Selection of pharmaceuticals of concern in reclaimed water for crop irrigation in the Mediterranean area.

The reuse of reclaimed water in agriculture is being fostered in areas suffering from water scarcity. However, water pollutants can compromise food safety and pose a risk for the environment. This study aims to select the pharmaceutical compounds worth monitoring and investigating when reclaimed water is used for tomato and lettuce irrigation. A comprehensive study was first conducted to identify the pharmaceuticals frequently detected in secondary wastewater effluents in Catalonia (Northeast Spain). Priority pharmaceuticals were further selected based on their occurrence in secondary effluents, persistence (removal in conventional treatment), bioaccumulation potential, toxicity for aquatic organisms, and the risks they pose to the terrestrial environment and human health (through the consumption of crops). Out of the 47 preselected priority compounds, six could pose a risk to organisms living in soil irrigated with reclaimed water and seven could be potentially taken up by the crops. Nonetheless, no risk for human consumption was foreseen.

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)).

Nature-based solutions as enablers of circularity in water systems: A review on assessment methodologies, tools and indicators.

Water has been pushed into a linear model, which is increasingly acknowledged of causing cumulative emissions of pollutants, waste stocks, and impacting on the irreversible deterioration of water and other resources. Moving towards a circular model in the water sector, the configuration of future water infrastructure changes through the integration of grey and green infrastructure, forming Nature-based Solutions (NBS) as an integral component that connects human-managed to nature-managed water systems. In this study, a thorough appraisal of the latest literature is conducted, providing an overview of the existing tools, methodologies and indicators that have been used to assess NBS for water management, as well as complete water systems considering the need of assessing both anthropogenic and natural elements. Furthermore, facilitators and barriers with respect to existing policies and regulations on NBS and circularity have been identified. The study concludes that the co-benefits of NBS for water management are not adequately assessed. A holistic methodology assessing complete water systems from a circularity perspective is still needed integrating existing tools (i.e. hydro-biogeochemical models), methods (i.e. MFA-based and LCA) and incorporating existing and/or newly-developed indicators.

Characterization of metoprolol biodegradation and its transformation products generated in activated sludge batch experiments and in full scale WWTPs.

Metoprolol (MTP) is a compound of concern, considered as an emerging contaminant due to its high consumption, pseudopersistence and potential ecotoxicity. Activated sludge batch experiments were performed to evaluate the biological transformation of MTP and the formation of transformation products under different treatment conditions. Total MTP removal was obtained in aerobic conditions, and the formation of MTP known metabolites (metoprolol acid (MTPA), α-hydroxymetoprolol (α-HMTP) and O-desmethylmetoprolol (O-DMTP)) and unknown transformation products (TPs) was investigated. The three known metabolites and two new TPs generated along the experiments were identified by liquid chromatography coupled to high resolution mass spectrometry. For the two new TPs plausible structures were proposed based on the tentative identification. MTPA had the major ratio formation for the TPs identified along the experiments (up to 40% of initial MTP concentration after 96 h treatment) and its persistence through biological treatment was proven. Ecotoxicity studies using Vibrio fischeri bioluminescent bacteria in an acute toxicity test showed that MTP and its known TPs are not toxic with the exception of o-DMTP. Finally, MTP and its TPs were monitored in a full scale membrane bioreactor and in a full scale conventional urban wastewater treatment plant (WWTP) and the results were compared with those obtained in batch experiments. α-HMTP was detected for the first time in a WWTP influent whereas MTPA was detected in influent and effluent WWTP samples at much higher levels (up to 100 folds higher) than MTP itself remarking its high persistence.

Pharmaceuticals occurrence in a WWTP with significant industrial contribution and its input into the river system.

Occurrence and removal of 81 representative Pharmaceutical Active Compounds (PhACs) were assessed in a municipal WWTP located in a highly industrialized area, with partial water reuse after UV tertiary treatment and discharge to a Mediterranean river. Water monitoring was performed in an integrated way at different points in the WWTP and river along three seasons. Consistent differences between therapeutic classes were observed in terms of influent concentration, removal efficiencies and seasonal variation. Conventional (primary and secondary) treatment was unable to completely remove numerous compounds and UV-based tertiary treatment played a complementary role for some of them. Industrial activity influence was highlighted in terms of PhACs presence and seasonal distribution. Even if global WWTP effluent impact on the studied river appeared to be minor, PhACs resulted widespread pollutants in river waters. Contamination can be particularly critical in summer in water scarcity areas, when water flow decreases considerably.

Effects on activated sludge bacterial community exposed to sulfamethoxazole.

The bacterial community shift on a lab scale Sequencing Batch Reactor (SBR) fed with synthetic wastewater and exposed to 50µgL(-1) of sulfamethoxazole (SFX) for 2months was investigated in this study. The impact on biological nutrient removal performance and SFX removal efficiencies were also studied. Satisfactory biological nutrient removal was observed as regards to COD and Nitrogen. SFX removal efficiencies ranged between 20% and 50% throughout the experimental period, enhanced within the aerobic phases of the SBR cycle, with no evident signs of biomass acclimation. Nevertheless, denaturing gradient gel electrophoresis (DGGE) analysis showed significant variance leading to not only the fading, but also the emergence of new species in the bioreactor bacterial community after SFX dosage. According to the phylogenetic analysis, bacteria belonging to Betaproteobacteria and Gammaproteobacteria classes were the dominant species, among them, the Thiotrix spp. (Gammaproteobacteria) cell number increased due to its tolerance to the antibiotic. On the other hand, the classes Sphingobacteria, Actinobacteria, Chloroflexi and Chlorobi were found to be more vulnerable to the antibiotic load and disappeared. The sulphonamide resistance gene sulI was also quantified and discussed, as there are very few studies on bacterial resistance in lab-scale treatment reactors.

Removal of ibuprofen and its transformation products: experimental and simulation studies.

Pharmaceutically active compounds (PhACs) deserve attention because of their effect on ecosystems and human health, as well as their continuous introduction into the aquatic environment. Classification schemes are suggested to characterise their biological degradation, e.g., based on pseudo-first-order kinetics, but these schemes can vary significantly, presumably due to pharmaceutical loads, sludge characteristics and experimental conditions. Degradation data for PhAC transformation products (TPs) are largely lacking. The present work focuses not only on the biodegradation of the pharmaceutical compound ibuprofen but also on its best-known TPs (i.e., carboxyl ibuprofen and both hydroxyl ibuprofen isomers). Ibuprofen is one of the most commonly consumed PhACs and can be found in different environmental compartments. The experiment performed consisted of a set of aerated batch tests with different suspended solid and ibuprofen concentrations to determine the influence of these parameters on the calculated biodegradation constant (K(biol)). Sampling of the liquid phase at different scheduled times was assessed, removal efficiencies were calculated and pseudo-first-order kinetics were adjusted to obtain experimental K(biol) values for the parent compound and its TPs. The experimental data were successfully fitted to ASM-based models, with K(biol) values for the target compounds ranging from almost 1 to 17 L gSST(-1) d(-1), depending on the concentrations of the biomass and ibuprofen. This work provides innovative knowledge not only regarding the removal of TPs but also the formation kinetics of these TPs.

Adsorption and removal at low atrazine concentration in an MBR pilot plant.

Atrazine is a persistent organic pollutant and it has been widely used in agriculture and forestry in the world for more than fifty years. Atrazine shows ecotoxicity effects in aquatic ecosystems even at very low level concentrations with endocrine disruptor activity. Few studies were carried out on atrazine removal performances in drinking and waste-water by biological treatments, especially in membrane bio-reactors (MBRs). MBR technology might be more efficient than the conventional one in the removal of micro-pollutants. The fate of atrazine in wastewater treatment plants and its influence on the biomass activity was evaluated in this study. The experimental work was divided in three different phases: inhibition studies on different types of biomass (by means of microcalorimetry); adsorption studies on different sludges (conventional activated sludge (CAS) - and MBR) calculating adsorption isotherms and, finally, atrazine removal in an MBR pilot plant (simulating a treatment of atrazine and nitrate contaminated groundwater). The absence of significant inhibition was observed; higher atrazine adsorption on MBR sludge was detected for lower atrazine concentration (<50 µg L(-1)); the removal efficiency in the MBR pilot plant was lower than 25% but higher than the theoretical one (based on adsorption isotherms).

Microcalorimetric and manometric tests to assess anammox activity.

The present study compares two experimental methods to evaluate Anammox activity based on the assessment of (1) the N(2) production rate by a manometric device, as previously proposed, and (2) the heat production rate by a microcalorimeter. Two samples of Anammox suspended biomass were taken from a pilot-plant, and their specific Anammox activity measured by both techniques. Both methods were successfully applied. As for calorimetric tests, they were performed for the first time on Anammox enriched sludge samples. Comparisons between the specific Anammox activities estimated by manometry and calorimetry and between expected (from the reaction enthalpy) and measured heat productions were performed. Promising results were obtained.

The use of microcalorimetry to compare the biological activity of a CAS and a MBR sludge-application to pharmaceutical active compounds.

Micropollutants removal, such as pharmaceutical substances, during wastewater treatment processes is becoming a greater issue everyday. In order to optimize it, their biodegradation processes have to be better understood. So far, microcalorimetry has been used worldwide to investigate chemical reactions. For few years now it has also been developed to model and control biological processes. In the case of micropollutants, respirometry is, most of the time, not precise enough to determine biodegradation. That is why, microcalorimetric experiments have been set up. For this purpose, a 2 L Bio-RC1 (Mettler-Toledo) has been modified to reach a resolution of 5-10 mW.L(-1).In this study, the biodegradation rate of standard substrates (Ethanol and Ammonia) by an activated sludge from a full-scale CAS and one from a MBR pilot plant operating in parallel have been compared by means of microcalorimetry. Then few trials to determine the biodegradation of selected pharmaceutical substances, as well as the eventual inhibition induced by them have been made. The first results did not exhibit any biological activity. However, they have displayed inhibition for both studied substances.