Removal of trace organic chemical contaminants by a membrane bioreactor.

Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.

The application of membrane bioreactors as decentralised systems for removal of endocrine disrupting chemicals and pharmaceuticals.

The concentrations of some important endocrine disrupting chemicals and pharmaceuticals after various stages of wastewater treatment were investigated. The endocrine disrupting chemicals included natural and synthetic estrogenic and androgenic steroids. The pharmaceuticals included a series of sulfonamide antibiotics and trimethoprim. The removal efficiency of a membrane bioreactor (MBR) was investigated and compared with a conventional activated sludge (CAS) system. Samples were analysed by liquid chromatography tandem mass spectrometry. Results showed that the MBR and CAS systems effectively removed steroidal estrogens and androgens, but only partially eliminated the target antibiotics from wastewater. The MBR was shown to be more effective than the CAS system which was possibly attributed to the high solid retention time and concentration of biosolids in the MBR. The results highlight the potential wider application of MBRs for the removal of trace chemical contaminants in wastewater and their potential for use as decentralised wastewater treatment systems.

Fate and levels of steroid oestrogens and androgens in waste stabilisation ponds: quantification by liquid chromatography-tandem mass spectrometry.

The capacity for removing wastewater-borne endocrine disrupting chemicals (EDCs) was investigated for two wastewater treatment plants (WWTPs) incorporating waste stabilisation ponds (WSPs) as the principal treatment technology. Samples were analysed for a number of steroidal oestrogens and androgens using liquid chromatography-tandem mass spectrometry (LC/MS/MS). Removal efficiency for steroid androgens was high for both WWTPs (93-100%) but WSP treatment was observed to be less effective for removing steroid oestrogens, particularly oestriol.

Fate and analysis of endocrine disrupting chemicals in some sewage treatment plants in Australia.

There are limited studies on the fate and levels of endocrine disrupting chemicals in sewage treatment plants in Australia. Research undertaken in Europe and North America has shown biologically significant levels of both oestrogenic and androgenic chemicals in sewage effluent. The aim of this work was to determine the oestrogenic and androgenic activities of raw and treated sewage from sewage treatment plants run by MidCoast Water, New South Wales, Australia. Oestrogenic and androgenic activities were measured using a yeast screen bioassay. Results showed that the raw effluent contained biologically significant levels of both oestrogenic (0.58-2.91 ng/l) and androgenic (216-480 ng/l) activities. Androgenic activity was significantly higher than oestrogenic activity, which was consistent with other Australian studies and was attributed to the higher levels of androgens in domestic waste from human excretion compared to oestrogens. Secondary treatment (using activated sludge) removed the majority of the oestrogenic and androgenic activity (up to 99%). Tertiary treatment by UV removed varying levels of oestrogenic (19-69%) and androgenic (5-55%) activities. A Membrane Bioreactor (MBR) at one of the STPs, which consists of an MBR followed by electrochlorination removed over 87% of the oestrogenic activity and over 98% of androgenic activity from raw sewage samples. However, levels which could be biologically significant still remained after secondary and tertiary treatment (>0.1 ng/l oestrogenic activity and >1 ng/l androgenic activity).

Removal of contaminants of concern in water using advanced oxidation techniques.

This research involves the removal of contaminants of concern in water supplies using advanced oxidation technologies, in particular titanium dioxide photocatalysis. Photocatalysis for the removal of 1,4-dioxane and the natural (17 beta-oestradiol, oestriol) and synthetic (17 alpha-ethynyloestradiol) oestrogens in water was investigated using both UVA and solar radiation. The H2O2/UVC process, solar, UVC and UVA light alone were also investigated and the processes compared. It was found that TiO2 photocatalysis is an effective method for the degradation of the natural (17 beta-oestradiol and oestriol) and the synthetic (17 alpha-ethynyloestradiol) oestrogens in water in immobilised Degussa P25 and sol-gel spiral reactors with both UVA and solar radiation as the light source. Photocatalysis using the commercial catalyst Degussa P25 as an immobilised reactor with a UVA lamp shows the best performance. Photocatalysis was shown to completely mineralise 1,4-dioxane to CO2 in Degussa P25 suspension and sol-gel reactors using both UVA and solar radiation. The commercial catalyst Degussa P25 in suspension with UVA radiation shows the best performance. Photocatalysis is much more efficient than H2O2/UVC, UVA, UVC and solar radiation alone for all contaminants investigated.

Degradation of 1,4-dioxane in water using TiO2 based photocatalytic and H2O2/UV processes.

1,4-dioxane is a synthetic compound found in industrial effluent and subsequently contaminates water bodies due to its high solubility and high volatility. It is of concern due to its toxic and hazardous nature and has been listed as a class 2B carcinogen. This study involved optimisation of the photocatalytic and H(2)O(2)/UVC processes for 1,4-dioxane removal. Different photocatalysts and loadings were investigated for the degradation of low concentrations of 1,4-dioxane in water including a commercial P25, a synthesised magnetic photocatalyst and an immobilised sol-gel system. A commercial catalyst (Degussa P25) was the most efficient. A lifetime study of the sol-gel reactor showed that the coating was stable over the time period studied. The optimum H(2)O(2) concentration in the H(2)O(2)/UVC process was found to be 30ppm. The addition of H(2)O(2) to the photocatalytic process for 1,4-dioxane removal caused a decrease in rate for the commercial P25 photocatalyst and an increase in rate for the lab-made magnetic photocatalyst.

Rapid loss of estrogenicity of steroid estrogens by UVA photolysis and photocatalysis over an immobilised titanium dioxide catalyst.

The presence of low levels of natural and synthetic steroid estrogens in the aquatic environment, and their biological effects on aquatic organisms, are presently issues of concern. In this study, we investigated the temporal removal of estrogenic activity of several potent and environmentally relevant steroid estrogens by photocatalysis over an immobilised titanium dioxide (TiO2) catalyst. We used a recombinant yeast assay to measure estrogenic activity, which provided detection limits within the reactor of 53 ng/l for 17beta-estradiol and 17alpha-ethinylestradiol, and 100 ng/l for estrone. Pseudo-first-order kinetic data showed that photocatalysis over titanium dioxide was equally effective at removing the estrogenic activity of all three steroid substrates in aqueous solutions (initial concentrations of 10 microg/l) with a 50% reduction in estrogenicity within 10 min. In control experiments without TiO2 catalyst, the rate of UVA photolysis of the steroid substrates varied, but was most effective with 17alpha-ethinylestradiol followed by estrone, and was least effective with 17beta-estradiol (0.42, 0.2 and < 0.1 times the rate achieved with photocatalysis, respectively). The application of photocatalysis for the removal of steroid compounds within STW effluent released into the aquatic environment is discussed.

Role of mitochondrial calcium metabolism in the altered contractility of pressure-hypertrophied right ventricular myocardium.

Pressure-hypertrophied right ventricular myocardium (RVH) demonstrates paradoxically increased oxygen consumption (MVO2) related to increase- in vitro energy-linked mitochondrial calcium flux. The present experiments were designed to measure mitochondrial Ca retention in intact RVH and relate changes in mitochondrial Ca metabolism to altered RVH contractility and relaxation. Sixteen cats were pulmonary artery banded and their hearts plus paired controls were perfused with 45Ca-labeled Krebs-Henseleit (30 degrees C) at 120 beats/min for 10 min. Papillary muscles from both right ventricles were studied in a muscle bath. Mitochondria were isolated from the right ventricles and retained 45Ca measured. At the length at which active tension is developed (Lmax) papillary muscle abnormalities were, for reduced active tension, 6.9 gm/mm2 +/- 0.6 SE for control, 4.0 +/- 0.6 for RVH, p less than 0.001; for slower contraction rate, 40.8 gm/mm2/sec +/- 6.3 control, 16.9 +/- 2.8 RVH, p less than 0.001; for slower relaxation rate, 22.0 gm/mm2/sec "/0 1.5 control, 11.1+/- 1.6 RVH, p less than 0.001; for greater time to peak tension, 317 msec +/- 7 control, 408 +/- 13 RVH, p less than 0.001; for greater relaxation time, 590 msec +/- 29 control, 800 +/- 39 RVH, p less than 0.001. Retained 45Ca of mitochondria was increased from 16.75 +/- 0.96 nM/mg of protein for control, to 20.82 +/- 0.98 for RVH, p less than 0.005. This increase in mitochondrial 45Ca retention correlated (r = 0.93, p less than 0.001) with the decreased rate of papillary muscle relaxation. These data show an increased 45Ca retention of mitochondria in pressure-induced RVH and relate this biochemical abnormality to a decreased myocardial relaxation in this state.