AbstractsEngineering

Wastewater and sludge treatment can decrease or increase estrogenic activity through degradation and transformation processes. Endocrine disrupting chemicals (EDCs) tend to adsorb to solids and partition into sludge during the wastewater treatment process. Analytical procedures to detect EDCs in sludge media can be time / labour intensive and require expensive analytical instrumentation. As a result, little information is available on EDC content or fate in municipal sludge. A gas chromatography-mass spectrometry (GC-MS) chemical analysis procedure to detect estrogens in mixed and digested sludges without freeze-drying prior to extraction could not be located in the literature. Therefore, GC-MS chemical analysis protocols were developed for detection of estrone (E1) and 17β-estradiol (E2) in municipal sludges that was also compatible with bioluminescent yeast assays. This protocol is elucidated and summarised for consideration and use by other researchers and the user community. Municipal trickling filter / solids contact wastewater treatment processes were examined for reduction of E1 and E2; whole estrogenic and androgenic activity; and toxic luminescence inhibition. Conventional heat and combinations of microwave irradiation and oxidation treatments were applied to municipal sludge and evaluated using the same methods. The specified wastewater treatment plant reduced total E1 and E2 by 54%; estrogenic activity by 27%; and androgenic activity by 38%. The most potent estrogen, E2, was reduced by 69% and E1 was reduced by 26%. More importantly, the increased ratio of E1 to E2 from 0.6 (influent) to 1.4 (pre-chlorinated effluent), indicated E2 was biologically degraded to the less estrogenic E1. Mesophilic (35–40 °C) sludge digestion reduced E1 by 12%, E2 by 63%, whole estrogenic activity by 73% and androgenic activity by 81%. The digestion process reduced toxicity to the yeast strain, BLYR, by threefold. Overall, microwave irradiation was more effective than conventional heating in reducing concentrations of E1 and E2 in mixed and digested sludges. Oxidative (H₂O₂) treatments did not reduce E1, E2, estrogenic or androgenic activity. The treatment plant reduced E1, E2, estrogenic activity and androgenic activity in the wastewater stream. The anaerobic mesophilic sludge digestion process reduced E1, E2, BLYR toxicity, and whole estrogenic and androgenic activity.