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Medium-chain carboxylates such as caproic acid, have a plethora of applications, ranging from food additives to bioplastics, and can be produced via microbial chain elongation (CE), a process that can be more sustainable than conventional production routes. During CE short fatty acids accept electrons from donors as lactate or ethanol elongating into medium-chain carboxylates with higher economic value and easier recoverability. Nowadays, waste activated sludge (WAS) and food waste (FW) are the most abundant waste steams generated in European cities impacting dramatically on environment, society, and economic sectors. A novel sustainable biotechnology is here proposed to produce marketable caproic acid from mixed WAS and FW with in-situ self-formed lactate without buffering agents addition. Different mix ratios between WAS and FW, and thermal pretreatment strategies were compared by fermentation batch tests. The production of lactate as electron donor (ED), together with acetate and butyrate, and hydrogen assured high production of caproate only in presence of thermal pretreated WAS, able to reduce the potential risk of lactate accumulation and drop in pH. The findings of this study demonstrate that the initial soluble carboydrate/protein ratio significantly affected the pH of the fermentation broth in the first hours of fermentation, and that only using FW and pretreated WAS mixed using a ratio of 60/40 in terms of volatile solids, CE pathway and lactate utilization as ED were promoted obtaining the highest percentage of caproate (about 21% of the total produced carboxylic acids; 2 gCOD/L). [Display omitted] • This strategy enables biowaste conversion targeted to marketable platform. • Chain elongation to caproate with in situ generated lactate as electron donor. • Thermal pretreatment of sludge promoted the natural buffering of the system. • The 60:40 ratio of FW and pretreated WAS resulted in the highest caproic yield. [ABSTRACT FROM AUTHOR]

Since 2020, human pharmaceuticals were included in the list of emerging contaminants from the UNESCO and their detection and elimination were incorporated in the 2030 Agenda for Sustainable Development Goal Targets. Among these, analgesic and antipyretic drugs are the most widely used drugs worldwide and, despite their advantages, unused or expired pharmaceuticals are a potential source of water pollution. Paracetamol is one of the most common drugs used for analgesic and antipyretic purposes and has been found to have a much higher concentration in water streams in many European countries. Considering that, an all-in-one paper-based 2 dimensional (2D) fluidic configuration, able to detect paracetamol, was developed in order to deal with environmental matrices without complex/expensive analytical procedures. An ad-hoc paper-based testing area, coupled with a channel was designed and wax-printed onto a porous filter paper. Successively three electrodes were screen-printed, and the whole system was applied for the detection of paracetamol in wastewaters (prior and after the filtration system) without pretreating the sample. In order to detect paracetamol with the easiest approach, the configuration of the paper-based device was optimized in terms of type of substrate used for printing, microfluidic paper strip length/width and combination of them in an integrated architecture, capable to detect paracetamol in the matrices tested in few seconds with a detection limit down to micromolar range, ca. 1 μM. The integrated device shown great promise for simple, fast, sensitive, and sustainable detection of paracetamol in its role of emerging contaminant, especially in the environmental matrices. [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]

• Aerobic syngas bioconversion towards microbial protein through HOB was investigated. • A wide variability in H 2 /CO 2 ratio did not influence syngas fermentation. • High resistance to H 2 S and CO concentrations up to 0.4 and 40 % was observed. • Microbial biomass with protein content up to 74 % was produced. • The stable long-term performances can enable direct MSS-derived syngas valorisation. Treating excess municipal sewage sludge (MSS) by means of thermochemical processes could enable its conversion into high-value microbial protein (MP) through syngas. Nevertheless, the variable composition and content of inhibitory compounds of the latter hinders the application potential of such a biorefinery scheme. Through a series of short- (48 to 96 h) and long-term (30 days) batch aerobic bioconversion tests, the present study aimed at investigating the potential of a mixed culture of hydrogen-oxidizing bacteria (HOB) to produce MP from a simulated syngas mixture characterized by variable H 2 and CO 2 concentrations, and different levels of CO and H 2 S as potential inhibitors of the HOB-driven process. Syngas was converted into MP with a protein content as high as 74 %, reaching biomass yields of 0.25 g VSS/g H 2 -COD, close to the maximum reported HOB yield of 0.28 g VSS/g H 2 -COD, and volumetric productivities of 16 mg VSS/L/h. The potential of the process to provide between 50 and 100 % of the total nitrogen requirement of HOB solely by means of the gaseous ammonia nitrogen recovered through syngas was also preliminarily calculated. The presence of H 2 S and CO concentrations up to 0.4 % and up to 40 %, respectively, and a wide range of H 2 /CO 2 ratios (2 – 10) had no negative influence on the main process performances. The role played by H 2 S- and CO-tolerant HOB species was fundamental to guarantee a high tolerance to microbial inhibitors, and demonstrated the high potential of mixed cultures for resource recovery and valorisation. [Display omitted] [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]