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The removal of persistent organic micropollutants (OMPs) from secondary effluent in wastewater treatment plants is critical for meeting water reuse standards. Traditional treatment methods often fail to adequately degrade these contaminants. This study explored the efficacy of a hybrid ozonation membrane filtration (HOMF) process using CeO2 and CeTiOx-doped ceramic crossflow ultrafiltration ceramic membranes for the degradation of OMPs. Hollow ceramic membranes (CM) with a 300 kDa molecular weight cut-off (MWCO) were modified to serve as substrates for catalytic nanosized metal oxides in a crossflow and inside-out operational configuration. Three types of depositions were tested: a single layer of CeO2, a single layer of CeTiOx, and a combined layer of CeO2 + CeTiOx. These catalytic nanoparticles were distributed uniformly using a solution-based method supported by vacuum infiltration to ensure high-throughput deposition. The results demonstrated successful infiltration of the metal oxides, although the yield permeability and transmembrane flow varied, following this order: pristine > CeTiOx > CeO2 > CeO2 + CeTiOx. Four OMPs were examined: two easily degraded by ozone (carbamazepine and diclofenac) and two recalcitrant (ibuprofen and pCBA). The highest OMP degradation was observed in demineralized water, particularly with the CeO2 + CeTiOx modification, suggesting O3 decomposition to hydroxyl radicals. The increased resistance in the modified membranes contributed to the adsorption phenomena. The degradation efficiency decreased in secondary effluent due to competition with the organic and inorganic load, highlighting the challenges in complex water matrices. [ABSTRACT FROM AUTHOR]

Water bodies are being contaminated daily due to industrial, agricultural and domestic effluents. In the last decades, harmful organic micropollutants (OMPs) have been detected in surface and groundwater at low concentrations due to the discharge of untreated effluent in natural water bodies. As a consequence, aquatic life and public health are endangered. Unfortunately, traditional water treatment methods are ineffective in the degradation of most OMPs. In recent years, advanced oxidation processes (AOPs) techniques have received extensive attention for the mineralization of OMPs in water in order to avoid serious environmental problems. Cold atmospheric plasma discharge-based AOPs have been proven a promising technology for the degradation of non-biodegradable organic substances like OMPs. This paper reviews a wide range of cold atmospheric plasma sources with their reactor configurations used for the degradation of OMPs (such as organic dyes, pharmaceuticals, and pesticides) in wastewater. The role of plasma and treatment parameters (e.g. input power, voltage, working gas, treatment time, OMPs concentrations, etc.) on the oxidation of various OMPs are discussed. Furthermore, the degradation kinetics, intermediates compounds formed by plasma, and the synergetic effect of plasma in combination with a catalyst are also reported in this review. [ABSTRACT FROM AUTHOR]

Adsorbable organic halogens (AOX) were measured at the outlet (AOXo) and after 24 h contact time with residual disinfectant (AOX24 h) for 10 samples obtained from 7 drinking water treatment plants (WTPs) that employ chlorine-based disinfectants. AOXo ranged from 0.75 to 7.60 µM (26.2-266.0 µgCl=L) and increased by up to 170% after 24 h contact time. The results were also compared with AOX formation potential (AOXFP) measured in the laboratory for the samples collected prior to disinfection at the same WTPs. In general, AOX24 h and AOXFP values varied by less than ±20%. A suite of disinfection byproducts (DBPs) were individually measured to elucidate the AOX composition. Trihalomethanes and haloacetic acids explained the largest fraction of AOX; however, the percentage of AOX not accounted for by measured DBPs varied greatly between samples (14.5-62.0%). Additionally, the fate of AOXFP was assessed across the seven WTPs. On average, coagulation removed 67 ± 7% of AOXFP across the WTPs, while dual media filtration did not substantially remove AOXFP. The effect of ozone on AOXFP varied between WTPs, while biological activated carbon filtration removed 33 ± 13% AOXFP. The ratio of known versus unknown AOXFP did not change across the WTPs. [ABSTRACT FROM AUTHOR]

Stormwater is one of the last major untapped urban water resources that can be exploited as an alternative water source in Australia. The information in the current Australian Guidelines for Water Recycling relating to stormwater harvesting and reuse only emphasises on a limited number of stormwater quality parameters. In order to supply stormwater as a source for higher value end-uses, a more comprehensive assessment on the potential public health risks has to be undertaken. Owing to the stochastic variations in rainfall, catchment hydrology and also the types of non-point pollution sources that can provide contaminants relating to different anthropogenic activities and catchment land uses, the characterisation of public health risks in stormwater is complex, tedious and not always possible through the conventional detection and analytical methods. In this study, a holistic approach was undertaken to assess the potential public health risks in urban stormwater samples from a medium-density residential catchment. A combined chemical-toxicological assessment was used to characterise the potential health risks arising from chemical contaminants, while a combination of standard culture methods and quantitative polymerase chain reaction (qPCR) methods was used for detection and quantification of faecal indicator bacteria (FIB) and pathogens in urban stormwater. Results showed that the concentration of chemical contaminants and associated toxicity were relatively low when benchmarked against other alternative water sources such as recycled wastewater. However, the concentrations of heavy metals particularly cadmium and lead have exceeded the Australian guideline values, indicating potential public health risks. Also, high numbers of FIB were detected in urban stormwater samples obtained from wet weather events. In addition, qPCR detection of human-related pathogens suggested there are frequent sewage ingressions into the urban stormwater runoff during wet weather events. Further water quality monitoring study will be conducted at different contrasting urban catchments in order to undertake a more comprehensive public health risk assessment for urban stormwater. [ABSTRACT FROM AUTHOR]

In this paper, we present pilot-scale solar Photo-Fenton and TiO2 treatment of a model compound (α-methylphenylglycine) dissolved in 500 mg/l concentration in water. Not only contaminant disappearance and mineralisation were evaluated, but also enhancement of biodegradability. The solar photoreactors, composed of 4.16 m2 of compound parabolic collectors, had a total volume of 82 l (44.6 l illuminated). Treatment was successful with both Advanced Oxidation Processes (AOPs) tested, but photo-Fenton was shown to be by far more efficient from the kinetic and practical point of view. To find out the conditions for biocompatibility using the AOPs as a pre-treatment, waste water after certain degradation time, unacclimated municipal sludge and mineral nutrients were placed together and evaluated by the Zahn–Wellens (Z-W) test. Biodegradability was enhanced (70% biodegradable) by both AOPs, but photo-Fenton was demonstrated to be more efficient, requiring a treatment time one order of magnitude shorter than TiO2. Hydrogen peroxide management for reduced consumption and elimination prior to discharging water to the biotreatment step is also discussed in detail. [ABSTRACT FROM AUTHOR]

Microbial pathogens present in stormwater, which originate from human sewage and animal faecal matters, are one of the major impediments in stormwater reuse. The transport of microbes in stormwater is more than just a physical process. The mobility of microbes in stormwater is governed by many factors, such as dissolved organic matter, cations, pH, temperature and water flow. This paper examined the roles of three environmental variables, namely: dissolved organic matter, positive cations and stormwater flow on the transport of two faecal indicator bacteria (FIB), Enterococcus spp. and Escherichia coli. Stormwater runoff samples were collected during twelve wet weather events and one dry weather event from a medium density residential urban catchment in Brisbane. Enterococcus spp. numbers as high as 3 × 104 cfu/100 mL were detected in the stormwater runoff, while Escherichia coli numbers up to 3.6 × 103 cfu/100 mL were observed. The dissolved organic carbon (DOC) in the stormwater samples was in the range of 2.2–5.9 mg/L with an average concentration of 4.5 mg/L in which the hydrophilic carbon constituted the highest mass fraction of 60–80%. The results also showed that the transport of FIB in stormwater was reduced with an increasing concentration of the hydrophilic organic fraction, especially the humic fraction. On the contrary, the concentration of trivalent cations and stormwater flow rate showed a positive correlation with the FIB numbers. These findings indicated the potentiality to make a good use and measurement of simple environmental variables to reflect the degree of microbe transport in stormwater from residential/suburban catchments. [ABSTRACT FROM AUTHOR]