Fates of chlorinated volatile organic compounds in aerobic biological treatment processes: The effects of aeration and sludge addition

• Published in: Chemosphere (Oxford) 2014-05, Vol.103, p.92-98
• Main Authors: Chen, Wei-Hsiang, Yang, Wen-Ben, Yuan, Chung-Shin, Yang, Jun-Chen, Zhao, Qing-Liang
• Format: Article
• Language: English
• Subjects: Aeration; Aerobiosis; Air; Applied sciences; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biotechnology; Chlorinated hydrocarbon; Environment and pollution; Environmental fate; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General purification processes; Hydrocarbons, Chlorinated - chemistry; Industrial applications and implications. Economical aspects; Pollution; Sewage - chemistry; Sludge; Volatile organic compound; Volatile Organic Compounds - chemistry; Waste Water - chemistry; Wastewater treatment process; Wastewaters; Water Purification - methods; Water treatment and pollution
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2013.11.039

•The VOC distributions in aerobic biological treatment processes were investigated.•The effects of aeration and sludge addition were studied.•The concept of fugacity was used to predict the fates of the VOCs in the processes.•The effects of aeration and sludge addition were limited.•The physicochemical properties of the VOCs are important to determine their fates. The emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) is becoming an environmental issue of increasing concern. As biological treatment has been considered as one important approach for VOC removal, lab-scale batch experiments were conducted in this study to investigate the fates of four chlorinated hydrocarbons, including chloroform, carbon tetrachloride, trichloroethylene (TCE), and tetrachloroethylene (PERC), in the biological treatment processes with respect to the effects of aeration and sludge addition. The VOC concentrations in the phases of air, water, and sludge under four simulated treatment stages (the first sedimentation, the forepart and rear part of aerobic biological treatment, and the second sedimentation) were analyzed. The results were used to understand the three-phase partitioning of these compounds and to estimate their potentials for volatilization and biological sorption and degradation in these technologies with the concept of fugacity. It was observed that the VOCs were mainly present in the water phase through the experiments. The effects of aeration or sludge addition on the fates of these VOCs occurred but appeared to be relatively limited. The concentration distributions of the VOCs were well below the reported partitioning coefficients. It was suggested that these compounds were unsaturated in the air and sludge phases, enhancing their potentials for volatilization and biological sorption/degradation through the processes. However, the properties of these chlorinated VOCs such as the volatility, polarity, or even biodegradability caused by their structural characteristics (e.g., the number of chlorine, saturated or unsaturated) may represent more significant factors for their fates in the aerobic biological treatment processes. These findings prove the complication behind the current knowledge of VOC pollutions in WWTPs and are of help to manage the adverse impacts on the environment and public health by the VOCs from these particular sources.