Experiment And Evaluation Study On Compost Maturity Of Municipal Solid Waste

With the development of the city, changes of the fuel structure and theimprovement of residents living standards, the proportion of some materials such asthe kitchen residua, paper, plastic, glass and metal in the garbage that can be classifiedand recycled is bigger and bigger, which makes the ratio of inorganic componentsgradually declined, while the organic composition's is on the increase. The traditionaltreatments, such as the refuse incineration, landfill and simple stack are restricted forthe increasingly serious land decrease, environmental pollution and secondarypollution.Therefore, as the important way of becoming resource, reduction, harmless formunicipal solid waste, the composting technology will get more and more attention.The compost products can be used to replace chemical fertilizer to be applied in theagricultural production, but the products into the soil must be mature, otherwise it willcause nitrogen deficiency of the plants, and cause microorganisms' acuteness activitywhich will result in lack of oxygen, and then produce extremely anaerobicenvironment to influence the growth of plant roots.To determine whether the products are mature, their maturity should be evaluated.Physical index, chemical index and the biological index are evaluated of the maturity.Because of the complexity of the compost raw material, a single index is difficult toevaluate maturity of the compost reasonably and comprehensively. So based onphysical index, chemical index and the biological index, this paper establishes arelatively perfect and reasonable evaluation standard of compost. This paper uses municipal solid waste of Urumqi as raw material for experimentby regulating the pH value and moisture content to conduct the compost research. Inthe experiment, the parameters such as temperature, moisture content, pH value,electric conductivity(EC), E4, E6, organic carbon, organic matter, carbon nitrogenratio (C/N), NH₄⁺-N, germination index (GI) and total phosphorus, total nitrogen,total potassium are assayed, and the changes of them are analyzed.Based on the analysis of the parameters of the above, this paper selects apparentindex, carbon nitrogen ratio (C/N), NH₄⁺-N and germination index (GI) to establishevaluation standard of the compost maturity, classifies the evaluation indexes,calculates the grade of membership of the compost products in mature, better mature,basal mature and immature grade, and evaluates the mature degree of them.In addition, by assaying the moisture content, pH, organic matter, total nitrogen,total phosphorus and total potassium, and according to organic fertilizer standard andtechnology evaluation indexes of the municipal solid waste compost treatment plantof our country, the paper also evaluates the quality of the compost products of thewaste treatment plant, finds out the reasons for the low effectiveness of the compost,and puts forward the relative feasible solutions to provide certain theoretical guidancefor the compost production of the waste treatment plant.