High‐temperature technology survey and comparison among incineration, pyrolysis, and gasification systems for water resource recovery facilities. (7th April 2022) - Winchell, Lloyd J.
Abstract: Solids from wastewater treatment undergo processing to reduce mass, minimize pathogens, and condition the products for specific end uses. However, costs and contaminant concerns (e.g., per‐ and polyfluoroalkyl substances [PFAS]) challenge traditional landfill and land application practices. Incineration can overcome these issues but has become complicated due to evolving emissions regulations, and it suffers from poor public perception. These circumstances are driving the re‐emergence of pyrolysis and gasification technologies. A survey of suppliers was conducted to document differences with technologies. Both offer advantages over incineration with tailored production of a carbon‐rich solid, currently less stringent air emission requirements, and lower flue gas flows requiring treatment. However, incineration more simply combines drying and thermal processing into one reactor. Equipment costs provided favor pyrolysis and gasification at lower capacities but converge with incineration at higher capacities. Long‐term operational experience will confirm technology competitiveness and elucidate whether pyrolysis and gasification warrant widespread adoption. Practitioner Points: Pyrolysis and gasification systems are gaining traction in the wastewater industry with several full‐scale installations operating, in construction, or design Several advantages, but some disadvantages, are considered in comparison with incineration Organic contaminants, including PFAS, will undergo transformation and potentially complete mineralization through each process Abstract : Solids generated during wastewater treatment require dedicated processing, dictated in part by intended end use. Landfill costs, land application challenges, and unregulated contaminant concerns have driven wastewater treatment providers to consider alternative solids handling processes that reduce the final residual mass and destroy polluting chemicals. Pyrolysis and gasification technologies are emerging in the market, providing a potential solution to the current end use challenges, and offer certain advantages over the historically proven incineration technology.