An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation

• Published in: Journal of environmental management Vol. 129; pp. 274 - 282
• Main Authors: Cho, Hyun Uk, Park, Sang Kyu, Ha, Jeong Hyub, Park, Jong Moon
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.11.2013; Elsevier; Academic Press Ltd
• Subjects: Aerobiosis; Anaerobiosis; Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biodegradation, Environmental; Biofuels - analysis; Biological and medical sciences; Bioreactors; Biotechnology; Chemical oxygen demand; Chromatography, Gas; Chromatography, High Pressure Liquid; Conservation, protection and management of environment and wildlife; Efficiency; Environmental management; Environmental Monitoring; Environmental Restoration and Remediation - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects; High efficiency digestion system; Hot Temperature; Mesophilic anaerobic reactor; Methane; Methane production; Methods. Procedures. Technologies; Microscopy, Electron, Scanning; Pollution; Sewage - analysis; sewage sludge; Sludge; Sludge reduction; solubilization; Thermal-alkaline treatment; Thermophilic aerobic reactor; Various methods and equipments; Waste Disposal, Fluid - methods; Wastes; Sludge reduction; High efficiency digestion system; Thermal-alkaline treatment; Methane production; Mesophilic anaerobic reactor; Thermophilic aerobic reactor; Methane; Heat treatment; Waste treatment; Thermophily; Recirculation; Aerobe; Digestion; Sewage sludge; Bioreactor; Innovation; Anaerobe; Chemical treatment; Mesophily; Basic medium; Wastes; Reactor
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2013.07.009

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. •A new-style HED system was developed for efficient sludge reduction.•Sewage sludge was highly solubilized by the thermal-alkaline treatment.•VSS removal was more than 90% in a new-style HED system.•Efficient methane production was observed in a new-style HED system.