Landfill leachate treatment strategies: Energy recovery and reduction of environmental impacts

The work commences by addressing characterization and regulatory constraints, underlining the spatio-temporal variability of leachates and the increasingly stringent requirements for their discharge. Following this, treatment technologies are reviewed, covering those from classical physico-chemical treatment schemes (coagulation and struvite precipitation) to advanced oxidation (ozonation and UV-light) and biological treatment approaches (anaerobic digestion treatment and aerobic granular sludge). The authors also look collectively at hybrid systems and focused attention on resource extraction and enhanced recovery, especially from leachates with attention being paid to the adoption of membranes enhanced for sustainability. The heart of the article discusses energy and material recovery pathways from leachates, which is considered the secondary focus of the paper treatment comes first. Attention is paid to biogas production from UASB reactors and co-digestion and nutrients recovered in the struvite form. Environmental impacts highlight the advantages that come through the donation of resource and material recovery from leachates and circularity. The article ends by looking at issues that remain in treatment such as variability of effluents, energy costs and membrane fouling as major issues and propositions for research perspectives encapsulating those areas. The authors conclude by talking about the necessity for progression to combined treatment that can turn storage sites into true biorefineries, and not just sites for storage, with the production of resources and an eye on environmental protection/security as key components.