Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 2009
Publication Date: April 27, 2009
Citation: Deng, D., Rice, C., Lozano, N., Andrade, N., Ramirez, M., Torrents, A. 2009. The fate of endocrine disrupting chemicals in biosolids during ag-bag composting practices. Meeting Abstract.
There is an increasing body of evidence that illustrates that low levels of manmade chemicals (xenobiotics) that made their way into wastewater influents accumulate onto the sewage sludge. There is a growing concern the release of these chemicals in the environment through the land application of biosolids have the potential to modulate or disrupt the endocrine system of living organisms. The U.S. Environmental Protection Agency (EPA) endorses the composting of biosolids (sewage sludge) as a way of managing this material. In this study, we evaluate the use of the Ag-Bag compost system to generate biosolids that would meet requirements for land application. This technology uses a low-cost containment vessel with forced aeration. This allows for a high degree of process control over the composting matrix. An elongated plastic tube (or POD) forms the containment vessel. The raw material used as feedstock is placed into the POD through an encapsulator with the correct mixture of woodchips/sludge. Forced aeration is introduced by supplying air with an electric blower through perforated pipe that runs the length of the POD. Aerobic conditions are maintained and prevent the generation of obnoxious odors. The POD provides complete containment and prevents dust generation and leachate runoff.
In this study, we evaluated the fate of organic micro constituents, Triclosan (TCS), triclocarban (TCC) and PBDEs, while composting. These compounds were selected due to increased concerns about their presence in biosolids and their range of fate and behavior. TCS and TCC are antibacterials with similar structures and environmental behaviors and aerobic biodegradation has been suggested. PBDEs are much more persistent and aerobic biodegradation is not expected. The removal rates of TCS, TCC and PBDEs during a 60 day composting procedure will be reported. Our study suggests that while PBDEs are stable during the aerobic composting, TCC and TCS do biodegrade with higher removal rates for TCS than for TCC. Concentrations of Me-TCS, the biodegradation product for TCS, will also be presented.