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Rapid and Extensive Debromination of Brominated Flame Retardants in Thermophilic Municipal Wastewater Digesters. Ke Yin, Jayashree Jayaraj , Kelly Granberg and Karl Rockne Department of Civil and Materials Engineering, University of Illinois at Chicago.
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Rapid and Extensive Debromination of Brominated Flame Retardants in Thermophilic Municipal Wastewater Digesters Ke Yin, JayashreeJayaraj , Kelly Granberg and Karl Rockne Department of Civil and Materials Engineering, University of Illinois at Chicago • Polybrominateddiphenyl ethers (PBDEs) • Used as flame retardants in textiles, electronics and furniture industries with up to 10 Br per molecule • Consumer products decompose and end up in wastewater treatment plants (WWTPs) • Deca (10 Br atoms) is relatively non-toxic to humans • Octa and Penta product more bioavailable and toxic • Banned by the European Union and California • Voluntary ban by US manufacturers • Deca is still used in electronics and other plastics • HOWEVER: Halogenated compounds CAN BE DEHALOGENATED by anaerobic bacteria Figure 1. Total BDE homolog concentrations normalized to deca BDE in the CWRP (left) and WGV (right) digesters at different locations in the plant. Shown are groupings of dibromodiphenyl ethers through nonabromodiphenyl ethers in primary digester feed (PF), primary digester draw (PD, CWRP only), secondary (methanogenic) digester feed (SF), secondary (methanogenic) digester effluent (SD) and sludge cake (SC, WGV only) samples. Note log scale on the y axis. HYPOTHESIS: Reductive dehalogenation of Deca and other PBDEs in sewage sludge will be extensive • Anaerobic digester sludge sampled from two WWTPs: • Calumet (CWRP)– Heavy industrial + domestic waste • Woodridge Green Valley (WGV)– Domestic waste only • Analyzed 49 PBDEs by mass spectrometry-NCI • Debromination rate in continuously mixed flow reactor: • PBDEs are much higher in domestic wastewater! • Deca BDE-209 is rapidly debrominated • Kinetic rate of 0.34 day-1 at WGV • Highest rate ever reported (100x higher!) • Extensive removal in only 10 d • The first report of lower brominated PBDEs being debrominated in the WWTPs • Banning Octa and Penta technical product will not eliminate their presence in the environment • Continued use of Deca may still release bioavailable and toxic lower brominated BDEs into the environment At Steady state: