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Investigation of endocrine disrupting compounds in membrane bioreactor and UV processesYang, Wenbo 12 January 2010 (has links)
Endocrine disrupting compounds (EDCs) in the environment have recently emerged as a major issue in Canada and around the globe. The primary objective of this thesis was to investigate the fate of EDCs in two wastewater treatment processes, membrane bioreactors (MBRs) and ultraviolet (UV) disinfection. Two submerged MBR systems using hollow fiber membranes from two membrane manufacturers were tested. The results from a bench-scale and a pilot scale MBR for the treatment of swine wastewater with high concentration of EDCs showed that over 94% of the estrogenic activity (EA) in the influent was reduced through the MBR process. Biological degradation was the dominant removal mechanism for the removal of EDCs in MBRs. Over 85% of the influent EA was reduced by biodegradation through the MBR process. The other MBR system was built to study the removal mechanisms of two estrogens in a hybrid MBR with the addition of powdered activated carbon (PAC). The effects of PAC dosing on MBR overall performance was studied as well. It was found that PAC dosing could increase the removal rates of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by 3.4% and 15.8%, respectively and result in a slower rate of trans-membrane pressure (TMP) increase during MBR operation, which could significantly reduce the operating cost for membrane cleaning and/or replacement. The operating cost for PAC dosing could be offset by the benefit achieved from reducing the cost for membrane maintenance. The slower rate of TMP increase in the PAC-MBR was associated with the lower concentrations of soluble extracellular polymeric substances and colloidal organic compounds in the PAC-MBR sludge.
The degradation kinetics of three estrogens, estrone (E1), E2, and EE2 in de-ionized water by UV irradiation was studied. The experimental results showed both the apparent concentrations and overall EA of all three investigated estrogens in water decreased with direct UV irradiation. To further study the impact of UV on the overall EA of wastewater, the EA of pre-UV and post-UV samples from five wastewater treatment plants were measured in both liquid and solid phase by Yeast Estrogen Screen assay. It was found that the EA of wastewater decreased after UV disinfection in three of the investigated plants whereas it increased in the other two plants. This observation needs to be further studied because it might have significant impacts on the application of UV systems for wastewater disinfection.
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Investigation of endocrine disrupting compounds in membrane bioreactor and UV processesYang, Wenbo 12 January 2010 (has links)
Endocrine disrupting compounds (EDCs) in the environment have recently emerged as a major issue in Canada and around the globe. The primary objective of this thesis was to investigate the fate of EDCs in two wastewater treatment processes, membrane bioreactors (MBRs) and ultraviolet (UV) disinfection. Two submerged MBR systems using hollow fiber membranes from two membrane manufacturers were tested. The results from a bench-scale and a pilot scale MBR for the treatment of swine wastewater with high concentration of EDCs showed that over 94% of the estrogenic activity (EA) in the influent was reduced through the MBR process. Biological degradation was the dominant removal mechanism for the removal of EDCs in MBRs. Over 85% of the influent EA was reduced by biodegradation through the MBR process. The other MBR system was built to study the removal mechanisms of two estrogens in a hybrid MBR with the addition of powdered activated carbon (PAC). The effects of PAC dosing on MBR overall performance was studied as well. It was found that PAC dosing could increase the removal rates of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by 3.4% and 15.8%, respectively and result in a slower rate of trans-membrane pressure (TMP) increase during MBR operation, which could significantly reduce the operating cost for membrane cleaning and/or replacement. The operating cost for PAC dosing could be offset by the benefit achieved from reducing the cost for membrane maintenance. The slower rate of TMP increase in the PAC-MBR was associated with the lower concentrations of soluble extracellular polymeric substances and colloidal organic compounds in the PAC-MBR sludge.
The degradation kinetics of three estrogens, estrone (E1), E2, and EE2 in de-ionized water by UV irradiation was studied. The experimental results showed both the apparent concentrations and overall EA of all three investigated estrogens in water decreased with direct UV irradiation. To further study the impact of UV on the overall EA of wastewater, the EA of pre-UV and post-UV samples from five wastewater treatment plants were measured in both liquid and solid phase by Yeast Estrogen Screen assay. It was found that the EA of wastewater decreased after UV disinfection in three of the investigated plants whereas it increased in the other two plants. This observation needs to be further studied because it might have significant impacts on the application of UV systems for wastewater disinfection.
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The suitability of estrogen and androgen bioassays for the measurement of endocrine activity in different water matricesNgcobo, Silindile January 2017 (has links)
Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and their
presence in water bodies is documented. They discharge into surface water (SW)
unmonitored, posing a threat to both aquatic and terrestrial lives. This is a challenge
as not all populations have access to treated drinking water (TDW). The EDC
contaminated serves as a route of exposure, together with ineffective treatment
plants. Given the complexity of the endocrine system, EDCs may mimic or
antagonise natural hormones or disrupt their synthesis, metabolism and excretion.
The associated health effects include testicular dysgenesis syndrome, metabolic
disorders and cancers. Policy and internationally standardised test methods are
however sti ll limited. This study therefore aimed to assess the suitability of two
assays used for screening estrogenic activity and one for androgenic activity in
different water sources.
The study consisted of two phases. In phase 1, water sample (tap, surface and
treated wastewater) were collected from a catchment area in Pretoria. The samples
and a spiked MilliQ laboratory water sample were extracted with solid phase
extraction (SPE) and sent to Germany for distribution to participating laboratories.
Samples (n=24) from six different countries were received to test for androgenic
activity in the MDA-kb2 reporter gene assay. In phase 2, SW and TDW samples
were collected from April 2015 until March 2016. The samples were filtered,
extracted using SPE and assayed with the YES assay, T47D-KBluc reporter gene
assay for estrogenic activity and MDA-kb2 reporter gene assay for androgenic
activity. In phase 1, androgenic activity was detected in 4 out of 24 (21%) samples and
ranged from 0.23 ± 0.040 ng/L to 0.008 ± 0.001 ng/L DHTEqs. In phase 2,
estrogenic activity was detected in 16 out of 24 (67%) SW samples in the T47DKBluc
reporter gene assay and ranged from 0.31 ± 0.05 pg/L to 10.51 ± 5.74 pg/L
EEqs. It was below the detection limit (dl) in the YES assay. Androgenic activity was
detected in 4 out of 24 (17%) SW samples, ranging from 0.0033 ± 0.0050 ng/L to
0.090 ± 0.040 ng/L DHTEqs. Androgenic and estrogenic activity was higher i n pretreatment
samples compared to post-treatment in both treatment plants. In phase 1, the MDA-kb2 reporter gene assay was successfully applied to water
samples from different sources. Androgenic activity was highest in treated
wastewater. In phase 2, treatment plants proved to be effective in removing
estrogens detected in the SW samples, as the TDW samples were below the dl.
Estrogenic activity is within the ranges reported in other studies. Positive samples
were below the 0.7 ng/L proposed trigger value for health risk assessments.
Detected androgenic activity was lower in TDW samples compared to the SW
samples supplying the two treatment plants indicating that they were both effective in
removing the androgenic activity detected. Few studies have reported androgenic
activity in tap water. This study strengthens the argument for using a battery of assays when monitoring
endocrine activity as EDCs occur at low concentrations in mixtures. / Dissertation (MSc)--University of Pretoria, 2017. / School of Health Systems and Public Health (SHSPH) / MSc / Unrestricted
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