title: An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation.
abstract: Lab-scale High Efficiency Digestion (HED) systems containing a Mesophilic Anaerobic Reactor (MAR), Thermophilic Aerobic Reactor (TAR), liquid/solid separation unit, and thermal-alkaline treatment were developed to evaluate the efficiencies of sludge reduction and methane production. The HED process was divided into three phases to examine the influence of sludge pretreatment and pretreated sludge recirculation using TCOD and VSS reduction, COD solubilization, and methane production. The VSS removal with a solid/liquid separation unit, sludge recirculation, and thermal-alkaline treatment drastically increased up to 95% compared to the feed concentration. In addition, the results of COD solubilization and VSS/TSS showed that the solubilization of cells and organic matters by the thermal-alkaline treatment was highly increased, which was also consistent with the SEM images. In particular, the methane production rate increased 24-fold when the feed sludge and recirculated sludge were pretreated together. Collectively, the HED experiments performed with sludge recirculation and thermal-alkaline treatment demonstrated that the HED systems can be successfully employed for highly efficient sewage sludge reduction and methane gas production.
authors: School of Environmental Science and Engineering, Pohang University of Science and Technology, Hyoja-dong, Nam-Gu, Pohang, Kyungbuk 790-784, Republic of Korea.
authors: Hyun Uk
authors: HU
authors: Cho
authors: Sang Kyu
authors: SK
authors: Park
authors: Jeong Hyub
authors: JH
authors: Ha
authors: Jong Moon
authors: JM
authors: Park
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D056804:Biofuels / Q000032:analysis*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D056804:Biofuels; D012722:Sewage
keywords: High efficiency digestion system; Mesophilic anaerobic reactor; Methane production; Sludge reduction; Thermal-alkaline treatment; Thermophilic aerobic reactor