Central Wastewater Treatment Plant Research Articles

ANALISIS RESIKO BAHAYA LIMBAH B3 MENGGUNAKAN METODE HIRARC PADA INSTALASI PEMBUANGAN AIR LIMBAH

Balai PIALAM, namely the Technical Implementation Unit (UPT) of the PUP-ESDM Office of the DIY Regional Government, is a centralized wastewater treatment plant. The problems that exist in Balai PIALAM are temporary storage of B3 waste does not meet the criteria, leaking storage, excessive capacity, methods that can be used to overcome B3 waste are using the HIRARC method, based on 9 activities of the B3 waste management process. Impact of hazard risk with research results Risk level: Medium 4 hazard effect 6.33%, High2 hazard effect 2.11%, extreme1 hazard effect 1.6%. The stages of making HIRARC are: decomposing the work into steps from the beginning to the end of the process, identifying the source of danger, determining the hazard posed by means of interviews, observations, observations, brainstorming, determining the impact on environmental workers, assessing the likelihood of occurrence is used to determine risk rating. Testing period January 2024, t BOD Input (min 99 mg/L,max 458 mg/L), Output (min 10 mg/L,max 59 mg/L), Average (input 206 mg/L, output 30 mg/L), testing period February 2024, testing t BOD Input (min 84 mg/L, max 288 mg/L), Output (min 12 mg/L, max 43 mg/L), Average (input 154 mg/L, output 24 mg/L). Use of APD such as laboratory coats, masks, special gloves, safety shoes, protective helmets and life vests, face shields. As well as implementing SOP. Control of hazards or risks both in laboratory and operational testing activities using APD: gloves, laboratory coats, safety shoes, protective glasses, masks, life vests, and special vests according to the work done and affirmation of SOP.

Equity-centered adaptive sampling in sub-sewershed wastewater surveillance using census data.

Sub-city, or sub-sewershed, wastewater monitoring for infectious diseases offers a data-driven strategy to inform local public health response and complements city-wide data from centralized wastewater treatment plants. Developing strategies for equitable representation of diverse populations in sub-city wastewater sampling frameworks is complicated by misalignment between demographic data and sampling zones. We address this challenge by: (1) developing a geospatial analysis tool that probabilistically assigns demographic data for subgroups aggregated by race and age from census blocks to sub-city sampling zones; (2) evaluating representativeness of subgroup populations for COVID-19 wastewater-based disease surveillance in Davis, California; and (3) demonstrating scenario planning that prioritizes vulnerable populations. We monitored SARS-CoV-2 in wastewater as a proxy for COVID-19 incidence in Davis (November 2021-September 2022). Daily city-wide sampling and thrice-weekly sub-city sampling from 16 maintenance holes covered nearly the entire city population. Sub-city wastewater data, aggregated as a population-weighted mean, correlated strongly with centralized treatment plant data (Spearman's correlation 0.909). Probabilistic assignment of demographic data can inform decisions when adapting sampling locations to prioritize vulnerable groups. We considered four scenarios that reduced the number of sampling zones from baseline by 25% and 50%, chosen randomly or to prioritize coverage of >65-year-old populations. Prioritizing representation increased coverage of >65-year-olds from 51.1% to 67.2% when removing half the zones, while increasing coverage of Black or African American populations from 67.5% to 76.7%. Downscaling had little effect on correlations between sub-city and centralized data (Spearman's correlations ranged from 0.875 to 0.917), with strongest correlations observed when prioritizing coverage of >65-year-old populations.

Microplastics in two different constructed wetlands systems for wastewater treatment: Removal and fate

Wastewater is one of the main sources of microplastics (MPs) in the environment, but so far, most research has focused on large-scale centralized wastewater treatment plants (WWTPs). This study investigated the removal and fate of MPs in two small-scale WWTPs (S1 and S2) using different constructed wetlands (CWs). Samples from the wastewater, substrates and macroinvertebrates of CWs were collected and analyzed to investigate the fate of MPs. Results showed that the total removal efficiency for MPs was 97 % in both S1 and S2 WWTPs, resulting in effluent concentrations approximately 0.5 particles/L. The CW units of S1 and S2 contributed 92 % and 89 %, respectively, indicating that both VF CWs and HSSF CWs have efficient MPs removal capability. Moreover, fibers were the most abundant shape detected in wastewater (74 % in S1 and 83 % in S2), as well as in substrates and macroinvertebrates. In the S2 CW, fibers had a lower removal efficiency (89 %) compared with other shapes, while in S1 CWs, all shapes had 93 % removal efficiency. The concentration of MPs in surface substrates (0.57–0.71 particles/g dry weight) of CWs did not show any differences between different CWs (p > 0.05). The concentration of MPs inside macroinvertebrates showed a significant decline between S1 CW1 (154.9 particles/g dw on average) and S1 CW2 (94.4 particles/g dw) (p < 0.05), which were consistent with the concentration of MPs in the influent of each CW. This study provides insights into MPs removal by different kinds of CWs and is beneficial for management of MPs with CWs.

Urban wastewater contains a functional human antibody repertoire of mucosal origin

Wastewater-based surveillance of human disease offers timely insights to public health, helping to mitigate infectious disease outbreaks and decrease downstream morbidity and mortality. These systems rely on nucleic acid amplification tests for monitoring disease trends, while antibody-based seroprevalence surveys gauge community immunity. However, serological surveys are resource-intensive and subject to potentially long lead times and sampling bias. We identified and characterized a human antibody repertoire, predominantly secretory IgA, isolated from a central wastewater treatment plant and building-scale wastewater collection points. These antibodies partition to the solids fraction and retain immunoaffinity for SARS-CoV-2 and Influenza A virus antigens. This stable pool could enable real-time tracking for correlates of vaccination, infection, and immunity, aiding in establishing population-level thresholds for immune protection and assessing the efficacy of future vaccine campaigns.

A superstructure-based model for the evolution of park-wide water infrastructure

Industrial parks are crucial to improve material efficiency, economic growth, as well as environmental protection. The increasing demand of freshwater poses a significant challenge for the sustainable development for industrial parks. This work reviews the evolution process of park-wide water infrastructure. A superstructure-based model was used to address the trade-off between water reuse and its impact on the wastewater treatment for the evolutionary state of water infrastructure. In the evolution process of park-wide water infrastructure, five scenarios were defined based on the evolution process of water infrastructure. For wastewater treatment system, centralized or decentralized wastewater treatment plants were deployed according to the evolutionary process of park-wide water infrastructure. The relationship among freshwater consumption, wastewater treatment, and discharge quality were investigated by optimizing the configuration of park-wide water infrastructure. The results indicate that the cost of park-wide water infrastructure with centralized wastewater treatment plant is lower than that with decentralized wastewater treatment plants. Improving the effluent standards for centralized wastewater treatment increases the total cost. For regeneration and reuse, improving the effluent standard for centralized wastewater treatment does not necessarily increase the total cost. The findings indicate that improvement in the discharge standard of centralized wastewater treatment depends on the specifications of the centralized wastewater treatment.

Long-term longitudinal monitoring of SARS CoV-2 in urban rivers and sewers of Nepal

In regions without adequate centralized wastewater treatment plants, sample collection from rivers and sewers can be an alternative sampling strategy for wastewater surveillance. This study aimed to assess the feasibility of alternative sampling strategies by testing samples collected from rivers (n = 246) and sewers (n = 244) in the Kathmandu Valley between March 2021 and February 2022. All samples were concentrated using the skimmed-milk flocculation method and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was quantified using the nucleocapsid (N) and envelope (E) genes qPCR assays. Of the total, 75 % (371/490) of the samples tested positive using at least one qPCR assay, with concentrations ranging from 3.0 to 8.3 log10 gene copies/L. No significant correlation between concentrations of SARS-CoV-2 from both sewers and river with the number of confirmed coronavirus disease 2019 (COVID-19) cases in the Kathmandu valley was observed (p > 0.05). Despite the high concentration of SARS-CoV-2 in rivers and sewers, we hypothesize this finding to be a result of inaccurate number of clinical cases possibly due to inadequate clinical testing. This longitudinal study further supports the statement to consider sampling strategies from sewers and rivers for WBS in Nepal and other low and middle-income countries.

Treatment appraisal and fate of HMs in up-flow anaerobic sludge blanket and trickling filter-based sewage treatment process: The case of a kaliti Centralized Wastewater Treatment Plant, Addis Ababa, Ethiopia

Heavy metals (HMs) in wastewater could pose a significant challenge to biological treatment systems such as in an Up-flow Anaerobic Sludge Blanket Reactor (UASBr) as well as Trickling Filter (TF) performances. These HMs are associated with retention and accumulation of solid precipitates, limitting solid-liquid separation, disrupting biochemical processes, which ultimately brings environmental risks, such as soil contamination and public health issues, dominantly due to the inhibited activities of degrading microorganisms. A cross-sectional study was applied to investigate the levels of HMs in sewage using composite and grab sampling taken from Kaliti Wastewater Treatment Plant and the samples were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The HMs concentrations in mean±(SD) were, Ag ranges from below detection level (BDL) to 63.5 (13.5) mg/kg; Ba 60 (4.47) μg/l to 1291(58.5) mg/kg; Al, BDL to 2358.5(662.5) mg/kg; Cd 0 μg/l to 0.35(0.15) mg/kg; Cr 0 μg/l to 10.5(0.7) mg/kg; Cu 0 μg/l to 23.9(1.2) mg/kg; Zn 5.45 (12.3) to 165(5.4) mg/kg, and Mn 165 (49.5) μg/l to 92.5(3.8) mg/kg. Results indicated that Kaliti Wastewater Treatment Plant was effective in removing pollutants and thereby meeting local and international discharge limits. The plant was also found to be effective in removing Al, Cd, Cu, and Cr, but not in removing Ba and Zn. However, a real time data collection and monitoring of seasonal physicochemical parameters and HM levels in the wastewater treatment plant is suggested useful.

Microplastics in wastewater and sludge from centralized and decentralized wastewater treatment plants: Effects of treatment systems and microplastic characteristics

Domestic wastewater treatment plants (WWTPs) play a vital role in limiting the release of microplastics (MP) into the environment. This study examined MP removal efficiency from five centralized and four decentralized domestic WWTPs in Bangkok, Thailand. MP concentrations in wastewater and sludge were comparable between centralized and decentralized WWTPs, despite these decentralized WWTPs serving smaller populations and having limited treatment capacity. The elimination of MPs ranged from 50 to 96.8% in centralized WWTPs and 14.2–53.6% in decentralized WWTPs. It is noted that the retained MPs concentrations in sludge ranged from 20,000 to 228,100 MP/kg dry weight. The prevalence of synthetic fibers and fragments could be attributed to their pathways from laundry or car tires, and the accidental release of a variety of plastic wastes ended up in investigated domestic WWTPs. Removal of MPs between the centralized and decentralized WWTPs was influenced by several impact factors including initial MP concentrations, longer retention times, MP fragmentation, and variations of MP concentrations in sludge leading to different activated sludge process configurations. Sewage sludge has become a primary location for the accumulation of incoming microplastics in WWTPs. The MPs entering and leaving each unit process were varied due to the unique characteristics of MPs, and their different treatment efficiencies. While the extended hydraulic retention period in decentralized WWTPs decreased the MP removal efficacy, the centralized WWTP with the two-stage activated sludge process achieved the highest MP removal efficiency.

Local residents' perception on factors affecting the willingness to pay for improved urban canal water: a case study in Can Tho city of Vietnam.

Urbanization and economic development cause water pollution in the inner-city canals and rivers globally. Bung Xang canal in Can Tho city of Vietnam is facing problems with water pollution due to the lack of centralized wastewater treatment plants and low public awareness on environmental protection. Perception of local residents was collected using structured questionnaires including both qualitative and quantitative information. Regression analysis was employed to evaluate the factors affecting the decision of respondents on the willingness to pay (WTP) to improve water quality in the Bung Xang canal. Knowledge about the environmental protection fee for domestic wastewater (10% of the VAT-excluded from the selling price of 1 m3 of tap water purchased), age of the respondents and their education levels affected the WTP positively, while respondents' perception on water quality affected the WTP negatively. There was 58.33% of the respondents showed the WTP for improved water quality in the canal. They agreed to pay a small fee of VND 10,000 to 15,000 (equivalent to USD 0.42-0.63)/month (1 US$= 23,700 VND). The result indicates that environmental education is the only way forward for a successful sustainable urban city.

Jilin city central wastewater treatment plant renovation design scheme

Jilin City is one of the top ten famous Chinese cities worth introducing to the world. To further improve the construction of urban infrastructure and meet the needs of the economic and social development of Jilin City, the Jilin City Government Joint Development and Reform Commission and the Ecological Environment Bureau decided to expand and renovate the former Jilin City wastewater treatment plant. This study designs a wastewater treatment plant by comprehensively considering the policy needs and the local basic background characteristics of Jilin to solve the wastewater overflow problem. The design modified the anaerobic tank and Carroussel oxidation ditch processes, which have more advantages than traditional treatment processes, mainly including better BOD, nitrogen and phosphorus removal efficiency, less power consumption, and lower operating costs. This treatment plant design contains two special characteristics: the design considers the overall plan and pipeline layout of the wastewater treatment plant, and the size data of each module are calculated through theoretical study conforming to the real case.

Analysis on Operation and Water Quality Characteristics of Centralized Wastewater Treatment Plants of Industrial Parks in Yellow River Basin, China

The Yellow River basin serves as an important economic belt and industrial base in China, featuring numerous industrial parks. However, alongside its economic significance, the basin struggles with significant water environmental challenges. This study analyzed the operational status, influent water quality, and energy consumption of 63 centralized wastewater treatment plants (WWTPs) from 54 major industrial parks in the Yellow River basin. The scale of these WWTPs was primarily within the range of 1 × 104~5 × 104 m3/d, with an average hydraulic loading rate of 53.8%. Aerobic treatment processes are predominant. The influent concentrations of chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP) in the WWTPs exhibited a right-skewed distribution. The BOD/COD ratio of the WWTPs fluctuated between 0.1 and 1.6, and 75% of the WWTPs showed a COD/TN ratio lower than eight. The average BOD5/TN was 2.7, and the probability of influent BOD5/TP &gt; 20 was 84.6%. A significant linear correlation exists between the influent BOD and COD concentrations, while moderate linear relationships are also observed among NH3-N, TN and TP, emphasizing the importance of maintaining appropriate nitrogen and phosphorus levels for efficient pollutant removal. The average electricity consumption of WWTPs in the Yellow River basin in 2023 was 1.1 kWh/m3. It is important to upgrade these WWTPs and reduce their energy consumption. Further strengthening the construction of industrial wastewater collection and treatment facilities based on regional characteristics is recommended to promote the high-quality development of industrial wastewater treatment in the Yellow River basin.

Wastewater generation model to predict impacts of urine separation on wastewater treatment plants.

Wastewater treatment plants (WWTPs) are under increasing pressure to enhance resource efficiency and reduce emissions into water bodies. The separation of urine within the catchment area may be an alternative to mitigate the need for costly expansions of central WWTPs. While previous investigations assumed a spatially uniform implementation of urine separation across the catchment area, the present study focuses on an adapted stochastic wastewater generation model, which allows the simulation of various wastewater streams (e.g., urine) on a household level. This enables the non-uniform separation of urine across a catchment area. The model is part of a holistic modelling framework to determine the influence of targeted urine separation in catchments on the operation and emissions of central WWTPs, which will be briefly introduced. The wastewater generation model is validated through an extensive sampling and measurement series. Results based on observed and simulated wastewater quantity and quality for a catchment area of 366 residents for two dry weather days indicate the suitability of the model for wastewater generation and transport modelling. Based on this, four scenarios for urine separation were defined. The results indicate a potential influence of spatial distribution on the peaks of total nitrogen and total phosphorus.

Emerging and legacy per- and polyfluoroalkyl substances (PFAS) in fluorochemical wastewater along full-scale treatment processes: Source, fate, and ecological risk

The increasing applications of emerging per- and polyfluoroalkyl substances (PFAS) have raised global concern. However, the release of emerging PFAS from the fluorochemical industry remains unclear. Herein, the occurrence of 48 emerging and legacy PFAS in wastewater from 10 fluorochemical manufacturers and mass flows of PFAS in a centralized wastewater treatment plant were investigated. Their distribution and ecological risk in neighboring riverine water were also evaluated. In wastewater from fluorochemical manufacturers, PFAS concentrations were in the range of 14,700–5200,000 ng/L and 2 H,2 H-perfluorooctanoic acid (6:2 FTCA), perfluorooctanoic acid (PFOA), N-ethyl perfluorooctane sulfonamide (N-EtFOSA), and 1 H,1 H,2 H,2 H-perfluorodecanesulfonate (8:2 FTS) were the major PFAS detected. Several PFAS displayed increased mass flows after wastewater treatment, especially PFOA and 6:2 FTCA. The mass flows of PFAS increased from − 20% to 233% after the activated sludge system but decreased by only 0–13% after the activated carbon filtration. In riverine water, PFAS concentrations were in the range of 5900–39,100 ng/L and 6:2 FTCA, 1 H,1 H,2 H,2 H-perfluorodecyl phosphate monoester (8:2 monoPAP), 1 H,1 H,2 H,2 H-perfluorooctyl phosphate monoester (6:2 monoPAP), PFOA, and perfluorohexanoic acid (PFHxA) were the major PFAS detected. PFOA and 6:2 FTCA exhibited comparable hazard quotients for ecological risk. Current wastewater treatment processes cannot fully remove various PFAS discharged by fluorochemical manufacturers, and further investigations on their risk are needed for better chemical management.

Heterogeneous application prospect and techno-economic analysis of hydrogen from wasted activated sludge: Using microbial electrolysis cell

The efficiency of hydrogen production from waste activated sludge (WAS) through combining anaerobic digestion and microbial electrolysis cell (AD-MEC) systems has been increasing. With advancements in materials science, the cost of MEC anode materials has decreased, making this technology potentially economically viable. By analyzing data from 3611 centralized wastewater treatment plants (WWTPs) in 276 prefecture-level cities in China, theoretical application scenarios and environmental benefits of hydrogen production in these WWTPs via AD-MEC were evaluated. Additionally, a theoretical economic model is constructed to validate the economic feasibility of AD-MEC technology. The key findings suggested that the theoretical potential for hydrogen production from WAS in China is 152,610.5 tons/year. The amount of CO2 emitted by natural gas, fuel diesel buses, or power electric public transportation could reduce approximately 1.51, 3.2, and 2.4 million tons/year, respectively, through utilizing hydrogen instead of the above energy sources. Due to the broader temperature adaptability of hydrogen fuel cells, this emission reduction effect was more pronounced in colder, high-latitude regions. Economic analysis revealed that, considering sludge reduction, the AD-MEC system could achieved a return on investment of 13%. This study demonstrated that with the rapid progression in urbanization, AD-MEC systems could contribute to reducing WAS treatment costs and providing clean hydrogen for carbon emission reductions in urban areas.

Phosphate Recovery from Urine-Equivalent Solutions for Fertilizer Production for Plant Growth.

This study presents a proof of concept for the recovery of phosphate from aqueous solutions with high phosphorus (PO4-P) initial contents to simulate the concentration of streams from decentralized wastewater systems. Solutions with ∼500 ppm phosphorus enable phosphate adsorption and recovery, in contrast to the highly diluted inlet streams (<10 ppm) from centralized wastewater treatment plants. In this work, Mg-Fe layered double hydroxide is used as a phosphate adsorbent, demonstrating its separation from aqueous streams, recovery, and use as a fertilizer following the principles of circular economy. We demonstrate that the mechanism of phosphate adsorption in this material is by a combination of surface complexation and electrostatic attraction. After the loss of crystallinity in the presence of water in the first cycle and its associated decrease in adsorption capacity, the Mg-Fe layered double hydroxide (LDH) is stable after consecutive adsorption/desorption cycles, where desorption solutions were reused to substantially increase the final phosphate concentration demonstrating the recyclability of the material in a semicontinuous process. Phosphate recovered in this way was used to complement phosphate-deficient plant growth medium, demonstrating its efficacy as a fertilizer and thereby promoting a circular and sustainable economy.

Industrial Wastewater Indirect Discharges in Integrated Pollution Prevention and Control Perspective: A Case Study of Prague

Wastewater discharge is one of the sources of environmental pollution. Wastewater pollution originates, inter alia, in industrial wastewater. After treatment, industrial wastewater can be discharged directly into the receiving water body or indirectly into a sewerage network terminated by the concluding stage of wastewater treatment. In the Czech Republic, indirect wastewater discharges are obeyed by the contractual relationship between the wastewater producer and the sewerage network operator. General limits for indirectly discharged wastewater are not set by any national legislation. The aim of this paper is a description of industrial wastewater discharged into the municipal sewerage system in Prague and possibilities of setting limits for installations undertaking the industrial activities listed in Annex I of the Integrated Prevention Act. The study showed that 72% of installations discharge industrial wastewater indirectly. The majority are energy plants that produce boiler blowdown wastewater. More than 80% of wastewater from studied installations is treated by one central wastewater treatment plant. The studied installations are equipped with a wastewater neutralization unit. However, despite the existence of the legislative framework to propose limits for studied installations, only two installations covered by BAT conclusions with relevant BAT-AELs for indirect discharges to the receiving water body were determined. Generally, a small percentage of installations can be limited by an integrated permit due to an inconsistent approach to the issue of indirect discharges from installations under the scope of the Integrated Prevention Act.

Identification of Factors Influencing the Presence of Fecal Coliforms in Densely Populated Areas with Centralized Wastewater Treatment Systems

Introduction: Tegal Panggung is a high population density sub-district of 26,326 inhabitants/km2. Most residents utilize wells to meet their water demands, but fecal coliform bacteria were found in several wells at Tegal Panggung. This type of contamination source is typically from on-site wastewater treatments. However, wastewater from Tegal Panggung is treated at a centralized wastewater treatment plant. This study is aimed at identifying the factors leading to the presence of fecal coliform bacteria in Tegal Panggung. Methods: Factors reviewed in this study were the amount of waste, drainage, cattle pens, toilets, types of wells, and building density. Statistical methods and GIS were applied to determine the influence of the factors on the presence of fecal coliform and to map its distribution along with potential sources of pollution. The number of wells tested was 32, with a research period from September to October 2021. The statistical methods used are the Kolmogorov-Smirnov Normality Test, the Spearman Correlation Test, and the spatial analysis method, which was carried out using QGIS. The statistical tests were conducted to determine the correlation value between fecal coliform and pollutant. Results and Discussion: The study showed that only 40.62% met the standard requirements when there should be no fecal coliform contents in well water. Conclusion: Based on the Spearman Correlation Test, it can be deduced that the factors affecting the presence of fecal coliform within 10 meters radius are garbage and of 30 meters radius are toilets and building density.

Hospitals and households as primary emission sources for risk-posing pharmaceuticals in municipal wastewater

A wide range of pharmaceutical residues is known to occur in the environment. While they are released into surface waters mainly through centralized wastewater treatment plants (WWTPs), their primary emission sources are located upstream in the sewer network. Information on emissions from different types of primary emission sources is scarce. However, such information could help direct emission reduction measures more efficiently. In this study, we analysed the concentrations of selected active pharmaceutical ingredients (APIs) in wastewater samples taken from altogether ten sites, covering primary emission sources (hospitals and households), and conventional WWTPs. The concentrations in WWTP effluents were used to identify APIs causing risk in recipient waterbodies. Furthermore, the API loads from households and hospitals were compared to those reaching the WWTP in mixed influents. Our results confirm previously published observations of several pharmaceuticals exceeding their predicted no-effect concentrations in effluent wastewaters. Moreover, the concentrations of most of the analysed APIs are comparatively high in hospital wastewaters, resulting in elevated risk quotients. While the total API loads are relatively low from primary emission sources, owing to the low wastewater volume generated at those sites, per capita emissions were shown to be several times higher at hospital sites than at household sites for APIs such as metronidazole, trimethoprim, and ofloxacin. These findings indicate, that directing emission reduction measures to hospitals could be an effective way to decrease the loads of several risk-posing APIs into the environment, especially where hospital contribution to overall wastewater flow to WWTPs is high.

Control Methods of Invasive Plant Species and the Influence of Cultural Vegetation on the Microclimate within the Central Wastewater Treatment Plant in Ostrava – Pilot Results

Control Methods of Invasive Plant Species and the Influence of Cultural Vegetation on the Microclimate within the Central Wastewater Treatment Plant in Ostrava – Pilot Results

Constructed wetlands for the treatment of combined sewer overflow upstream of centralized wastewater treatment plants

Combined sewer overflows (CSOs) constitute nowadays a major environmental concern, representing one of the main untreated sources of pollution for receiving water bodies. Additional, in recent years, the frequency and intensity of CSOs have increased due to the growing urbanisation and climate change. Although there is no single effective strategy, one of the most promising approaches for the control and treatment of CSOs can be found in nature-based solutions (NBS), such as constructed wetlands (CWs). Despite the demonstrated potential of CWs to treat CSOs, the only data reported in the literature refer to CSO-CW systems located along the sewerage network. This research represents, to the best of our knowledge, the first monitoring of a full-scale CSO-CW designed to treat the combined sewer overflow upstream of the WWTP located in Carimate, in the province of Como (Italy). The system is a multistage CW, composed by a 1st vertical subsurface flow (VF) stage (total area of 8500 m2) and a 2nd free water surface (FWS) stage (total area of 4500 m2). The observed removal rates during the 3 years monitoring campaign (mean values equal to 83.2%, 64.6%, 63.8% for COD, TP, and N-NH4+ respectively) confirmed the treatment efficiency of CW system for all the investigated parameters, consistent with literature data for CSO-CWs in line with the sewerage network, despite its large scale and different hydraulic characteristics. Furthermore, the system also provides additional ecosystem services such as flood mitigation (average CSO interception of 82%), enhancement of biodiversity and a low operational and maintenance cost.