Concentrations Of Organic Micropollutants Research Articles

Rapid photodegradation of organic micro-pollutants in water using high-intensity pulsed light

The rising concentration of organic micro-pollutants (OMPs) in water resources has become a major concern for aquatic ecosystems and human health. Advanced oxidation processes (AOPs), based on ultraviolet (UV) photolysis and photochemical reactions, have been suggested for the degradation of various micropollutants present in water and wastewater. However, the application of these methods on large scale is limited due to the long treatment times. Here we evaluate the efficiency of high-intensity pulsed light treatment (HIPL) for the degradation of organic compounds in aqueous conditions. A solution containing 11 OMPs was treated with short (<2 ms) and high-intensity light pulses produced by a Xenon flash lamp. It was observed that the HIPL parameters, such as the number of pulses and optical energy dose, have a significant impact on the efficiency of the treatment. The main advantage of HIPL is the fast kinetics that allows efficient photodegradation of OMPs from the aqueous solution rapidly and within milliseconds. The present work showcases the potential of HIPL technique for the post-treatment of contaminated water containing pharmaceuticals and endocrine disruptor compounds.

Cold atmospheric plasma technology for removal of organic micropollutants from wastewater\u2014a review

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.Graphic

Occurrence and exposure risk assessment of organic micropollutants in indoor dust from Malaysia

Indoor dust is an important source of human exposure to hazardous organic micropollutants (OMPs) because humans spend about 90 % of their time in the indoor environments. This study initially analyzed the concentrations and compositions of OMPs in the dust of different indoor environments from Kuala Lumpur, Malaysia. A total of 57 OMPs were detected and assigned to 7 chemical classes in this study. The total concentration of OMPs ranged from 5980 to 183,000 ng/g, with the median concentration of 46,400 ng/g. Personal care products, organophosphate esters, and pesticides were the dominant groups, with their median concentrations at 12,000, 10,000, and 5940 ng/g, respectively. The concentrations and compositions of influential OMPs varied in different microenvironments, suggesting different sources and usage patterns in the house. Then, the noncarcinogenic and carcinogenic risks of exposure to these substances for diverse age groups were assessed based on the median concentration. Cumulative noncarcinogenic risks of these OMPs via ingestion pathway were estimated to be negligible (1.41 × 10−4 - 1.87 × 10−3). The carcinogenic risks of these OMPs were higher than 10−6 (1.63 × 10−6 - 6.17 × 10−6) and should be noted. Theobromine accounted for more than 89 % of the cumulative cancer risk, implying that the carcinogenic risk of theobromine needs further monitoring in the future. Toddler was the most affected group for cancer risk among all the age groups, regardless of the microenvironments. These findings from this study may provide a benchmark for future efforts to ensure the safety of indoor dust for the local residents.

Comprehensive Monitoring of More Than 1000 Organic Micro-pollutants in Drainage Water: Case Study in a Rural Village with End-of-Life Vehicle Processing Activities in Northern Vietnam

A comprehensive and detailed monitoring scheme was applied to examine more than 1000 organic micro-pollutants (OMPs) in drainage water samples collected from a rural village with informal end-of-life vehicle processing activities in northern Vietnam. Concentrations of total OMPs ranged from 8900 to 34,100 (median 11,400) ng L−1. In our water samples, major classes of organic pollutants were n-alkanes, squalane, synthetic phenolic antioxidants and derivatives (SPAs), and polycyclic aromatic hydrocarbons (PAHs), which together accounted for 97% in average of total OMPs. Trace levels of polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) were also detected. In particular, CB-11 (3,3′-dichlorobiphenyl), which is a minor component of technical PCB mixtures but is a dominant impurity in many organic pigments, was found in all the samples (median 0.20; range 0.14–0.23 ng L−1; accounting for 5% in average of total PCBs). In general, concentrations of almost all the OMPs investigated in this study were lower than critical values for any ecotoxicological risk.

Temporal dynamics and ecotoxicological risk assessment of personal care products, phthalate ester plasticizers, and organophosphorus flame retardants in water from Lake Victoria, Uganda

For the first time the occurrence of 25 organic micropollutants (OMPs) including; 11 personal care products (PCPs), six phthalate ester plasticizers (PEPs) and eight organophosphorus flame retardants (OPFRs) was investigated in 72 water samples obtained from five bays in the Uganda sector of Lake Victoria. In addition, an assessment of the potential ecotoxic risk of the target OMPs to aquatic organisms was conducted. Water samples were analyzed for the target OMPs using gas chromatography coupled with mass spectrometry (GC/MS). All the target PCPs were found in all the water samples with the exception of musk ketone and 2,6-di-tert-butylphenol. Triclosan (89–1400 ng L−1), benzophenone (36–1300 ng L−1), and 4-methylbenzylidine camphor (21–1500 ng L−1) were the most predominant PCPs. All the six plasticizers were found in all the water samples with dibutyl phthalate (350-16 000 ng L−1), and bis-(2-ethylhexyl) phthalate (210–23 000 ng L−1) detected at the highest concentrations. Five OPFRs out of the eight targeted were found in all the water samples. Tricresyl phosphate (25–8100 ng L−1), tris-(2-chloroethyl) phosphate (24–6500 ng L−1) and triphenyl phosphate (54–4300 ng L−1) were the most dominant OPFRs. The highest concentrations of OMPs were recorded in Murchison and Thurston Bays, presumably due to industrial wastewater effluents from the highly industrialized localities of the two Bays. Ecotoxicological risk assessment showed that PCPs (triclosan, musk ketone, and 4-MBC), plasticizers (dibutyl phthalate, bis-(2-ethylhexyl) adipate and bis-(2-ethylhexyl) phthalate) and OPFRs (tricresyl phosphate, triphenyl phosphate and tris-(2-chloroethyl) phosphate) pose a high ecotoxic risk to lives of aquatic organisms (risk quotients, RQ > 1).

Process type is the key driver of the fate of organic micropollutants during industrial scale treatment of organic wastes

Organic micropollutants (OMPs) such as polycyclic aromatic hydrocarbons, nonylphenols and pharmaceutical products are ubiquitous in organic wastes generated by most human activities. Those wastes are mainly recycled by land spreading, most often after treatments, such as liming, dewatering, composting or anaerobic digestion. It has been shown essentially at lab scales that biological treatments have an effect on the removal of some OMPs. However, less is known on the role of each step of industrial treatment lines combining physico-chemical and biological treatments on the OMP fate and removal. The present study focuses on the impact of waste treatment on the fate of 53 OMPs along 10 industrial treatment lines treating urban, agricultural wastes or mixtures. The combination of studying a diversity of organic wastes and of OMPs with different characteristics (solubility, ionic charges, hydrophobicity etc.), sampling in situ industrial sites, quantifying native OMP concentrations and looking at each step of complete treatment lines allows for a global and representative view of the OMP fate in the French organic waste treatment sector. Less studied wastes, i.e. territorial mixtures, revealed intermediate OMP contents and compositions, between urban and agricultural wastes. Dewatering and liming, usually dismissed, had a noticeable effect on concentrations. Anaerobic digestion and composting had significant effects on the removal of all pollutant families. Combination of processes enhanced most OMP dissipation. Here we showed for the first time that the process type rather than the waste origin affects dissipation of organic micropollutants. Such data could be used to build and validate dynamic models for the fate of OMPs on solid waste treatment plants.

Water Browning Controls Adaptation and Associated Trade-Offs in Phytoplankton Stressed by Chemical Pollution.

The acquisition of tolerance to an environmental stressor can result in organisms displaying slower growth after stress release. While well-grounded in the theory, empirical evidence of the trade-off between stress tolerance and organism fitness is scarce and blurred by the interaction with different environmental factors. Here, we report the effects of water browning on the responses, tolerance acquisition, and associated trade-offs in a population of microalgae exposed to sublethal concentrations of organic micropollutants over multiple generations. Our results show that dissolved organic matter (DOM) reduces toxic responses and modulates tolerance acquisition by the algae, possibly by complexing micropollutants. Microalgae that acquire tolerance allocate resources to fitness at the cost of reduced cell size. They yield higher productivity than nonadapted ones when grown in the presence of micropollutants but lower in their absence. The net trade-off was positive, indicating that adaptation can result in a higher productivity and fitness in tolerant species in recurrently stressed environments.

New efficient methodology for screening of selected organic micropollutants in raw- and drinking water from 90 Swedish water treatment plants

A new, efficient method for analysis of organic micropollutants (OMPs) in water samples was developed, validated and applied in a nationwide survey. The goal with the survey was to identify common compounds with relatively high concentrations to be used as markers e.g. for routine monitoring of removal efficiencies. The method comprises sample concentration by evaporation, and large volume injection on a standard UHPLC-MS/MS system. The OMPs selected for this approach were mainly semi-polar and non-volatile, with molecular weights below 300 Da. Except one outlier, the limit of detection (LoD) ranged from 0.01 to 1 ng/L which is sufficient for most surface waters, and also useful for many ground waters. The method requires low manual labor and comparably small sample volumes, enabling a cost-efficient nationwide screening.Raw- and drinking water from 90 Swedish water treatment plants (WTPs) were investigated for occurrence of the selected OMPs. Carbamazepine and tramadol were the most widespread compounds, detected in around 50% of the surface waters. Ground water from rock aquifers were least contaminated, while soil aquifers were more similar to surface waters. Due to the frequent use of ground water in Sweden, many samples did not contain any of the investigated compounds (i.e. below LoD). In the positive samples, the median estimated concentrations of individual OMPs were generally <1 ng/L in raw water and <0.5 ng/L in drinking water. Swedish waters were in general less contaminated than those investigated in similar Brazilian, Chinese, pan-European and US studies.Altogether, the presented methodology gave a cost-efficient overview on the occurrence and estimated concentrations of OMPs in raw- and drinking water on a national level in Sweden. From the data, WTPs can find suitable OMPs to monitor at their site, for example for measuring removal efficiencies on a routine basis.

Spatial and seasonal trends of organic micropollutants in Sweden’s most important drinking water reservoir

The main objective of this study was to comprehensively investigate the occurrence of organic micropollutants (OMPs) in the surface water in Lake Mälaren over a period of one year and assess the spatial (horizontal and vertical) distribution and seasonal trends of OMPs. The applied multi-residue method comprised 111 OMPs covering compounds with wide range of physicalal–chemical properties. In total, 46 OMPs were detected at least once above limit of quantification (LOQ). DEET (diethyltoluamide), lamotrigine, bicalutamide, tolyltriazole, caffeine, carbamazepine, metoprolol, oxazepam, cetirizine, fexofenadine, lidocaine and tramadol were detected in more than 75% of the sampling points. The highest detected concentration was found for lamotrigine with 140 ng/L. The locations Ekoln and Västeråsfjärden were identified to be most affected by OMPs pollution. In the surface water (0.5 m depth) most highest concentrations of OMPs were observed in spring and lower concentrations in summer. Antihistamine demonstrated a seasonal trend that can be related to seasonal consumption patterns. The investigation of the vertical distribution of OMPs demonstrated that thermal lake stratification can lead to different concentrations within the water column. For instance, in February the highest concentration for most OMPs was observed in the deepest sampled water depth (30 m). Two industrial chemicals, tolyltriazole and tris(2-butoxylethyl)phosphate were detected frequently and it is recommended to incorporate these compounds more regularly in future analysis. To the best of our knowledge, this study is the first one to report the occurrence and distribution of OMPs representing such wide physico-chemical properties, including industrial chemicals, in a Swedish lake.

In situ removal of four organic micropollutants in a small river determined by monitoring and modelling

Organic micropollutants (OMPs) are widely detected in surface waters. So far, the removal processes of these compounds in situ in river systems are not yet totally revealed. In this study, a combined monitoring and modelling approach was applied to determine the behaviour of 1-H benzotriazole, carbamazepine, diclofenac and galaxolide in a small river system. Sewage treatment plant effluents and the receiving waters of the river Swist were monitored in 9 dry weather sampling campaigns (precipitation < 1 mm on the sampling day itself and <5 mm total precipitation two days before the sampling) during different seasons over a period of 3 years. With the results gained through monitoring, mass balances have been calculated to assess fate in the river. With the DWA Water Quality Model, OMP concentrations in the river were successfully simulated with OMP characteristics gained through literature studies. No removal was determined for 1-H benzotriazole and carbamazepine, whereas diclofenac showed removal that coincided with light intensity. Moreover, modelling based on light sensitivity of diclofenac also suggested relevant degradation at natural light conditions. These two approaches suggest removal by photodegradation. The highest removal in the river was detected for galaxolide, presumably due to volatilisation, sorption and biodegradation. Furthermore, short-term concentration variability in the river was determined, showing that daily concentration patterns are influenced by dynamics of sewage treatment plant effluent volumes and removal processes in the river.

Exploring co-occurrence patterns between organic micropollutants and bacterial community structure in a mixed-use watershed.

Complex mixtures of low concentrations of organic micropollutants are commonly found in rivers and streams, but their relationship to the structure of native bacterial communities that underlie critical ecological goods and services in these systems is poorly understood. To address this knowledge gap, we used correlation-based network analysis to explore co-occurrence patterns between measured micropollutant concentrations and the associated surface water and sediment bacterial communities in a restored riparian zone of the Des Plaines River (DPR) in Illinois that is impacted by both wastewater treatment plant (WWTP) effluent and agricultural runoff. Over a two year period, we collected 55 grab samples at 11 sites along the DPR and one of its tributaries (48 surface water samples) and from WWTP effluent (7 samples), and screened for 126 organic micropollutants. In parallel, we used high-throughput 16S rRNA gene amplicon sequencing to characterize the bacterial community in sediment and surface water. Our results revealed quantifiable levels of 102 micropollutants in at least one surface water or WWTP effluent sample, 85 of which were detected in at least one surface water sample. While micropollutants were temporally and spatially variable in terms of both presence and concentration, 21 micropollutants were measured in over 75% of the 48 surface water samples. 16S rRNA gene sequencing documented diverse bacterial communities along the DPR transect, with highly distinct community structures observed in sediment and water. Bacterial community structure in surface water, but not in sediment, was significantly associated with concentrations of micropollutants, based on a Mantel test. Correlation-based network analyses revealed diverse strong and significant co-occurrence and co-exclusion patterns between specific bacterial OTUs and both micropollutant groups (defined based on k-means clustering on chemical substructure) and individual micropollutants. Significantly more associations were documented between micropollutants and bacterial taxa in the water compared to the sediment microbiomes. Taken together, our results document a significant link between complex mixtures of micropollutants commonly found in aquatic systems and associated bacterial community structure. Furthermore, our results suggest that micropollutants may exert a more significant impact on water-associated than on sediment-associated bacterial taxa.

Spatiotemporal resolved sampling for the interpretation of micropollutant removal during riverbank filtration

Riverbank filtration (RBF) systems along rivers are widely used as public water supplies. In these systems, many organic micropollutants (OMPs) are attenuated, but some compounds have shown to be rather persistent. Their fate and transport has been studied in RBF sites along lakes and small rivers, but not extensively along large and dynamic rivers. Therefore, the influence of flood events on OMP behavior in these large and dynamic RBF sites was investigated. Monthly samples were taken from surface- and groundwater up to a distance of 900 m from the riverbank of the Danube from March 2014 till May 2016. Two flood events were sampled more extensively nearby the river. Results showed that changes in flow conditions in the river not only caused changes in OMP concentrations, but also in their load. It was seen that the load of benzotriazole, carbamazepine and sulfamethoxazole in the river increased with increasing river discharges. After a relatively long, oxic groundwater passage, several OMPs were reduced. In contrast to previous work, we found that benzotriazole was almost fully removed under oxic conditions. When entering the aquifer, benzotriazole concentrations were significantly reduced and at a distance of 550 m from the river, >97% was degraded. Carbamazepine and sulfamethoxazole showed relatively persistent behavior in the aquifer. The concentrations measured during flood events were in the same range as seasonal sampling. Furthermore concentrations in the groundwater were higher during these events than in the Danube and can reach further into the aquifer. During flood events some highly degradable compounds (i.e. diclofenac) were found up to a distance of 24 m from the river. These results implied that drinking water utilities with RBF wells in oxic, alluvial aquifers located close to highly dynamic rivers need to consider a potential reduction in groundwater quality during and directly after flood events.

Tandem Action of Natural and Chemical Stressors in Stream Ecosystems: Insights from a Population Genetic Perspective

Agricultural and urban land use has dramatically increased over the last century and one consequence is the release of anthropogenic chemicals into aquatic ecosystems. One of the rarely studied consequences is the effect of land use change on internal concentrations of organic micropollutants (OMPs) in aquatic invertebrates and its effects on their genotype diversity. Here, we applied population genetic and internal concentrations of OMPs analyses to determine evolutionary implications of chemical pollution on Gammarus pulex populations from a natural and two agricultural streams. Along 14 consecutive months sampled, 26 different OMPs were quantified in G. pulex extracts with the highest number, concentration, and toxic pressure in the anthropogenically stressed stream ecosystems. Our results indicate distinct internal OMP profiles and changes in both genetic variation and genetic structure in streams affected by anthropogenic activity. Genetic variation was attributed to chemical pollution whereas changes in the genetic structure were attributed to environmental disturbances, such as changes in discharge in the impacted stream ecosystems, which worked both independently and in tandem. Finally, we conclude that human-impacted streams are subjected to severe alterations in their population genetic patterns compared to nonimpacted stream ecosystems.

Fate of leaf litter deposits and impacts on oxygen availability in bank filtration column studies

Degradation of particulate organic carbon (POC) such as leaf litter might deplete dissolved oxygen within the upper layers of bank filtration, an efficient and robust barrier for pathogens and for various organic micro-pollutants (OMP) in water supply systems worldwide. The degradation of OMP during bank filtration depends on the redox conditions. The present study aimed at identifying the impacts and fates of different local leaves on the oxygen consumption and the possible biological degradation of indicator OMP. Oxygen concentrations initially decreased within the columns from around 8 mg/L in the influent to low concentrations indicating extensive consumption within a short travel distance. Still a substantial oxygen consumption was observed after 250 days. OMP concentrations were not significantly affected by the microbial processes. A layer of calcium carbonate crystallites was observed on the POC layer. Some leaf fragments appeared to be persistant towards degradation and the carbon content relative to nitrogen and sulfur contents decreased within 250 days. The results demonstrate that trees at bank filtration sites might have a strong long-term impact on the subsurface redox conditions.

Efficient and synergistic removal of tetracycline and Cu(II) using novel magnetic multi-amine resins

A series of magnetic multi-amine resins (MMARs, named E1D9-E9D1) was proposed for the removal of tetracycline (TC) and Cu(II) in sole and binary solutions. Results showed that the N content of the resins increased sharply from 1.7% to 15.49%, and the BET surface areas decreased from 1433.4 m2/g to 8.9 m2/g with methyl acrylate ratio increasing from E1D9 to E9D1. Their adsorption capacities for TC and Cu(II) could reach 0.243 and 0.453 mmol/g, respectively. The adsorption isotherms of TC onto MMARs transformed from heterogeneous adsorption to monolayer-type adsorption with DVB monomer ratio in resin matrix decrease, suggesting the dominant physical adsorption between TC and benzene rings. TC adsorption capacity onto E9D1 was higher than that onto E7D3 when the equilibrium concentration of TC exceeded 0.043 mmol/L because the electrostatic interaction between negatively charged groups of TC and protonated amines of adsorbents could compensate for the capacity loss resulting from BET surface area decrease. In the binary system, the electrostatic interaction between negatively charged TC-Cu(II) complex and protonated amines of adsorbents was responsible for the synergistic adsorption onto E7D3 and E9D1. The XPS spectra of magnetic resins before and after adsorption were characterized to prove the probable adsorption mechanisms. This work provides alternative adsorbent for the efficient treatment of multiple pollution with different concentrations of organic micropollutants and heavy metal ions.

Elimination of micropollutants by activated carbon produced from fibers taken from wastewater screenings using hydrothermal carbonization

Activated Carbon (AC) can be used to reduce organic micropollutants (OMPs) in wastewater treatment plants (WWTPs). While producing ACs conventionally still damages the environment, this can be reduced by using renewable raw material from waste streams und producing AC locally. In this study, fibers (toilet paper) were separated out of wastewater by screening WWTP influents in full scale and then used as a no-cost, carbon-rich and heavy metal-poor raw material to produce ACs. Pretreatment was hydrothermal carbonization (HTC). Thereafter, they were activated using KOH to generate activated carbons (HTC-ACs). Their functional groups were characterized using FT-IR, and the alteration of their chemical composition was traced by elementary analysis. Adsorption tests were performed with nitrogen (BET surface) and methylene blue as standard tests. The adsorption capacity was tested with WWTP effluent and the removal of UVA254 as a surrogate for OMP removal was measured. After HTC and activation 13–16% of the fibers dry mass was obtained as HTC-ACs. Higher dehydration and formation of aromatic structures on the HTC-ACs were detected with FT-IR as HTC and activation temperature increased. BET surface and methylene blue adsorption of some HTC-ACs was higher than the Reference AC. Nevertheless, their ability to reduce OMPs is still lower than the Reference AC due to the different nature of their functional groups and their microporous structure that is not fully accessible for OMPs in real wastewater. Further research has to be carried out to adjust the production process so as to obtain mesoporous HTC-ACs tailored to reduce OMP concentrations and to close the carbon loop within WWTPs.

A crosslinked β-cyclodextrin polymer used for rapid removal of a broad-spectrum of organic micropollutants from water

Organic micropollutants in aquatic environment such as plasticizer, pesticide and pharmaceuticals, have posed a serious threat to human health and are emerging as a great challenge to humanity. Traditional water treatment techniques fail to achieve high removal efficiency for low concentration of organic micropollutants. Here we demonstrate a water-insoluble crosslinked β-cyclodextrin (β-CD) polymer able to remove a broad-spectrum of organic micropollutants from water by rapid adsorption. A family of β-CD polymers (β-CDPs) were synthesized by nucleophilic aromatic substitution of β-CD hydroxyl groups and 4,4′-difluorodiphenylsulfone. The β-CDPs were used to adsorb various organic micropollutants in water by static or dynamic adsorption process. It was found that more than 99% micropollutants in water were removed by flowing the feed water through the column of β-CDPs. The results of static adsorption experiments indicated the adsorption process was fast and the adsorption capacity was very high (the maximal value was 113.0mg of bisphenol A per gram of β-CDP). The adsorption process was fitted well with the quasi-second-order kinetics and the Langmuir isothermal adsorption model, suggesting that it is mainly a chemical adsorption of monolayer. The water-insoluble characteristic of the β-CDPs is convenient for their separation from the treated solution after adsorption saturation for regeneration and reuse. The adsorption ability of β-CDPs was kept nearly unchanged after five filtration-regeneration cycles.

Study on the removal of organic micropollutants from aqueous and ethanol solutions by HAP membranes with tunable hydrophilicity and hydrophobicity

A biocompatible and uniquely defined hydroxyapatite (HAP) adsorption membrane with a sandwich structure was developed for the removal of organic micropollutants for the first time. Both the adsorption and membrane technique were used for the removal of organic micropollutants. The hydrophilicity and hydrophobicity of the HAP adsorbent and membrane were tunable by controlling the surface structure of HAP. The adsorption of organic micropollutants on the HAP adsorbent was studied in batch experiments. The adsorption process was fit with the Freundlich model, while the adsorption kinetics followed the pseudo-second-order model. The HAP membrane could remove organic micropollutants effectively by dynamic adsorption in both aqueous and ethanol solutions. The removal efficiencies of organic micropollutants depended on the solution composition, membrane thickness and hydrophilicity, flow rate, and the initial concentration of organic micropollutants. The adsorption capacities of the HAP membrane with a sandwich structure (membrane thickness was 0.3 mm) were 6700, 6510, 6310, 5960, 5490, 5230, 4980 and 4360 L m−2 for 1-naphthyl amine, 2-naphthol, bisphenol S, propranolol hydrochloride, metolachlor, ethinyl oestradiol, 2,4-dichlorophenol and bisphenol A, respectively, when the initial concentration was 3.0 mg L−1. The biocompatible HAP adsorption membrane can be easily regenerated by methanol and was thus demonstrated to be a novel concept for the removal of organic micropollutants from both aqueous and organic solutions.

Optimization of UV/H2O2 processes for the removal of organic micropollutants from drinking water: effect of reactor geometry and water pretreatment on EEO values

Increasing concentrations of organic micropollutants, like pharmaceuticals, in surface water may require additional treatment for drinking water production. The UV/H2O2 process is very effective for this purpose, but is known for its relatively high energy demand. This energy demand may be decreased by improving the water matrix composition and/or by optimizing UV reactor geometry. Thus, operational costs of the process may be decreased. This can be visualized by calculating the Electrical Energy per Order (EEO). By optimizing the water matrix, e.g. by pretreating the water by filtration over activated carbon or with O3/H2O2, the energy demand decreased up to 70%. This is affected by the concentration and type of the natural organic matter present. By optimizing reactor geometry an additional decrease in energy demand, up to 40%, could be obtained. How efficient the process may become strongly depends on the characteristics of the micropollutants involved.

Comparing and modeling organic micro-pollutant adsorption onto powdered activated carbon in different drinking waters and WWTP effluents

The adsorption of organic micro-pollutants (OMP) onto powdered activated carbon (PAC) was compared between regionally different waters within two groups, namely five drinking waters and seven wastewater treatment plant (WWTP) effluents. In all waters, OMP were spiked to adjust similar ratios of the initial OMP and DOC concentrations (c0,OMP/c0,DOC). PAC was dosed specific to the respective DOC (e.g. 2 mg PAC/per mg DOC). Liquid chromatography with online carbon detection shows differences of the background organic matter (BOM) compositions. The OMP removals at given DOC-specific PAC doses vary by ±15% (drinking waters) and ±10% (WWTP effluents). Similar BOM-induced adsorption competition in the waters of the respective group results in overall relationships between the PAC loadings and the liquid phase concentrations of each OMP (in the case of strong adsorbates). Weaker adsorbates show no overall relationships because of the strong BOM-induced adsorption competition near the initial OMP concentration. Correlations between OMP removals and UV254 removals were independent of the water (within the respective group). The equivalent background compound (EBC) model was applied to the experimental data. Using global EBC Freundlich coefficients, the initial EBC concentration correlates with the DOC (both water groups separately) and the low molecular weight (LMW) organics concentrations (all waters combined). With these correlations, the EBC could be initialized by using the DOC or the LMW organics concentration of additional drinking water, WWTP effluent, and surface water samples.