Decentralized water reclamation is emerging as a new paradigm that pairs local wastewater resources with local users; however, one of the challenges that must be addressed to advance its implementation is the low energy efficiency associated with small treatment plants and the lack of available small-scale energy recovery technologies. Gasification is a technology that could be used to convert wastewater solids to energy at small wastewater resource recovery facilities (WRRF). A model developed for air-blown gasification coupled with internal combustion engine for energy production demonstrated that gasification of wastewater solids could produce up to one third of the electrical demand at a small WRRF. Results based on samples collected from local wastewater treatment plants show that the energy embedded in wastewater solids does not vary substantially with treatment processes implemented or point of solids generation, and thus gasification is feasible for a wide variety of WRRF sizes and processes. Further modeling revealed that feedstocks generated by three different processes have similar power output for one metric ton per day of solids gasified (~20. kW), but the net power produced by a 19. ML/d. WRRF varies more substantially (110-140. kW) because the mass of solids produced vary with each treatment scheme.
Bibliographical noteFunding Information:
This project was supported by the National Science Foundation under Cooperative Agreement EEC-1028968 (ReNUWIt Engineering Research Center), and by the State of Colorado through the Higher Education Competitive Research Authority (CHECRA). The authors wish to express their gratitude to the wastewater facilities that allowed us access to their plants for sampling and information gathering, and to Greta Buschmann, of the Universität Duisburg-Essen, who assisted with sample collection and preparation.
© 2014 Elsevier Ltd.
- Decentralized water reclamation
- Energy recovery
- Thermochemical conversion
- Waste to energy