Impact of natural organic matter and inorganic ions on the stabilization of polystyrene micro-particles.

The orthokinetic coagulation of irregularly shaped polystyrene micro-particles (PS-MP) was investigated in solutions of inorganic cations with different valence (NaCl, CaCl, LaCl) using a coagulation jar test set-up combined with light extinction particle counting. The stabilizing effect of model natural organic matter (NOM from reverse-osmosis (RO-NOM), humic (HA) & fulvic acid (FA)) and of surface water components (SW-NOM) was studied. Collision efficiencies were calculated from the decrease in particle concentration applying first order reaction kinetics.

Screening for 26 per- and polyfluoroalkyl substances (PFAS) in German drinking waters with support of residents.

The occurrence of per- and polyfluoroalkyl substances (PFAS) in water cycles poses a challenge to drinking water quality and safety. In order to counteract the large knowledge gap regarding PFAS in German drinking water, 89 drinking water samples from all over Germany were collected with the help of residents and were analyzed for 26 PFAS by high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). The 20 PFAS recently regulated by sum concentration (PFAS), as well as six other PFAS, were quantified by targeted analysis.

Automated scraping and analyses of drinking water quality data.

Drinking water quality data, though regularly monitored, is not available in Germany as national overview, but only decentralized from the water suppliers. On the national level, only the number of limit exceedances are reported. An overview on drinking water qualities as complete as possible however is necessary to assess and develop regulations and helpful for authorities, political decision makers, the public and the scientific community.

Seasonal variations in dissolved organic matter concentration and composition in an outdoor system for bank filtration simulation.

Dissolved organic matter (DOM) in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity, UV radiations and temperature. Changes in DOM as well as temperature and rainfall intensity over the year can affect the biochemical processes occurring in bank filtration (BF). Identification and characterization of DOM in the surface water could help to optimize the water treatment and provide stable and safe drinking water.

Fates of potentially persistent and mobile organic substances in embedded outdoor columns for artificial groundwater recharge simulation.

Persistent and mobile organic micropollutants (OMP) are ubiquitously found in the aquatic environment and have a high propensity to distribute in water resources and are difficult to remediate. Managed aquifer recharge systems such as artificial groundwater recharge, produce high-quality drinking water by removing numerous OMP from the source water. In this study, the fates of selected emerging and potentially persistent and mobile OMP were investigated in outdoor columns for artificial groundwater recharge simulation.

Fates of selected pharmaceuticals in a large recirculated mesocosm with a pond and bank filtration.

Pharmaceuticals such as carbamazepine (CBZ), sulfamethoxazole (SMX) and diclofenac (DCF) are detected at a high frequency in the aquatic environment. The fates of these compounds in bank filtration (BF), a nature-based water treatment system, have been extensively studied, mainly in batch and laboratory column studies. This study, for the first time, investigated the fates of CBZ, SMX and DCF in a large recirculated mesocosm with a pond and subsequent BF.

Transformation of potentially persistent and mobile organic micropollutants in column experiments.

The occurrence of potentially persistent and mobile (PM) organic micropollutants (OMP) in the aquatic environment is recognized as a severe threat to water resources and drinking water suppliers. The current study investigated long-term fate (persistency and bio-transformation) of several emerging contaminants in a simulated bank filtration (BF) for the first time. In parallel, four sand column systems were operated with groundwater and continuously spiked with an average concentration of 1 μg/L for 24 OMP.

Pilot-scale removal of persistent and mobile organic substances in granular activated carbon filters and experimental predictability at lab-scale.

Present knowledge about the fate of persistent and mobile (PM) substances in drinking water treatment is limited. Hence, this study assesses the potential of fixed-bed granular activated carbon (GAC) filters to fill the treatment gap for PM substances and the elimination predictability from lab-scale experiments. Two parallel pilot filters (GAC bed height 2 m, diameter 15 cm) with different GAC were operated for 1.

Is adsorption onto activated carbon a feasible drinking water treatment option for persistent and mobile substances?

Persistent and mobile (PM) substances among the organic micropollutants have gained increasing interest since their inherent properties enable them to enrich in water cycles. This study set out to investigate the potential of adsorption onto activated carbon as a drinking water treatment option for 19 PM candidates in batch experiments in a drinking water matrix using a microporous and a mesoporous activated carbon. Overall, adsorption of PM candidates proved to be very variable and the extent of removal could not be directly related to molecular properties.

The fate of nitrification and urease inhibitors in simulated bank filtration.

The application of nitrification and urease inhibitors (NUI) in conjunction with nitrogen (N) fertilizers improves the efficiency of N fertilizers. However, NUI are frequently found in surface waters through leaching or surface runoff. Bank filtration (BF) is considered as a low-cost water treatment system providing high quality water by efficiently removing large amounts of organic micropollutants from surface water.

Bisphenol A removal in treated wastewater matrix at neutral pH using magnetic graphite intercalation compounds as persulfate activators.

Effluents of municipal wastewater treatment plants (WWTPs) are major sources for releasing contaminants of emerging concern (CECs) into the aquatic environment, which can result in negative effects on aquatic ecosystems and, as a consequence, on humans. Herein, the graphite intercalation concept was used to synthesize heterogeneous catalysts to degrade bisphenol A (BPA) as a model CEC in municipal WWTP effluents at neutral pH. The catalyst was synthesized using the simple molten salt method and showed several benefits, such as iron leaching prevention and stability in environmental matrices.

Impacts of autochthonous particulate organic matter on redox-conditions and elimination of trace organic chemicals in managed aquifer recharge.

Autochthonous carbon fixation by algae and subsequent deposition of particulate organic matter can have significant effects on redox conditions and elimination of trace organic chemicals (TOrCs) in managed aquifer recharge (MAR). This study investigated the impacts of different algae loadings (0-160 g/m) and infiltration rates (0.06-0.

A quick test method for predicting the adsorption of organic micropollutants on activated carbon.

Controlling the contamination of water cycles with organic micropollutants (OMPs) has been targeted in many regions. Adsorption with activated carbon is an effective technology to remove OMPs from different water matrices. To efficiently design or operate the adsorption process, the adsorption of OMPs should be properly assessed, usually with time-consuming batch adsorption tests and sophisticated analyses.

Varying attenuation of trace organic chemicals in natural treatment systems - A review of key influential factors.

The removal of trace organic chemicals (TOrCs) from treated wastewater and impacted surface water through managed aquifer recharge (MAR) has been extensively studied under a variety of water quality and operating conditions and at various experimental scales. The primary mechanism thought to dictate removal over the long term is biodegradation by microorganisms present in the system. This review of removal percentages observed in biologically active filtration systems reported in the peer-reviewed literature may serve as the basis to identify future indicators for persistence, as well as variable and efficient removal in MAR systems.

Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine.

The adsorption of organic micropollutants onto activated carbon is a favourable solution for the treatment of drinking water and wastewater. However, these adsorption processes are not sufficiently understood to allow for the appropriate prediction of removal processes. In this study, thermogravimetric analysis, alongside evolved gas analysis, is proposed for the characterisation of micropollutants adsorbed on activated carbon.

Quantification and isotherm modelling of competitive phosphate and silicate adsorption onto micro-sized granular ferric hydroxide.

Adsorption onto ferric hydroxide is a known method to reach very low residual phosphate concentrations. Silicate is omnipresent in surface and industrial waters and reduces the adsorption capacity of ferric hydroxides. The present article focusses on the influences of silicate concentration and contact time on the adsorption of phosphate to a micro-sized iron hydroxide adsorbent (μGFH) and fits adsorption data to multi-component adsorption isotherms.

Tire and road wear particles in road environment - Quantification and assessment of particle dynamics by Zn determination after density separation.

In this study, a method for the determination of tire and road wear particle (TRWP) contents in particulate samples from road environment was developed. Zn was identified as the most suitable elemental marker for TRWP, due to its high concentration in tire tread and the possibility of separation from other Zn sources. The mean concentration of 21 tire samples was 8.

Competition in chromate adsorption onto micro-sized granular ferric hydroxide.

Hexavalent chromium is highly toxic and elaborate technology is necessary for ensured removal during drinking water production. The present study aimed at estimating the potential of a micro-sized iron hydroxide (μGFH] adsorbent for chromate removal in competition to ions presents in drinking water. Freundlich and Langmuir models were applied to describe the adsorption behaviour.

Fast empirical lab method for performance projections of large-scale powdered activated carbon re-circulation plants.

Powdered activated carbon (PAC) for organic micro-pollutant (OMP) removal can be applied effectively on wastewater treatment plant (WWTP) effluents by using re-circulation schemes, accumulating the PAC in the system. This technique is complex because several factors are unknown: (i) the PAC concentration in the system, (ii) specific and average contact times of PAC particles, and (iii) PAC particle loadings with target compounds/competing water constituents. Thus, performance projections (e.

The challenge in preparing particle suspensions for aquatic microplastic research.

The occurrence of small particles consisting of organic polymers, so-called microplastic (MP), in aquatic environments attracts increasing interest in both public and science. Recent sampling campaigns in surface waters revealed substantial numbers of particles in the size range from a few micrometers to a few millimeters. In order to validate sample preparation, identification and quantification and to investigate the behavior of MP particles and potential toxic effects on organisms, defined MP model particles are needed.

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.

Characterization and quantification of dissolved organic carbon releases from suspended and sedimented leaf fragments and of residual particulate organic matter.

Bank filtration is a powerful and established barrier for pathogens and organic pollutants. The aerobic degradation of the pollutants competes with the microbial respiration of dissolved and particulate organic matter (DOC and POC). The fate of terrestrial POC (tPOC) in bank filtration is currently not fully understood.

Where to dose powdered activated carbon in a wastewater treatment plant for organic micro-pollutant removal.

Emissions of many organic micro-pollutants (OMP) into the aquatic environment can be efficiently reduced with advanced treatment at wastewater treatment plants (WWTP). Post-treatment with activated carbon is currently considered as one of the most promising options, but powdered activated carbon (PAC) could also be dosed into the existing biological treatment process instead. Due to much greater concentrations of suspended and dissolved constituents the adsorptive OMP removal was expected to be severely hindered.

Impacts of backwashing on granular activated carbon filters for advanced wastewater treatment.

The use of granular activated carbon (GAC) in fixed bed filters is a promising option for the removal of organic micropollutants (OMP) from wastewater treatment plant effluents. Frequent backwashing of the filter bed is inevitable, but its effect on potential filter stratification is not well understood yet and thus has been evaluated in the present study for two commercial GAC products. Backwashing of GAC filters was simulated with 10 or 100 filter bed expansions of 20 or 100% at backwash velocities of 12 and 40 m/h, respectively.