Integrated Mechanical Separation And Parameter Optimization For Municipal Solid Wastes

Mechanical separation is a preliminary step for municipal solid wastes recycling and reuse. Moisture and components in the wastes, equipment used, etc., will greatly affect the separation efficiencies. In the past 10 years, the mechanical separation for MSW has witnessed a fast progress in China, though the key technology and equipment may be imported abroad outside China. However, the moisture and components in China MSW is quite different to those in the developed countries, and the separation facilities imported seem inefficient in practical uses. Hence, it is necessary to develop a cost-effective and efficient MSW separation system appropriate to the characteristics of the MSW in China.Moreover, as traced in literature, it seems that the exact parameters for the traditional separation facilities such as trommel screener and air-separator have not been deeply studied and the optimum operational conditions subject to the MSW characteristic to be separated have not been well developed.In this work, the typical MSW generated in downtown in Shanghai was manually separated and characterized in terms of their valuables and components, and then the integrated mechanical separation facilities were established to mechanically sort the wastes, aiming to get the optimum operational parameters appropriate to the wastes properties in Shanghai. The conclusions are drawn below.1. The fractions less than 40 mm in size in the MSW occupied 41～47%, in which over 97% were the putrescibles, and accounted for about 68% in the MSW as a whole. Fraction with 40 to 80 mm in size occupied 18～24%, in which 70～80% were the putrescibles and 15～24% plastics, and 21% putrescible in the MSW. For the MSW fraction over 80 mm in size, it occupied 20～31% in the wastes, in which 30～49% were plastics, 61～83% in all plastics present in the MSW as a whole. Hence, different valuables may be available from various waste fractions, implying that the mechanical separation facilities to be developed may be designed so that the valuables can be obtained in size.