Wetland Units Research Articles

Performance Evaluation of a Pilot-Scale Constructed Wetland with Typha latifolia for Remediation of Domestic Wastewater in Zimbabwe

The management of wastewater remains a challenge, particularly in developing countries. The potential use of constructed wetlands to treat wastewater is promising but their contaminant removal efficiencies, particularly in a tropical country such as Zimbabwe, are not fully understood. A pilot-scale study was undertaken in Zimbabwe to evaluate the efficiency of vertical-flow constructed wetlands planted with Typha latifolia in the treatment of domestic wastewater. Four pilot subsurface vertical-flow constructed wetland units (measuring 1 m × 1 m × 1.1 m) were built from concrete. The units were filled with waste rock from a nickel mine. Three units were planted with Typha latifolia while the fourth one was left unplanted, acting as the control. Each unit was loaded with wastewater at a rate of 220 dm3/day. Physico-chemical and bacteriological parameters were analyzed during the winter season. Physico-chemical and bacterial contaminant concentrations were significantly lower in the effluent than in the influent, and the system achieved maximum removals for BOD5, COD, TDS, TSS, nitrates, phosphates, phosphate pentoxide, phosphorus, and E. coli of 56.01%, 82.87%, 30.61%, 90.40% 17.26%, 35.80%, 36.19%, 40.64%, and 90.28%, respectively. The study shows that constructed wetland systems can be successfully established for the removal of physical, chemical, and microbial contaminants from domestic wastewater.

Potential of phragmites australis in vertical flow constructed wetland for heavy metals removal from urban wastewater

ABSTRACT Constructed wetlands (CWs) have emerged as effective biotechnological solutions for wastewater treatment in recent decades. While plants are recognized components of these systems, their specific role in nutrient and heavy metal (HM) uptake warrants further investigation. This study assesses the efficacy of a vertical flow constructed wetland (VFCW) unit planted with Phragmites australis in treating HM-laden wastewater. Through standard methods, wastewater samples from inlet and outlet were analyzed for HMs (Cd, Zn, Pb, Cu), alongside plant and sediment samples. Planted CWs demonstrated remarkable removal efficiencies: 89.34% for Cd, 76.27% for Zn, 68.14% for Cu, and 66.42% for Pb, surpassing unplanted systems (18.27% to 33.16% removal). Notably, P. australis exhibited strategic pollutant absorption, with highest HM concentrations below-ground. Though above-ground HM accumulation was relatively minor, it exceeded soil concentrations. Analysis of accumulation factors confirmed roots and rhizomes as primary bio-accumulators, with transfer factor values (Cd > Pb > Zn > Cu) indicating efficient uptake. These findings underscore the pivotal role of P. australis in enhancing HM removal within VFCW systems, emphasizing the importance of plant-based strategies in HM remediation. Recommendations include further exploration of plant-assisted methods to optimize HM treatment in CWs.

Optimized Design of Modular Constructed Wetland for Treating Rural Black–Odorous Water

In recent years, the phenomenon of black–odorous water has occurred frequently, and constructed wetlands have been widely used as an effective means of treating black–odorous water. In order to achieve the goal of low-carbon and high-efficiency long-term clean-up of black–odorous water, the modular constructed wetland system was optimized in this study. The optimized modular constructed wetland consisted of aeration, denitrification, and phosphorus removal, of which the denitrification module was a sulfur–iron autotrophic denitrification unit and the phosphorus removal module was a polyaluminum chloride composite filler phosphorus-removal unit. Experimental findings indicated that modular systems with layout ratios of 1:3:1 (A) and 1:2:2 (B) exhibit outstanding performance in remediating contaminants from black–odorous water. Notably, system B demonstrated superior treatment efficiency. Under conditions of high pollution loading, system B consistently achieved stable removal rates for COD (95.79%), TN (91.74%), NH4+-N (95.17%), and TP (82.21%). The combination of along-track changes and high-throughput sequencing results showed that the synergies among the units did not produce negative effects during the purification process, and each unit realized its predefined function. Changes in the substrate and internal environment of the wetland units caused changes in the microbial populations, and the unique microbial community structure of the units ensured that they were effective in removing different pollutants.

Study on the applicability of free water surface wetland (fws) scale of wastewater treatment laboratory for green rest stops

The Free Water Surface wetland (FWS) has emerged as a promising technological solution for wastewater treatment in natural environments. The study aimed at investigating the performance of a laboratory-scale Free Water Surface wetland (FWS) unit designed to treat domestic wastewater with a daily capacity of 20 liters. This model can be applied at some rest stops towards creating "Green Rest Stops" on highways. The laboratory experiments on bronze banana plants have shown that the model operates effectively under specific settings and with the characteristics of residential wastewater from public toilets, which has undergone pretreatment through septic tanks. These conditions are conducive to promoting healthy growth in the plants. The FWS model for cultivating canna hybrid plants (Canna generalis) has a total surface area of 0.26 square meters and operates based on the principles of free wastewater flow. The model has a water retention duration of 70 hours, approximately three days. The treatment efficiency for TSS, BOD5, NH4+ - N, and Coliform is 37-53%, 73-77%, 41-46%, and 37-54%, respectively. The treated wastewater complies with the National technical regulations on water quality, QCVN 14:2008/BTNMT (B) standards

Anaerobic baffled reactor followed by up-flow constructed wetland for treatment of municipal wastewater

A laboratory-scale anaerobic baffled reactor followed by up-flow constructed wetland are designed and developed with different filter media, and emergent plants. The effectiveness of an anaerobic baffle reactor (ABR) for settling down inorganic and treatment of the organic matter is observed in the present study. Further, two up-flow constructed wetland (UCW) units filled with Autoclaved Aerated Concrete (ACC) blocks and coconut shells as a filter media and wetland plants are combined for bio-phyto treatment. The performance of the treatment system is analyzed with hydraulic retention times (HRTs) of 12 h, 18 h, and 24 h. The removal of TSS, COD, TN, and TP are found to be 96 %, 84 %, 68 %, and 65.5 %, respectively, with 24 h HRT, which complied with the discharge standards. Due to the simplicity of construction as well as low operation and maintenance, the present treatment combination is considered eco-friendly, sustainable, and a cost-effective option for households or communities prior to its safe discharge. The treated water is ready to use for irrigation, gardening, floriculture, cleaning, and flushing.

Design of floating treatment wetland in PT Antam Tbk UBP Bauksit Kalimantan Barat

The wastewater that comes from bauxite ore washing at PT ANTAM Tbk UBP Bauksit Kalimantan Barat is not treated optimally, because of that it needs another alternative treatment other than coagulant. This research aims to establish the design of floating treatment wetland, arrange the application and maintenance procedure of floating treatment wetland, and arrange the draft cost budget of floating treatment wetland. The result of this research is design of floating treatment wetland plan that has 24 m2 or 4 x 6 m dimension with 600 plants for 1 unit. The selected plant is eleocharis dulcis which is able to absorb iron (FE) that contained in wastewater. Based on calculation if FA (bouyant force) higher than W (weight), than the media will be floated. All the design criteria from hydraulic loading rate, hydraulic retention time, water depth and surface coverage are accordant. The procedure of application and maintenance includes preparation and application procedure as well as operational and maintenance procedure. The cost required for 124 floating treatment wetland units is IDR 1.162.996.000.

Coastal wetland restoration framework based on hydrogeomorphic units of the coastal wetland of Yancheng, China

Effective implementation of restoration projects is essential to solving the degradation of coastal wetlands. Due to the lack of systematic guidance or unsuitable engineering measures, some coastal wetland restoration projects have suffered from lower-than-expected results and poor sustainability. Therefore, it is necessary to construct a regional-scale wetland restoration framework from a macro perspective prior to project implementation, which can guide pre-study and follow-up restoration practices. In this study, the hydrogeomorphic units (HGUs) of Yancheng coastal wetlands were delineated according to the regional hydrogeomorphic conditions, and the changes in land use/cover and hydrological connectivity of each HGU from 1980 to 2019 were analyzed. The results showed that the area of natural wetlands in the study area declined rapidly, with a decline of 48.38%, and was mainly converted to aquaculture ponds or farmland during the 40 years. The structural complexity and transport capacity of tidal creeks decreased significantly, which indicated that the hydrological connectivity decreased. The main problems of degradation in the region were the reduction of large areas of natural wetlands, the rapid expansion of exotic species, and the decline in hydrological connectivity, etc. Combining the degradation problems and the restoration objectives, feasible strategies and methods were selected for different types of HGUs from both active and passive restoration categories, thus forming a coastal wetland restoration framework for the Yancheng coastal wetlands based on HGUs. This study takes regional hydrogeomorphology as the antecedent context condition, and the idea of a systematic restoration framework constructed by combining landscape perspectives can provide scientific support for wetland restoration practice.

Identification of a wetland ecological network for urban heat island effect mitigation in Changchun, China

The rapid development of cities has led to severe fragmentation of wetland landscapes, destroying their ecological function in climate regulation. However, most studies on the climate regulation services of wetlands focused on isolated wetland units, ignoring the overall function of wetland networks. The climate regulation function of wetlands can be improved by integrating fragmented wetland resources and building a stable wetland network. A case study was carried out in Changchun City, China, to improve the method of identifying ecological networks by considering the network energy flows. First, morphological spatial pattern analysis and landscape connectivity index combined with the wetland cooling index were used to identify ecological sources with high cooling capacity, and an ecological resistance surface was constructed with surface temperature as the main factor. The minimum cumulative resistance model was then used to identify the ecological network, which was then optimized by integrating patches as stepping stones to form the optimized ecological network. Finally, the importance of ecological corridors was evaluated by identifying ventilation corridors and integrated with the complex network theory to determine the ecological network robustness. We found that the degree of fragmentation in the studied wetlands was relatively high, and that construction of an ecological network with patches as stepping stones can improve its robustness. Each component in the ecological network had a high potential to mitigate the urban heat island effect, which can be further promoted by ecological corridors with high ventilation potential. Mutations in ecological nodes that cause network robustness played a key role in maintaining ecological network stability. This improved methodology effectively improves the scientific and practical application of wetland networks to mitigate the urban heat island effect and provides regions facing the contradiction of rapid development and wetland protection with strategies to reduce the threat of this effect.

A novel autotrophic denitrification and nitrification integrated constructed wetland process for marine aquaculture wastewater treatment

We undertook a lab-scale evaluation of a novel autotrophic denitrification and nitrification integrated constructed wetland (ADNI-CW) for improved carbon (C), nitrogen (N), and sulfur (S) cycling to treat mariculture wastewater. The process involved an up-flow autotrophic denitrification constructed wetland unit (AD-CW) for sulfate reduction and autotrophic denitrification, and an autotrophic nitrification constructed wetland unit (AN-CW) for nitrification. The 400-day experiment investigated the performance of the AD-CW, AN-CW, and entire ADNI-CW processes under various hydraulic retention times (HRTs), nitrate concentrations, dissolved oxygen levels, and recirculation ratios. Under various HRTs, the AN-CW achieved a nitrification performance exceeding 92%. Correlation analysis of the chemical oxygen demand (COD) revealed that, on average, approximately 96% of COD was removed by sulfate reduction. Under different HRTs, increases in influent NO3−–N concentrations caused the amount of sulfide to gradually decrease from sufficient to deficient, and the autotrophic denitrification rate also decreased from 62.18 to 40.93%. In addition, when the NO3−–N load rate was above 21.53 g N/m2·d, the transformation of organic N by mangrove roots may have increased NO3−–N in the top effluent of the AD-CW. The coupling of N and S metabolic processes mediated by various functional microorganisms (Proteobacteria, Chloroflexi, Actinobacteria, Bacteroidetes, and unclassified_d__Bacteria) enhanced N removal. We intensively explored the effects of changing inputs as culture species developed on the physical, chemical, and microbial changes of CW to ensure a consistent and effective management of C, N, and S. This study lays the foundation for green and sustainable mariculture development.

Carbon Reduction and Pollutant Abatement by a Bio-Ecological Combined Process for Rural Sewage.

In order to explore the treatment effect of a bio-ecological combined process on pollution reduction and carbon abatement of rural domestic wastewater under seasonal changes, the rural area of Lingui District, Guilin City, Guangxi Province, China was selected to construct a combined process of regulating a pond, biological filter, subsurface flow constructed wetland, and ecological purification pond. The influent water, effluent water, and the characteristics of pollutant treatment in each unit were investigated. The results showed that the average removal rates of COD, TN, and NH3-N in summer were 87.57, 72.18, and 80.98%, respectively, while they were 77.46, 57.52, and 64.48% in winter. There were significant seasonal differences in wastewater treatment results in Guilin. Meanwhile, in view of the low carbon:nitrogen ratio in the influent and the poor decontamination effect, the method of adding additional carbon sources such as sludge fermentation and rice straw is proposed to strengthen resource utilization and achieve carbon reduction and emission reduction. The treatment effect of ecological units, especially constructed wetland units, had a high contribution rate of TN treatment, but it was greatly impacted by seasons. The analysis of the relative abundance of the microbial community at the phylum level in constructed wetlands revealed that Proteobacteria, Acidobacteria, Chloroflexi, Firmicutes, Bacteroidetes, Planctomycetota, and Actinobacteria were the dominant phyla. The relative abundance of microbial communities of Proteobacteria, Chloroflexi, and Acidobacteria decreased to a large extent from summer to winter, while Firmicutes, Bacteroidetes, and Planctomycetota increased to varying degrees. These dominant bacteria played an important role in the degradation of pollutants such as COD, NH3-N, and TN in wetland systems.

Spatial modeling of Sarus Crane nest site suitability in Cambodia to help target conservation of breeding areas

To understand the breeding habitat requirements of the small, highly threatened migratory population of Eastern Sarus Crane (Grus antigone sharpii) in Cambodia and Vietnam, we assessed nest site selection at two different spatial scales: at the scale of individually occupied wetlands within the deciduous dipterocarp forests of Kulen Promtep and Chep Wildlife Sanctuaries, and at a landscape scale covering all such forested areas in northern Cambodia. To model the likelihood of nest occupancy within the landscape, results of aerial surveys for Sarus Crane nests, conducted in 2001, were combined with topographical and environmental spatial data. A second model incorporated deforestation and road development in the landscape between 2001 and 2016.We found that Sarus Cranes in Cambodia typically nested in remote rain-fed wetlands that formed on flat terrain in the upper reaches of drainage basins. Within these small, forested wetland units, nests were often placed in deeper, well-defined ponds, although three-quarters of all nests were placed randomly in relation to water level. Nest locations were further from roads and agricultural areas than random points.Most of the best nesting habitat, including Kulen Promtep and Chep Wildlife Sanctuaries, was located on Cambodia’s Northern Plains (247 km2 of habitat with a predicted occupancy likelihood of >75 % inside protected areas and 77 km2 outside), with smaller patches of highly suitable areas scattered across the Eastern Plains (15 km2 inside protected areas and 11 km2 outside).Between 2001 and 2016, 14,215 km2 (15 %) of the original deciduous dipterocarp forest cover was cleared for agriculture, 1,605 km of road was constructed and the area of habitat with a predicted occupancy likelihood of >75 % shrank by 69 % in the Northern Plains (66 % inside protected areas and 79 % outside) and 73 % in the Eastern Plains (80 % inside and 64 % outside). In Kulen Promtep and Chep, cranes continued to nest but in areas modeled as having lower suitability. We recommend (i) strengthening protection of Kulen Promtep and Chep Wildlife Sanctuaries in the Northern Plains and of remaining nesting habitat in other protected areas; (ii) surveying for active nesting in areas having the highest suitability classes based on the 2001 model but not currently protected, particularly south of Kulen Promtep; (iii) in the meantime, take immediate steps towards protecting as much remaining habitat as possible, that was modeled as highly suitable, to allow for population recovery or in case subsequent surveys find it occupied.

Costa Rican wetlands vulnerability index

Costa Rica comprises approximately 6% of the world’s biodiversity. Among these lush ecosystems, wetlands are represented in mangrove forests near the sea, along river lowlands, sedimentary and volcanic mountains, and highland páramo landscapes. In 2018, the Ministry of Environment and Energy (MINAE), through the National System of Conservation Areas (SINAC), the United Nations Development Program (UNDP), and the Global Environment Facility (GEF) carried out the new National Wetlands Inventory (NWI) which identified 10,699 wetland polygons. This assessment collected key information such as location, characteristics of the wetland, land use in the vicinity, threats, and other generalities. Based on these valuable results, we propose a wetland Vulnerability Index composed of a Condition Index and a Hazard Index to determine the different vulnerability conditions of each wetland unit. Our findings provide a better comprehension of the status of wetlands in Costa Rica with an environmental geography perspective. Located in a climate change hotspot, Costa Rica’s conservation policies and actions should consider how to manage the most vulnerable wetlands at different scales. This methodology can improve and generate regional and national wetlands inventories as a basis for evidence-based decision making in other latitudes.

Fecal sludge treatment in a pilot-scale vertical-flow constructed wetland for the removal of helminth eggs

Abstract Eliminating parasites in fecal sludge (FS) remains one of the major concerns in developing countries. To address this issue, experiments were conducted in triplicate vertical-flow constructed wetland (VFCW) units corresponding to free flow, 7 days and 14 days of retention time (RT). The effect of plant density on the system's performance was monitored in each planted bed unit and compared to the non-planted unit (standard). Following a bi-monthly application rate of FS at a nominal load of 200 kg TS m−2 year−1, the performance of the system in terms of helminth egg removal was calculated for each hydraulic RT tested. Untreated FS applied on the bed units contained high parasitic egg loads with a median number of 62.51 helminth eggs/g. The removal efficiencies of helminth eggs ranged from 82 to 100% in the leachates and were affected by the hydraulic RTs and the presence of plants (p < 0.05). On the other hand, accumulated biosolids on the bed units still contained high concentrations of pathogens exceeding the WHO standards and should not be applied directly in agriculture.

Performance evaluation of vertical constructed wetland units with hydraulic retention time as a variable operating factor

The current research intends to assess the impact of shorter hydraulic retention time (HRTs) and different sized filter material on the pollutant removal performance of two pilot-scale vertical sub-surface flow constructed wetlands (VSSF CW) to treat dairy wastewater. Two CWs (CW-1 & CW-2) were filled with 10 and 20 mm gravels, respectively, planted with Arundo donax, and operated at three different HRTs for treating dairy farm wastewater viz. 6, 12, and 24 h. Over three months, the effluent was tested for TSS, BOD5, TP, and NH4–N removal using standard procedures at regular intervals. Average concentrations of TSS, BOD5, TP, and NH4–N at the final outlets CW-1 and CW-2 were recorded in the range of; TSS: 44.7–118.7 mg L−1, BOD5: 8.1–33.9 mg L−1, TP: 13.7–22.2 mg L−1and NH4–N: 9.1–11.4 mg L−1, respectively. The highest removal of TSS (81.2%), BOD5 (90.2%), TP (65.1%), and NH4–N (82.5%) from wastewater was seen after a 12 h HRT, whereas maximum DO rise (579.0%) was reported after a 6 h HRT in 20 mm gravel-filled CW units. Short HRTs of 6, 12, and 24 h were found to be effective in removing all pollutants from wastewater and maintaining a constant treatment throughout the evaluation period. Results suggest that VSSF CW systems can be operated efficiently under short HRTs while still effectively removing contaminants from dairy wastewater.

Frequency-dependent wave damping by tidal wetlands under storm conditions

Climate change is increasing the threat of coastal flooding worldwide, and the incorporation of tidal wetlands into coastal protection is being widely promoted. These circumstances have motivated extensive research on wetland-induced wave damping, while its distribution across the frequency scales remains poorly understood. Here, field observations during Typhoon Rumbia were adopted to examine the frequency-dependent wave damping by a Changjiang estuarine wetland, which consists of a salt marsh followed seaward by an unvegetated mudflat, under storm conditions. The results showed that the typhoon produced waves with approximately trimodal spectra comprising low-frequency swell (0.02–0.15 Hz), moderate-frequency wind-sea (0.15–0.48 Hz) and high-frequency components (0.48–0.70 Hz) at the mudflat edge. As the waves propagate landward across the mudflat and salt marsh, the integral wave heights are successively attenuated by 16 % and 32 % and the wind-sea waves continuously experienced the largest height attenuation. Mechanisms for the frequency-dependent wave damping were explored by discriminating energy dissipation and nonlinear transfer and reconstructing wave spectra induced by each of them. The frequency-dependent wave damping by unvegetated mudflats is controlled by nonlinear energy transfer, which shifts 10 % of the gross energy from the wind-sea to high-frequency components; the wind-sea waves’ attenuation is increased by 66 % but the high-frequency wave attenuation is reduced by 88 %, compared with the regime controlled solely by direct dissipation. Direct dissipation regulates the frequency-dependent wave damping across the salt marsh, and the contribution of nonlinear energy transfer to height attenuation of the wave components is below 15 %. The similar regime but differing mechanisms by which the studied wetland units damp waves of different frequencies provide new insights for wetland-wave interactions.

Constructed Wetland Units Filled with Waterworks Sludge for Remediating of Wastewater Contaminated with Congo Red Dye

The disposal of textile effluents to the surface water bodies represents the critical issue especially these effluents can have negative impacts on such bodies due to the presence of dyes in their composition. Biological remediation methods like constructed wetlands are more cost-effective and environmental friendly technique in comparison with traditional methods. The ability of vertical subsurface flow constructed wetlands units for treating of simulated wastewater polluted with Congo red dye has been studied in this work. The units were packed with waterworks sludge bed that either be unplanted or planted with Phragmites australis and Typha domingensis. The efficacy of present units was evaluated by monitoring of DO, Temperature, COD and dye concentration in the effluents under the variation of detention time (1-5 day) and dye concentration (10-40 mg/L). The maximum removal of dye and COD were 98 and 82% respectively for 10 mg/L of Congo red dye after five-day hydraulic retention time (HRT). The results have shown that the removal of COD and dye concentration significantly increased with higher contact time and lower dye concentration. The values of monitored parameters adopted to evaluate the wastewater quality (i.e. DO, COD and Congo red dye) are satisfied the requirements of irrigation water. The dye concentration variation in the effluent with contact time was formulated efficiently by Grau kinetic model. Functional groups (specified by FT-IR analysis) have a remarkable role in the entrapment of dye on the waterworks sludge bed.

Assessment of plants radial oxygen loss for nutrients and organic matter removal in full-scale constructed wetlands treating municipal effluents

Bidirectional cross flow wetlands with different plant species were set to investigate seasonal variation in radial oxygen loss (ROL) and its effects on COD and NH4+-N removal. Findings demonstrated a strong seasonal effect on the rate of ROL, with Arundo donax var.versicolor showing the highest ROL of 2.99 μmol·h−1·g−1. Additionally, ROL showed strong positive correlations with plant total biomass (P < 0.01), aboveground biomass (P < 0.01), height, maximum root length (P < 0.01), root porosity (P < 0.01), and removal efficiency of COD and NH4+-N (P < 0.01). Furthermore, high-throughput sequencing analysis of substrate samples from three wetland units planted with Thalia dealbata, Canna indica and Arundo donax var. versicolor revealedProteobacteria as the predominant rhizospheric phylum. Relative abundance of Alpha- and Gamma-Proteobacteria were higher in the Arundo donax var.versicolor samples due to its higher oxygen transport capacity. These results demonstrate that root properties are important determinants for selecting appropriate plants for constructed wetland.

How far damming induced wetland fragmentation and water richness change affect wetland ecosystem services?

In inland wetland, river and lakes, the ecosystem service values (ESV) vary from 4267 to 25682 US$/ha/year, but when the landscape gets fragmented and becomes hydrologically inconsistent, will they produce the same ESV? With this fundamental query, the present work evaluated the ESV in different fragmented wetland units and over different water richness zones in reference to hydrological alteration introduced by damming (1992) over Punarbhaba river (a transboundary of India and Bangladesh). The wetlands were mapped using the support vector machine (SVM) model for pre and post-dam conditions. Subsequently, satellite image-derived parameters, such as hydro-period, water depth, and water presence consistency, were prepared and used for spatial weighted and fuzzy logic-based water richness modelling and wetland fragmentation analysis for both pre (1989) and post-dam periods (2019). Results showed that wetland area was reduced from 205.24 km2 to 73.22 km2 in between pre-and post-dam periods, and consequently, the ESV was reduced from 10596 × 104 US$ to 3874 × 104 US$. Damming effect has decreased the high-water richness area from 71.83% to 7.65%, which caused a 62% of ESV reduction in the post-dam period. Due to increasing patch frequency and decreasing the core area in the post-dam period, the ESV value was reduced by 45%, which could be considered the fragmentation effect. As the study identified the areas with decreasing ESV values, this work has very good policy implications on a priority basis for wetland conservation.

A pilot system integrating a settling technique and a horizontal subsurface flow constructed wetland for the treatment of polluted lake water

An integrated system was tested at pilot-scale for treating polluted water from the Marriot Lake in Egypt, comprising a settling technique followed by three parallel horizontal subsurface flow constructed wetland (HFCWs) units operating under a continuous flow mode; one HFCW unit was planted with Typha angustifolia and contained a perforated pipes network for enhanced passive aeration (CWA), one unit was planted without the perforated pipe network (CWR) and one served as a Control unit (unplanted and without perforated pipes). Changes in physicochemical parameters, BOD5, nutrients (nitrogen, phosphorus), microbial community, and trace metals at different hydraulic retention times (HRT; 0.5–6 h) and hydraulic loading rates (HLR; 750, 1000, 1250, and 2000 L/m2/d) were monitored. The CWA unit had an overall better performance than the CWR unit, while both planted units outperformed the Control unit. CWA showed the highest performance at HLR of 1000 L/m2/d and 4-6 h-HRT with 95.3% removal for turbidity, 83% for BOD5, 99.3% for ammonia nitrogen (NH4–N), 70.8% for Total Nitrogen (TN), and 66.7% for Total Phosphorus (TP), while higher NO3–N and NO2–N effluent concentrations were observed. Trace metals levels were significantly reduced and accumulated in plant tissues. Microbial communities’ densities fluctuated in the CWA unit. The integrated system with the settling stage and the planted CWA unit was proved to achieve a high removal efficiency and reached the national discharge limits, thus representing a novel nature-based solution for the sustainable remediation of polluted lake water.

Endangered Cape Sable seaside sparrow ecology: actions towards recovery through landscape-scale ecosystem restoration

Understanding the ecology of endangered taxa and the factors affecting their population growth and decline is imperative for their recovery. In the southeastern USA, the Everglades wetland ecosystem supports a high diversity of species and communities, including many endemic and imperiled taxa, such as the federally endangered Cape Sable seaside sparrow Ammospiza maritima mirabilis (CSSS). The Everglades, once a completely connected wetland with a slow-moving sheet flow of water, is now compartmentalized into separated wetland units where water distribution is managed year-round. The CSSS is affected by, and at the crux of, many Everglades ecosystem restoration decisions. The CSSS faces conservation challenges, including limited habitat availability, low population numbers, dispersal limitations, and constraints on suitable breeding conditions owing to wetland water levels. Despite these challenges, ecological knowledge of the factors affecting CSSS population numbers in the context of ongoing ecosystem-level restoration can help inform protection of this bird while restoring the Everglades. Existing research shows target hydroperiods between 90 and 210 days, a minimum of 90 consecutive dry days during the breeding season, and non-breeding season fires approximately every 5-10 years may aid in CSSS recovery. There are numerous tools and models to support habitat and water management for the CSSS, and the most recent ecosystem-level water operations plan for the Everglades indicates potential for increased CSSS habitat. Here, we provide a review on the ecology of the CSSS, factors affecting population decline, and ecosystem-level restoration actions that may aid in CSSS recovery.