Conventional Wastewater Treatment Plants Research Articles

Removal efficiencies for 52 pesticides and pharmaceuticals from wastewater effluent by coupling solar heterogeneous photo-oxidation with TiO2 and infiltration in saturated soil column

Water resource management has become a hot button issue in recent decades. Countries facing water shortages as a result to climate change must adapt their water supply. The reuse of wastewater treatment plant effluents is becoming increasingly common around the world. However, the effluent quality must be improved before its reutilization to avoid contamination of the receiving environment. Pharmaceuticals and pesticides are particularly monitored because of their ubiquitous behaviours and limited removal by conventional wastewater treatment plants. The aim of this study was to combine heterogeneous photo-oxidation with TiO2 and soil infiltration to increase the elimination of contaminants of emerging concern (CECs). These advanced treatments were applied on an effluent coming from a WWTP equipped with a Ultrafor membrane bioreactor (sludge ages: 8–30 days, biomass concentration: 8-12 g.L−1, hydraulic retention: 6.7-8 h). The concentration of CECs was determined to evaluate the efficiency of coupling treatments. Photo-oxidation alone showed an impressive 98 % removal under spring conditions, while 66 % removal was observed under winter conditions. The differences observed for photo-oxidation were related to UV flux density, lower in winter than in spring (4.4 kJ.L−1 vs 6.6 kJ.L−1) and initial concentrations of the effluent higher in winter (50 μg.L−1 vs 26 μg.L−1). For both experiments, additional soil infiltration increased the global concentration of CECs removal to at least 89 % with equal removal contributions observed for some compounds. From the 52 CECs quantified in the WWTP effluent, at least 30 were totally removed by the advanced treatments while 4 compounds showed recalcitrant behaviours with global removal <60 %.

Generic and site-specific social life cycle assessment of municipal wastewater treatment systems in Spain: challenges and limitations of the method when applied to resource recovery systems

Abstract Purpose This work aims to provide insights on the application of social life cycle assessment (S-LCA) in evaluating the social impacts associated with municipal wastewater treatment (WWT). The study assesses the social risks and social performance of two municipal WWT systems in Catalonia, Spain: a conventional wastewater treatment plant (WWTP) (Reference System) and a novel system that recovers water and other valuable resources (Novel System). Methods S-LCA was conducted at Generic and Site-Specific levels using 1 m3 of wastewater treatment as the functional unit (FU). The Generic assessment was conducted via the Product Social Impact Life Cycle Assessment (PSILCA) database, while the Site-Specific assessment employed the Subcategory Assessment Method (SAM) with four-level reference scales to assess the social performance of the WWTP operator and its first-tier suppliers. Furthermore, activity variables were calculated based on organizations’ shares in the total costs per FU, and the Novel System’s multifunctionality was solved through economic allocation. Results were aggregated by (i) assigning equal weights to organizations and (ii) factoring in organizations’ weights and the allocation factor, leading to results per FU. Results and discussion The Generic analysis results indicated that the Novel System entailed fewer social risks than the Reference System. Most social risks in both systems occurred in the subcategories “Access to material resources,” “Fair salary,” “Freedom of association and collective bargaining,” “Contribution to economic development,” and “Corruption.” In the Site-Specific assessment, the Novel System presented better social performance than the Reference System per 1 m3 of wastewater treatment. The latter’s performance per FU did not meet the basic requirement in four out of eleven subcategories, mainly due to the performance and weight of a chemical supplier. Allocation greatly benefitted the Novel System’s results per FU compared to the results obtained when equal weights were applied. Conclusions Activity variables were used to connect organizations’ conduct with particular WWT systems, and multifunctionality was solved. This approach allowed for obtaining results per FU at both assessment levels. However, social performance was also evaluated by calculating the average social performance of each system without considering activity variables and the FU, leading to different results. The social performance of the Novel System per FU was satisfactory across all subcategories but required improvement in four subcategories based on the average results. Given the limitations of using activity variables and allocation in S-LCA, further research is necessary to appropriately evaluate and compare the social effects of novel resource recovery systems.

Advanced oxidation processes by UV/H2O2 for the removal of anionic surfactants in a decentralized wastewater treatment plant in Ecuador

ABSTRACT Surfactants are persistent pollutants that pose risks to ecosystems and human health due to their low removal efficiency in conventional wastewater treatment plants. In Guayaquil, Ecuador, a decentralized facility discharges water with a surfactant concentration that exceeds the national legislation up to 20 times. This work aims to demonstrate the effectiveness of the advanced oxidation process UV/H2O2 in removing anionic surfactants as a tertiary treatment for the decentralized facility investigated. A laboratory-scale batch system was tested for the treatment of real effluent with three hydrogen peroxide concentrations (100, 250, and 500 mg L−1) and UV exposure up to 120 min. All experimental trials were run in duplicate. After 60 min of UV exposure with 250 mg L−1 of H2O2, the anionic surfactant removal was 94.3 ± 4.3%, and the effluent complied with the discharge limits (&amp;lt;0.5 mg L−1). These operational parameters were selected for continuous laboratory-scale experiments to simulate the facility operation, achieving a maximum removal of 92.3 ± 2.5%. Although the reactor demonstrates a high removal rate, improvements to its configuration are necessary to meet discharge limits. The UV/H2O2 process allowed the removal of anionic surfactants, suggesting its feasibility as a complementary treatment in decentralized plants with similar problems.

A low-carbon-emission photoelectrochemical system using Ov-Fe2O3@BiVO4 photoanode for integrated multiple pollutant removal and energy harvesting from real saline sewage

Conventional wastewater treatment plants (WWTPs) face challenges due to high carbon emissions and energy consumption. Herein, a low-carbon-emission photoelectrochemical (PEC) system using an oxygen-vacancy-rich Fe2O3@BiVO4 (Ov-Fe2O3@BiVO4) photoanode that is aimed at replacing biological treatment and disinfection, is developed to simultaneously remove organic compounds, ammonia (NH4+-N), and bacteria from real saline sewage (after primary treatment) while generating green H2. The PEC system demonstrates remarkable performance in the treatment of real saline sewage, as evidenced by the fact that the treated sewage is able to meet local discharge standards of chemical oxygen demand (COD), ammonia-N, and Escherichia coli (E. coli) after two hours of operation under simulated solar light at 2.0 V (vs. Ag/AgCl). Most importantly, it generates 11.51 mol/m3 of green H2 (equal to 0.458 kWh/m3 of electricity) and results in notable reductions of 76.7 % in scope 1 emissions (direct GHG emissions) and 62.5 % in total carbon emissions compared to conventional WWTPs. The scavenging tests and estimated steady-state concentrations of reactive species indicate that Cl•, ClO•, and Cl2•− are the primary contributors to the degradation of organic pollutants, while ClO• is dominant in converting ammonia to N2. Additionally, the excellent reusability, stability and easy regeneration of the Ov-Fe2O3@BiVO4 photoanode and its good performance in treating different batches of real sewage guarantee the high practicability of the PEC system. This study has successfully validated the PEC system as a low-carbon-emission technology approach for saline sewage treatment coupled with green H2 generation, demonstrating its enormous practical potential.

Resolving the dilemma of wastewater treatment plants: An empirical study on public acceptance for publicly accessible WWTPs

Wastewater treatment plants (WWTPs) play an indispensable role in the process of urbanization and sustainable development, while their construction often faces challenges due to diverse public opinions. Therefore, strategies to improve public acceptance of WWTPs are essential for their implementation and the planning of wastewater system. To resolve this dilemma, publicly accessible WWTPs designed in conjunction with public spaces have emerged globally. In order to validate its effectiveness, this research investigated the public acceptance of publicly accessible WWTPs and the determinants of public acceptance in China, where an online questionnaire survey was launched with 3000 responses and hypothesis testing was conducted using Structural Equation Modeling (SEM). The results indicated that compared to conventional WWTPs, publicly accessible WWTPs were much more preferred by the majority of respondents (92.3%). Moreover, this study revealed that factors including perceived benefit, perceived risk, and public spaces directly impact public acceptance, while trust and perceived fairness indirectly influence it. What's more, this research highlighted and validated the significant role of public spaces in enhancing public acceptance of WWTPs, and enriched the understanding of how multiple factors influence public acceptance, providing practical implications for the site selection, design and management of publicly accessible WWTPs.

Strategies for Removing Endocrine Disrupting Chemicals (EDCs) from Wastewater.

Endocrine-disrupting drugs, also called endocrine disruptors or micropollutants, cause serious environmental and public health problems due to their ability to disrupt the endocrine functions of organisms and humans, even at low concentrations. This report provides a summary of current removal techniques, such as activated sludge processes, membrane filtration, adsorption, and membrane bioreactor techniques for endocrine-disrupting chemicals, including their efficiency, limitations, and practical implementation. This review evaluates these methods by considering their treatment efficiency, costs, and environmental impact. To curb this menace, several developed countries have distinct strategies, such as physical remediation techniques, biological processes, phytoremediation, and chemical processes to remove endocrine disruptors. In developing nations, most conventional wastewater treatment plants do not even monitor those contaminants due to the low biodegradability and high complexity of such compounds. Hence, in this review work, potential endocrine-disrupting chemicals, their impacts, mechanisms of action, consequences for human health, and bio-mitigation strategies reported so far have been discussed in the context of the relevant literature.

Monitoring of organic micropollutant behavior and fate in a full-scale conventional biological urban wastewater treatment plant

Monitoring of organic micropollutant behavior and fate in a full-scale conventional biological urban wastewater treatment plant

A Dataset of Distribution and Characterization of Underground Wastewater Treatment Plants in China

Underground wastewater treatment plants (U-WWTPs) have emerged as a novel paradigm for urban wastewater pollutants management, offering benefits such as alleviating the Not-in-my-backyard (NIMBY) effect and utilizing land resources efficiently. China stands at the forefront, witnessing swift advancements in U-WWTP technology and deployment. However, the absence of a thorough understanding of their geographical distribution and operational characteristics could lead to misaligned planning and construction, resulting in inefficient resource allocation and treatment capacities for urban wastewater treatment. This dataset provides an up-to-date overview of the spatial distribution, process selection, and discharge standards for all U-WWTPs in China (with a total number of 201) constructed since 1995. To enhance comparative analysis, the dataset has been supplemented with information on conventional aboveground wastewater treatment plants (A-WWTPs), comprising a total of 2464 records, which enriches a more comprehensive evaluation of different wastewater treatment approaches. Utilizing this dataset can provide essential data support for the strategic management of urban wastewater systems and serve as a valuable reference for the paradigmatic renovation of existing wastewater treatment plants.

Investigating upflow anaerobic sludge blanket process to treat forward osmosis effluents of concentrated municipal wastewater under psychrophilic temperature

This work investigated the stability of the Upflow Anaerobic Sludge Blanket (UASB) reactor under psychrophilic temperatures with varying feed streams, simulating typical and concentrated sewage. In Phase I, treating municipal wastewater, chemical oxygen demand (COD) removal dropped from 77 ± 6 % to 41 ± 2 % as hydraulic retention time decreased from 24 to 12 h and organic loading rate (OLR) increased from 0.6 to 1.3 gCOD/(L∙d). In Phase II, at a similar OLR (≈1.2 gCOD/(L∙d)), the UASB treated organic-rich effluents (from 1.0 to 2.1 ± 0.1 gCOD/L) resulting from the pre-treatment of the forward osmosis (FO) process. The UASB performance improved significantly, achieving 87 ± 3 % COD removal and 63 ± 4 % methane recovery, with microbial analysis confirming methanogen growth. The COD mass balance showed up to 30 % more electrical energy recovery from sewage compared to conventional wastewater treatment plants (WWTPs), indicating that the FO-UASB combination is a promising approach to achieve energy-neutral operation in WWTPs.

Circular hybrid membrane process treating high-salinity ammonium-rich pharmaceutical wastewater

Ammonia-rich saline wastewater is a common byproduct of the pharmaceutical industry. Hollow fiber membrane contactors (HFMCs) show potential for NH3 recovery, enabling valuable product recycling. Our previous work indicated that excessive NaOH usage and increased salinity of the treated effluent are major setbacks when employing HFMCs for NH3 recovery from pharma wastewater. Therefore, finding alternative approaches to reduce chemical use and salinity is vital. This study demonstrates the integration of bipolar membrane electrodialysis (BMED) with HFMC for NH3 recovery, chemical recycling, and salinity reduction. This novel, highly circular concept was tested using real pharmaceutical wastewater. We varied the volume ratios between compartments to assess the BMED flexibility in attaining different treatment goals. BMED achieved over 90% salinity reduction and produced concentrated base and acid in all volume ratios tested, saving 70% of the NaOH required for pH increase before the HFMC step. The HFMC achieved over 98% NH3 recovery in two sets of five consecutive cycles, using either a BMED-generated base or NaOH. A preliminary economic analysis revealed a 47% reduction and 86% increase in expenses on chemicals and energy, respectively, compared to HFMC without BMED. Nevertheless, since the largest operating expense was the purchase of chemicals, integrating the BMED step reduced the overall operating expenses of the treatment by 33% (from $3.76 to $2.54 per kg N). The treated effluent’s quality allows discharge to conventional wastewater treatment plants, resulting in economic and environmental benefits. This work highlights the importance of innovative separation processes in advancing toward cleaner drug manufacturing.

Investigation of pharmaceutical bioaccumulation in Daphnia sp. living in a wastewater treatment plant

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used pharmaceuticals. Their presence in natural waters is due to the low removal efficiency in conventional wastewater treatment plants (WWTPs). Interestingly, certain zooplankton species can survive the mixture of pollution and abnormal water conditions in WWTPs. In our study, for the first time, we tested the in-situ bioaccumulation of NSAIDs and their metabolites in Daphnia pulex, which were obtained in high numbers in one WWTP during the summer. It was found that diclofenac (DCF) and 4-hydroxy DCF were present in the studied clarifiers and ponds. Among these chemicals, only DCF was detected in daphnia. The bioaccumulation factor of DCF in daphnia was below 36 L kg−1ww and was lower than those obtained under experimental conditions for Daphnia magna. The tested daphnia adapted to chronic exposure to mixtures of drugs in μg L−1 level and could be implemented in biobased WWTPs. According to our data, there is a need to supplement the risk assessment of anthropogenic pollutants with in-situ cases to demonstrate the adaptation possibilities of wild-living organisms.

Activated carbon adsorption for mitigating the harmful effects of antibiotics on the biological activated sludge: Effect on heterotrophic kinetics through respirometry.

Conventional wastewater treatment plants (WWTPs) are not designed for the abatement of antibiotics, and their effluents are one of the main entry ways of these emerging contaminants to the aquatic environment, causing major concern due to their toxicity, persistence, and bioaccumulation. When wastewater containing antibiotics enters the bioreactor, they can impact microbial communities of the activated sludge, affecting biodegradation processes of organic matter and nutrients. There is scarce information about the effect of activated carbon on the activated sludge within the bioreactor in presence of antibiotics. In light of this, the effect of representative antibiotics, ciprofloxacin (CIP), nalidixic acid (NAL), and erythromycin (ERY), on the performance of a conventional activated sludge of a WWTP was analyzed by respirometry with and without activated carbon. NAL and ERY negatively affected the net heterotrophic biomass growth rate (r'x,H), with reduction percentages of 26%-90% and 31%-81%, respectively. The addition of activated carbon mitigated this effect, especially for ERY, with increments of even 8% in the r'x,H for the hybrid process when working with 5 ppm of ERY and 80 ppm of activated carbon compared with the value in the absence of antibiotic and activated carbon. This effect was attributed to the enhanced retention of ERY, in comparison to NAL, on the surface of the activated carbon, probably due to its higher molecular size and affinity towards the activated carbon (log Kow = 3.06). This effect was more marked at low sludge retention times (below 8 days). PRACTITIONER POINTS: Ciprofloxacin (CIP), nalidixic acid (NAL), and erythromycin (ERY) were studied. NAL and ERY exerted negative impact on heterotrophic growth rate. Effect of antibiotics on microorganisms in the presence of activated carbon was studied. Activated carbon was mainly relevant for ERY due to its adsorption retention. Enhancement by activated carbon was more significant at low sludge retention times.

Monitoring of OPFRs in WWTPs: Unveiling environmental insights with high resolution mass spectrometry

Exploring the occurrence pattern of organophosphate flame retardants (OPFRs) in environmental samples has attracted increasing attention lately. In the conventional wastewater treatment plants (WWTPs), OPFRs are not sufficiently removed and therefore are discharged to the aquatic environment. However, concerns arise from their release regarding the potential risk posed to organisms. Consequently, closely monitoring this group of emerging contaminants, along with the evaluation of the associated ecological risk are matters of utmost importance. Given the aforementioned information, influents and effluents from two WWTPs (WWTP-A and WWTP-S) in Thessaloniki were gathered during a 36-month sampling initiative spanning from 2020 to 2023 in order to evaluate the occurrence and concentration levels of OPFRs. The collected samples underwent solid-phase extraction and then preceded to analysis with a Q Exactive Focus Orbitrap mass analyzer. In the present study, except for the implementation of the target analysis approach, removal efficiencies and mass loads were further calculated. TBEP (tris-2-butoxyethylphosphate) and TEP (triethyl phosphate) were detected in all influent samples (%DF = 100 %) in WWTP-A while in WWTP-S only TCPP (tris-1-chloro-2-propyl phosphate) was omnipresent. In effluents of both WWTPs, only TEP maintained the same detection frequency (%DF = 100 %). The highest mean concentration levels in WWTP-S influents were calculated for TEP (327 ng/L) followed by TCPP (277 ng/L) while in WWTP-A the highest mean concentrations in influents were detected for TCPP (405 ng/L) and TDCP (Tris(1,3-dichloro-2-propyl)phosphate) (124 ng/L). In effluents, the highest mean concentration was reported for TCPP, in both WWTPs, reaching 295 ng/L and 240 ng/L in WWTP-S and WWTP-A respectively. Generally, OPFRs exhibited low to moderate average removal efficiencies. Positive and negative removal efficiencies were also noticed during the monitoring campaign. The average mass load in WWTP-S was as high as 10.1 mg/day/1000 inhabitants and in WWTP-A, 11 mg/day/1000 inhabitants in effluents. Finally, different mathematical tools were employed for the assessment of the risk posed to algae, invertebrates and fish. For the toxicity assessment in these three trophic levels the worst-case scenario was taken into consideration. Generally, all the target analytes presented low or medium values in all trophic levels for acute and chronic toxicity.

Removal Of Pharmaceuticals from Municipal Wastewater Using Malaysian Ganoderma Lucidum Fungal Strain

Emerging contaminants are currently a serious issue primarily because conventional wastewater treatment plants are unable to eliminate them. Environmental pollution caused by various emerging pollutants (particularly pharmaceutical active compounds) in wastewater poses a significant threat to public health and ecological balance. In 21st century, bioremediation is regarded as the most environmental friendly and cost-effective treatment technology. In this study, we investigated the removal efficiency of 19 popular pharmaceutical active compounds (PhACs) from municipal wastewater using Malaysian Ganoderma lucidum fungal strain (G. lucidum). The initial and final concentrations of each compound were determined using liquid chromatography time of flight mass spectrometry (LC-TOF/MS), and the percentage of removal was calculated. In this study, experimental results revealed diverse removal efficiencies for the investigated PhACs in municipal wastewater. The PhACs Azithromycin, doxycycline, clindamycin, ciprofloxacin, sulfamethoxazole, loratadine, and citalopram, showed remarkable removal rates of 90% and above in municipal wastewater, indicating their potential for effective treatment. Conversely, trimethoprim, ketoprofen, diclofenac, venlafaxine, dexamethasone, atenolol, propranolol, losartan, valsartan, metoprolol, fluconazole, and carbamazepine, demonstrated varying removal efficiencies, suggesting the need for further optimization in wastewater treatment processes for these compounds. This study highlights the importance of understanding the biodegradation of different PhACs in municipal wastewater to develop efficient and targeted bioremediation treatment strategies using local fungal strain of G. lucidum. Overall, this study provides promising suggestions for the bioremediation of pharmaceuticals from wastewater.

Bioremediation of complex contaminated Yamuna River India by using selected cyanobacteria

River Yamuna serves as a major lifeline in Delhi and the people living along its banks rely on it for their livelihoods. However, it faces severe contamination due to anthropogenic activities, such as industrial and domestic waste discharge through various drains. Bioremediation emerges as a promising approach to mitigate such contamination, offering environmentally friendly solutions. This study focuses on the remediation potential of Nostoc, Anabaena, Phormidium, and Oscillatoria, which represent a better solution than traditional wastewater treatment plants (WWTP). BOD (120 ± 4.31 mg/L) and COD (241 ± 5.6 mg/L) were found in water samples collected from the Najafgarh drain at Wazirabad and BOD (90 ± 3.56 mg/L) and COD (180 ± 5.1 mg/L) were recorded in a water sample collected from the Wazirabad wastewater treatment plant (WWTP). Phycoremediation analysis shows that Oscillatoria removes 72.4 ± 4.11% of BOD and 63.90 ± 3.67% of COD, while Nostoc removes 59 ± 5.1% of BOD and 68.46 ± 3.87% of COD. In comparison, wastewater treatment plant (WWTP) only removes 25 ± 3.12% of BOD and 25.13 ± 2.92% of COD. The biosorption activity showed that Nostoc absorbed a maximum of 3.07 µg/ml (30.7 ± 2.13%) of chromium (Cr (VI)), followed by Phormidium at 2.27 µg/ml (22.7 ± 1.9%) only 3 days of incubation. This is the first study to examine how selected cyanobacteria can reduce pollution in the Yamuna River by treating both drain and treated water. The results show cyanobacteria are better at removing chromium and other pollutants than conventional WWTPs. This highlights the need to combine biological solutions with traditional methods for sustainable river restoration and effective environmental management.

Elucidating the role of organic loading rate on the performance and microbial dynamics of a novel continuous-flow aerobic granular sludge reactor

Aerobic granular sludge technology operated in continuous-flow reactors enables the upgrading of existing conventional wastewater treatment plants. The viability of applying this technology at full-scale increases with the simplicity of the bioreactor design. Hence, in contrast to previous research carried out in complex configurations, this study is based on evaluating the capacity of a novel single-chamber continuous-flow bioreactor to operate at different loads found in domestic sewage, highlighting that this configuration combines and joins the advantages of activated sludge and granular sludge technologies. At organic loading rates ranging from 0.45 to 1.85 kg COD•m−3•d−1, the reactors achieved high performance, removing >80 % of the chemical oxygen demand, regardless influent characteristics. The trend of ammonium removal rates was risen over operational time. Moreover, the granular size and biomass concentration increased with the organic loading rate. Changes in the influent did not compromise the structure of the granules. Microbiota studies showed a high diversity in communities at lower organic loading rates, whereas a strong microbial competition was detected at high loading rates, linking with lower evenness. Phylotypes belonging to Hypocreales played a key role in mature granules.

Native Microalgae-Bacteria Consortia: A Sustainable Approach for Effective Urban Wastewater Bioremediation and Disinfection.

Urban wastewater is a significant by-product of human activities. Conventional urban wastewater treatment plants have limitations in their treatment, mainly concerning the low removal efficiency of conventional and emerging contaminants. Discharged wastewater also contains harmful microorganisms, posing risks to public health, especially by spreading antibiotic-resistant bacteria and genes. Therefore, this study assesses the potential of a native microalgae-bacteria system (MBS) for urban wastewater bioremediation and disinfection, targeting NH4+-N and PO43--P removal, coliform reduction, and antibiotic resistance gene mitigation. The MBS showed promising results, including a high specific growth rate (0.651 ± 0.155 d-1) and a significant average removal rate of NH4+-N and PO43--P (9.05 ± 1.24 mg L-1 d-1 and 0.79 ± 0.06 mg L-1 d-1, respectively). Microalgae-induced pH increase rapidly reduces coliforms (r > 0.9), including Escherichia coli, within 3 to 6 days. Notably, the prevalence of intI1 and the antibiotic resistance genes sul1 and blaTEM are significantly diminished, presenting the MBS as a sustainable approach for tertiary wastewater treatment to combat eutrophication and reduce waterborne disease risks and antibiotic resistance spread.

Sequential Anaerobic-Aerobic Treatment Enhances Sulfamethoxazole Removal: From Batch Cultures to Observations in a Large-Scale Wastewater Treatment Plant.

Sulfamethoxazole (SMX) passes through conventional wastewater treatment plants (WWTPs) mainly unaltered. Under anoxic conditions sulfate-reducing bacteria can transform SMX but the fate of the transformation products (TPs) and their prevalence in WWTPs remain unknown. Here, we report the anaerobic formation and aerobic degradation of SMX TPs. SMX biotransformation was observed in nitrate- and sulfate-reducing enrichment cultures. We identified 10 SMX TPs predominantly showing alterations in the heterocyclic and N4-arylamine moieties. Abiotic oxic incubation of sulfate-reducing culture filtrates led to further degradation of the major anaerobic SMX TPs. Upon reinoculation under oxic conditions, all anaerobically formed TPs, including the secondary TPs, were degraded. In samples collected at different stages of a full-scale municipal WWTP, anaerobically formed SMX TPs were detected at high concentrations in the primary clarifier and digested sludge units, where anoxic conditions were prevalent. Contrarily, their concentrations were lower in oxic zones like the biological treatment and final effluent. Our results suggest that anaerobically formed TPs were eliminated in the aerobic treatment stages, consistent with our observations in batch biotransformation experiments. More generally, our findings highlight the significance of varying redox states determining the fate of SMX and its TPs in engineered environments.

Biodegradation kinetics of organic micropollutants in biofilters for advanced wastewater treatment – Impact of operational conditions and biomass origin on removal

Biofiltration processes are often part of advanced wastewater treatment (aWWT) technologies for the removal of organic micropollutants (OMP) from conventional wastewater treatment plant (WWTP) effluents. Although biological effects are not always the main focus of these technologies (e.g. filtration through granular activated carbon), they have been shown to contribute significantly to total OMP removal. While OMP biodegradation kinetics in conventional biological wastewater treatment are well researched, no systematic comparison to biomass from aWWT is available. This biomass faces different growth conditions and higher OMP concentrations relative to the background organic matter. Adaptation to these conditions could be possible and could lead to faster OMP biodegradation kinetics, which would show in a larger pseudo first-order biodegradation kinetic constant kbiol. In this work, kbiol values for biomass obtained from aWWT biofilters were determined by evaluating OMP removals measured in lab-scale biofilters using a mechanistic model of the experimental setup. A comparison to kbiol values from literature for conventional wastewater treatment (with nutrient removal) revealed similar OMP biodegradation kinetics without any advantages of biomass from aWWT. A conceptual evaluation of influencing factors on OMP removal in biofilters showed that operational parameters (such as the biomass concentration or the empty bed contact time) and the affinity of OMPs to adsorb on biomass have a significant additional effect on biological OMP removal. Therefore, kbiol values alone are not sufficient to estimate biological OMP removal in biofilters and further information about the system is required.

Amphetamine-like substances and synthetic cathinones in Portuguese wastewater influents: Enantiomeric profiling and role of suspended particulate matter

Wastewater based epidemiology (WBE) has been used worldwide to estimate drug consumption routinely. Even though WBE provides valuable data to support legal and health interventions associated to drug use, monitoring studies in Portuguese wastewaters are scarce. Hence, this work aimed to estimate the consumption of some conventional abuse and illicit drugs such as amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxymethamphetamine (MDMA), and the synthetic cathinones buphedrone (BPD), butylone (BTL), 3,4-dimethylmethcathinone (3,4-DMMC) and 3-methylmethcathinone (3-MMC), considering not only the liquid phase, but also the suspended particulate matter (SPM). Moreover, the enantiomeric profiling of the samples was studied, exploring for the first time the possible enantioselective sorption of these drugs onto SPM. For that, 24 h composite raw wastewaters were collected from a conventional wastewater treatment plant (WWTP) in Portugal. After extraction, the liquid phase and SPM extracts were derivatized with an enantiomerically pure reagent and then, analysed using a gas chromatography-mass spectrometry (GC-MS) analytical method. The results showed a low and non-enantioselective adsorption to SPM at environmental relevant levels. Only (S)-AMP was detected in two SPM samples, whereas AMP, MAMP, MDMA, BPD, and 3,4-DMMC were detected in the liquid phase. AMP was the most frequently found drug with an estimated load up to 166.0 mg day−1 1000 people−1 and mostly found with enrichment of (S)-AMP. Nevertheless, (R)-AMP was also determined, which may be related to the consumption of either the illicit racemic AMP or the medicine (R)-deprenyl. The use of MDMA, MAMP and synthetic cathinones (BPD and 3,4-DMMC) was also suggested in Portugal. Nevertheless, the levels and the consumption estimate of the target chemicals were lower than in other European countries or worldwide. These findings provide the first step to the implementation of WBE monitoring campaigns to assess the status of drug consumption in Portuguese communities, contributing to the understanding of drug use patterns and trends worldwide and helping enforce preventive measures.