'Green' coagulant application with activated carbon: dosing sequence and removal of selected micropollutants and effluent organic matter from municipal wastewater.

Combination of 'green' coagulation and powdered activated carbon adsorption was tested for removal of benzophenone (BP), benzophenone-3 (BP-3) and caffeine (CF) from treated municipal wastewater at realistic concentration levels (1-2 µg/L). At the same time it was tracked how the process affected effluent organic matter (EfOM) by measuring chemical oxygen demand (COD). Green coagulant was produced from dry common bean seed in laboratory. Combined coagulation-adsorption experiments were performed by applying different dosing sequences of process materials. Removal of hydrophobic BP and BP-3 by separate adsorption (from 79 to 98%) was not significantly hindered by the addition of the coagulant (activated carbon dose of 5 or 20 mg/L). However, in some cases negative effects were observed for hydrophilic caffeine, depending on the carbon dose, dosing sequence and presence of total suspended solids (TSS). Thus, when coagulant was firstly added into water without TSS before low activated carbon dose of 5 mg/L, caffeine removal dropped from 26% to 5%. Conversely, when TSS were present in the water sample, the removal of caffeine was not hindered under the same PAC dose and dosing sequence. The importance of the process optimisation related to removal of organic micropollutans of different hydrophilicity has been shown in this paper. Removal of around 30% of COD regardless of the dosing sequence was achieved.

Fate of Benzophenone, Benzophenone-3 and Caffeine in Lab-Scale Direct River Water Treatment by Hybrid Processes.

Emerging microcontaminants benzophenone (BP), benzophenone-3 (BP-3) and caffeine (CF) are widely used anthropogenic markers from a group of pharmaceuticals and personal care products. They have different logD values and charges at neutral pH (2.96 neutral for BP; 3.65 negative and neutral for BP-3; 0.28 and neutral for CF). The goal of this study was to assess the efficacy of coagulation/flocculation/sedimentation (C/F/S), adsorption onto two types of powdered activated carbon (PAC)/sedimentation (PAC/S) and the combination of these two processes in different dosing sequences (PAC/C/F/S) and with/without ultrafiltration (powdered activated carbon/ultrafiltration-PAC/UF, coagulation/UF-CoA/UF) for the removal of selected micropollutants from river water. It was shown that the removal efficiency of benzophenones by coagulation depends on the season, while CF was moderately removed (40-70%). The removal of neutral BP by two PACs unexpectedly differed (near 40% and ˃93%), while the removal of BP-3 was excellent (>95%). PACs were not efficient for the removal of hydrophilic CF. Combined PAC/C/F/S yielded excellent removal for BP and BP-3 regardless of PAC type only when the PAC addition was followed by C/F/S, while C/F/S efficiency for CF diminished. The combination of UF with PAC or coagulant showed also high efficacy for benzophenones, but was negligible for CF removal.

17th ICCE Satellite Event University Education in Environmental Sciences.

Recently, nearly 500 study programmes related to environmental disciplines were detected in Europe (Lammel et al, Environ Sci Pollut Res 21:7211-7218 2014). Following good practice from the 16th International Conference on Chemistry and the Environment (ICCE) in Oslo, during the 17th ICCE that took place in Thessaloniki, Greece, between 16 and 20 June 2019, a special Satellite Event dedicated to University Education in Environmental Sciences was organised. The session attracted students, teachers and experts from academia and industry/consulting. As conveners of the event, our aim was to provide an inspirative platform for presentation and discussion of curricula, present and future teaching methods and tools, and existing and new concepts of higher education of environmental topics.

Removal of selected emerging micropollutants from wastewater treatment plant effluent by advanced non-oxidative treatment - A lab-scale case study from Serbia.

The presence of 48 emerging micropollutants was tested in influent and effluent from primary and secondary treatment at a municipal wastewater treatment plant (WWTP) in Serbia. Sixteen emerging micropollutants (active pharmaceutical ingredients, bisphenols, parabens and UV filters) had concentrations >LOQ (max. conc. 33.4 µg/L). The removal efficiency of primary treatment ranged from 2.0% - 96.0%. In the case of secondary treatment, except for ketoprofen (61.0%), diclofenac (62.6%) and carbamazepine (-20.0%), all other measured micropollutants had removal efficiency above 77.0%. Advanced non-oxidative lab-scale treatments were investigated. Powdered activated carbon (PAC) adsorption achieved removal efficiencies in the range 52.4-99.9%, novel coagulation with natural coagulant isolated from beans achieved removal efficiencies in range 3.2-99.9%, conventional coagulation with ferric chloride 3.12-96.4%, combined adsorption/coagulation 2.69-99.9% and combined PAC/ultrafiltration (PAC/UF) 60-99.9%. For most of the micropollutants, their removal efficiencies were similar to that reported in the literature. Novel natural coagulant showed significant potential compared to the conventional coagulant during a short episode of sub-optimal WWTP operation. When natural coagulant was applied as a part of an adsorption/coagulation hybrid process, there was no negative effect on PAC adsorption, while for conventional coagulant that was not always the case. Also, a structure property relationship (SPR) study revealed correlations between the removal efficiency of the majority of treatments applied and total polar surface area (TPSA) of the micropollutants.

Insight into selected emerging micropollutant interactions with wastewater colloidal organic carbon: implications for water treatment and analysis.

This study reports how adding a membrane filter (0.45-µm cellulose nitrate filter) between a glass fibre filter and the solid phase extraction (SPE) cartridge affected the GC/MS analysis of 48 emerging organic micropollutants in wastewater. Most of them are widely used as active pharmaceuticals, cosmetic and packaging material ingredients including classes of parabens, benzophenones and bisphenols among other chemicals tested. A high artificial organic carbon (OC) content in wastewater (DOC = 280 ± 14 mg/L) was investigated to gain insight into micropollutants/colloidal OC filter cake interactions. The results show that even with the use of matrix-matched calibration, the introduction of a second (membrane) filtration step can affect the analysis. Both positive, negative and no effects on the theoretical concentrations calculated from the calibration curves with and without additional filtration were observed. Positive effects on the concentration for the same analyte peak area relative to its surrogate standard were the consequence of a reduced signal for the same concentration, while the negative effects are the consequence of increasing signal for the same concentration. Effect types were dependent on the concentration and the nature of the analytes. Results show that bisphenols and parabens significantly interact with colloidal OC. Statistical analysis of molecular descriptor distribution with effect type showed that micropollutants that have a stronger interaction with colloidal OC have significantly higher ability to act as hydrogen bond donors (HBD) and have larger molar volume (MV). All compounds that experienced either positive or negative effects have a significantly higher median logD. However, further exploration within a single class of compounds (parabens, benzophenones and bisphenols) revealed that selected descriptors are unrelated to an effect type. Pearson's correlations showed that a correlation exists for certain concentration levels and groups of compounds between a negative effect and MV and logD and a positive effect with MV, MW and rotatable bond (RB) count.

Overview of Erasmus+ NETCHEM project: ICT networking for overcoming technical and social barriers in instrumental analytical chemistry education.

The paper briefly presents goals, activities, challenges, and outcomes of the NETCHEM project ( http://www.netchem.ac.rs/ ) that was co-funded by the Erasmus+ Program of European Union (573885-EPP-1-2016-1-RS-EPPKA2- CBHE-JP). The project has been started in October 2016 and with extension lasted until April 2020. Western Balkan region has been targeted by upgrading capacities for education and research in environmental and food analysis in cooperation with partners from France, the UK, and Czech Republic. NETCHEM platform providing Web Accessed Remote Instrumental Analytical Laboratories (WARIAL) network, Database service and Open education system was created in order to improve the cooperation, educational, and research capacities of Higher Education Institutions involved, but also targeting whether audience not only from academic domain but from industry as well. The NETCHEM platform is free for access to public; thus, the external users to NETCHEM consortium can not only see its content but also actively participate, enter Database and WARIAL network, and upload their own educational/research material.

The impact of humic acid on toxicity of individual herbicides and their mixtures to aquatic macrophytes.

This study investigates the impact of humic acid (HA) on the toxicity of selected herbicides and their binary mixtures to aquatic plants. The focus was on two auxin simulators (2,4-D and dicamba) and two photosynthetic inhibitors (atrazine and isoproturon). The results suggested that the addition of HA to the standard synthetic medium does not affect Lemna minor growth nor the toxicity of atrazine, but increases the toxicity of 2,4-D and the binary mixture of atrazine and 2,4-D. The addition of HA to the standard synthetic medium reversibly decreased the growth (biomass) of Myriophyllum aquaticum and enhanced the toxicity of individually tested herbicides (isoproturon and dicamba) as well as their binary mixture. The results showed delayed toxic effects of auxin simulators, especially 2,4-D in the Lemna test. The recovery after the exposure to individual photosystem II inhibitors (atrazine and isoproturon) is fast in both plant species, regardless of the presence of HA. In the case of selected mixtures (atrazine + 2,4-D and isoproturon + dicamba), recovery of both plant species was noted, while the efficiency depended on the herbicide concentration in the mixture rather than the presence or absence of HA.

Consolidated vs new advanced treatment methods for the removal of contaminants of emerging concern from urban wastewater.

Urban wastewater treatment plants (WWTPs) are among the main anthropogenic sources for the release of contaminants of emerging concern (CECs) into the environment, which can result in toxic and adverse effects on aquatic organisms and consequently on humans. Unfortunately, WWTPs are not designed to remove CECs and secondary (e.g., conventional activated sludge process, CAS) and tertiary (such as filtration and disinfection) treatments are not effective in the removal of most CECs entering WWTP. Accordingly, several advanced treatment methods have been investigated for the removal of CECs from wastewater, including consolidated (namely, activated carbon (AC) adsorption, ozonation and membranes) and new (such as advanced oxidation processes (AOPs)) processes/technologies. This review paper gathers the efforts of a group of international experts, members of the NEREUS COST Action ES1403 who for three years have been constructively discussing the state of the art and the best available technologies for the advanced treatment of urban wastewater. In particular, this work critically reviews the papers available in scientific literature on consolidated (ozonation, AC and membranes) and new advanced treatment methods (mainly AOPs) to analyse: (i) their efficiency in the removal of CECs from wastewater, (ii) advantages and drawbacks, (iii) possible obstacles to the application of AOPs, (iv) technological limitations and mid to long-term perspectives for the application of heterogeneous processes, and (v) a technical and economic comparison among the different processes/technologies.

Removal of diclofenac from water by in/out PAC/UF hybrid process.

Results from a lab-scale investigation of a hybrid in/out ultrafiltration and powdered activated carbon adsorption PAC/UF for removal of diclofenac (c0 = 5 mg/L) are presented. The efficiency of the process was compared for single pulse and continuous carbon dosing (PAC dose 5 mg/L) in dechlorinated tap water under fluxes of 87 and 135 L/(m2 h). For higher flux conditions, it was observed that single pulse dosing has an advantage over continuous dosing procedure when comparing cycle average removal efficiency. Increase of carbon dose under these conditions increased cycle average removal only to a limited extent. PAC dose above 15 mg/L did not give improvements of the removal. Hypothesis was made that non-effective carbon distribution might be the possible reason.

Toxicological and chemical investigation of untreated municipal wastewater: Fraction- and species-specific toxicity.

Absence of a municipal wastewater (WW) treatment plant results in the untreated WW discharge into the recipient. The present study investigated toxic effects and chemical composition of water extracts and fractions from untreated WW and recipient Danube River (DR). Samples were prepared by solid-phase extraction and silica gel fractionation and screened for EROD activity and cytotoxicity using aquatic models, comprising of fish liver cells (PLHC-1) and a model of the early development of zebrafish embryos, while rat (H4IIE) and human (HepG2) hepatoma cells served as mammalian models. Polar fraction caused cytotoxicity and increased the EROD activity in PLHC-1 cells, and increased mortality and developmental abnormalities in developing zebrafish embryos. In H4IIE, polar fraction induced inhibition of cell growth and increased EROD activity, whereas HepG2 exerted low or no response to the exposure. Non-polar and medium-polar fractions were ineffective. Tentative identification by GC/MS showed that WW is characterized by the hydrocarbons, alkylphenols, plasticizers, and a certain number of benzene derivatives and organic acids. In DR, smaller number of organic compounds was identified and toxicity was less pronounced than in WW treatments. The present study revealed the potent toxic effect of polar fraction of untreated WW, with biological responses varying in sensitivity across organisms. Obtained results confirmed that fraction- and species-specific toxicity should be considered when assessing health risk of environmental pollution.

The fate and importance of organics in drinking water treatment: a review.

In the pioneer days, the main driving forces for research of organics in drinking water treatment (DWT) were human health risks and optimisation of technology. The focus was on natural organic matter (NOM) structure, disinfection by-products (DBPs) formation, NOM removal by means of coagulation, adsorption, and oxidation, and development of the most efficient water treatment trains. Surprisingly, after decades of research, rapid development of analytical techniques and progress in risk assessment, the same driving forces are still in the limelight - although the topics have changed slightly. The attention switched from trihalomethanes to a new generation of DBPs. The definition of hydrophilic/hydrophobic NOM depends on the technique used for characterisation. It has become evident that numerous organic compounds can threaten water supply sources. Some of them had been ignored or overlooked in the past, but have recently been detected by advanced analytical tools even in drinking water. Prioritisation becomes priority per se. As far as processes are concerned, mainstream research has been following three lines: fouling mechanisms, application of hybrid processes and interactions between synthetic organic chemicals, other water constituents and materials used in DWT. Significant development has been made in membrane technology. This paper presents a broad overview of the recent organics research. Although the state-of-the-art technologies seem to have an answer to each and every question raised, it is still necessary to deal with specific problems on a case-by-case basis mainly due to the unique nature of NOM and different xenobiotics that may appear in various types of waters. In the end, human health risk, which derives from the presence/absence of organics, is only the tip of the iceberg - underneath lies a whole new universe - the socio-economic aspect of water treatment and quality that deserves much more attention.

Toxicological profiles assessment of the water and sediments from the Krivaja and Jegricka Rivers, Serbia.

This study utilizes a combinatorial bio/chemical approach to assess the toxicological profiles of organic pollutants in water and sediment samples from two watercourses that are under significant anthropogenic pressure-the Krivaja and Jegricka rivers in Serbia. Sample preparation by solid-phase extraction and silica-gel fractionation followed by GC/MS analysis, allowed the tentative identification of a variety of non-target contaminants, divided into non-polar, medium-polar and polar fractions. The instrumental analysis revealed slightly different toxicological profiles for the water and sediment from both rivers, and confirmed the presence of various classes of organic contaminants, from non-polar hydrocarbons, to more polar compounds such as aldehydes, ketones and phenols. Polycyclic aromatic hydrocarbons and pesticides were identified, but below toxicologically relevant concentrations. The results of bioanalyses on H4IIE and PLHC-1 cells indicated that cytotoxic potential was pronounced in Jegricka water and sediment samples, and CYP1A inducing potential was observed in both Krivaja and Jegricka sediment samples, although they did not reflect high levels of contamination. Based on the overall data, the sediments of the Krivaja and Jegricka rivers are a more toxicologically relevant matrix than the water.

Tracking disinfection by-products and arsenic removal during various drinking water treatment trains.

In the central Banat region (Northern Serbia), groundwater is used as a drinking water source. Raw water originates from a 40-80 m and 100-150 m deep layer. It contains a high amount of natural organic matter (DOC = 9.17+/-0.87 mg C/L) with a trihalomethanes formation potential of 448+/-88.2 microg/L and a haloacetic acid formation potential of 174+/-68.9 microg/L. A high amount of arsenic (86.0+/-3.4 microg/L) is also found in this water. This study used a pilot-scale system to investigate the possibilities of combining polyaluminium chloride and ferrous-chloride to remove disinfection by-products precursors and arsenic by coagulation. Two treatment trains with different pre-treatment steps were investigated (ozone vs. H2O2/O3). For the final water polishing, filtration with granulated activated carbon (GAC) was applied. Both investigated treatment lines achieved a satisfactory chemical water quality. Simulation of disinfection conditions was performed and the contents of trihalomethanes and haloacetic acids measured, to investigate whether the chemical quality of the water remained satisfactory over a 48 hour period.

Removal of arsenic and natural organic matter from groundwater using ferric and alum salts: a case study of central Banat region (Serbia).

This paper presents a comparison of the efficacy of three different coagulants (polyaluminium chloride (PACl), Aluminium sulphate (Al(2)(SO(4))(3)) and ferrous chloride (FeCl(3))) for natural organic matter and arsenic (As) removal from groundwater. Coagulation efficacy was evaluated for the coagulants alone and for combinations of them (PACl/FeCl(3); Al(2)(SO(4))(3)/FeCl(3)), on the basis of changes in dissolved organic matter (DOC) and arsenic content. For single coagulants, PACl (30 mg Al/L) showed optimal efficacy for DOC removal (57%, relative to raw water). The highest arsenic reduction (< 5 microg As/L in coagulated water) was achieved when a very high 300 mg/L dose of FeCl(3) was used. However, if PACl (30 mg Al/L) and FeCl(3) (10 mg FeCl(3)/L) are combined, the efficacy of DOC removal increases compared to PACl and FeCl(3) alone under similar doses (66% decrease in DOC relative to raw water). The DOC and As contents of the coagulated water after application of these doses were 2.26 mg C/L and 9.7 microg/L, respectively, compared to 6.44 mg C/L and 60.5 microg As/L measured in the raw groundwater. The combination of Al(2)(SO(4))(3) and FeCl(3) did not show any improvement in DOC and As removal efficacy relative to using those coagulants alone.

The relationship between whole effluent toxicity (WET) and chemical-based effluent quality assessment in Vojvodina (Serbia).

The relationship between whole effluent toxicity (WET) and chemical-based effluent quality assessment across a range of effluent types was examined for the first time in Serbia. WET was determined by Daphnia magna acute tests, while chemical-based toxicity was taken as theoretical for concentrations of priority chemicals and effluent quality assessment based on the valid Serbian regulations. A poor correlation was found between WET and chemical-based effluent quality assessment: positive toxicity tests were found, in general, in cases where samples satisfied the requirements of mandatory effluent monitoring. Statistically insignificant correlation between the predicted and observed toxicity indicated that the presence of priority substances accounted to the overall toxicity only to a certain degree, most probably due to a rather short list of priority pollutants regularly analysed in effluents. Current monitoring requirements neglect hazards that derive from potentially present toxicants and unpredictable toxicity of complex mixtures, which led to poor correlation between the WET and chemical-based results in this study.

p-Nitrophenol removal by combination of powdered activated carbon adsorption and ultrafiltration - comparison of different operational modes.

Ultrafiltration is classified as a low-pressure membrane technology which effectively removes particulate matter and microorganisms and to a certain extent dissolved organic matter (15-25%) and colour. The technology has been optimized and is becoming competitive compared to conventional processes for larger scale plant capacities. In combination with activated carbon it is an effective barrier regarding the removal of synthetic organic chemicals. Growing interest in ultrafiltration raises the question of better usage of the adsorption capacity of powdered activated carbon (PAC) used in combination with this low-pressure membrane technique. This paper presents a pilot plant study of different PAC dosing procedures within a combined hybrid membrane IN/OUT process for removal of p-nitrophenol (PNP) from water (c(0)=1mg/L) under real case conditions (e.g. usage of the same module for the whole duration of the experiment, backwashing with permeate water, no separate saturation of the membrane with substance without presence of carbon). p-Nitrophenol was chosen as an appropriate test substance to assess the efficiency of different operation modes. Dead-end and cross-flow filtration were compared with respect to different PAC dosing procedures: continuous dosing into a continuously stirred tank reactor (CSTR) in front of the module and direct dosing into the pipe in front of the module (continuous, single-pulse and multi-pulse dosing). There was no advantage in cross-flow mode over dead-end referring to PNP concentration in the permeate. Relating to the carbon dosing procedure, the best results were obtained for continuous PAC addition. The option of dosing directly into the pipe has the advantage of no additional tank being necessary. In the case of single-pulse dosing, the formation of a carbon layer on the membrane surface was assumed and an LDF model applied for a simplified estimation of the "breakthrough behaviour" in the thus formed "PAC filter layer".