High-Solids Anaerobic Digestion of Municipal Sludge Pretreated by Thermal Hydrolysis

ISSN： 1061-4303

Source： Water Environment Research, Vol.80, Iss.7, 2008-07, pp. : 654-662

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

High-solids anaerobic digestion can consistently achieve 55 to 60% volatile solids destruction after thermal hydrolysis pretreatment, which reduces its viscosity and increases the fraction of soluble organic matter. For feed sludge with total solids concentrations between 6.8 and 8.2%, the process is stable at hydraulic retention times of 9 to 12 days, significantly increasing the treatment capacity of existing digesters or, in treatment plants without spare capacity, helping to postpone, reduce, or even avoid costly infrastructure investments. Process stability is related to the high concentration of soluble organic matter in the digesters. High-solids temperature-phased digestion appears to be superior to high-solids mesophilic digestion, with respect to process flexibility and stability, biosolids stabilization, and biogas generation, although ammonia inhibition may have occurred. Implementation of high-solids digestion could significantly reduce operation and maintenance costs of solids-handling operations.