Urban Wastewater Effluents Research Articles

Hydrogen production from non-potable water resources: A techno-economic investment and operation planning approach

The production of hydrogen through water electrolysis facilitates large-scale energy storage, provides ancillary services, and supports the decarbonization of industries with hard-to-reduce emissions. As renewable energy adoption expands, the demand for these applications is increasing. However, water electrolysis currently faces challenges in cost competitiveness compared to other hydrogen production methods. Additionally, its reliance on potable water sources places additional strain on freshwater reserves. This study addresses these issues by exploring the economically optimal investment and operational strategy for hydrogen production using non-potable water sources. The goal is to maximize net profit through mathematical optimization, utilizing three advanced electrolysis technologies: alkaline electrolysis, proton exchange membrane electrolysis, and solid oxide electrolysis. The study examines three non-potable water sources: seawater, urban wastewater effluent, and rainwater. The model takes into account electricity market values from day-ahead and balancing markets, as well as the market values for hydrogen, oxygen, freshwater, and mixed solid salt. Two scenarios are analysed, reflecting varying levels of uncertainty in electricity price forecasts. Each scenario includes nine case studies, representing various combinations of water sources and electrolysis technologies. The results indicate that alkaline electrolysis and proton exchange membrane electrolysis are financially viable technologies, with potential annual net profits of up to 6.4 and 6.2 million euros, respectively. In contrast, solid oxide electrolysis incurs a negative net profit across all scenarios and is not economically viable under the given conditions. The main revenue sources are hydrogen sales and combined up-balancing and down-balancing services in electricity markets. Participation in the balancing market constitutes a significant portion (35 to 61%) of the total revenue in all cases with positive net profits, making it critical for economic viability. Rainwater is identified as the most cost-effective water source for hydrogen production. However, the costs associated with water treatment and brine management are minimal, contributing only 0.7 to 3.7% to the total cost of hydrogen production. Thus, differences in net profit are primarily attributed to the type of electrolysis technology used.

Prolonged exposure to the synthetic glucocorticoid dexamethasone induces brain damage via oxidative stress and apoptotic response in adult Daniorerio

Due to its extensive use as a painkiller, anti-inflammatory, and immune modulatory agent, as well as its effectiveness in treating severe COVID-19, dexamethasone, a synthetic glucocorticoid, has gained attention not only for its impact on public health but also for its environmental implications. Various studies have reported its presence in aquatic environments, including urban waters, surface samples, sediments, drinking water, and wastewater effluents. However, limited information is available regarding its toxic effects on nontarget aquatic organisms. Therefore, this study aimed to investigate the mechanism of toxicity underlying dexamethasone-induced brain damage in the bioindicator Danio rerio following long-term exposure. Adult zebrafish were treated with environmentally relevant concentrations of dexamethasone (20, 40, and 60 ng L-1) for 28 days. To elucidate the possible mechanisms involved in the toxicity of the pharmaceutical compound, we conducted a behavioral test battery (Novel Tank and Light and Dark tests), oxidative stress biomarkers, acetylcholinesterase enzyme activity quantification, histopathological analysis, and gene expression analysis using qRT-PCR (p53, bcl-2, bax, caspase-3, nrf1, and nrf2).The results revealed that the pharmaceutical compound could produce anxiety-like symptoms, increase the oxidative-induced stress response, decrease the activity of acetylcholinesterase enzyme, and cause histopathological alterations, including perineuronal vacuolization, granular and molecular layers deterioration, cell swallowing and intracellular spaces. The expression of genes involved in the apoptotic process (p53, bax, and casp-3) and antioxidant defense (nrf1 and nrf2) was upregulated in response to oxidative damage, while the expression of the anti-apoptotic gene bcl-2 was down-regulated indicating that the environmental presence of dexamethasone may pose a threat to wildlife and human health.

Valorization of Field-Spent Granular Activated Carbon as Heterogeneous Ozonation Catalyst for Water Treatment.

Developing sustainable cost-effective strategies for valorization of field-spent granular activated carbon (s-GAC) from industrial water treatment has gained much interest. Here, we report a cost-effective strategy for the regeneration of s-GAC as an adsorbent in a large-scale drinking water treatment plant and used as an efficient and durable ozonation catalyst in water. To achieve this, a series of samples is prepared by subjecting s-GAC to thermally controlled combustion treatments with and without pyrolysis. The catalytic performance of the optimized sample is evaluated for oxalic acid degradation as the model pollutant under batch (>15 h) and continuous flow operations (>200 h). The partially deactivated catalyst upon reuse is restored by thermal treatment. Electron paramagnetic resonance and selective quenching experiments show the formation of singlet oxygen (1O2) during catalytic ozonation. The GAC-ozonation catalyst is efficient to minimize the formation of chlorinated disinfection by-products like trihalomethanes and haloacetic acids in an urban wastewater effluent.

Removal of neonicotinoid insecticides in a large-scale constructed wetland system

Neonicotinoid insecticides are among the most used insecticides and their residues are frequently found in surface water due to their persistence and mobility. Neonicotinoid insecticides exhibit toxicity to a wide range of aquatic invertebrates at environmentally relevant levels, and therefore their contamination in surface water is of significant concern. In this study, we investigated the spatiotemporal distribution of six neonicotinoids in a large wetland system, the Prado Wetlands, in Southern California, and further evaluated the wetlands’ efficiency at removing these insecticides. Total neonicotinoid concentrations in water ranged from 3.17 to 46.9 ng L−1 at different locations within the wetlands, with imidacloprid and dinotefuran among the most detected. Removal was calculated based on concentrations as well as mass flux. The concentration-based removal values for a shallow pond (vegetation-free), moderately vegetated cells, densely vegetated cells, and the entire wetland train were 16.9%, 34.2%, 90.2%, and 61.3%, respectively. Principal component analysis revealed that pH and temperature were the primary factors affecting neonicotinoids removal. Results from this study demonstrated the ubiquitous presence of neonicotinoids in surface water impacted by urban runoff and wastewater effluent and highlighted the efficiency of wetlands in removing these trace contaminants due to concerted effects of uptake by wetland plants, photolysis, and microbial degradation.

Treatment of urban wastewater by coupling planted filters with anodic oxidation process

ABSTRACT The wastewater reuse strategy has the advantage of providing an effective resource to reduce water deficits, protect natural resources and alleviate future water shortages caused by climate change. In many arid and semi-arid regions, water reuse provides the majority of irrigation water, which is why appropriate treatment techniques are needed. These include planted filters, with restricted reuse of agricultural treated water. The main innovation is therefore to develop a new technique with reduced operating costs and increased efficiency for wastewater treatment that can be used in different sectors (household, industrial, washing centers…). The current work aimed to assess the performance of coupling planted Filters with anodic oxidation on platinum to remove contaminants and pathogens from urban wastewater effluents. To evaluate the efficiency of this hybrid process, urban sewage was first treated by filters planted with reeds, then by anodic oxidation on platinum using photovoltaic panels. Results showed that this treatment system allows a complete elimination of organic matter, ammonium nitrogen, and pathogenic bacteria. Removal rates were ~ 100% for COD, ~100% for BOD, ~100% for NH4 +, 93.24% for NO3 −, and ~100% for TC, FC, and FS. Due to the satisfactory performance, treated water can be reused without restriction in different sectors.

Ozonation Processes for Color Removal from Urban and Leather Tanning Wastewater

The need to ensure adequate levels of both human and environmental health protection calls for the identification of efficient wastewater treatment processes that target the removal of conventional pollutants as well as emerging contaminants, including synthetic dyes. This study explores the potential of ozone for use in the decolorization of both pretreated tannery wastewater and urban wastewater effluents. Different ozone contact times (15, 30, and 45 min) were applied to such wastewater samples at an uncontrolled (7.5–8.2) pH as well as at a pH adjusted to 10. The highest color removal efficiencies (REs) (>90%) were obtained with urban wastewater after a 45 min contact time and at pH 10. Under the same conditions, a COD RE from 31 to 51% was achieved. Even without pH adjustment, color and COD REs ranging from 81 to 92% and 39 to 41%, respectively, were obtained. A preliminary evaluation of the costs associated with the implementation of an ozonation stage within the wastewater treatment plant (WWTP) generating the urban wastewater used here was carried out. The energy cost of the ozone treatment would account for a 69% increase in the total energy cost of the WWTP, suggesting the need to identify proper strategies to enhance the cost-competitiveness of this technology.

Emerging Pollutants- A review of current understanding and future scenario

A recently identified community of chemicals found in aquatic ecosystems are pollutants of increasing concern or, literally, emerging pollutants (EPs). It was only the advances in analytical techniques that enabled the identification of these pollutants even at low concentrations. The persistent discovery of new chemicals prompts concerns about their origin routes, their destiny, their transport, their transition and their effect on the aquatic ecosystem. As new chemical substances are continually being generated and scientific research optimizes its awareness of existing and previous pollutants, pollutants of increasing concerns will stay a moving target. EPs primarily originating from the disposal of urban and industrial wastewater effluents, are widespread in the aquatic ecosystems. Owing to the potential biological effect on organisms within the ecosystem, their existence is of worry. A holistic approach to sampling is needed in order to understand their fate and transformations in wastewater and ecosystem. This implies the attainment of relevant evidence and promotes a deeper interpretation of spatiotemporal pollutant patterns and occurrence. During treating of wastewater, owing to more planning criteria and absence of good analytical techniques, there is a shortage of residual pollutants study. This leads to under-reported analysis of many EPs joining wastewater treatment works and the aquatic ecosystem. Sludge can hold concentrations of certain chemicals, during the treatment of wastewater that ends up being applied to agriculture without analysis for EPs. Hence a framework for environmental reporting that is more holistic is needed, so that the destiny and effect of EPs are explored in all environmental systems. This review discusses current understanding of EPs and provides recommendations for better future analysis.

Assessment of new immobilized photocatalysts based on Rose Bengal for water and wastewater disinfection

The aim of this study was to evaluate the water disinfection capability of new immobilized photocatalysts based on the organic photosensitizer Rose Bengal (RB) supported on glass wool and with two different photocatalyst load (RB_GW_0.22 and RB_GW_0.02). Tests were carried out under different operating conditions in a solar simulator at 30 W/m2 average UV-A irradiation. Isotonic water (IW) (with 9 g/L NaCl), simulated tap water (STW) and simulated urban wastewater effluent (SUWWE) spiked with Escherichia coli and Enterococcus faecalis (106 CFU/mL initial concentrations) were used as water model microbial strains. The mere effect of only irradiance was also investigated as reference of the photocatalytic performance over both bacteria. Results showed that RB_GW_0.22 presented high inactivation for E. faecalis, reaching 6 Log Reduction Value (LRV) in 2 min in IW and STW at pH 5 and 6 in comparison with only irradiance (60 min). In SUWWE, the effect of RB_GW_0.22 was also better for E. faecalis inactivation (60 min), compared to that produced in E. coli (120 min) and without the presence of the photocatalyst (where total inactivation was not achieved after 120 min of treatment). Ecotoxicity (ISO 11348–3:2007) and phytotoxicity (EN ISO 18763:2020) tests of the treated water were also assessed and results showed any significant effect, concluding that the use of RB_GW_0.22 is a promising solar photocatalytic treatment for urban wastewater reclamation and reuse.

Comparative Assessment of Microplastics in Surface Waters and Sediments of the Vaal River, South Africa: Abundance, Composition, and Sources.

We extracted microplastics from surface water and sediment samples from the Vaal River in Johannesburg, South Africa. Average abundances of 0.61 ± 0.57 particles/ and 4.6 × 102 ± 2.8 × 102 particles/kg dry weight were recorded for water and sediment samples, respectively. In both sediment and water samples, more than 80% of microplastics were fragments and fibers of smaller than 2 mm. High-density polyethylene, low-density polyethylene, and polypropylene were the dominant polymers identified in both sample types. In addition, polyethylene co-vinyl acetate, polyester, polyurethane, and polyethylene/hexene-1-copolymer were also detected in sediment samples. Colored microplastics were the most commonly observed in both sample types; pigment yellow 83 was detected in surface water, and carbon black was detected in both sediment and water samples during Raman analysis. Taking into consideration the physical and chemical characteristics of the detected microplastics, their potential sources include inflow from tributaries, surface run-off from urban city centers, recreational activities, and wastewater effluent from industries and households. Environ Toxicol Chem 2022;41:3029-3040. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Simultaneous disinfection and microcontaminants elimination of urban wastewater secondary effluent by solar advanced oxidation sequential treatment at pilot scale

The effect of different times of Fe:Ethylenediamine-N, N′-disuccinic acid (EDDS) dosing and H2O2 as well as different Fe:EDDS concentrations in the sequential treatment sunlight/H2O2 followed by sunlight/H2O2/Fe:EDDS at circumneutral pH was investigated for the first time focusing both in contaminants of emerging concern (CECs) and bacteria removal in urban wastewater treatment plant effluents. Process efficiency was evaluated in terms of (i) degradation of five CECs (namely caffeine, carbamazepine, diclofenac, sulfamethoxazole and trimethoprim) at the initial concentration of 100 μgL−1 each and (ii) bacteria inactivation (Escherichia coli (E. coli) and Salmonella spp). The effect of H2O2, Fe and EDDS concentration and Fe:EDDS dosing time was evaluated. 60% removal of the sum of total CECs and pathogens inactivation below the detection limit (DL) were observed by the sequential treatment with Fe:EDDS additions at 60 min and 45 min in simulated urban wastewater effluent. Sequential treatment was validated in actual urban wastewater effluent, being able to remove 60% of the target CECs and inactivate bacteria below the DL. Increasing EDDS concentration negatively affected Salmonella spp inactivation. Sequential treatment based on 120 min of sunlight/H2O2 (50 mg L−1) and subsequent SPF with Fe:EDDS (0.1:0.1 mM) was chosen as best operation conditions for full scale treatment in urban wastewater treatment plants.

Effect of land use on microplastic pollution in a major boundary waterway: The Arvand River

The occurrence of microplastics (MPs) was investigated in the Arvand River (Iran). The Arvand River (200 Km) is a major water body that flows through land with diverse use and it meets the Persian Gulf. This study constitutes the first assessment of MP pollution (prevalence and physico-chemical characteristics) in the Arvand river, both in the sediment and in the water. MP monitoring has been carried out in 24 stations located along the river. The MP pollution found ranged between 1 and 291 items·L−1 and 70 to 15,620 items·kg−1 (dw), in water and sediment, respectively. The majority of MPs were fibres, black/grey and yellow/orange in colour, and mainly 250–500 μm and >1000 μm in size. Polyethylene terephthalate (PET), polypropylene (PP), nylon (NYL), high-density polyethylene (HDPE), and polystyrene (PS) were found in sediment samples. All these polymers, except HDPE, were also identified in the water samples. PET and PP were dominant in the water samples; whereas PET and PS were the most abundant in the sediments. The vicinity of urban wastewater effluents could be behind MP pollution in both water and sediments. Significant differences (p < 0.05) of MP concentrations were affected by different land uses when comparing MP levels in undisturbed natural area with urban areas. A strong correlation between MP fibres and fragments found with PCA biplots revealed their similar distribution in water. In the sediment samples, fibre and fragment MP particles were significantly correlated with colloidal particles (e.g., clay and organic matter) suggesting a relevant role of colloidal particles in the aquatic ecosystem of the Arvand River in transporting MPs. This study contributes to the better understanding of the presence of MP in major rivers, which are systems that have been scarcely investigated for this type of pollution, and it can inform interventions to reduce MP inputs to the river and sea.

Physico-Chemical Characterization of an Urban Wastewater Effluent and Its Impact on the Receiving Environment: Oued Nfifikh (Morocco)

Physico-Chemical Characterization of an Urban Wastewater Effluent and Its Impact on the Receiving Environment: Oued Nfifikh (Morocco)

Energy limitation or sensitive predators? Trophic and non-trophic impacts of wastewater pollution on stream food webs.

Impacts of environmental stressors on food webs are often difficult to predict because trophic levels can respond in divergent ways, and biotic interactions may dampen or amplify responses. Here we studied food-web-level impacts of urban wastewater pollution, a widespread source of degradation that can alter stream food webs via top-down and bottom-up processes. Wastewater may (1) subsidize primary producers by decreasing nutrient limitation, inducing a wide-bottomed trophic pyramid. However, (2) wastewater may also reduce the quality and diversity of resources, which could decrease energy transfer efficiency by reducing consumer fitness, leading to predator starvation. Additionally, (3) if higher trophic levels are particularly sensitive to pollution, primary consumers could be released from predation pressure. We tested these hypotheses in 10 pairs of stream sites located upstream and downstream of urban wastewater effluents with different pollutant levels. We found that wastewater pollution reduced predator richness by ∼34%. Community size spectra (CSS) slopes were steeper downstream than upstream of wastewater effluents in all except one impact site where predators became locally extinct. Further, variation in downstream CSS slopes were correlated with pollution loads: the more polluted the stream, the steeper the CSS. We estimate that wastewater pollution decreased energy transfer efficiencies to primary consumers by ∼70%, limiting energy supply to predators. Additionally, traits increasing vulnerability to chemical pollution were overrepresented among predators, which presented compressed trophic niches (δ15 N-δ13 C) downstream of effluents. Our results show that wastewater pollution can impact stream food webs via a combination of energy limitation to consumers and extirpation of pollution-sensitive top predators. Understanding the indirect (biotically mediated) vs. direct (abiotic) mechanisms controlling responses to stress may help anticipating impacts of altered water quantity and quality, key signatures of global change.

Unravelling the performance of UV/H2O2 on the removal of pharmaceuticals in real industrial, hospital, grey and urban wastewaters

This study provides an integrated assessment of UV/H2O2 treatment of different real wastewater matrices: two urban wastewater treatment plants (WWTPs) secondary effluents, greywater, hospital, and pharmaceutical industrial effluents. It considers micropollutant removal (up to 30 pharmaceuticals and 13 transformation products at environmental concentrations), energy efficiency and effluent toxicity. The complexity of the wastewater matrix negatively affected the UV fluence in the photo-reactor, scavenged hydroxyl radicals and hindered a proper H2O2 utilization thus reducing the treatment efficiency. At the optimal treatment conditions, overall pharmaceuticals removal was the highest for urban WWTPs effluents (69%–86%), followed by greywater (59%), hospital (36%) and industrial (17%) effluents. The ecotoxicity of the treated samples was reduced around one toxicity unit after the UV/H2O2 treatment in all cases except in industrial wastewater. The average observed removal in urban wastewater effluents and greywater for photo-susceptible, moderately photo-susceptible, and most photo-resistant compounds was 93%, 73% and 46% including outliers, respectively. The calculated electrical energy per order (EEO) values were 0.9–1.5 kWh/(m3·order) for urban WWTP effluents and greywater while for hospital and industrial effluents was much higher (7.3–9.1 kWh/(m3·order)).

Sustainable Energy Management Benchmark at Wastewater Treatment Plant

Urban wastewater effluents bring large amounts of nutrients, organic matter, and organic microcontaminants into freshwater ecosystems. Ensuring the quality of wastewater treatment (WWT) is one of the main challenges facing the management of wastewater treatment plants (WWTPs). However, achievement of high-quality standards leads towards significant energy consumption: usually the more intensive WWT process requires additional energies. Energy efficiency at WWTP is actual mainstream on the current sustainable development agenda. The WWTP processes and methods can be considered from the standpoint of material and energy flows according to circular economy paradigm, which offers great possibilities to reuse waste originating from WWT in order to receive renewable energy. The correlation between energy and quality issues to evaluate WWTP efficiency is of a great scientific and practical interest. The main goal of the paper is to check the dependency between these two main issues in WWTP management—WWT quality and energy efficiency—and to determine possible limits of such relation. The municipal sewerage system of Ekaterinburg, Russia was studied within this paper. The total length of centralized sewerage system in Ekaterinburg is over 1500 km of pipes within two main sewerage basins: northern and southern. The methodological framework for the current research consisted of three steps: (i) WWT quality evaluation, (ii) energy efficiency evaluation, and (iii) WWTP Quality/Energy (Q/E) efficiency dependency matrix. For the purpose of research, authors investigated the 2015–2018 period. The results showed that the outputs correlate with the technical conditions of WWTPs and the implementation of the best available techniques (BATs): most of the northern WWTP values are referred to the green zone (good rank), while the southern WWTP values are situated generally in the orange zone (unsatisfactory rank). The proposed methodological approach for Q/E dependency of WWT process creates a strong but simple tool for managers to evaluate the current success of the operation of WWTP and progress towards circular economy practices implementation.

Assessment of the performance of intermittent planted filters in treating urban wastewater under arid climate.

Intermittent planted filters are extensive biological purification techniques aimed at oxidizing and decontaminating urban wastewater at a low cost and with minimum environmental impacts. The main purpose of this study was to evaluate the performances of intermittent planted filters in treating urban wastewater under arid conditions of southern Tunisia. The experimental study was carried out on a pilot scale plant comprising five constructed gravel-sand basins. Screened urban wastewater effluent was intermittently applied with a daily hydraulic load of 400 L/m2. Several water quality parameters were monitored at the inlet and outlet of this treatment plant. The average removal rate were 94.8%, 92.3%, 99.3%, 89.9% and 93.3% for chemical and biological oxygen demand, total suspended solids, ammonium nitrogen and orthophosphate, respectively. Additionally, results demonstrated that this treatment system is capable of removing 3.67, 3.22 and 2.44 log units of total and faecal coliforms, and faecal streptococci, respectively. Results showed that Phragmites australis allowed the development of biofilm in the sand filter beds, improving their purification efficiency. Furthermore, no bio-sludge production, no mechanical aeration, low energy requirement (0.02 kW/m2) and green aesthetic ambience are the additional particular strengths of the proposed pilot plant.

Identifying Chemicals and Mixtures of Potential Biological Concern Detected in Passive Samplers from Great Lakes Tributaries Using High-Throughput Data and Biological Pathways.

Waterborne contaminants were monitored in 69 tributaries of the Laurentian Great Lakes in 2010 and 2014 using semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCIS). A risk‐based screening approach was used to prioritize chemicals and chemical mixtures, identify sites at greatest risk for biological impacts, and identify potential hazards to monitor at those sites. Analyses included 185 chemicals (143 detected) including polycyclic aromatic hydrocarbons (PAHs), legacy and current‐use pesticides, fire retardants, pharmaceuticals, and fragrances. Hazard quotients were calculated by dividing detected concentrations by biological effect concentrations reported in the ECOTOX Knowledgebase (toxicity quotients) or ToxCast database (exposure–activity ratios [EARs]). Mixture effects were estimated by summation of EAR values for chemicals that influence ToxCast assays with common gene targets. Nineteen chemicals—atrazine, N,N‐diethyltoluamide, di(2‐ethylhexyl)phthalate, dl‐menthol, galaxolide, p‐tert‐octylphenol, 3 organochlorine pesticides, 3 PAHs, 4 pharmaceuticals, and 3 phosphate flame retardants—had toxicity quotients >0.1 or EARs for individual chemicals >10–3 at 10% or more of the sites monitored. An additional 4 chemicals (tributyl phosphate, triethyl citrate, benz[a]anthracene, and benzo[b]fluoranthene) were present in mixtures with EARs >10–3. To evaluate potential apical effects and biological endpoints to monitor in exposed wildlife, in vitro bioactivity data were compared to adverse outcome pathway gene ontology information. Endpoints and effects associated with endocrine disruption, alterations in xenobiotic metabolism, and potentially neuronal development would be relevant to monitor at the priority sites. The EAR threshold exceedance for many chemical classes was correlated with urban land cover and wastewater effluent influence, whereas herbicides and fire retardants were also correlated to agricultural land cover. Environ Toxicol Chem 2021;40:2165–2182. Published 2021. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Post-treatment of real municipal wastewater effluents by means of granular activated carbon (GAC) based catalytic processes: A focus on abatement of pharmaceutically active compounds

Pharmaceutically active compounds (PhACs) widely present in urban wastewater effluents pose a threat to ecosystems in the receiving aquatic environment. In this work, efficiency of granular activated carbon (GAC) - based catalytic processes, namely catalytic wet peroxide oxidation (CWPO), peroxymonosulfate oxidation (PMS/GAC) and peroxydisulfate oxidation (PDS/GAC) at ambient temperature and pressure were studied for removal of 22 PhACs (ng L−1 level) that were present in secondary effluents of real urban wastewater. Concentrations of PhACs were measured using Ultra Performance Liquid Chromatography – Triple Quadrupole Mass Spectrometry (UPLC-QqQ-MS/MS). Catalytic experiments were conducted in discontinuous mode using up-flow fixed bed reactors with granular activated carbon (GAC) as a catalyst. The catalyst was characterized by means of N2 adsorption-desorption isotherm, mercury intrusion porosimetry (MIP), elemental analysis, X-ray fluorescence spectroscopy (WDXRF), X-ray diffraction (XRD), thermal gravimetry and differential temperature analyses coupled mass spectrometry (TGA-DTA-MS). Results indicate that the highest efficiency in terms of TOC removal was achieved during CWPO performed at optimal operational conditions (stoichiometric dose of H2O2; TOC removal ~ 82%) followed by PMS/GAC (initial PMS concentration 100 mg L−1; TOC removal ~73.7%) and PDS/GAC (initial PDS concentration 100 mg L−1; TOC removal ~ 67.9%) after 5 min of contact time. Full consumption of oxidants was observed in all cases for CWPO and PDS/GAC at contact times of 2.5 min, while for PMS/GAC it was 1.5 min. In general, for 18 out of 22 target PhACs, very high removal efficiencies (> 92%) were achieved in all tested processes (including adsorption) performed at optimal operational conditions during 5 min of contact time. However, moderate (40 – 70%) and poor (< 40%) removal efficiencies were achieved for salicylic acid, ofloxacin, norfloxacin and ciprofloxacin, which can be possibly attributed to insufficient contact time. Despite high efficiency of all studied processes for PhACs elimination from urban wastewater effluent, CWPO seems to be more promising for continuous operation.

Assessment of emerging polar organic pollutants linked to contaminant pathways within an urban estuary using non-targeted analysis.

A comprehensive, non-targeted analysis of polar organic pollutants using high resolution/accurate mass (HR/AM) mass spectrometry approaches has been applied to water samples from San Francisco (SF) Bay, a major urban estuary on the western coast of the United States, to assess occurrence of emerging contaminants and inform future monitoring and management activities. Polar Organic Chemical Integrative Samplers (POCIS) were deployed selectively to evaluate the influence of three contaminant pathways: urban stormwater runoff (San Leandro Bay), wastewater effluent (Coyote Creek, Lower South Bay), and agricultural runoff (Napa River). Grab samples were collected before and after deployment of the passive samplers to provide a quantitative snapshot of contaminants for comparison. Composite samples of wastewater effluent (24 hours) were also collected from several wastewater dischargers. Samples were analyzed using liquid-chromatography coupled to high resolution mass spectrometry. Resulting data were analyzed using a customized workflow designed for high-fidelity detection, prioritization, identification, and semi-quantitation of detected molecular features. Approximately 6350 compounds were detected in the combined data set, with 424 of those compounds tentatively identified through high quality spectral library match scores. Compounds identified included ethoxylated surfactants, pesticide and pharmaceutical transformation products, polymer additives, and rubber vulcanization agents. Compounds identified in samples were reflective of the apparent sources and pathways of organic pollutant inputs, with stormwater-influenced samples dominated by additive chemicals likely derived from plastics and vehicle tires, as well as ethoxylated surfactants.

Removal of pharmaceutically active compounds (PhACs) and bacteria inactivation from urban wastewater effluents by UVA-LED photocatalysis with Gd3+ doped BiVO4

In this study, gadolinium doped bismuth vanadate powders were synthesized, characterized, and tested as a potential photocatalyst for the removal of pharmaceutically active compounds (PhACs) and bacterial inactivation in a real wastewater effluent using UVA as irradiation source. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies revealed that the bismuth vanadate system was successfully doped with 4% of gadolinium in molar mass leading to the formation of a heterostructured photocatalyst.Up to 98.3 % of diclofenac was removed from pure water after 120 min through photocatalysis. However, the photocatalytic performance of the photocatalyst on wastewater effluent was rather variable due to the complexity of the matrix where 22 different PhACs were detected by means of Ultra Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry (UPLC-QqQ-MS/MS). High photocatalytic removal efficiency (80–100%) was observed for some of the studied PhACs (e.g. naproxen and furosemide) whereas moderate efficiency (40–70%) was observed for others (e.g. acetaminophen and azithromycin) after 180 min (UVA dose = 139.5 Wh m−2, t30W = 279 min-1). Some of the studied PhACs like clarithromycin and Ibuprofen showed poor removal efficiency (< 30 %). In disinfection tests, Total coliforms, Escherichia coli, Enterococci, and Klebsiella pneumoniae showed inactivation after direct UVA LED photolysis. Nevertheless, higher inactivation was achieved for Enterococci in the presence of the synthesized photocatalyst showing an increase of 41.1 % in kmax.