Sludge management forms a huge part of wastewater operations; contributing about 40–50% and up to 40% of total wastewater treatment costs and emissions respectively. Whereas in the past, sludge was viewed as nuisance waste to be disposed of, there is now a general consensus in the wastewater industry that sludge is a potential source of valuable resources and alternative green energy. Despite many established pathways for sludge handling, treatment, disposal and utilization; sludge management continues to present major environmental, technical, financial, and regulatory challenges for the wastewater sector. Emerging technologies are thus providing alternative feasible pathways through conversion of wet sludge into biofuels, thereby expanding waste-to-energy conversion options while still recovering other valuable materials and destroying bioactive contaminants as well as substances of concern. One such technology developed in BC, Canada is the enhanced hydrothermal polymerization (EHTP) Polymeric Carbon Solid (PCS) process. The PCS technology processes a wide range of biomass to a sterile carbon neutral hydrochar that can be used as a biofuel and for other applications (e.g. as a soil conditioner, adsorption media, building material, energy storage). This paper discusses the findings of a research project that investigated the efficacy of the PCS technology at both laboratory and pilot scale when processing sludge on its own and in combination with fine screenings from the inlet works. Analysis results showed a 8 – 47% increase in the caloric value of the produced hydrochar indicating that the hydrochar can potentially be used as a biofuel. Cost benefit analysis indicated that the PCS technology is the most economically attractive sludge management solution compared to established sludge to energy technologies like anaerobic digestion and gasification. The technology also demonstrated other advantages that include (i) ability to process a wide range of biomass thus combining sludge, screenings and general biomass waste management (ii) lowest greenhouse gas emissions and (iii) potential to destroy contaminants of concern such as endocrine disrupting compounds to produce a sterile product with multiple applications.

Emerging sustainable wastewater sludge management innovations for value recovery

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.