Attenuation of polychlorinated biphenyls (PCBs) under anaerobic conditions

Download

index.pdf

Date

2012

Author

Kaya, Devrim

Metadata

Show full item record

Item Usage Stats

257
views

111
downloads

Polychlorinated biphenyls (PCBs) are toxic and persistent anthropogenic contaminants. Concern on their adverse health effects has led to their regulation in air, water and/or soil in addition to sludge. Hence, removal of PCBs in various matrices, including transformer oils (TO) is a priority. This study aims to investigate PCB-118 and Aroclor 1254 toxicity and dechlorination by varying certain critical experimental components including electron donor (sludge or fatty acids), inocula (unacclimated or acclimated culture) and the doses of PCB and TO under anaerobic conditions. Anaerobic toxicity assays (ATA) reactors, lab-scale anaerobic batch digesters and sediment microcosms were used for this purpose. Increase in PCB-118 and TO doses affected anaerobic digester performance by negatively influencing methanogenesis, while favoring dechlorination only with the increase in PCB-118 dose. Up to 22% PCB-118 removal was attained with unacclimated culture. Studies with acclimated cultures showed Grasse River (GR) sediment to be the most active when compared to Fox River and Baltimore Harbor sediments. In GR sediment microcosms, PCB-118 and Aroclor 1254 removal efficiencies decreased when TO was present (1%), while 10% TO inhibited PCB dechlorination. Waste activated sludge was shown to be an effective electron donor, similar to fatty acids. Aroclor 1254 dechlorination was dechlorinated through removal of flanked meta and para chlorines, however, dechlorination pathways appeared to differ according to the presence/absence of TO. No ortho or unflanked chlorines were removed. Molecular tools (qPCR and DHPLC) were used to confirm the presence of active PCB dechlorinators. Dechlorination of PCBs was shown to be growth-linked.

Subject Keywords

Anaerobic bacteria., Sludge bulking., Sewage, Sewage

URI

http://etd.lib.metu.edu.tr/upload/12614933/index.pdf
https://hdl.handle.net/11511/22076

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Effects of ultrasound pretreatment and anaerobic digestion on the energy potential of sludge Çelebi, Emrehan Berkay; Sanin, Faika Dilek; Aksoy, Ayşegül; Department of Environmental Engineering (2015) The by-product of wastewater treatment, sludge, is generated in tons everyday all around the world. As environmental regulations in Turkey are becoming stricter during the European Union adaptation period, the previously wide-spread disposal method of landfilling the sludge will not be applicable. Instead, dried sludge is expected to be used in revenue generating methods like land application or combustion. Combustion can be thought of as more beneficial as it uses sludge as an energy source. However, it is...
Fate and degradation kinetics of nonylphenol compounds in aerobic batch digesters Omeroglu, Seçil; Sanin, Faika Dilek (2014-11-01) Nonylphenol (NP) compounds are toxic and persistent chemicals that are not fully degraded either in natural or engineered systems. Current knowledge indicates that these compounds concentrate in sewage sludge. Therefore, investigating the degradation patterns and types of metabolites formed during sludge treatment are important for land application of sewage sludge. Unfortunately, the information on the fate of nonylphenol compounds in sludge treatment is very limited. This study aims to investigate the bio...
Investigation of activated sludge bioflocculation : influence of magnesium ions Turtin, İpek; Sanin, Faika Dilek; Department of Environmental Engineering (2005) Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a...
Triclosan in biological wastewater treatment: fate, kinetics and population dynamics aspects / Koç Orhon, Aybala; Yetiş, Ülkü; Dilek, Filiz Bengü; Department of Environmental Engineering (2014) Biocides like Triclosan (TCS) have been detected in several surface waters due to common usage and following wastewater discharges. This situation necessitates detailed researches on accumulation of these compounds in environment, their effects and removal in treatment systems. In this study, a detailed investigation on biological treatability of TCS bearing wastewaters (100 ng/L-100 mg/L) was conducted. A laboratory-scale activated sludge unit was operated for TCS-acclimated and non-acclimated cultures. Fa...
Treatment and valorization of anaerobic digestate Ülgüdür, Nilüfer; Bayramoğlu, Tuba Hande; Demirer, Göksel Niyazi; Department of Environmental Engineering (2019) Anaerobic digestion is a widely applied process for the stabilization and treatment of high-strength wastes. The process has two outputs, biogas and digestate. Even though biogas produced during the treatment is a renewable energy source and has positive impacts on improving the economics of the plant, the treatment and disposal of the digestates present a challenge. The treatment methods offered so far are either costly or low yielded which drives off these uneconomic and non-viable treatment processes fro...

Citation Formats

D. Kaya, “Attenuation of polychlorinated biphenyls (PCBs) under anaerobic conditions,” Ph.D. - Doctoral Program, Middle East Technical University, 2012.