城市生活垃圾中可降解有机物降解规律研究

On the degradation regularity of degradable organic matter in the municipal solid waste

通过室内降解试验,测定了城市生活垃圾中可降解有机物降解过程中的纤维素及木质素含量,提出采用C/L(纤维素含量/木质素含量)归一化后的相对变化量来表征城市生活垃圾(MSW)的生物降解程度。分析生物降解程度指标随时间的变化规律,结果表明,生物降解程度随着降解时间的增加呈倒"S"型变化,可降解有机物的降解过程是由慢到快再到慢的过程;Slogistic模型可以较好地模拟MSW的降解过程,而模型参数可以反映降解条件对降解速率的影响。Slogistic模型预测的填埋场稳定化时间与实测结果相符,表明了建议的表征降解程度指标及Slogistic模型的合理性与正确性。

This paper is dedicated to finding a degradation regularity of degradable organic matters in the municipal solid waste （MSW） based on defining the characteristic features of its components and their variations in the degradation process. Our study has been done by taking 24 samples of MSW, ranging from the middle to low predicted degradability, which were then put in the plastic containers in laboratory at the mean temperature of 25 ℃ . Results of our findings indicate that the waste samples size turned to be smaller and smaller with some components getting more and more indistinguishable, that is, gradually decomposed. And finally their degradation extent can be quantified by normalized ratio of cellulose content to lignin content in comparison with their initial data, and tends to increase with time. In addition, it is found that the degradation regularity of cellulose and lignin with degradation time can be analyzed by means of the degradation extent index. The results prove that the degradation reaction rate tends to be very slow at the initial degradation stage because of small quantities of microorganisms and large quantities of organic matters. Actually, the degradation reaction tends to be sped up due to the acclimatization of microorganisms in the middle stage of degradation, though the degradation reaction turns to slow down again later due to the process in the need of consuming some amount of organic matters in the final stage. Thus, we would like to propose Slogistic model to describe the regularity of the degradable organic, which indicates the reaction rate is related in some degree with the moisture, temperature, bacterization and leachate recirculation. The proposed model can be shown that the results obtained from degradation tests in the laboratory conditions can be reproduced as the data recorded in the sanitary landfill site.