High value-added biomaterials recovery from granular sludge based wastewater treatment process

Abstract Due to high biomass retention and outstanding setting property, granular sludge has been widely applied in wastewater treatment plants to reduce the footprint, lower energy consumption and increase capacity. Granular sludge consists of microorganisms embedded in extracellular matrix which contains a variety of extracellular biomaterials. Those biomaterials are renewable, biodegradable, nontoxic and without secondary pollution, and have similar properties with industrial products. Therefore, granular sludge offers promising opportunities for recovering high value-added biomaterials, which could contribute to sustainable wastewater treatment and resource recycle. This work presents a comprehensive and up to date review on resources recovery of various extracellular biomaterials from granular sludge. And we mainly focus on the characteristics, extraction and recovery technologies as well as potential applications of these biomaterials. In addition, impacts of biomaterials extraction on subsequent sludge treatment, such as anaerobic digestion, energy recovery and sludge dewaterability are discussed. The technologies options and potential applications analysis presented in this study could contribute to the development of the recycling of extracellular biomaterials from granular sludge-based wastewater treatment process.