Optimization of Solid Waste Conversion Process and Risk Control of Groundwater Pollution

The book proposes an optimal scheme for full-life-cycle solid waste management that addresses the critical technological bottlenecks, and introduces a new technical model that reflects the synergies of resource utilization and secondary pollution control. A set of technical methods has been set out for scientific and reasonable on-site investigation, risk assessment, management and control, to minimize the risk of groundwater contamination by solid waste at landfill site. This book will provide useful guidance on optimal management of solid waste and risk assessment and management of groundwater pollution at landfill site for government managers, environmental researchers, and people involved in and concerned about solid waste disposal.

A systemic study of the metabolic process of solid waste and the law of conversion and environmental effects of major pollutants will facilitate the solution to solid waste pollution, recycling pathways and multi-objective optimization strategies. Focusing on solid waste, this chapter probes into the law of material conversion, builds a metabolic dynamics model for typical pollutants integrating different disposal patterns, and reveals the metabolism mechanisms, migration pathways and major influencing factors in solid waste treatment and disposal. A mechanism of management towards effective environmental and economic trade-offs is formed, covering optimization, validation, and feedback.

In order to achieve effective recycling of solid waste and control the secondary pollution, the characteristics and potential of the solid waste were studied This chapter expounds on technologies for resourcization of solid waste and control of secondary pollution from a systemic and holistic perspective, covering the whole process from waste collection, transportation and mechanical sorting, bioaugmentation and resourcization, control of secondary pollution, and system integration and management optimization.

Bioreactor landfill marks the final disposal of solid waste. Traditionally, mixed waste is buried directly, resulting in low stabilization efficiency. However, the microenvironment of bioreactor landfill is unfavorable for nitrification and blocks nitrogen transformation, leading to nitrogen accumulation and severe leachate pollution. By means of process optimization, in particular, using biofortification, the biofermentation of organic components and landfill of inorganic components are combined to reduce landfills and environmental risks caused by landfill of organic components. To this end, this chapter reveals the rapid reduction mechanism of organic matter, nitrogen conversion process, constraints, and the impact mechanism. Based on this, technical principles and methods for landfill structural optimization and in situ nitrogen reduction are put forward, to effectively decompose organic matter, prevent the nitrogen accumulation, and accelerate landfill stabilization. The practice is crucial to synergies between the disposal of solid waste and control of secondary pollution.

Landfill, the eventual way of disposing solid wastes, inevitably comes with a certain degree of pollution to surrounding groundwater due to construction, broken impervious layer, and uneven geological subsidence. The survey and risk assessment of groundwater pollutions are the important technical means for knowing the current status of landfill site pollution, forecasting the pollution trend, and assessing its risk. This chapter elaborates the general procedures for survey of groundwater pollution on various landfill sites, including the collection of basic data, setting out of monitoring points, selection of monitoring items, and data organization method, according to China’s current mode of construction and operation of landfill sites, in combination with the research progress in groundwater survey both domestic and foreign. On this basis, the typical model—3 MRA risk assessment model—is optimized.

To realize scientific hierarchy and effective management for groundwater pollution of landfill in China, and to ensure that the landfills with significant occurrence probability of groundwater pollution accident are subjected to major supervision, index system and technical methods suitable for groundwater pollution risk ranking of landfill in China are established in this chapter. Management procedures and methods for groundwater pollution of landfill are proposed on this basis. In combination with risk control node, specific risk control measures and management plan are proposed in respect to the established landfills and landfills under planning and construction respectively. It provides scientific basis and technical support for the environmental protection department in China to carry out ranking management for groundwater pollution risk of landfill, and to ensure environmental safety of groundwater.