Resources Recovery from Landfill Leachate: Current Status, Challenges, and Prospects

Nowadays, the average generation of global municipal solid waste (MSW) is about 2.00 billion tons, and is anticipated to reach 3.40 billion tons by 2050 due to urbanization and increase in population. Landfill is the most popular method due to cost-effectiveness, and about 90% of global MSW is landfilled, producing massive landfill leachate. Landfill leachate includes various pollutants, such as organic compounds, heavy metals, ammonia, and inorganic salts, leading to serious pollution to the surrounding environment. In this work, the traditional methods for treating landfill leachate, and recovery technologies of nutrients (N and P), inorganic salts, bioenergy, and humic substances from landfill leachate are summarized, and the corresponding progress and bottlenecks of these technologies are identified. Among these resources recovery, nutrients (N and P) are extracted by struvite precipitation, adsorption, ammonium stripping, and membrane filtrations. The extraction of metals from landfill leachate is summarized. In terms of energy recovery, methane production, hydrogen production, and cultivating microalgae are included and discussed. In addition, humic substances as liquid fertilizer are recovered by using membrane technologies, adsorption, and other technologies are identified. Finally, the challenges, and prospects of traditional methods and resource recovery are discussed. Overall, this work can provide insights into resources recovery from landfill leachate, facilitating the sustainable development of landfill leachate disposal.