Abstract
The high moisture content of biosolid from a wastewater treatment plant limits its use for agriculture and energy applications. This limitation could be obviated by hydrothermal carbonization, which requires less energy compared to other thermochemical treatment processes, and results in stabilized solid hydrochar product. The present study examined this option by hydrothermally treating the biosolid at three temperatures (180, 200 and 220 °C) for 30 min, and at 200 °C for 15, 30 and 60 min. An increase of 50% in the heating value of the biosolid was obtained after this carbonization. A reduction in the nitrogen concentration in hydrochar was noted with an increase in phosphorus concentration, but potassium concentration remained largely unchanged. Additionally, the carbon to nitrogen ratio in the hydrochar product was higher than the biosolid that makes it suitable for agriculture applications. The chemical oxygen demand of the process water was in the range of 83,000 to 96,000 mg/L. The study thus provides insight into high-value products that can be generated by the hydrothermal carbonization of biosolids.
Highlights
The terms sewage sludge and biosolids represent the same semi-liquid end product of wastewater treatment
The final products after hydrothermal treatment can be categorized into solid-hydrochar, liquid-process water and gas
The heating values of solid produced from raw biosolid increased by 50% after hydrothermal carbonization
Summary
The terms sewage sludge and biosolids represent the same semi-liquid end product of wastewater treatment. Biosolid (or sewage sludge) is treated to make it suitable for land applications [1]. Disposal or management options for biosolids include incineration and landfills. One of the practical issues is its high moisture content, which makes transportation difficult [4] Such is the case of the wastewater treatment plant of Charlottetown in the province of Prince Edward Island, Canada. This plant treats approximately 7 million cubic meters of wastewater annually producing roughly 3700 tonnes of biosolid. The sewage sludge is pre-pasteurized, anaerobically digested and dewatered producing biogas and class-A biosolid
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
