Waste valorization technology options for the egg and broiler industries: A review and recommendations

Abstract Poultry production, including for both meat and eggs, is projected to have the highest growth rate among livestock sectors between 2005 and 2050. Poultry are recognized as relatively efficient converters of feed to food relative to other livestock species. Nonetheless, increased production of poultry products will lead to larger volumes of associated by-product and waste streams. Principal methods for handling these materials are currently either landfill or rendering for spent hens and mortalities, landfill for egg shells and direct land application of manure as organic fertilizer. However, a variety of established and emerging technological alternatives exist which may present more or less efficacious means of valorizing these waste streams, which have yet to be prioritized. This review identifies, categorizes and describes current and emerging waste valorization technologies for livestock materials and evaluates their potential applicability for key poultry waste streams from a theoretical perspective. Literature specific to poultry waste streams (105 studies) were identified and reviewed in detail using a set of specified criteria. Four well-developed technologies were identified as potentially suitable for valorization of key poultry waste streams: anaerobic co-digestion, anaerobic mono-digestion (biological technologies), pyrolysis and gasification (thermochemical technologies). Comparative life cycle assessment studies are recommended to comprehensively evaluate the potential net sustainability benefits and impacts of these technologies compared to conventional alternatives as well as cost comparisons to assess their feasibility for commercial application. This will support pollution reduction, innovation and change management for sustainability, and overall achievement of a sustainable supply chain.