A SUSTAINABLE METHOD TO DRY BIOSOLIDS USING SOLAR ENERGY

摘要

The Kent County Regional Wastewater Treatment Facility (KCRWTF) established aSustainability Management System (SMS) in 2009. The SMS set an objective to beginmoving away from dependency on fossil fuels due to their cost and negativeenvironmental impact. The plant has long used a three-step process for treating theirsludge production. In the first step, sludge is dewatered using one of three belt filterpresses. The second step is to stabilize the biosolids through lime stabilization. The finalstep in the process is to dry the stabilized biosolids to approximately 50% solids using anindirect thermal dryer, where heat for the heat transfer fluid is provided from natural gasfired boilers and allows the biosolids product to meet the 40 CFR Part 503.32 (Class A)limits under the time and temperature requirements. The resulting biosolids have beenreferred to as Kentorganite and been land applied as Class A biosolids on local farms.This paper looks at the results the plant has experienced from testing an alternativetechnology - the Parkson Thermo-System~? Active Solar Sludge Dryer – to replace theirlime stabilization and natural gas fired dryer processes and ultimately meet theirsustainability goals.