times per day,the mixture has the shortest maturity time(42 days).At this time,the surface temperature of the stockpile dropped to the ambient temperature,the ratio of C/N value after composting and before composting(T)is 0.54(reference value 0.53～0.72),rate of emergence(GI)is 83%(reference value 80%),which meet the maturity requirements.Under the conditions of 30 cm height and 3 times/day,three kinds of green wastes,including street sweeping,wetland mowing and garden season-changing,and three different fineness of each materials and biogas residue mixed composting were carried out.The results showed that: in the 9 experimental groups,after 60 days of mixed composting of 30 mm and20mm street sweeping greening waste and biogas residue,total nutrient,organic matter content,and moisture content of these two groups of products reached the requirements of "Organic Fertilizer",exceeded the standard requirements of "Organic media for greening" and "Microbio organic fertilizers".After 42 days of mixed composting of 20 mm garden season-changing greening waste and biogas residue,the product met the requirements of maturity,which was the most mature experimental group among all comparison groups.The research results provide basic data and technical support for kitchen waste anaerobic digestion residue and various types of green waste mixed composting,and provide an alternative technical path for full resource utilization of kitchen waste. |
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