Combining Thermal Hydrolysis with Thermal Processing to Decrease Operating Costs and Increase Capacity

Barber, W.P.F.

New Jersey Efluents, 2023

Introduction

Thermal processing can play an important role with respect to sludge management. In cases where regulations prevent biosolids land application, sludge contains hazardous materials, or local topography is inconsistent with biosolids application, thermal processing can provide a viable outlet. Incineration provides a final disposal method, reduces reliance on landfills and can be used for energy recovery, whilst drying and similar processes can provide a level of flexibility for biosolids end use. Contrary to these benefits, incineration is expensive, may generate hazardous wastes, is not considered as sustainable and suffers unfavorable public perception. Drying processes have a thirst for fossil-fuels making them vulnerable to volatilities in gas markets as well as being potentially high carbon emitters, in addition to being complex to maintain relative to other infrastructure. The operation of thermal processes can be fundamentally optimized by both minimizing the quantity of sludge and, more importantly, the water content of the sludge to be processed. In this regard, thermal hydrolysis combined with anaerobic digestion can play a fundamental role in sludge management.

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