Permanent landfill and stabilization for the remediation of municipal and industrial wastes

Worldwide, a large amount of municipal solid waste (MSW) is generated. For reasons of low cost and simplicity, municipal solid waste is generally disposed of in the landfill (Zhang et al., 2011). In developing countries, direct dumping of MSW in landfill or storage areas is commonly seen. On the other hand, the waste is screened, fractionated and processed before being deposited in the landfill site. For example, approximately 42% of the waste (∼22.2 million tonnes) generated in Australia during 1782009–2010 was disposed of in sanitary landfills [Australian Bureau of Statistics] (Xie et al., 2015). The increasing growth in population is producing a corresponding increase in the amount of MSW, posing adverse impacts on land resources and generating environmental pollution from landfill leachate and gas emissions (Komilis et al., 1999). Developing countries are facing difficult noxious issues due to the lack of proper management of MSW, its high moisture and organic matter (OM) content (Munnich et al., 2006; Zhang et al., 2008). A landfill is a complex biological system that can stabilize MSW when biodegradable OM is decomposed (Shalini et al., 2010; He et al., 2011), and the biological stability of MSW significantly controls the long-term emission potential and environmental impact of landfills (Cossu and Raga, 2008). Different geohazards are associated with the construction of closed MSW landfill sites that include settlements, gas (and odour) release, hydrological control on flushing of contaminants from the waste, the quality of leachate and the breach of containment systems and other environmental controls (Powrie et al., 2015). Kumar et al. (2011) reviewed leachate recirculation and stabilization, nitrogen transformation, the bioreactor landfill concept and their benefits, design and operational issues and research trends related to applied landfill. The municipal solid waste stream in Asian cities shows almost identical characteristics that include a high fraction of biodegradable material of more than 50% with high moisture content, and the trend of an increasing generation rate over time (Visvanathan et al., 2004). For example, in Thailand, the organic fraction in MSW consists of food waste (50%), paper (10%), and yard waste (5%) and the remaining inorganic or non-compostable fraction is comprised of plastics (14%), glass/stone/can (5%), wood (4%), metals (3%), textile (3%), rubber/leather (2%), and soil/other (4%).