Search

The Circular and Green Economy principles is inspiring new approaches to municipal wastewater treatment plants (MWWTPs) design and operation. Recently, an ever-growing interest is devoted to exploring the alternatives for switching the WWTPs from being able to 'simply' removing contaminants from water to biorefinery-like plants where energy and material can be recovered. In this perspective, both wastewater and residues from process can be valorised for recovering nutrients (N and P), producing value added products (i.e. biopolymers), energy vectors and biofuels (i.e. bio-H2, bio-CH4 and bioethanol). As an additional benefit, changing the approach for WWTPs design and operation will decrease the overall amount of landfilled residues. In this context, the present research is aimed at evaluating the CH4 production potential of MWW screening units' residues. While such a stream is typically landfilled, the expected progressive increase of biodegradable matter content due to the ban on single-use plastic along with the boost of bioplastics makes the investigation of different biochemical valorisation routes more and more interesting from an environmental and economical perspective. Thus, a full-scale data collection campaign was performed to gain information on screening residues amount and properties and to analyse the relationship with influent flowrate. The most relevant residue properties were measured, and lab-scale tests were carried out to evaluate the bio-CH4 potential. [ABSTRACT FROM AUTHOR]

Methamphetamine (MET) is one of the most used illicit drugs in Europe and is recognized as one of the Emerging Organic Micropollutants. It is discharged into the sewerage system from different sources and then enters the wastewater treatment plants. The present study aimed at providing a better knowledge of the fate of MET through the wastewater treatment plants. The study addressed two different issues: (1) optimization of the analytical methods for MET determination in both liquid and sludge phases, focusing on the effects of potentially interfering substances and (2) investigation on the behaviour of MET in the biological treatment process, with specific concern for the biomass activity at different drug concentrations. Results of the study on issue 1 highlighted that the applied analytical method for MET determination (UPLC-MS/MS) is affected by the main components of wastewater for about 9-23%, which is comparable with the uncertainties of the method (about ± 28%). The method showed also to be repeatable and reliable (recovery > 75%; repeatability < 10-15%; bias uncertainty < 30%), and relatively easy-to-use. Therefore, it can be considered suitable for measurements on routine base in the WWTPs. Batch tests conducted to address issue 2 showed total removal of 84, 90, and 96% at 50, 100, and 200 ng/L initial MET concentration, respectively, for a contact time of 6 h. The removal process was mainly ascribed to the biological activity of both heterotrophic and autotrophic bacteria. The pseudo first-order kinetic model provided the best fitting of the experimental data of the overall biological processes at all the tested concentrations. Furthermore, the respirometric tests showed that MET does not induce any inhibition. Adsorption of MET on activated sludge was always very low. [ABSTRACT FROM AUTHOR]

• A monitoring campaign of 34 months was conducted on 76 Wastewater Treatment Plants. • Influent and effluent concentrations of 13 Organic Micropollutants were determined. • Some illicit drugs and Ketoprofen showed the highest concentrations. • Steroid concentrations were in most cases under the detection limits. • Secondary-tertiary treatment provided the best removal for most of the pollutants. The present study shows the results of an experimental survey conducted over 34 months on 76 full-scale Wastewater Treatment Plants located in central Italy with the aim to determine the influent and effluent concentrations of 13 Organic Micropollutants belonging to the class of illicit drugs, pharmaceuticals and steroids. The survey focused on a large set of plants differing for the main characteristics (e.g. treatment capacity, type of lay-out). Based on the values measured in the influent and effluent, removal efficiency of each contaminant in each plant was also determined, as well as the seasonal variation of the influent concentration. Among the monitored pollutants, some illicit drugs (i.e. Benzoylecgonine, 11-nor-carboxy-Δ9-tetrahydrocannabinol) and Ketoprofen showed the highest concentrations in the influent and were also the most frequently detected in the wastewater; nonetheless, the plants were capable of removing these pollutants at high extent (median removal value of 70 %, 65 % and 74 %, respectively). On the other side, steroid concentrations were in most cases under the detection limits. About the type of lay-out, the comparison of the efficiency obtained by the different plants showed that combination of secondary and tertiary treatment provides the best removal for most of the target Organic Micropollutants. [ABSTRACT FROM AUTHOR]

• Removals were 59–68% of PFOA and 66–96% of PFOS, depending on the concentrations. • Adsorption on the sludge was the main responsible of the removal, particularly for PFOS. • Loss from the system was observed, due to processes other than biological and adsorption. • The inhibition index was found equal to 14 % at 4000 ng/L concentrations. • Adsorbed pollutants were released from the sludge for less than 1 %. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the most investigated compounds in the class of perfluoroalkyl substances for their persistence and wider diffusion in the environment. However, fate and behaviour of PFOA and PFOS in the Wastewater Treatment Plants (WWTPs) have not been fully understood yet. The aim of the present study was to obtain a better understanding of the processes occurring to PFOS and PFOA in the activated sludge reactor. Several experimental tests were performed in the presence of activated sludge and sterilized sludge. PFOA and PFOS showed removals from the liquid phase from 59 % to 68 % and from 66 % to 96 %, respectively, for initial concentrations from 200 ng/L to 4000 ng/L in the presence of activated sludge. A significant fraction of the initial contaminant load was found adsorbed on the sludge, mainly in the case of PFOS. Other processes occurred, not fully identified, which were responsible of a further loss from the system. Leaching tests showed negligible release of the adsorbed pollutants from the sludge. Carbon and ammonia removal in the activated sludge reactor were not significantly affected by the presence of PFOA and PFOS. The pseudo-second order kinetic model and the Freundlich isotherm provided the best fitting of the experimental data. [ABSTRACT FROM AUTHOR]

Abstract The present study focused on 11-nor-9carboxy-Δ9-THC (THC-COOH) and Benzoylecgonine (BE), the most common metabolites of cannabis and cocaine, respectively, present in the domestic sewage entering the wastewater treatment plants. The aims of the study were: (1) to validate the analytical method of detection in wastewater and sludge; (2) to determine contribution of biodegradation and other processes to the removal in the biological reactor of the wastewater treatment plant (WWTP) and the response of biomass to different drug concentrations. The Ultra-Performance Liquid Chromatography coupled to tandem Mass Spectrometry method showed to be repeatable and reliable (recovery>75%; repeatability<10–15%; bias uncertainty<10) for measurements in wastewater; the ultrasound assisted extraction (USE) demonstrated to be reliable as pre-treatment of activated sludge solid phase. Both drugs were fully removed from the liquid phase in the lab-scale biological reactor within 24 h. Biodegradation was the main BE removal mechanism, and the first order kinetic model provided the best fitting of the experimental data. THC-COOH was mainly removed due to a combination of adsorption and biodegradation; adsorption was better described by the pseudo-second order kinetic model and the Freundlich isotherm. Both drugs at the higher concentrations caused inhibition of nitrogen oxidation and carbon removal. Graphical abstract Image 1 Highlights • BE in the range 500–4000 ng L−1 was fully removed in the biological reactor. • Biodegradation was the main removal process of BE. • THC-COOH in the range 150–2000 ng L−1 was fully removed in the biological reactor. • Removal of THC-COOH was mainly due to adsorption on sludge. • At the highest concentrations, both BE and THC-COOH caused partial inhibition. [ABSTRACT FROM AUTHOR]

The presence of Contaminants of Emerging Concern (CECs) in water systems has been recognized as a potential source of risk for human health and the ecosystem. The present paper aims at evaluating the effects of different characteristics of full-scale Wastewater Treatment Plants (WWTPs) on the removal of 14 selected CECs belonging to the classes of caffeine, illicit drugs and pharmaceuticals. Particularly, the investigated plants differed because of the treatment lay-out, the type of biological process, the value of the operating parameters, the fate of the treated effluent (i.e. release into surface water or reuse), and the treatment capacity. The activity consisted of measuring concentrations of the selected CECs and also traditional water quality parameters (i.e. COD, phosphorous, nitrogen species and TSS) in the influent and effluent of 8 plants. The study highlights that biodegradable CECs (cocaine, methamphetamine, amphetamine, benzoylecgonine, 11-nor-9carboxy-Δ9-THC, lincomycin, trimethoprim, sulfamethoxazole, sulfadiazine, sulfadimethoxine, carbamazepine, ketoprofen, warfarin and caffeine) were well removed by all the WWTPs, with the best performance achieved by the MBR for antibiotics. Carbamazepine was removed at the lowest extent by all the WWTPs. The environmental risk assessed by using the site-specific value of the dilution factor resulted to be high in 3 out of 8 WWTPs for carbamazepine and less frequently for caffeine. However, the risk was reduced when the dilution factor was assumed equal to the default value of 10 as proposed by EU guidelines. Therefore, a specific determination of this factor is needed taking into account the hydraulic characteristics of the receiving water body. [Display omitted] • 14 CECs were monitored in 8 different full-scale WWTPs for 2-years. • The CECs removal was mainly dependent on biological process. • The Membrane Biological Reactor achieved the best performance. • A high environmental risk was observed for carbamazepine and caffeine. • The risk changed depending on the dilution factor of effluent into the rivers. [ABSTRACT FROM AUTHOR]