北京市垃圾分类后厨余垃圾与分类前生活垃圾性质变化分析

2020年5月1日起,北京市正式实施了《北京市生活垃圾管理条例》。为了解北京市垃圾分类后厨余垃圾与分类前生活垃圾性质变化,对居民区垃圾分类收集点厨余垃圾桶内的垃圾进行了采样分析,并与北京市分类前混合收运的生活垃圾性质进行比对。结果表明,北京实施垃圾分类后,厨余垃圾桶内厨余组分占比逐渐增加,实施1年后,厨余组分占比可达99%;含水率和容重较分类前明显增加,可燃分和热值明显降低,故不适宜采用焚烧处理;pH和C/N呈下降趋势,电导率呈小幅度增长趋势,有机质、总氮(以N计)、总磷(以P₂O₅计)和总钾(以K₂O计)含量上升,垃圾资源化利用潜力增大。Cd、Pb、Cr、Hg、As、Cu和Zn 7种危害较大的重(类)金属元素中,除As外其余的金属元素含量均呈下降趋势;Na、Ca、Mg、Fe、Mn等金属元素,除Na外均呈下降趋势。故垃圾源头分类可以有效控制厨余垃圾中金属含量,使其种子发芽指数升高,减小对植物的生物毒害作用,降低环境风险。该研究结果可为北京市垃圾资源化利用和处理设施规划提供参考和依据。

ANALYSIS OF CHANGES IN CHARACTERISTICS OF KITCHEN WASTE AFTER SORTING AND DOMESTIC WASTE BEFORE SORTING IN BEIJING

On May 1st, 2020, Beijing officially implemented the Beijing Municipal Household Waste Management Regulations. In order to understand the changes in the characteristics of kitchen waste after garbage classification and domestic waste before classification in Beijing, the garbage in the kitchen waste garbage bins in the garbage classification collection points of residential areas was sampled and analyzed, and then compared with the domestic garbage mix collected and transported in Beijing before classification. The results showed that after Beijing implemented garbage classification, the proportions of kitchen waste components in kitchen waste bins gradually increased. After one year of implementation, the proportion of kitchen waste components reached 99%. The moisture content and bulk density of kitchen waste increased significantly, compared with that before classification, and the combustible points and calorific value were significantly reduced, so it was not suitable for incineration treatment; pH and C/N showed a downward trend, conductivity showed a tiny growing trend, and the contents of organic matter, total nitrogen (in terms of nitrogen element), total phosphorus (in terms of P₂O₅) and total potassium (in terms of K₂O) increased, and the potential for waste resource utilization also increased. Among the seven kinds of heavy (metalloid) metals with greater harm, such as Cd, Pb, Cr, Hg, As, Cu and Zn, except for As, the content of the remaining metal elements showed a downward trend; among the metal elements such as Na, Ca, Mg, Fe, and Mn, the content of the remaining elements, except Na, showed a downward trend. Therefore, the metal content in kitchen waste could be effectively controlled through the garbage sorting, so that the seed germination index could be increased, the biological toxic effect on plants reduced, and the environmental risk reduced. This study can provide a reference and basis for the planning of waste resource utilization and treatment facilities in Beijing.