Challenges and engineering application of landfill leachate concentrate treatment

Landfill leachate concentrate (LLC) is a concentrated waste stream from landfill leachate treatment systems and has been recognized as a key challenge due to its high concentration of salts, heavy metals, organic matters, etc. Improper management of LLC (e.g. reinjection) would exacerbate the performance of upstream treatment pro-cesses and pose risks to the surrounding environments near landfill sites. Addressing the challenge and recov-ering resources from LLC have thus been attracting considerable attention. Although many LLC treatment technologies have been developed, a comprehensive discussion about the challenges still lacks. This review critically evaluates mainstream LLC treatment technologies, namely incineration, coagulation, advanced oxidation, evaporation and solidification/stabilization. We then introduce a geopolymer-based solidification (GS) process as a promising technology owning to its simple casting process and reusable final product and summarize engineering applications in China. Finally, we suggest investigating hybrid systems to minimize LLC production and achieve the on-site reuse of LLC. Collectively, this review provides useful information to guide the selection of LLC treatment technologies and suggests a sustainable alternative for large-scale application, while also highlighting the need of joint efforts in the industry to achieve efficient, ecofriendly and economical on-site management of landfill waste streams.

Automated summary

Landfill leachate concentrate (LLC) is a concentrated waste stream containing high levels of salts, heavy metals, and organic matter, posing significant challenges for proper treatment and management. This review examines various LLC treatment technologies, such as incineration, coagulation, advanced oxidation, evaporation, and solidification/stabilization, and introduces a promising geopolymer-based solidification process with potential engineering applications in China. The review also suggests exploring hybrid systems to reduce LLC production and promote on-site reuse, emphasizing the importance of collaborative efforts in the industry for efficient, eco-friendly, and cost-effective landfill waste management.