USE OF AGED REFUSE FROM LAOGANG REFUSE LANDILL AS SOIL CONDITIONER FOR FEASIBILITY STUDY

摘要

Municipal solid waste (MSW) in landfill is degraded during the long-term stabilized process, and this process is also referred to as mineralization process and the resultant stabilized refuse is regarded as aged refuse in this paper. Aged refuses excavated from 3 to 15 years capped cell compartments in Laogang Refuse Landfill at Shanghai, China, were characterized in terms of TN (Total nitrogen), available nitrogen, TP (Total phosphate), available phosphate, TK, available potassium, organic matter, HM (heavy metal), and then the relationships between these parameters and ages were co-related. It is found that aged refuses contained higher strength concentrations of macro-nutrient elements, such as TN was 0. 23%～0. 55%, TP was 2. 13 ～ 6. 8 mg/kg, TK was 23. 07 ～ 38. 75mg/kg, organic matter was 5.7%～13.71%, and these data apparently declined in general as refuse age extends, although these values seemed to fluctuate with refuse age. Meanwhile, some physical porosities, such as particle distribution, moisture content, were also tested, and it is found that the proportions of finer fractions increased as the ages of refuse at the landfill increases, following a logarithm equation as Y=33. 345 Ln(t, years) — 20.406, (R~2 =0.9738). Furthermore, the concentrations of heavy metals in aged refuse meet the Control standards for urban wastes for agricultural use except to Pb. Therefore, aged refuse have a potential as a soil conditioner in conservation practices aimed at increasing the nutrients elements of soils, and it also may be possibly used as organic fertilizer for non-crop cultivation. Finally, approaches for improvement of quality in lean soil and redevelopment of both the land and aged refuse in the stabilized landfill are proposed.