Pyrolysis of Wastewater Biosolids: Lab-Scale Experiments and Modeling

Biosolids handling is an energy intensive and expensive process. Thus, the use of beneficial end-products is strongly desired to reduce costs. Pyrolysis, the thermal decomposition of organic matter under anaerobic conditions, has potential to be a beneficial biosolids handling process. Pyrolysis results in biochar that can be used as a fertilizer, pyrolysis oil (py-oil), and pyrolysis-gas (py-gas), which can be used to fuel the pyrolysis process. Two objectives of this work were to determine i) the impact of temperature on product yields and gas energy content and ii) the enthalpy of pyrolysis of biosolids from bench-scale experiments and modeling. Increased temperatures resulted in decreased char yields, but py-oil content did not increase after 500°C. The increase in temperature resulted in higher permanent gas yields, and higher energy content in the py-gas.