Floating Wetland Islands Implementation and Biodiversity Assessment in a Port Marina

Linkages between the concept of nature-based solutions and the notion of landscape

As the effects of Nature-based solutions (NBS) application are usually much broader than only the area under the project implementation, it is necessary to capture the impact on these actions of landscape as well as the influence of landscape type on the NBS effectiveness. The main aim of this study was to detect linkages between the operational of NBS and the landscape dimention, based on a systematic literature review. The results showed the existence of seven linkages: (1, 2) 'input' and 'output' resulting from the consideration of landscape as a scale of NBS implementation; (3, 4) 'stimulator' and 'inspiration' based on the contribution of landscape-based management to the implementation of NBS; (5) 'co-beneficiary' since the implementation of NBS affects aesthetic dimensions of landscape; (6) 'tool' as landscape-based indicators are used to assess the impacts of NBS; and (7) 'foundation' as health-supporting landscapes may be considered as a type of NBS action.

Industrial wastewater treatment using floating wetlands: a review

Industrial wastewater generated from various production processes is often associated with elevated pollutant concentrations and environmental hazards, necessitating efficient treatment. Floating wetlands (FWs) have emerged as a promising and eco-friendly solution for industrial wastewater treatment, with numerous successful field applications. This article comprehensively reviews the removal mechanisms and treatment performance in the use of FWs for the treatment of diverse industrial wastewaters. Our findings highlight that the performance of FWs relies on proper plant selection, design, aeration, season and temperature, plants harvesting and disposal, and maintenance. Well-designed FWs demonstrate remarkable effectiveness in removing organic matter (COD and BOD), suspended solids, nutrients, and heavy metals from industrial wastewater. This effectiveness is attributed to the intricate physical and metabolic interactions between plants and microbial communities within FWs. A significant portion of the reported applications of FWs revolve around the treatment of textile and oily wastewater. In particular, the application reports of FWs are mainly concentrated in temperate developing countries, where FWs can serve as a feasible and cost-effective industrial wastewater treatment technology, replacing high-cost traditional technologies. Furthermore, our analysis reveals that the treatment efficiency of FWs can be significantly enhanced through strategies like bacterial inoculation, aeration, and co-plantation of specific plant species. These techniques offer promising directions for further research. To advance the field, we recommend future research efforts focus on developing novel floating materials, optimizing the selection and combination of plants and microorganisms, exploring flexible disposal methods for harvested biomass, and designing multi-functional FW systems.

Ameliorative effect of natural floating island as fish aggregating devices on heavy metals distribution in a freshwater wetland

Growing human population and climate change are leading reasons for water quality deterioration globally; and ecologically important waterbodies including freshwater wetlands are in a vulnerable state due to increasing concentrations of pollutants like heavy metals. Given the declining health of these valuable resources, the present study was conducted to evaluate the effect of natural floating island in the form of fish aggregating devices (FADs) made of native weed mass on the distribution of heavy metals in the abiotic and bio compartments of a freshwater wetland. Lower concentrations of surface water heavy metals were observed inside the FADs with a reduction of 73.91%, 65.22% and 40.57-49.16% for Cd, Pb and other metals (viz. Co, Cr, Cu, Ni and Zn), respectively as compared to outside FAD. These led to 14.72-55.39% reduction in the heavy metal pollution indices inside the FAD surface water. The fish species inside the FADs were also found less contaminated (24.07-25.07% reduction) with lower health risk indices. The study signifies the valuable contribution of natural floating island as FADs in ameliorating the effect of heavy metals pollution emphasizing the tremendous role of the natural floating islands in sustainable maintenance of freshwater wetlands for better human health and livelihood.

Water Quality Assessment of Urban Ponds and Remediation Proposals

Ponds are a common feature in urban parks to provide aesthetic and recreational functions, but also deliver a wide range of ecosystem services. The objective of this study was to assess the water quality of six urban ponds in the city of Lisbon, Portugal, to determine the factors that influence it and consider remediation measures for them. Besides that, our study aims to deliver data in order to support the best approach for a future monitoring program, toward more strategic and sustainable management. Floating treatment wetlands (FTW) were installed in three of the ponds during the study, where nutrient levels were higher. Water sampling was performed since 2016, with more intensive campaigns in 2020 and 2021. Average pH ranged from 7.9 to 9.0, average Chemical Oxygen Demand ranged from 36 mg/L to 90 mg/L and average Total Suspended Solids ranged from 7 to 93 mg/L. The main factors that contribute to these values were identified as the presence of waterbirds, vegetative debris that falls in ponds, and contamination with sewage. The FTW that were installed in some of the ponds could help to improve the water quality, but additional measures such as removal of bottom sediments and leaves in the fall, may be necessary. It is expected that the assessment of water quality carried out in the urban ponds can contribute to the overall improvement of urban water management.

Efficacy of Juncus maritimus floating treatment saltmarsh as anti-contamination barrier for saltwater aquaculture pollution control

Floating treatment saltmarsh (FTS) is a new concept proposed to name floating treatment wetlands made of estuarine halophytes especially engineered for the control of contamination in brackish and saline waterbodies. The first full-scale FTS was implemented in 2018 to create an anti-contamination barrier for saline aquaculture wastewater treatment in an estuarine tidal lagoon. Results of a two-year investigation validated 'Phytobatea' modular technology for floating wetlands implementation and operation. Juncus maritimus crossflow FTS efficiency on main mariculture wastewater constituents' removal under low hydraulic retention time was remarkable, i.e., total phosphorus (86%), total suspended solids (82%), biochemical oxygen demand (78%), total organic carbon (55%), turbidity (53%), Escherichia coli (30%), and dissolved oxygen increased (19%). Key features of the native halophyte Juncus maritimus were determined to ensure 75-100% survival under high water salinities up to 38 g/L. A scientific literature review confirmed strategic sectors' growing interest in Juncus maritimus as raw material, supporting its possible cultivation as an added-value by-product within integrated aquaculture systems. Plants' root systems colonization by crabs, shrimps, and young individuals of the critically endangered European eel (Anguilla anguilla), revealed the role of FTS for biodiversity conservation, and its potential as functional habitat, nursery, and refuge for aquatic fauna species in contaminated waterbodies.

Ecosystem Service Assessments within the EU Water Framework Directive: Marine Mussel Cultivation as a Controversial Measure

To combat the persistent eutrophication in coastal waters, sustainable sea-based measures are recommended. Yet, they are the subject of controversial stakeholder discussion, which hampers the implementation and planning process. The aim of this study is to evaluate if a participatory mapping (PM) approach and ecosystem service assessments (ESA) can be suitable tools within Water Framework Directive (WFD) implementation to support the communication with different target groups to improve and accelerate the planning and realization of new sea-based mitigation measures. We conducted three stakeholder-based PMs to visualize the perception of sea-based mitigation measures in coastal waters and seven different ESAs to investigate the perceptions of different mussel cultivation scenarios as mitigation measures. The PMs showed that ecological measures were preferred. The ESA approach showed that, while experts rated mussel cultivation scenarios positively overall, non-expert stakeholders still seemed skeptical and preferred alternative measures like floating wetlands. The methodological results indicate that PM can be a cost-effective tool to visualize stakeholders’ perceptions, but it needs to be applied with an ESA to be beneficial for the WFD implementation process. A web-based ESA improves the discussion with stakeholders and can reveal potential misperceptions and concerns faster and lead to a more focused discussion.

Screening Life Cycle Environmental Impacts and Assessing Economic Performance of Floating Wetlands for Marine Water Pollution Control

The growing environmental awareness of society, the advancement of nature-based solutions (NbSs), and the need for reliable and cost-effective solutions create a favorable environment of opportunities for floating wetlands as alternative solutions for marine water pollution control. The aim of this work was to screen, through OpenLCA, the environmental impacts of floating wetlands for marine water pollution control at various life cycle stages of the system, and assess its economic performance and contribution to the welfare of society. The stage of raw materials production and acquisition was found to be responsible for the main environmental impacts of the floating wetlands, especially on global warming potential, whereas the main impact of the operational stage was related to the eutrophication potential due to N and P residuals in the effluent. The economic performance indicators of economic net present value (ENPV), economic rate of return (ERR), and benefits/costs ratio (B/C ratio) indicate, although marginally, that floating wetlands may constitute a viable investment with potential positive socioeconomic impacts. However, there are still several scientific challenges and technical issues to be considered for the operational application of such systems at full-scale in marine environments.

Alkylphenols and Chlorophenols Remediation in Vertical Flow Constructed Wetlands: Removal Efficiency and Microbial Community Response

This study aims to investigate the effect of two different groups of phenolic compounds (the alkylphenols nonylphenol (NP) and octylphenol (OP), and the chlorophenol pentachlorophenol (PCP)) on constructed wetlands (CWs) performance, including on organic matter, nutrients and contaminants removal efficiency, and on microbial community structure in the plant bed substrate. CWs were assembled at lab scale simulating a vertical flow configuration and irrigated along eight weeks with Ribeira de Joane (an urban stream) water not doped (control) or doped with a mixture of NP and OP or with PCP (at a 100 μg·L−1 concentration each). The presence of the phenolic contaminants did not interfere in the removal of organic matter or nutrients in CWs in the long term. Removals of NP and OP were >99%, whereas PCP removals varied between 87% and 98%, mainly due to biodegradation. Microbial richness, diversity and dominance in CWs substrate were generally not affected by phenolic compounds, with only PCP decreasing diversity. Microbial community structure, however, showed that there was an adaptation of the microbial community to the presence of each contaminant, with several specialist genera being enriched following exposure. The three more abundant specialist genera were Methylotenera and Methylophilus (methylophilaceae family) and Hyphomicrobium (hyphomicrobiaceae family) when the systems were exposed to a mixture of NP and OP. When exposed to PCP, the three more abundant genera were Denitromonas (Rhodocyclaceae family), Xenococcus_PCC_7305 (Xenococcaceae family) and Rhodocyclaceae_uncultured (Rhodocyclaceae family). To increase CWs efficiency in the elimination of phenolic compounds, namely PCP which was not totally removed, strategies to stimulate (namely biostimulation) or increase (namely bioaugmentation) the presence of these bacteria should be explore. This study clearly shows the potential of vertical flow CWs for the removal of phenolic compounds, a still little explored subject, contributing to promote the use of CWs as nature-based solutions to remediate water contaminated with different families of persistent and/or emergent contaminants.