Biodegradation Of Decabromodiphenyl Ether(BDE-209) In Sediments By Composting Technique

Sediments are regarded as ultimate sink of persistent organic pollutants in aquatic environment and high level of poison in sludge will be produced during the process of treatment technology for dealing POPs. Therefore, economic and effective technologies for treatment of contaminated sediments of high toxicity are important issues. Polybrominated diphenyl ethers (PBDEs) are potentially harmful and persistent environmental pollutants, and they were widely used in electronic equipment, textile fiber products. As a kind of flame retardant additives, they could entry into the environment by production, use, transportation and scrap processing of waste. At present, they widely exist in environmental medium, and they were also the most studied in BFRs currently. Composting is one of the main techniques in biological degradation of toxic organic pollutants. In order to understand the repair efficiency and application feasibility of composting on PBDEs, the efficiency of four different composting processes to bioremediate decabromodiphenyl ether (BDE-209)-contaminated sediments was investigated. A comparative analysis of the four composting process (addition of activated sludge, co-metabolic substances and sawdust ingredients) on BDE-209degradation rates was evaluated with initial BDE-209concentration of2mg/kg. After78days treatment, the degradation rate in four groups were, activated sludge group, co-metabolic substance and wood group were87.845±4.298%,96.300±3.309%,95.7334±1.616%,95.473±3.104%, respectively. There are15species of monitored BDE-209metabolites, mainly including tetra-, penta-and nona-polybrominated diphenyl ethers. The maximum temperature during composting process appeared in about20days and was above the ambient temperature (18℃).70%reduction of organic matter process was observed with initial OM of30%. The water contents in four composts were evaporated in the late. The maximum microbial numbers were observed at15d and decreased thereafter. Urease activities in composts after composting which signify microbial activity were higher than the initial and highest Urease activities reached at15d. The dehydrogenase activity of activated sludge group and general technology group was significantly enhanced, while did not significantly changed in the wood group. The above results demonstrated that composting of BDE-209contaminated sediments with high efficient was feasible.