Woodland for Sludge Disposal in Beijing: Sustainable?

The sludge products of urban sewage treatment plants in Beijing are increasing year by year, and there is a large amount stagnation, which requires scientific reasonable disposal strategies. Currently, the woodland mountainous area considered main means for disposal; however, because heavy metals may cause potential pollution to soil groundwater, it unclear how much can be applied per unit area. To ensure sustainable sludge, necessary measure risk on groundwater under different application rates determine most plan. In this study, undisturbed columns obtained from field were used clarify migration behaviors accumulation eight hazardous simulated rainfall conditions, three sets tests (the 30 t·ha−1·a−1, 60 t·ha−1·a−1 120 respectively) set based supply–demand relationship between Beijing’s annual output available disposal. results showed that significant differences rules rates, mainly reflected each layer soil. terms leaching efficiency metals, except Cadmium, other did not exceed 0.1%, indicating accumulated During process products, Arsenic Cadmium posed greater than should paid sufficient attention. Based soil, was factor limiting frequency product application. rate preferred compared with two presented minimal short term, while total maximized.