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Constructed wetlands (CWs) are well-proven ecologically engineered systems that remove nutrients, pathogens, and other contaminants from wastewater. The inherent role of CWs as wastewater polishing systems makes them hotspots for microplastic accumulation. To investigate the transport and characteristics of microplastic pollution in full-scale surface flow municipal CWs, environmental microplastic samples were collected from the Se7en/Seven Wetlands in Lakeland (Florida), one of the largest wastewater CWs in the United States (650 hectares). Both water and sediment samples were collected at eight control stations in each of the seven wetland cells and at six locations in the influent distribution channel to investigate the linkage between water and sediments in microplastic fate and transport. This study found that the Se7en Wetlands has a near complete retention of microplastics greater than 300 μm. Concentrations at each sampling site in the CW ranged from 0 to 17 particles/m3 in water and 0–1217 particles/kg dry weight in sediment. The highest concentrations of particles were found in sediment samples, especially those found in locations of reduced flow, signaling settling occurring as water velocities decrease. Microplastics were also analyzed for size, shape indicators, and polymer type to inform how their properties change as they travel through the system. Particles were extracted visually and analyzed using ImageJ and Raman spectroscopy. Polyethylene and polypropylene were the most abundant polymer types with the highest proportion of particles being fragments between 1 and 5 mm in size. Shape indicators (particle area, circularity, and solidity) in water decreased through the treatment stream, whereas sediment samples saw no clear trend. Overall, this study finds that large CWs retain a vast amount of microplastics. It sheds light on how the dynamics of natural processes affect the fate and transport of microplastics as well as the importance of evaluating multimedia concentrations in CWs. [ABSTRACT FROM AUTHOR]

Partially Saturated Vertical Constructed Wetlands (PSV-CWs) are novel wastewater treatment systems that work through aerobic and anaerobic conditions that favor the removal of pollutants found in high concentrations, such as rivers contaminated with domestic wastewater and landfill leachate. The objective of the study was to evaluate the efficiency of PSV-CWs using monocultures and polycultures of Typha latifolia and Heliconia psittacorum to treat river waters contaminated with leachates from open dumps and domestic wastewater. Six experimental units of PSV-CWs were used; two were planted with Typha latifolia monoculture, two with Heliconia psittacorum monoculture and two with polycultures of both plants. The results indicated better organic matter and nitrogen removal efficiencies (p < 0.05) in systems with polycultures (TSS:95%, BOD5:83%, COD:89%, TN:82% and NH4+:99%). In general, the whole system showed high average removal efficiencies (TSS:93%, BOD5:79%, COD:85%, TN:79%, NH4+:98% and TP:85%). Regarding vegetation, both species developed better in units with monocultures, being Typha latifolia the one that reached a more remarkable development. However, both species showed high resistance to the contaminated environment. These results showed higher removals than those reported in the literature with conventional Free Flow Vertical Constructed Wetlands (FFV-CWs), so PSV-CWs could be a suitable option to treat this type of effluent. NOVELTY STATEMENT: The research addresses the contamination of water resources in developing countries by landfill leachate and domestic wastewater discharges. It proposes treatment through Partially Saturated Vertical Constructed Wetlands (PSV-CWs), which, despite the limited information available, have been shown to be effective in removing pollutants in effluents with high concentrations. In addition to evaluating PSV-CWs, the study examines the impact of different types of vegetation on pollutant removal efficiency, concluding that PSV-CWs are a promising and viable option for the treatment of these effluents. [ABSTRACT FROM AUTHOR]

Natural water resources often contain fluorides and chlorides due to wastewater discharge; however, excessive exposure to fluorides can pose health risks to humans. Elevated chloride levels can negatively affect aquatic fauna and disrupt the reproductive rates of plants. This study assessed constructed wetlands (CWs) featuring monocultures (including Canna hybrid, Alpinia purpurata, and Hedychium coronarium) and polycultures (combinations of species from the monoculture systems) of ornamental plants (OPs) to evaluate their efficiency in removing fluorides and chlorides. The results revealed that the ornamental plants flourished in the CW conditions without sustaining any physical damage. C. hybrid demonstrated the longest roots and the highest volume, as well as greater height compared to other species. However, this did not affect the ion removal efficiency. In polyculture systems, 42.2 ± 8.8% of fluoride was removed, a result that was not significantly different (p > 0.05) from the removal rates observed in monocultures of C. hybrid (42.5 ± 7.5%), H. coronarium (36.8 ± 7.0%), or A. purpurata (30.7 ± 7.9%). For chloride, a similar pattern emerged, with 32.4 ± 4.8% removed in constructed wetlands (CWs) using a polyculture of ornamental plants, a figure that was also not significantly different (p > 0.05) from the removal percentages in monocultures of C. hybrid (29.1 ± 5.3%), H. coronarium (28.1 ± 5.0%), or A. purpurata (32.0 ± 5.7%). Our results indicate that CWs with polyculture species contribute to pollutant removal at levels comparable to those found in monoculture systems. However, polyculture systems offer enhanced aesthetic appeal and biodiversity, incorporating various ornamental flowering plants. The use of this eco-technology for removing fluoride and chloride pollutants helps prevent river contamination and associated health issues. [ABSTRACT FROM AUTHOR]

The pig farming industry in Mexico is an important economic activity that is growing significantly, generating large volumes of wastewater that negatively affect water bodies and human health. The lack of adequate treatment systems exacerbates this problem. Hybrid constructed wetlands that combine Vertical Flow Constructed Wetlands (VF-CWs) and Horizontal Flow Constructed Wetlands (HF-CWs) offer an economical and effective treatment using natural processes. The objective was to evaluate the removal of contaminants from pig farm wastewater using two configurations of hybrid systems with ornamental plants. Two configurations were established: System I: VF-CWs + HF-CWs and System II: HF-CWs + VF-CWs. The VF-CWs were planted with Canna hybrids and the HF-CWs with Heliconia latispatha. The results indicated higher removal efficiencies of organic matter, nitrogen, and phosphorus in System I (BOD5: 72.99 %, COD: 71.41 %, TN: 79 %, NH4+: 84.31 %, NO3-: 74.29 %, TP: 59.54 %, FC: 99.88 %) compared to System II (BOD5: 66.80 %, COD: 67.01 %, TN: 77.90 %, NH4+: 82.31 %, NO3-: 70.48 %, TP: 55.81 %, FC: 99.89 %), regarding FC, the same results were obtained in both systems. Both plant species showed vigorous development, although the growth of Heliconia latispatha was more notable. In conclusion, the results suggest that the VF-CWs + HF-CWs configuration in hybrid wetlands could be a suitable option for treating this type of effluent.

This study investigated the use of nature‐based solutions for treating real pharmaceutical industry wastewater in Jordan. A pilot‐scale hybrid treatment wetland (TW) equipped with local zeolite was employed, comprising a tidal flow TW and a horizontal subsurface flow TW. This system was efficient in treating pharmaceutical wastewater with removal efficiencies of 61.4%, 52.6%, 60.1%, and 61.9% for chemical oxygen demand, total phosphorus, total nitrogen, and NH4+‐N, respectively. The final effluent met Jordanian standards for the reuse of treated wastewater in irrigation (Class B). Five pharmaceuticals, namely, enrofloxacin, ciprofloxacin, ofloxacin, lincomycin, and trimethoprim, demonstrated nearly completed removal (93.6–99.9%). Moderated removal performances (59.2–68.2%) were observed for two compounds, flumequine and sulfaquinoxaline. However, three pharmaceuticals, namely, carbamazepine, diclofenac, and sulfadimidine, showed limited removal performances (1.1–20.5%). This study supported the feasibility of using nature‐based solutions for treating pharmaceutical wastewater and highlighted that future studies are required to optimize this strategy for removing a broader range of pharmaceuticals. Highlights: Treatment wetland (TW) as a nature‐based solution can treat pharmaceutical wastewater.Tidal flow TW with a better aerobic condition was favourable for pollutant removal.Jordanian zeolite was a promising wetland media to enhance the treatment performance.The final effluent complied with Jordanian standards for wastewater reuse in irrigation.Some pharmaceuticals could achieve completed removal by the hybrid TW system. [ABSTRACT FROM AUTHOR]

Treatment wetlands are recognized as an effective technology for mitigating the impacts of urban runoff. However, there is no consensus on the design guidelines, and the effects of some design features, such as the underdrain system, remain unexplored. A simple analog model has been developed to mimic the underdrain network (when operating at saturation) and to evaluate the spatial heterogeneity of the flow entering it. The model has been applied to a treatment wetland in the Paris area and shows that the underdrain network was largely undersized, likely causing an uneven distribution of infiltrating flow along the length of the treatment wetland. It was also shown that this analog model can be used for optimization purposes and that it is important to use conservative values of the rugosity coefficient when designing an underdrain network. HIGHLIGHTS A brand-new analog model has been developed to mimic the hydraulic functioning of the underdrain.; Inflows into the underdrain decrease with the distance to the outlet.; Undersized underdrains can create uneven distribution of the percolating flow along the length of a treatment wetland (TW).; The analog model allows optimizing the design of underdrains for TWs with a saturated layer at the bottom.;

Natural water resources often contain fluorides and chlorides due to wastewater discharge; however, excessive exposure to fluorides can pose health risks to humans. Elevated chloride levels can negatively affect aquatic fauna and disrupt the reproductive rates of plants. This study assessed constructed wetlands (CWs) featuring monocultures (including Canna hybrid, Alpinia purpurata, and Hedychium coronarium) and polycultures (combinations of species from the monoculture systems) of ornamental plants (OPs) to evaluate their efficiency in removing fluorides and chlorides. The results revealed that the ornamental plants flourished in the CW conditions without sustaining any physical damage. C. hybrid demonstrated the longest roots and the highest volume, as well as greater height compared to other species. However, this did not affect the ion removal efficiency. In polyculture systems, 42.2 ± 8.8% of fluoride was removed, a result that was not significantly different (p > 0.05) from the removal rates observed in monocultures of C. hybrid (42.5 ± 7.5%), H. coronarium (36.8 ± 7.0%), or A. purpurata (30.7 ± 7.9%). For chloride, a similar pattern emerged, with 32.4 ± 4.8% removed in constructed wetlands (CWs) using a polyculture of ornamental plants, a figure that was also not significantly different (p > 0.05) from the removal percentages in monocultures of C. hybrid (29.1 ± 5.3%), H. coronarium (28.1 ± 5.0%), or A. purpurata (32.0 ± 5.7%). Our results indicate that CWs with polyculture species contribute to pollutant removal at levels comparable to those found in monoculture systems. However, polyculture systems offer enhanced aesthetic appeal and biodiversity, incorporating various ornamental flowering plants. The use of this eco-technology for removing fluoride and chloride pollutants helps prevent river contamination and associated health issues.

Nature-based solutions are increasingly used in domestic wastewater treatment, because of their potential to remove contaminants and pathogens from water (e.g., stormwater, river water, wastewater) as well as their provided co-benefits, such as mitigation of the heat island effect or enhanced biodiversity. The transition from traditional grey technologies towards nature-based solutions in domestic wastewater treatment might yield multiple benefits for local communities while enhancing biodiversity. Although some nature-based solutions such as treatment wetlands have been used for decades in domestic wastewater treatment, this is not the case for others such as green walls or roofs, which lack implementation guidelines and design criteria. Aiming to support implementation of nature-based solutions in domestic wastewater treatment, we have developed an online decision-support system for the pre-selection of the best nature-based solution to use in each socio-environmental context and adapted to the needs, as well as an estimate of the required area. Our decision-support system's recommendations are based on an expert knowledge-driven approach, building on two complementary expert knowledge elicitation workshops. We hope the developed online decision-support system will support the transition towards integrating nature-based solutions into urban water and wastewater treatment systems. HIGHLIGHTS We lack implementation guidelines and design criteria for nature-based solutions (NBS) in water sanitation.; We have developed an online decision-support system to facilitate NBS implementation.; NBS implementation in domestic wastewater treatment will support SDG6 achievement.;

This work aimed to evaluate the performance of modified vertical flow treatment wetlands (VF-TWs) in terms of depth and medium to assess the effect of the feeding/resting periods and footprint (FP). The modifications were proposed for treating domestic wastewater in rural areas with flow variations such as tourist sites. The experimental setup included six laboratory-scale VF-TWs: (a) normal (VF-N), bed depth 1.0 m, filled with sand and (b) modified (VF-M), bed depth 0.5 m, filled with sand (upper) and zeolite (bottom, saturated). The operation was divided into three phases (3 months each), varying the feeding/resting period and FP: phase I, 5 d/10 d, 2.6 m2/person-equivalent (PE); phase II, 3.5 d/3.5 d, 1.7 m2/PE; and phase III, only feeding no resting, 0.85 m2/PE. Influent and effluent grab samples were taken every 2 weeks. The results showed effective removal (above 60%) of total solids, organic matter, and pathogens for both VF-N and VF-M. Regarding nutrients, VF-M showed a phosphate removal below 60%, but no consistent removal (15–60%) of total nitrogen. Thus, the results suggest that proposed modifications can be an option to be established in tourist sites, but further work should be conducted to improve and optimize total nitrogen removal. HIGHLIGHTS VF-TWs with the proposed modifications (bed depth, feeding/resting period; footprint reduction; zeolite as medium) had effective removal of total solids, organic matter, and pathogens.; VF-TWs with the proposed modifications were shown to be robust and able to cope with flow variations in tourist facilities of rural areas.; Further work should be conducted for consistent nitrogen removal in VF-TWs with the proposed modifications.;

Distillery wastewater is a difficult type of wastewater to treat because of its low pH (pH = 3.3), high chloride and sulfate content, high organic matter concentrations (3.2 gTSS/L, 6.8 gBOD5/L and 14.6 gCOD/L). Moreover, the rum production is intermittent over the season (5 months per year). The acidity of this type of wastewater, combined with the relatively underbalanced nitrogen concentrations, requires the addition of specific chemicals such as soda solution and urea, when a biological treatment technology is envisioned. In this full scale experiment, located in a tropical zone (Martinique island), the objective was to demonstrate the ability of treatment chain composed of a sequencing batch reactor (SBR) followed by vertical flow treatment wetlands (VFTWs). The objective was to use VFTWs for treatment polishing as well as sludge/water separation and sludge treatment over years. The VFTWs are planted with Heliconia psittacorum and Cyperus papyrus. The monitoring occurred during three rum production seasons. The treatment chain allows an overall average removal of TSS of 92% and 96% for organic matter (COD and BOD5). The average annual load applied to the filter in operation was 32 kgTSS/m²/y, which is equivalent to 78 kgTSS/m²/y over the distillation period. The applied load was too high for the plants tested and lead to plant death and surface clogging of the filters. Nevertheless, this experiment allowed specifying the way to operate the whole treatment plant as well as acceptable daily loads that should be applied on the VFTWs. Even if the operation of the filters and the selection of plants in a tropical climate still need to be optimized, this combination of intensive and extensive processes is an effective and sustainable nature-based solution for rum distillery wastewater treatment.

In recent decades, previously unobserved trace compounds have become more widely detected in wastewater treatment effluents and freshwater ecosystems. Emanating from various sources and presenting potential human health and ecological risks at much lesser concentrations than traditional contaminants, detection of "emerging contaminants" has increased with improvements in analytical techniques. The behavior of emerging contaminants in wetlands is a topic of increasing interest, as natural wetlands are known to transform and sequester pollutants and constructed or treatment wetlands are widely utilized to address elevated concentrations of constituents of concern. Both natural and constructed wetlands are complex biogeochemical systems with interrelated abiotic and biotic mechanisms leading to the removal of emerging contaminants. A literature review was performed to assess the current state of knowledge of various wetland mechanisms involved in removing these contaminants from surface waters and effluents. The primary mechanisms discussed in the literature are sorption, photodegradation, microbial biodegradation and phytoremediation. The most influential mechanisms are dependent on the properties of the contaminants and wetland systems studied. Common trends exist for different constructed wetland designs to leverage various mechanisms based on hydrology, substrate and vegetation plantings. Much remains to be understood about the various processes occurring in wetlands as they relate to emerging contaminant removal. Improving the understanding of the potential role of wetland mechanisms can help manage this environmental challenge more effectively. [ABSTRACT FROM AUTHOR]

Free water surface (FWS) wetlands can be used to treat agricultural runoff, thereby reducing diffuse pollution. However, as these are highly dynamic systems, their design is still challenging. Complex models tend to require detailed information for calibration, which can only be obtained when the wetland is constructed. Hence simplified models are widely used for FWS wetlands design. The limitations of these models in full-scale FWS wetlands is that these systems often cope with stochastic events with different input concentrations. In our study, we compared different simple transport and degradation models for total nitrogen under steady- and unsteady-state conditions using information collected from a tracer experiment and data from two precipitation events from a full-scale FWS wetland. The tanks-in-series model proved to be robust for simulating solute transport, and the first-order degradation model with non-zero background concentration performed best for total nitrogen concentrations. However, the optimal background concentration changed from event to event. Thus, to use the model as a design tool, it is advisable to include an upper and lower background concentration to determine a range of wetland performance under different events. Models under steady- and unsteady-state conditions with simulated data showed good performance, demonstrating their potential for wetland design. HIGHLIGHTS The most robust model combination: the tanks-in-series model under steady conditions.; First-order kinetics with non-zero background concentration was the best for degradation.; The optimal background concentration changed from event to event.; Potential use of TIS model in unsteady conditions when infiltration and evapotranspiration occur.;

[Display omitted] • Coupling of anaerobic process with constructed wetlands. • Full-scale sub-mesophilic sewage treatment with high-purity CH 4 recovery. • Anaerobic reactor COD utilization correlation with temperature. • >94 % BOD 5 and > 97 % TSS removal from the integrated system. • Nutrient-rich reclaimed water suitable for fertigation. This work investigated the long-term (>1000 days) performance of an integrated process consisting of an upflow anaerobic sludge blanket (UASB) coupled to a two-stage (saturated and unsaturated) vertical subsurface flow constructed wetland (VSSF-CW) for the treatment of up to 91.3 ± 10.3 m3/d domestic wastewater. The UASB reactor operated under ambient conditions during both the winter (temperature of 13.5 ± 0.7 °C) and the summer (temperature of 26.4 ± 0.8 °C). The two-stage CW treated the UASB effluent to maximize the total suspended solids (TSS) and chemical oxygen demand (COD) removal of the integrated process and oxidize ammonium to nitrate. The UASB reactor was able to remove 50 % ± 17 % to 83 % ± 9 % of TSS and 43 % ± 18 % to 76 % ± 3 % of COD, producing on average 0.36 Nm3 CH 4 kg COD rem –1 of biogas, which varied significantly with season. The two-stage CW contributed to the further removal of the pollutants achieving overall removal of TSS ranging from 97 % ± 3 % to 99 % ± 0 % and COD from 91 % ± 2 % to 96 % ± 1 %. The influent ammonium nitrogen removal ranged between 87 % ± 4 % and 99 % ± 0 % via nitrification. This operation scheme allowed nutrient retention in the final effluent as the total nitrogen and total phosphorus removal was only partial (no more than 41 % ± 7 % and 44 % ± 13 %, respectively). The results suggest that the UASB – CW integration is a very promising solution to produce energy and Class A reclaimed water (EU Regulation 2020/741). The robustness and effectiveness of the treatment process against loading and temperature fluctuations can prevent the quality compromise of the final effluent. [ABSTRACT FROM AUTHOR]

Constructed Wetlands (CW) have gained popularity over the last decades due to their cost-effectiveness, easy and simple operation and environmental compatibility in wastewater treatment. This ecological engineering technology appears particularly ideal for low-income regions. In this study, three widely used CW types (horizontal flow, vertical flow, and hybrid CW) were constructed and evaluated for their effectiveness in removing various pollution parameters (BOD 5 , COD, TSS, NH 4 -N, NO 3 -N, and TP) from an industrial effluent. Different configurations were tested such as CW type, hydraulic residence time, plants presence, and artificial aeration. Results showed that the hybrid CW configuration (i.e., vertical flow CW followed by horizontal subsurface flow CW) achieved the highest removal rates of all pollutants, i.e., more than 90% of BOD 5 , COD, TSS, and NH 4 -N. The single horizontal flow and vertical flow CW designs showed variations in the removal of NO 3 -N and TP (less than 30%), which were significantly improved (50% and 70%, respectively) by using the hybrid CW system. Artificial aeration significantly improves the performance of the CW system, especially for ammonia nitrogen and organic matter removal, while plants presence is also beneficial in the treatment performance. An 8-days HRT seems to be adequate for high removal rates in passive CW designs, though in aerated wetlands a lower HRT of 4 days seems sufficient. These findings suggest that the hybrid CW system could be a promising option for efficient wastewater treatment in developing regions. [Display omitted] • High effect of artificial aeration on BOD 5 and NH 4 -N removal compared to other variables. • The presence of plants in all designs enhances the system performance. • The hybrid system (VF combined with HF) provides the highest pollutant removal rates. • Increasing the retention time significantly increases the nutrient removal efficiency. • An efficiency of over 95% in BOD 5 , COD, TSS and NH 4 -N removal was achieved. [ABSTRACT FROM AUTHOR]

Treatment wetlands have the potential to treat a range of water and wastewater pollutants while using less energy and chemicals than conventional treatment processes, making them a viable option for improving the sustainability of water treatment systems. However, water treatment systems used for water reuse must also be protective of human health. To date, the human health protection benefits of treatment wetlands have not been rigorously quantified in the context of current human health risk frameworks. This study presents a comprehensive review of the ability of treatment wetlands to provide reliable pathogen reduction to meet risk-based treatment targets for water reuse. Following an existing protocol for establishing log reduction credits, we systematically reviewed the documented pathogen reduction performance of major treatment wetland types in terms of core components of that protocol, including pathogen removal mechanisms, identification of target pathogens, and influencing factors. Results of the review point to design and operational conditions under which treatment wetlands could likely be credited with a log reduction value of approximately 0.5 or greater for virus, protozoa and bacteria. These conditions are specified in terms of preliminary operating envelopes, or design and operational parameter windows associated with optimal performance. Important caveats are noted, as are specific and tractable recommendations for future research and data collection efforts that would help refine operating envelopes and define log reduction credits for these promising water treatment technologies. As a resource to other practitioners, we have also included the detailed performance characterization database as Supplemental Information. This database includes a detailed tracking of log reduction values as well as design and operational parameters reported in the literature., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier B.V.)

Wastewater treatment using constructed wetlands (CWs) based on natural wetlands constitute a viable alternative with excellent cost and benefit, presenting themselves as efficient technologies in the secondary and tertiary treatment of wastewaters with low implementation, operation, and maintenance costs. The present study aims to evaluate the use of bamboo species, as an alternative to macrophytes, frequently used in CWs, through bibliometric analysis, besides to a review based on case studies. The maps generated by the VOSviewer software and by the analyses of the Web of Science and Scopus databases allowed for a review of typical concepts of CWs, in addition to revealing potential benefits of using bamboos in CWs, such as their hyperaccumulation capacity and bioproduct generation. Other promising aspects were identified, for example the use of bamboo charcoal as a substrate used in subsurface wetlands and the application of ornamental bamboo species for landscape improvements, among other observations. The efficiencies found in six case studies showed values between 89–99.7%, 47.6–99.7%, 58.3–99.9%, and 85.5–99.8% for BOD5, COD, total nitrogen (TN), and total phosphorus (TP), respectively. Despite the promising results, the lack of studies using bamboos in CWs for the treatment of wastewaters limits an assertive statement about the use of this technology, requiring further research, focusing on the morphological functions of bamboos in this treatment with landscape integration and resources recovery. [ABSTRACT FROM AUTHOR]

Upgrading treated wastewater systems can provide reclaimed water for different uses. In this paper, the potential for wetland creation and maintenance is evaluated. The upgrading treatment consists of intensified vertical flow constructed wetlands (VFCWs), where the physicochemical and microbiological water quality is improved, followed by free-water surface constructed wetlands (FWSCWs), where biodiversity is enhanced. This renaturalization system has been implemented in two wastewater treatment plants (WWTPs): Monasterios, where one VFCW 60 m2 and two FWSCWs (50 m2 each) have been built, and Carricola, where two VFCWs in series (20 m2 each) have been constructed. The VFCWs were filled with drinking water treatment sludge (DWTS), a waste produced in drinking water treatment plants, hence the circularity of the project. Data obtained during the first year of operation is presented. The mean hydraulic loading rates in the VFCWs were 0.79 and 0.62 m/d in Monasterios and Carricola, respectively. In FWSCWs, the HLRs were 0.35 and 0.32 m/d in FWSCW1, which receives the effluent of the VFCW, and FWSCW2, which receives the secondary treatment effluent, respectively. In the VFCWs, an important reduction of total phosphorus was achieved, 77% in Monasterios and 70% in Carricola, and other pollutants were fairly reduced as well. In FWSCWs, some pollutants, such as total nitrogen or phosphorus, were reduced, but other, such as total suspended solids or organic matter, increased due to algae growth and external inputs. The critical point is that biodiversity is increased thanks to these systems, aquatic invertebrate presented better diversity indexes in the FWSCW receiving the upgraded water from the intensified VFCW. Birds, amphibians, and reptiles have also colonised the created habitats. • Treated wastewater can be upgraded by intensified vertical flow constructed wetlands. • Drinking water treatment sludge is an appropriate adsorbent material. • Valorisation of drinking water treatment sludge integrates circularity in urban water cycle. • Upgraded water benefits the receiving water bodies, enhancing biodiversity. • Birds use the created wetlands to feed, rest and nest. [ABSTRACT FROM AUTHOR]

In response to the global loss and degradation of wetland ecosystems, extensive efforts have been made to reestablish wetland habitat and function in landscapes where they once existed. The reintroduction of wetland ecosystem services has largely occurred in two categories: constructed wetlands (CW) for wastewater treatment, and restored wetlands (RW) for the renewal or creation of multiple ecosystem services. This is the first review to compare the objectives, design, performance, and management of CW and RW, and to assess the status of efforts to combine CW and RW as Integrated Constructed Wetlands (ICW). These wetland systems are assessed for their ecological attributes and their relative contribution to ecosystem services. CW are designed to process a wide variety of wastewaters using surface, subsurface, or hybrid treatment systems. Designed and maintained within narrow hydrologic parameters, CW can be highly effective at contaminant transformation, remediation, and sequestration. The ecosystem services provided by CW are limited by their status as high-stress, successionally arrested systems with low landscape connectivity and an effective lifespan. RW are typically situated and designed for a greater degree of connection with regional ecosystems. After construction, revegetation, and early successional management, RW are intended as self-maintaining ecosystems. This affords RW a broader range of ecosystem services than CW, though RW system performance can be highly variable and subject to invasive species and landscape-level stressors. Where the spatial and biogeochemical contexts are favorable, ICW present the opportunity to couple CW and RW functions, thereby enhancing the replacement of wetland services on the landscape. [ABSTRACT FROM AUTHOR]

Passive treatment wetlands are conventionally designed with the primary objective of purifying contaminated mine water; any benefit of enhanced biodiversity is ancillary. We propose a new approach that incorporates enhanced biodiversity as an explicit objective. In this approach, treatment units are selected based on water flows and chemistry and the ecological requirements of key species are identified. Elements of the wetland design that meet these distinct requirements are selected and sized, then merged within the constraints imposed by site geomorphology and hydrology. This concept is illustrated with the wetland design for the Los Bronces Mine in Chile, where aspects of treatment, biodiversity, and water management were developed separately, and then integrated into a holistic design. The treatment wetlands are integrated within the local ecology. This approach adheres more closely to the objective of designing wetlands that offer ecosystem services and also meets the requirements for long-term water treatment. [ABSTRACT FROM AUTHOR]

Drinking water treatment sludge (DWTS) is the main waste produced in drinking water treatment plants (DWTPs). Its valorisation as substrate for constructed wetlands (CWs) aimed at upgrading treated urban wastewater is presented. Keeping a holistic approach in mind, this study looks for nutrient and organic matter removal but also contaminants of emerging concern (CECs) and pathogens. Three pilot subsurface flow CWs (1 m2) were installed under outdoor conditions in real WWTPs. Different operation modes (sequential: S-CW and continuous saturated flow: C-CW, CC-CW), different nutrient influent concentrations (S-CW and C-CW: 0.6 mg TP/l, 12.7 mg TN/l; CC-CW: 6.5 mg TP/l, 48 mg TN/l) and high hydraulic loading rates (HLRs, 0.9-5.1 m3/m2/d) were tested. C-CW presented higher removal efficiencies than S-CW for TP (C-CW: 56-86%; S-CW: 32-66%), total nitrogen (C-CW: 23-38%; S-CW: -3 to 6%) and E. coli (C-CW: 94%; S-CW: 84%), while S-CW performed better for ammonium (C-CW: 29-45%; S-CW: 72-86%) and CECs removal. Among fifteen CECs monitored, most pharmaceuticals, four were significantly reduced in C-CW and nine in S-CW, which had more aerobic conditions. CC-CW reduced nutrients and organic matter by 62% (TP), 8% (TN), 23% and 40% (chemical and biochemical oxygen demands, respectively). The potential release of aluminium was negligible. Novel values for the first-order reaction coefficient of P-k-C* model are provided for the TP removal process using DWTS (0.6-1.0 h-1). The main conclusion is that DWTS is a suitable substrate to significantly upgrade WWTP effluents, even at high HLRs. A hybrid system combining sequential and continuous flow modes could optimize the upgrading treatment. A proposal for the full valorisation of the sludge produced in one DWTP is presented. [ABSTRACT FROM AUTHOR]

This study deals with the dairy wastewater treatment using laboratory scale vertical flow (VF) constructed wetlands with the Canna indica plantation over wetland beds due to phytoremediation capabilities. Three laboratory scale VF CWs (CW-A, CW-B and CW-C) each with an area of 0.135 m2 filled with gravel (CW-A: 20 mm; CW-B:10 mm gravel) and sand (CW-C) receiving 0.04 m³ d-1 dairy wastewater were operated for the wastewater purification. Each unit was operated at three hydraulic retention times (HRTs) i.e. 12 h, 24 h and 48 h for assessing its effect on wastewater purification. Among all units, removal rates fluctuated as: total suspended solids (TSS): 64.2-74.5%; biochemical oxygen demand (BOD): 45.3 - 63.1%; ammonium nitrogen (NH4-N): 29.6 - 56.5% and phosphate phosphorous (PO4-P): 20.5 - 57.8% at different HRTs. Increase in HRT showed better removal of pollutants in all CWs. Moreover, maximum removal of pollutants excluding TSS and NH4-N was achieved in CW-B at 48 h HRT. CW-B with similar HRT provided maximum removal of PO4-P (57.8%), BOD (63.1%) and chemical oxygen demand (COD): 67.4%. Increase in the size of filter media, from sand (0.25 mm) to 20 mm gravel resulted in higher removal of NH4 -N from wastewater. [ABSTRACT FROM AUTHOR]

Chromium (Cr), Nickel (Ni), and zinc (Zn) removal from landfill leachate using mesocosm-scale vertical flow wetlands, the effect of recirculation, and the ability of macrophytes to retain metals were evaluated. Wetlands were filled with coarse sand and light expanded clay aggregates and planted with Typha domingensis or Canna indica. Wetlands were operated using intermittent loading, with and without recirculation. Raw leachate was diluted and spiked with metals to reach the following concentrations: 0.2 mg L−1 Cr , 0.2 mg L−1 Ni, and0.2 mg L−1 Zn and 1.0 mg L−1 Cr, 1.0 mg L−1 Ni, and 1.0 mg L−1 Zn. Wetlands planted with T. domingensis presented higher metal removal than those planted with C. indica. Recirculation enhanced metal removal efficiencies significantly, being for T. domingensis/C. indica: 60/54, 49/47, 61/47% for Cr, Ni, and Zn at 0.2 mg L−1, and 80/71, 76/62, 73/59% for Cr, Ni, and Zn at 1.0 mg L−1, respectively. Metals were efficiently retained by macrophytes. Plant biomass and metal concentrations in roots were significantly higher than in shoots. Scanning electron microscopy and X-ray microanalysis showed that metals were absorbed by internal root tissues. A hybrid wetland planted with T. domingensis may be implemented to improve not only metal but also chemical oxygen demand and total nitrogen removals. Landfills generate leachate that contains a wide range of contaminants in concentrations that vary over time. Even when a landfill ceases to receive solid waste, the leachate will continue to be generated for years. To avoid environmental impact, such leachate should be treated. This work evaluated chromium (III), nickel (II), and zinc (II) removal from landfill leachate using vertical flow wetlands (VFWs) at mesocosm-scale. The performance of wetlands planted with Typha domingensis or Canna indica, and with and without recirculation were compared. VFWs have demonstrated to be efficient for landfill leachate treatment. At a global scale, studies on metal removal using this type of wetlands are scarce. Despite the advantages of treatment wetlands in Argentina (easy operation and maintenance and usual large availability of land inside factories), they are scarcely implemented. [ABSTRACT FROM AUTHOR]

In recent decades, previously unobserved trace compounds have become more widely detected in wastewater treatment effluents and freshwater ecosystems. Emanating from various sources and presenting potential human health and ecological risks at much lesser concentrations than traditional contaminants, detection of “emerging contaminants” has increased with improvements in analytical techniques. The behavior of emerging contaminants in wetlands is a topic of increasing interest, as natural wetlands are known to transform and sequester pollutants and constructed or treatment wetlands are widely utilized to address elevated concentrations of constituents of concern. Both natural and constructed wetlands are complex biogeochemical systems with interrelated abiotic and biotic mechanisms leading to the removal of emerging contaminants. A literature review was performed to assess the current state of knowledge of various wetland mechanisms involved in removing these contaminants from surface waters and effluents. The primary mechanisms discussed in the literature are sorption, photodegradation, microbial biodegradation and phytoremediation. The most influential mechanisms are dependent on the properties of the contaminants and wetland systems studied. Common trends exist for different constructed wetland designs to leverage various mechanisms based on hydrology, substrate and vegetation plantings. Much remains to be understood about the various processes occurring in wetlands as they relate to emerging contaminant removal. Improving the understanding of the potential role of wetland mechanisms can help manage this environmental challenge more effectively.

Managed treatment wetlands technology is now used around the world to treat wastewater and stormwater by removing nutrients and other contaminants to obtain a desired water quality. In this paper we present a brief review of a large-scale application of the nature-based technology known as stormwater treatment areas (STAs). These STAs were constructed to treat agricultural and urban runoff to reduce outflow total phosphorus (TP) concentrations to <20 μg P L−1, which is required to protect downstream water quality and preserve the remaining Everglades ecosystem. Five STAs with a total area of approximately 25,000 ha were built at strategic locations to reduce TP loads to the Everglades Protection Area. For the past three decades, these Everglades STAs have done remarkable job by 70 to 85% TP load reduction, with an average outflow TP concentrations of 15-40 μg P L−1. In this Everglades STAs special issue, we present research findings on the influence of both external and internal drivers influencing STA performance and potential adaptive management strategies to enhance treatment efficiency to further reduce outflow TP concentrations. • Introduction of the Everglades STAs – largest constructed treatment wetland network in the world. • Everglades STAs serve as 'kidneys' of the Everglades ecosystem by reducing phosphorus loads to downstream waterbodies. • Phosphorus loading is one of the key drivers regulating treatment efficiency STAs. [ABSTRACT FROM AUTHOR]

In response to the global loss and degradation of wetland ecosystems, extensive efforts have been made to reestablish wetland habitat and function in landscapes where they once existed. The reintroduction of wetland ecosystem services has largely occurred in two categories: constructed wetlands (CW) for wastewater treatment, and restored wetlands (RW) for the renewal or creation of multiple ecosystem services. This is the first review to compare the objectives, design, performance, and management of CW and RW, and to assess the status of efforts to combine CW and RW as Integrated Constructed Wetlands (ICW). These wetland systems are assessed for their ecological attributes and their relative contribution to ecosystem services. CW are designed to process a wide variety of wastewaters using surface, subsurface, or hybrid treatment systems. Designed and maintained within narrow hydrologic parameters, CW can be highly effective at contaminant transformation, remediation, and sequestration. The ecosystem services provided by CW are limited by their status as high-stress, successionally arrested systems with low landscape connectivity and an effective lifespan. RW are typically situated and designed for a greater degree of connection with regional ecosystems. After construction, revegetation, and early successional management, RW are intended as self-maintaining ecosystems. This affords RW a broader range of ecosystem services than CW, though RW system performance can be highly variable and subject to invasive species and landscape-level stressors. Where the spatial and biogeochemical contexts are favorable, ICW present the opportunity to couple CW and RW functions, thereby enhancing the replacement of wetland services on the landscape.

• Constructed wetlands provide an optimal environment for cyanotoxin biodegradation. • First report of cylindrospermopsin degradation in constructed wetlands. • Cyanotoxins induced a shift in the constructed wetland prokaryotic community. • The enzymatic gene known to be responsible for microcystin-LR was not observed. • Removal seem to be more associated with the microbial community than the plants. Cyanobacterial blooms releasing harmful cyanotoxins, such as microcystin (MC) and cylindrospermopsin (CYN), are prominent threats to human and animal health. Constructed wetlands (CW) may be a nature-based solution for bioremediation of lake surface water containing cyanotoxins, due to its low-cost requirement of infrastructure and environmentally friendly operation. There is recent evidence that microcystin-LR (MC-LR) can efficiently be removed in CW microcosms where CYN degradation in CW is unknown. Likewise, the mechanistic background regarding cyanotoxins transformation in CW is not yet elucidated. In the present study, the objective was to compare MC-LR and CYN degradation efficiencies by two similar microbial communities obtained from CW mesocosms, by two different experiments setup: 1) in vitro batch experiment in serum bottles with an introduced CW community, and 2) degradation in CW mesocosms. In experiment 1) MC-LR and CYN were spiked at 100 µg L−1 and in experiment 2) 200 µg L−1 were spiked. Results showed that MC-LR was degraded to ≤1 µg L−1 within seven days in both experiments. However, with a markedly higher degradation rate constant in the CW mesocosms (0.18 day−1 and 0.75 day−1, respectively). No CYN removal was detected in the in vitro incubations, whereas around 50 % of the spiked CYN was removed in the CW mesocosms. The microbial community responded markedly to the cyanotoxin treatment, with the most prominent increase of bacteria affiliated with Methylophilaceae (order: Methylophilales , phylum: Proteobacteria). The results strongly indicate that CWs can develop an active microbial community capable of efficient removal of MC-LR and CYN. However, the CW operational conditions need to be optimized to achieve a full CYN degradation. To the best of our knowledge, this study is the first to report the ability of CW mesocosms to degrade CYN. [Display omitted] [ABSTRACT FROM AUTHOR]

The Everglades Stormwater Treatment Areas (STAs) are a 25,000 ha (61,000 acre) complex of constructed wetlands built to remove phosphorus (P) from agricultural and urban runoff in support of Everglades restoration. These STAs treat inflow waters that contain P in concentrations from 100 to 200 μg L−1, average calcium (Ca) concentrations of 60–90 mg L−1, and alkalinity (Alk) in the range of 150–350 mg L−1 as calcium carbonate (CaCO 3). Photosynthesis, primarily from submerged aquatic vegetation (SAV) within these STAs, increases water pH resulting in CaCO 3 formation, which is thought to contribute to P removal through coprecipitation and other processes. Since 2002, the STA complex has removed over 3000 MT of P and over 400,000 MT of Ca. Because the STAs at times treat Lake Okeechobee waters that are lower in Ca and Alk (35–50 mg L−1 and 95–125 mg L−1 as CaCO 3 , respectively), we conducted two experiments to explore the role of Ca and Alk on wetland P removal. First, in outdoor flow-through microcosms (0.18 m2) containing Najas guadalupensis and treating artificial inflow solutions, Ca/Alk at typical STA inflow concentrations (77 mg Ca L−1/316 mg L−1 as CaCO 3) resulted in significantly lower outflow P concentrations compared to lower Ca/Alk treatments (28 mg Ca L−1/67 mg L−1 as CaCO 3). Based on sediment organic carbon to total P (TP) ratios, organic matter production and sedimentation was the P removal mechanism under low Ca/Alk levels, where CaCO 3 precipitation did not occur, and also under high Ca/Alk, low P (31 μg L−1) conditions, despite CaCO 3 formation. High Ca/Alk increased organic matter sedimentation and associated P burial at low and high (168 μg L−1) water P concentrations. Additional P removal associated with CaCO 3 precipitation occurred only under high Ca/Alk, high P concentrations, and accounted for about 47% of P sedimentation in those microcosms. Second, in flow-through mesocosms (4.75 m2) containing STA muck soil and common STA SAV species, elevated Ca/Alk (94 mg Ca L−1/185 mg L−1 as CaCO 3) produced significantly lower outflow TP concentrations than treatments receiving unamended Lake Okeechobee inflow water with lower Ca/Alk concentrations (44 mg Ca L−1/112 mg L−1 as CaCO 3). In the same experiment, Ca/Alk levels had no effect on P removal in mesocosms containing Typha domingensis , a common STA emergent macrophyte species. SAV mesocosms produced lower outflow TP concentrations than Typha , regardless of Ca/Alk levels. In a follow-on laboratory incubation, low Ca/Alk concentrations in incubation waters did not increase P release from sediments formed under prior low or high inflow Ca/Alk concentrations in the SAV mesocosms, but anoxia sharply increased P release from both. These experiments suggest that coprecipitation with CaCO 3 is a meaningful P removal process in hardwater wetlands where high P concentrations and SAV coincide. Conversely, in STA outflow regions, where surface water P has already been treated to a low level, coprecipitation with CaCO 3 probably does not contribute to further P reductions. However, Ca/Alk also may contribute to inorganic-C availability which influences submerged aquatic productivity, so the role of inorganic C limitation on STA vegetation communities and P removal merits further study. • CaCO 3 precipitates in wetlands with SAV treating P for Everglades restoration. • Ca/Alk increased P removal in SAV systems via greater organic matter production. • Additional P coprecipitated with CaCO 3 only under high water P and Ca/Alk levels. • SAV outperformed Typha for P removal at both high and low Ca/Alk concentrations. • Low Ca/Alk inflow waters should not destabilize P in calcareous soils. [ABSTRACT FROM AUTHOR]

The potential of using the biomass of four wetland plant species (Iris pseudacorus, Juncus effusus, Phragmites australis and Typha latifolia) grown in treatment wetland systems and under natural conditions were tested to produce high-value materials using hydro-thermal liquefaction (HTL). The results show that the wetland plants biomass is suitable for biocrude and biochar production regardless of the origin. The hydrothermal liquefaction products’ (biocrude, biochar, aqueous and gaseous phase) yields vary according with the specific biomass composition of the species. Furthermore, the results show that the biomass composition can be affected by the growing condition (treatment wetland or natural unpolluted conditions) of the plants. None of the single components seems to have a determinant effect on the biocrude yields, which reached around 30% for all the analyzed plants. On the contrary, the biochar yields seem to be affected by the composition of the biomass, obtaining different yields for the different plant species, with biochar yields values from around 12% to 22%, being that Phragmites australis is the one with the highest average yield. The obtained aqueous phase from the different plant species produces homogeneous compounds for each plant species and each growing environment. The study shows that biomass from treatment wetlands is suitable for biocrude production. The environmental value of this biomass lies on the fact that it is considered a residual product with no aggregated value. The treatment wetland biomass is a potential sustainable source for biofuel production since these plants do not need extra land or nutrients for growing, and the biomass does not compete with other uses, offering new sources for enhancing the bioeconomy concepts.

Dissolved organic matter (DOM) plays an important role in the phosphorus (P) and nitrogen (N) cycle, but the examination of coupled biogeochemical cycling in treatment wetlands, like the Everglades Stormwater Treatment Areas (STAs), has been limited. Here, we studied eight STA inflow waters to gain insights into the production and potential photo- and biolability of DOM in surface waters flowing into these treatment wetlands. A suite of optical and fluorometric indices was coupled with amino acid and bulk elemental analyses to evaluate differences in inflow water quality for particulate organic matter (POM), DOM (<0.2 μm), and high and low molecular weight DOM (HMW-DOM and LMW-DOM). A photochemical experiment was conducted with these inflow waters to assess how solar exposure alters DOM turnover and its relationship with nutrient concentrations, and to evaluate the influence of photochemistry on potential STA performance. The DOM of STA inflow water was predominantly composed of allochthonous terrestrial sources, and the LMW-DOM fraction represented 70 to 94% of the total DOM pool. Inflow waters separated along the biophysical dimension of our PCA based on their photolability and bioavailability, driven by differences in the inflow water's DOM composition. UV exposure decreased humic and aromaticity proxies with concomitant photo-production of LMW compounds and increases in bioavailability proxies. Photo-exposure significantly decreased nitrate and dissolved organic carbon (DOC) concentrations for most of the sites and dissolved organic N (DON) for three of the eight sites, but no significant changes were noted for ammonia. One site exhibited an increase in nitrate with UV exposure and had DOM primarily from terrestrial origins. Spectroscopic indices, PARAFAC components, and amino acids provided corroborating evidence that further supported the differences in photo- and biolability at each inflow site, which is likely driven by their original DOM characteristics. PARAFAC components were correlated with dissolved organic P (DOP) and suggest that there may be adsorption of DOP with humic components in the LMW fraction. This work highlights the importance of photochemistry in the STAs, the complexity of DOM turnover in STA source waters, and the potential interactions between dissolved P and other DOM components, which may further influence the treatment efficiency of the STAs. • Inflow waters were distinguished by their susceptibility to bio/photodegradation • DOM entering the STAs may contribute to the photoproduction of bioavailable LMW compounds • Lake Okeechobee outflow had unique indicators of freshly produced, autochthonous DOM • DOP was correlated with PARAFAC components, suggesting P partitioning in LMW DOM [ABSTRACT FROM AUTHOR]

Ultrafine particulate SRP may have an important role in the transfer of P from the Everglades Stormwater Treatment Areas (STAs), constructed wetlands designed to reduce phosphorus (P) in stormwater that is discharged to the Everglades Protection Area, to sensitive downstream water bodies due to increases in mobility associated with small particle size. P concentrations in discharges from the STAs are monitored using routine methods for particulate P (>0.45 μm) and dissolved P (<0.45 μm), an approach that does not consider ultrafine particulate P within the <0.45 μm fraction. Ultrafine particulate SRP was determined by ultrafiltration and was operationally defined as SRP associated with particles between <0.45 μm and <3 kDa. This study determined the magnitude and proportion of ultrafine particulate SRP within the <0.45 μm fraction of inflow, outflow, and in some cases, midflow waters from a selection of well-performing (discharge flow weighted mean concentration (FWMC) of P ≤ 20 μg L−1) and under-performing flow-ways (FWs) (FWMC P > 20 μg L−1) containing emergent aquatic vegetation (EAV), submerged aquatic vegetation (SAV) or a mix of EAV/SAV during the wet and dry season. During the wet season, inflow <0.45 μm SRP was predominately (60–100%) truly dissolved SRP (< 3 kDa) in all flow-ways. In the under-performing flow-ways, <0.45 μm SRP remained largely as truly dissolved, highly available SRP from inflow to outflow, whereas in the well-performing flow-ways, the percentage of <0.45 μm SRP present as ultrafine particulate SRP increased up to 100% as the distance from the inflow increased and the amount of truly dissolved SRP was very low. Two flow-ways having 100% particulate SRP at the outflow (STA-3/4 CFW and STA-5/6 FW1) contain an EAV cell followed by an EAV/SAV cell. However, in flow-ways containing more SAV (STA-2 FW3), ultrafine particulate SRP was a smaller proportion of outflow SRP (29%). During the dry season, ultrafine particulate SRP similarly increased from inflow to outflow at some well and under-performing sampling locations, but to a smaller proportion, and ultrafine particulate SRP never made up 100% of the <0.45 μm SRP fraction. These findings reveal that ultrafine particulate SRP is largely present within the <0.45 μm SRP fraction, at times making up >50% of TP, making it an important but poorly understood component of STA P budgets. • At some sites, the <0.45 μm fraction was entirely ultrafine particulate SRP. • The proportion of ultrafine particulate SRP increased from inflow to outflow. • The proportion of ultrafine particulate SRP was greater in well-performing STAs. • Outflows of under-performing STAs had a higher magnitude of ultrafine particulate SRP. [ABSTRACT FROM AUTHOR]

This paper describes the ecology and management of two flow-through created wetlands that, in turn, defined 30 years of research by Bill Mitsch, 20 years in Columbus, Ohio (1992–2012) and 10 years in Naples, Florida (2012−2022). The Olentangy River Wetland Research Park was built in several stages from 1993 through 2010. The first stage was the creation of dual 1-ha kidney-shaped wetlands primarily fed by pumped Olentangy River water. A pattern of inflow that depended on river stage was maintained for 17 years. The two experimental wetlands were established by planting one of the wetlands with a variety of wetland macrophytes and leaving the second wetland unplanted to ultimately determine whether human introduction of wetland plants matter in the long run. In addition to maintaining data collection for hydrology, water quality, and other functions, these wetlands and several others constructed on the 20-ha floodplain site were heavily used as was the mesocosm compound, mostly for short-term (2 to 3 year) experiments by graduate students. Another 20-ha created wetland complex, called Freedom Park Wetlands, was constructed in 2007–2008 in Naples, Florida, at an abandoned citrus grove, to seasonally treat urban stormwater runoff. During that wet season, the design calls for an average water detention time of 18 days. The wetland system included a 1.9-ha deepwater pond for temporary storage of the urban stormwater pulses from what is mostly an urban watershed, followed by 2.7 ha of shallower vegetated wetland ponds designed to sequentially improve water quality. Within each wetland, there are three deep-water cells and two shallow-water cells. The water eventually exits the treatment wetlands via a rectangular and travels diffusely through a restored bottomland forest to the Gordon River and ultimately toward Naples Bay and the Gulf of Mexico. During our tenure at Florida Gulf Coast University's (FGCU) Everglades Wetland Research Park, Freedom Park was a venue with active mesocosm experiments in a constructed mesocosm compound. Several of these mesocosm experiments were the subjects of master's theses from FGCU and doctoral dissertations from our partner, University of South Florida. Our students also contributed to the local environmental communities by giving tours of the Freedom Park wetlands and our mesocosm research. • This paper describes the ecology and management of two created wetlands. • The Olentangy River Wetland Research Park in Ohio, USA has provided data since 1994. • The Freedom Park wetlands in Florida, USA were constructed in 2007–2008. • Both wetlands offer ecosystem services (i.e. nutrient reduction and flood protection). • These wetlands provide the framework for thirty years of wetlands research. [ABSTRACT FROM AUTHOR]