Water Management Priorities in a Post-COVID World

This paper maintains that the growing crisis of water scarcity cannot be addressed from within the paradigm that created the problem. The extractive paradigm which prevails views high economic growth as the main goal of development to be achieved through the increasing extraction of natural resources. Approaches to water management that are based on this paradigm view water as a resource primarily meant for human consumption. In contrast, the paper proposes an ecosystem paradigm in which water is viewed as being embedded within the ecosystem as an essential part of it to be conserved and preserved for future generations. The author identifies five areas of action for water management in the post-COVID context: move away from water-intensive agriculture through crop diversification;sustainable and community-based groundwater management;protection of river systems and wetlands;ensuring water quality and drinking water security and the creation of strong legal frameworks for water governance. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

Assessing lake water quality during COVID-19 era using geospatial techniques and artificial neural network model.

The present study evaluates the impact of the COVID-19 lockdown on the water quality of a tropical lake (East Kolkata Wetland or EKW, India) along with seasonal change using Landsat 8 and 9 images of the Google Earth Engine (GEE) cloud computing platform. The research focuses on detecting, monitoring, and predicting water quality in the EKW region using eight parameters-normalized suspended material index (NSMI), suspended particular matter (SPM), total phosphorus (TP), electrical conductivity (EC), chlorophyll-α, floating algae index (FAI), turbidity, Secchi disk depth (SDD), and two water quality indices such as Carlson tropic state index (CTSI) and entropy­weighted water quality index (EWQI). The results demonstrate that SPM, turbidity, EC, TP, and SDD improved while the FAI and chlorophyll-α increased during the lockdown period due to the stagnation of water as well as a reduction in industrial and anthropogenic pollution. Moreover, the prediction of EWQI using an artificial neural network indicates that the overall water quality will improve more if the lockdown period is sustained for another 3 years. The outcomes of the study will help the stakeholders develop effective regulations and strategies for the timely restoration of lake water quality.

The Role of Aquatic Plants in Natural Products and Drug Discovery

Background: Phytochemicals and their derivatives/analogues represent over 50% of the current medicines worldwide in clinical use. Despite a significant contribution to the total bioactive natural plant products, aquatic plants are underestimated, and several species are extinct and in the endangered list. Objective(s): The aim of this review article is to draw the attention of common people and scientists toward a few important contributions of the aquatic plants to natural product chemistry and drug discovery by highlighting the chemical and pharmaceutical aspects of the same. Method(s): The presented data were collected and selected from the literature obtained by an online search for the ethnomedicinal properties, biological activities and bioactive chemical constituents of aquatic plants using Google Scholar, PubMed and Scifinder chemical abstract service. Result(s): The selected literature data revealed that the extract and compounds isolated from several aquatic plants possess significant biological/pharmaceutical properties. For example, the alpha-asarone (24) and asiatic acid (33) isolated from Acorus calamus and Centella asiatica, respectively, exhibited significant neuroprotective effects in vitro and in vivo. The cripowellin A (59), cripowellin C (60), cripowellin B (61) and cripowellin D (62), isolated from Crinum erubescens, exhibited potent antiplasmodial and antiproliferative activities with half maximal inhibitory concentration (IC50) in nanomolar range (11-260 nM). Several other alkaloids from different Crinum species have also shown anticancer properties against different cancer cell lines with IC50 value <5 microM. Alkaloids and resin glycosides, isolated from different Ipomoea species, have displayed significant psychotropic, psychotomimetic, anticancer, and antibacterial activities with IC50 value <5 microM. Conclusion(s): The aquatic plants play a significant role in the discovery of bioactive natural products. Although several biological activities and bioactive compounds have been reported from these plants, further assessment and scientific validation of most of their traditional usages still need to be done. There are several other similar species that are underestimated and not much explored. Many aquatic plants, such as Ipomoea carnea Jacq., Juncus lomatophyllus Spreng., Commelina benghalensis Linn, Gunnera perpensa L., Scirpus maritimus L. and Mentha longifolia (L.) L., may be considered for further evaluation. In addition to these, one should not undermine the potential of Crinum macowanii for COVID-19 pathogenesis, as its chemical constituent lycorine has shown significant SARS-CoV-2 inhibitory potential (EC50, 0.3 muM;SI >129). Furthermore, most rural communities are still using the wetland resources for their cultural, medicinal, economic, domestic, and agricultural needs. Hence, the conservation of aquatic plants and wetlands is an issue of great concern.Copyright © 2023 Bentham Science Publishers.

Efficacy Evaluation of Silty-Sandy Soil and Chrysopogon zizanioides to Attenuate Doxycycline from Wastewater in a Constructed Wetland System

In recent years, the emergence of COVID-19 has created disastrous health effects worldwide. Doxycycline, a member of the tetracycline group, has been prescribed as a treatment companion for attending this catastrophe. Due to extensive use and high solubility, a significant amount of un-metabolized doxycycline has been found to reach water bodies within a short time, and consumption of this water may lead to the development of fatal resistance in organisms and create health problems. Therefore, it has become necessary to develop suitable technologies from a geoenvironmental point of view to remove these unwanted antibiotics from wastewater. In this context, locally obtainable silty-sandy soil was explored as a low-cost material in a constructed wetland with Chrysopogon zizanioides (vetiver sp.) for phytoremediation to mitigate doxycycline spiked wastewater. The obtained soil hydraulic conductivity was 1.63×10-7 m/s. Batch adsorption tests conducted on silty-sandy soil, vetiver leaf, and vetiver root provided maximum removal efficiencies of 90%, 72%, and 80% percent, respectively, at optimal sorbent doses of 10 g/L, 17 g/L, and 16 g/L, and contaminant concentrations of 25 mg/L, 20 mg/L, and 23 mg/L, with a 30-min time of contact. The Freundlich isotherm was the best fit, indicative of sufficient sorption capacity of all the adsorbents for doxycycline. The best match in the kinetic research was pseudo-second-order kinetics. A one dimensional vertical column test with the used soil on doxycycline revealed a 90% breakthrough in 24 h for a soil depth of 30 mm. Studies on a laboratory-scale wetland and numerically modeled yielded removal of around 92% by the selected soil and about 98% combined with Chrysopogon zizanioides for 25 mg/L of initial doxycycline concentration, which is considered quite satisfactory. Simulated results matched the laboratory tests very well. The study is expected to provide insight into remedies for similar practical problems. © 2023 American Society of Civil Engineers.

The potential of decentralised wastewater treatment in urban and rural sanitation in South Africa: lessons learnt from a demonstration-scale DEWATS within the eThekwini Municipality

The design principles of decentralised wastewater treatment systems (DEWATS) make them a practical sanitation option for municipalities to adopt in fast-growing cities in South Africa. Since 2014, a demonstration-scale DEWATS with a modular design consisting of a settler, anaerobic baffled reactor (ABR), anaerobic filter (AF), vertical down-flow constructed wetland (VFCW) and horizontal flow constructed wetland (HFCW) has been in operation in eThekwini. A performance evaluation after the long-term operation was undertaken in 2019 by comparing the final effluent with national regulatory requirements. Despite limitations in characterising the raw wastewater, a comparison of the settler and final effluent quality indicated high (≥ 85%) removal efficiencies of total chemical oxygen demand (CODt), ammonium-N (NH4-N) and orthophosphate-P (PO4-P), 75% removal of total suspended solids (TSS) and 83.3% log10 removal of Escherichia coli. Lack of exogenous and endogenous carbon and high dissolved oxygen (DO) concentrations (> 0.5 mg·L−1) inhibited denitrification in the HFCW, resulting in 12.5% of the effluent samples achieving compliance for nitrate-N (NO3-N). Moreover, mixed aggregate media and low residence times in the HFCW may have also contributed to poor NO3-N removal. During the COVID-19 lockdown, an unexpected shutdown and subsequent resumption of flow to the DEWATS indicated a 16-week recovery time based on achieving full nitrification in the HFCW. Although design modifications are necessary for the HFCW, the installation of urine diversion flushing toilets at the household level will reduce the nutrient loading to the DEWATS and potentially achieve fully compliant effluent. Alternatively, the application of two-stage vertical flow constructed wetlands to improve denitrification should also be explored in the South African context. With an improved design, DEWATS has the potential to fill the gap in both urban and rural sanitation in South Africa, where waterborne sanitation is still desired but connections to conventional wastewater treatment works (WWTWs) are not possible. © The Author(s) Published under a Creative Commons Attribution 4.0 International Licence (CC BY 4.0).

Towards Effective, Sustainable Solution for Hospital Wastewater Treatment to Cope with the Post-Pandemic Era.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has spread across the globe since the end of 2019, posing significant challenges for global medical facilities and human health. Treatment of hospital wastewater is vitally important under this special circumstance. However, there is a shortage of studies on the sustainable wastewater treatment processes utilized by hospitals. Based on a review of the research trends regarding hospital wastewater treatment in the past three years of the COVID-19 outbreak, this review overviews the existing hospital wastewater treatment processes. It is clear that activated sludge processes (ASPs) and the use of membrane bioreactors (MBRs) are the major and effective treatment techniques applied to hospital wastewater. Advanced technology (such as Fenton oxidation, electrocoagulation, etc.) has also achieved good results, but the use of such technology remains small scale for the moment and poses some side effects, including increased cost. More interestingly, this review reveals the increased use of constructed wetlands (CWs) as an eco-solution for hospital wastewater treatment and then focuses in slightly more detail on examining the roles and mechanisms of CWs' components with respect to purifying hospital wastewater and compares their removal efficiency with other treatment processes. It is believed that a multi-stage CW system with various intensifications or CWs incorporated with other treatment processes constitute an effective, sustainable solution for hospital wastewater treatment in order to cope with the post-pandemic era.

Switching intention and behaviors to wetland ecotourism after the COVID-19 pandemic: the perspective of push-pull-mooring model

This study used a push-pull-mooring model (PPM model) to build an integrated model to explain the influencing factors of tourists' switching intention to wetland ecotourism after the COVID-19 pandemic. The push effect is crowding perception, the pull effect is nature-based destination attractiveness, and the mooring effect is the risk perception of COVID-19. The study collected 551 valid research samples by questionnaire survey in two world-class wetlands in Taiwan. The results of the regression analysis showed that push, pull, and mooring influenced tourists' switching intention to wetland ecotourism. Among them, the mooring effect regulated the relationship between the push effect and switching intention to wetland ecotourism, but did not regulate the relationship between the pull effect and switching intention to wetland ecotourism. Finally, the switching intention to wetland ecotourism further influenced wetland ecotourism behaviors. It is expected that people can go outdoors after the COVID-19 pandemic and bring substantial economic benefits of tourism to wetland ecological attractions in Taiwan.

Natural climate solutions in Indonesia: wetlands are the key to achieve Indonesia’s national climate commitment

Indonesia offers a dramatic opportunity to contribute to tackling climate change by deploying natural climate solutions (NCS), increasing carbon sequestration and storage through the protection, improved management, and restoration of drylands, peatlands, and mangrove ecosystems. Here, we estimate Indonesia’s NCS mitigation opportunity for the first time using national datasets. We calculated the maximum NCS mitigation potential extent using datasets of annual national land cover, peat soil, and critical lands. We collated a national emissions factor database for each pathway, calculated from a meta-analysis, recent publications from our team, and available literature. The maximum NCS mitigation potential in 2030 is 1.3 ± 0.04 GtCO2e yr−1, based on the historical baseline period from 2009–2019. This maximum NCS potential is double Indonesia’s nationally determined contribution (NDC) target from the forestry and other land use sector. Of this potential opportunity, 77% comes from wetland ecosystems. Peatlands have the largest NCS mitigation potential (960 ± 15.4 MtCO2e yr−1 or 71.5 MgCO2e ha−1 yr−1) among all other ecosystems. Mangroves provide a smaller total potential (41.1 ± 1.4 MtCO2e yr−1) but have a much higher mitigation density (12.2 MgCO2e ha−1 yr−1) compared to dryland ecosystems (2.9 MgCO2e ha−1 yr−1). Therefore, protecting, managing, and restoring Indonesia’s wetlands is key to achieving the country’s emissions reduction target by 2030. The results of this study can be used to inform conservation programs and national climate policy to prioritize wetlands and other land sector initiatives to fulfill Indonesia’s NDC by 2030, while simultaneously providing additional co-benefits and contributing to COVID-19 recovery and economic sustainability.

Ecological restoration for the Liangtan river by Rotating biological contactors combined with hybrid constructed wetlands

Rotating biological contactors (RBCs) were first used as pretreatment units for hybrid constructed wetlands (HCWs) in practical engineering to treat polluted river water. The experimental results during 2019–2021, except the period of global COVID-19 pandemic (January to April, November and December in 2020), indicated the average removal efficiencies of ammonia nitrogen (NH4+–N), total phosphorous (TP), and chemical oxygen demand (COD) were 95.06%, 41.03%, and 45.46%, which met the Chinese Environmental Quality Standards Ⅰ, Ⅲ, Ⅳ (CEQS Ⅰ, Ⅲ, Ⅳ), respectively. RBCs and HCWs had synergistic and complementary effects on purification efficiency, especially on nitrogen removal. The remarkable nitrification efficiency of RBCs was not influenced by temperature and influent loads. The relative abundances of microorganisms at HCWs in cold seasons were comparable to that in warm seasons, which promoted the recovery of decontamination efficiency after overwintering. These results support RBCs combined with HCWs (R-HCWs) is an effective polluted river purification process, providing a new perspective on water ecological restoration.

Participatory Approach to Wetland Governance: The Case of The Memorandum of Understanding of the Sečovlje Salina Nature Park

Wetlands are defined as dynamic ecosystems that combine the characteristics of aquatic and terrestrial ecosystems and are important from ecological as well as social and economic perspectives. In response to the intense degradation and alteration of wetlands, communities have developed various management strategies. One of the ways to achieve more effective participatory wetland management is to introduce the concept of a Wetland Contract, a voluntary agreement that ensures sustainable management and development of wetlands. This study on the Sečovlje Salina Nature Park in Slovenia follows the methodology of the preparation (legal framework, scientific description and stakeholder analysis) and implementation (organization of Territorial Labs, scenario planning and development) stages of the Wetland Contract concept. Of approximately 200 potential stakeholders, 34 participated in the Territorial Labs, and 16 stakeholders signed the less binding type of Wetland Contract, called the Memorandum of Understanding. The Memorandum of Understanding and its implementation process, which included systematic cross-sectoral participation, successfully overcame conflicts between stakeholders with different interests. The methodology used has shown great potential for further applications in wetlands of common interest.

Exploring the influence of the interaction of climate change, manmade threats and COVID-19 on the livelihoods of wetland communities in sub-Saharan Africa

Wetlands are very important because of the wide range of ecosystem services they provide. Despite their ecological, social and environmental importance, these ecosystems are threatened and fragmented under the combined effects of climate change (CC) and man-made activities (MMA). Such a state of things could be exacerbated by the advent of the coronavirus disease 2019 (COVID-19) pandemic with its many implications. In order to help decision-makers take good decisions, the combined effect of CC, MMA and COVID-19 on the livelihoods of communities around wetland ecosystems have been reviewed based on available scientific knowledge. First, we analyzed the different concepts and theories underlying the wetlands-related studies and then summarized the merits and demerits of the different methodologies underlying wetland studies. The empirical evidences that exist in previous literatures have been highlighted. Similarly, common livelihood strategies for wetland communities in Sub-Saharan Africa (SSA) have been highlighted. The diversity of wetlands' functions and services makes them a source of livelihood, food security and poverty alleviation for riverside communities. However, these communities lack the knowledge and awareness to understand the impact of their activities and CC on their livelihoods. The review also helped to identify that, out of the three factors investigated, the livelihoods of rural wetland dwellers in SSA are mostly influenced by CC and MMA. However, climate change and COVID-19 remain life-altering transboundary threats that extend in space and time, with large uncertainties on wetlands communities livelihoods.

Hospital superbug traced to remote island beach

Anuradha Chowdhary, professor of mycology, Vallabhbhai Patel Chest Institute, University of Delhi, and corresponding author of the study, says that while C. auris isolates found on the beach were multidrug-resistant, those found in the remoter salt marshes of the Andaman islands were not resistant to ordinary anti-fungal drugs. “Thorough screening of patients and their environment is required as also cohorting (putting together) of patients who are colonised by C. auris —since they continuously shed viable yeast cells from their skin and contaminate hospital environments.” The present study notes that a hypothesis published July 2019 in mBiosuggests that C. auris might be native to wetlands and that its emergence as a human pathogen may be linked to the effects of global warming effects on wetlands.

Buffering Climate Change with Nature

It is increasingly evident that climate sustainability depends not only on societal actions and responses, but also on ecosystem functioning and responses. The capacity of global ecosystems to provide services such as sequestering carbon and regulating hydrology is being strongly reduced both by climate change itself and by unprecedented rates of ecosystem degradation. These services rely on functional aspects of ecosystems that are causally linked—the same ecosystem components that efficiently sequester and store carbon also regulate hydrology by sequestering and storing water. This means that climate change adaptation and mitigation must involve not only preparing for a future with temperature and precipitation anomalies, but also actively minimizing climate hazards and risks by conserving and managing ecosystems and their fundamental supporting and regulating ecosystem services. We summarize general climate–nature feedback processes relating to carbon and water cycling on a broad global scale before focusing on Norway to exemplify the crucial role of ecosystem regulatory services for both carbon sequestration and hydrological processes and the common neglect of this ecosystem–climate link in policy and landscape management. We argue that a key instrument for both climate change mitigation and adaptation policy is to take advantage of the climate buffering and regulative abilities of a well-functioning natural ecosystem. This will enable shared benefits to nature, climate, and human well-being. To meet the global climate and nature crises, we must capitalize on the importance of nature for buffering climate change effects, combat short-term perspectives and the discounting of future costs, and maintain or even strengthen whole-ecosystem functioning at the landscape level. Significance Statement Natural ecosystems such as forests, wetlands, and heaths are key for the cycling and storage of water and carbon. Preserving these systems is essential for climate mitigation and adaptation and will also secure biodiversity and associated ecosystem services. Systematic failure to recognize the links between nature and human well-being underlies the current trend of accelerating loss of nature and thereby nature’s ability to buffer climate changes and their impacts. Society needs a new perspective on spatial planning that values nature as a sink and store of carbon and a regulator of hydrological processes, as well as for its biodiversity. We need policies that fully encompass the role of nature in preventing climate-induced disasters, along with many other benefits for human well-being.

Ultrashort Hydraulic Retention Time of Aeration and Nonaeration Constructed Wetlands for a Large Volume of Primary-Treated Wastewater from a Medical Rubber Glove Factory

A substantial volume of primary-treated wastewater from a medical rubber glove factory caused public freshwater to become sewage. The ultrashort hydraulic retention time in constructed wetlands was urgently employed for wastewater remediation. Pilot-scale, aeration, and nonaeration horizontal surface flow constructed wetlands (HSFCWs) with emergent plants were designed, compared, and optimized. Activated carbon, coconut shells, and oyster shells were subsequently transferred into a plastic basket as a substrate layer, while Typha angustifolia L. was used as an emergent plant. The experiments were conducted at a hydraulic retention time of 2, 4, 6, and 8 hr. per effluent recirculation. Sampling data were collected for each of the four effluent recirculations. The removal efficiencies of BOD, COD, FOG, TKN, TSS, TDS, EC, and salinity in the aeration HSFCWs were high—53.25, 67.28, 97.93, 78.93, 95.87, 87.52, 86.36, and 90.38%—at the first effluent recirculation of sampling, respectively, while the removal efficiencies in the nonaeration HSFCWs were also high—55.12, 57.38, 94.62, 83.10, 95.95, 88.09, 89.54, and 93.46%, respectively. Increasing the hydraulic retention time increased removal efficiencies. The removal efficiency of BOD in aerated HSFCWs was higher than in nonaerated HSFCWs in the second effluent recirculation of sampling. This is because the oxygen supplied by aeration in the system increased the organic and inorganic pollutant removal efficiencies. Other pollutants were removed more effectively during the second effluent recirculation. Excluding BOD and COD, Duncan’s multiple test revealed that the number of effluent recirculations for removal efficiencies of FOG, TKN, TSS, TDS, EC, and salinity was nonsignificant at the p≤0.001 level. These findings led to optimization of the medical rubber glove wastewater treatment at an ultrashort hydraulic retention time of 2–4 hr. This process and the control of CWs may be the best industrial wastewater treatment practice and a long-term solution for the industrial sector.

The specter of empty countrysides and wetlands—Impact of hunting take on birds in Indo‐Burma

Hunting for the wild meat trade, medicines and other human uses has decimated Indo‐Burma's vertebrate biota and has led to widespread defaunation. Yet, there is surprisingly little data on how hunting impacts wild bird assemblages in different landscapes here. Based on concurrent snapshot surveys of bird hunting, food markets and hunting attitudes across six Indo‐Burma countries, we found that hunting threatens species not only in forested landscapes but also wetlands and farmlands such as orchards and paddy fields—ecosystems overlooked by past studies, with at least 47 species associated with wetlands and agricultural lands identified from market surveys across the region. High rates of mortality are suffered when hunting tools such as nets are used to exclude perceived bird pests in both aquaculture and agricultural landscapes, with over 300 individual carcasses of at least 29 identifiable species detected in one aquaculture landscape sampled in Thailand. We warn that the potentially unsustainable trapping of species for consumption and trade in Indo‐Burma, coupled with high incidental mortalities, could decimate the populations of erstwhile common and/or legally unprotected species. There is an urgent need for stronger regulatory oversight on the hunting take of wild birds and the use of hunting tools such as nets. Alongside this, conservation practitioners need to better engage with rural communities to address unsustainable hunting practices, especially outside of protected areas.

INNOVATIONS FOR TACKLING POST-PANDEMIC RELATED CHALLENGES - A COLLABORATIVE RESEARCH TO DISCOVER NEW SOLUTIONS FOR HYBRID WORK IN THE CONTEXT OF 15-MINUTE CITIES

Recently we have developed a public-private partnership initiative call: UrbanLink15' which aims to identify healthier lifestyles and sustainable facilities that support residents of economic, social, and environmental impact;The initiative focuses both on promoting hybrid work developed as a relationship between organizational workspaces, living spaces, and co-working spaces in the neighborhood, and the (re)connection with sustainable mobility solutions of the concept of '15 minute city'. The article presents the research results (a survey, two focus groups and solutions of application projects) achieved with the support of researchers, practitioners, and students from different specialties such as architecture, engineering, management, applied science organized in two main topics: (1) work relationships, living spaces within the framework of "15-minute city";(2) alternative mobility through green-blue corridors and gardens. The discussion of the research results refers to the metropolitan area of Timisoara, Romania.

Greening Urban Areas with Decentralized Wastewater Treatment and Reuse: A Case Study of Ecoparque in Tijuana, Mexico

In rapidly growing urban areas, such as Tijuana, Mexico, the presence of urban green spaces (UGSs) can help stem soil erosion, improve infiltration, slow runoff, decrease flooding, reduce air pollution, and mitigate climate change. In many water-scarce parts of the world, where centralized wastewater treatment is not accessible or practical, decentralized wastewater treatment systems (DEWATSs) have the potential to supply the water needed for irrigating UGSs. Here, we first review UGS systems supported by DEWATSs and the water quality guidelines and challenges associated with implementing DEWATSs for urban greening in different countries, including Mexico. We also critically examine the linkages between the lack of UGSs in Tijuana, Mexico, extensive soil erosion, and failing sanitation infrastructure that has led to the infamously poor water quality in the Tijuana River. Tijuana’s Ecoparque Wastewater Treatment Facility, a low-energy, aerobic DEWATS, which collects, treats, and discharges residential sewage for localized landscape irrigation, demonstrates how DEWATSs can meet the water demands for urban greening in rapidly urbanizing cities. The aerobic decentralized treatment using a gravity-fed trickling biofilter resulted in a >85% removal of chemical oxygen demand and dissolved organic carbon. Prior to treatment facility upgrades, there was a ~2 log reduction in total coliform and Escherichia coli and a <20% decrease in ammonia from the influent to final effluent. After the addition of a maturation pond in 2020, the effluent met Mexico standards for irrigation reuse, with a ~4 log reduction in fecal coliforms from the influent to final effluent. Case study results demonstrated the potential for decentralized wastewater treatment to meet effluent standards for landscape irrigation, provide water for urban greening, and prevent pollution in the Tijuana River and other urban waterways.

Urban Fabrics to Eco-Friendly Blue–Green for Urban Wetland Development

In an urbanized world, the sustainability of cities will depend on their form and urban structure. In this sense, fabrics that are compact, dense, green, and suitable for non-motorized transport methods are more environmentally efficient. For the purpose of contributing new tools to the design, urban planning, and sustainability of nature in residential areas, this study characterizes the urban fabrics of six urban wetlands in the Latin American city of Concepción (Chile), which is known for its blue–green spaces. In a wetland city, we model urban patterns through spatial relationship using a statistical regression model (OLS—ordinary least squares) with the urban variables of density, distance, population, housing, highways, green areas, and building permits. Concepción shows predominantly low- to medium-density fabrics, and it is not integrated with the urban wetlands. In fact, it was observed that the residential areas do not take advantage of the blue–green spaces and that the urban fabrics do not favor proximity, with a transportation network that promotes the use of cars, leading to the wetlands being inaccessible and fragmented. However, as they are still surrounded by open spaces with abundant vegetation, there are highly feasible opportunities for the future development of blue–green infrastructure.

Constructed wetlands implementation in Kathmandu Valley, Nepal

Constructed wetlands can be considered as a strategic nature-based wastewater treatment technology for Nepal, where the discharge of untreated wastewater into rivers, lakes or any other water body is a common practice and where the big wastewater treatment plants are not well functioning or are not sufficiently used. The successful implementation of constructed wetlands in Nepal is conditioned by many factors, which should be considered. Legislation is weak and hygienic standards are low;therefore, wastewater treatment is usually not a priority for city governments and private or public institutions, as well as for communities themselves. Under these circumstances, it is not an exception that it might be difficult to convince people to pay for constructed wetlands implementation and maintenance. Our paper discusses conditions influencing the applicability of constructed wetlands in the Kathmandu Valley, Nepal, by empirically analysing the best and bad practices of their application. The focus is paid to present the social situation and history of analysed communities and organisations. Implementation of constructed wetlands for schools is discussed as a special case, as well as the change of the communities’ approach towards constructed wetlands’ importance, as it appeared during the pandemic situation of COVID-19 in 2020.

The effect of microplastics on earthworm-assisted sludge treatment wetlands

Due to the characteristics of rapid transmission of COVID-19 and extended survival time on the plastic surface, resulting in a sharp increase in the number of microplastics (MPs) in sludge. In this paper, different amounts of terephthalate (PET) were added to four earthworm-assisted sludge treatment wetland (ESTW) reactors to investigate the effect of MPs on the operation process of ESTW. The results show that the addition of a small number of MPs had little effect on the ESTW reactor, and the negative impact was evident when a large number of MPs. The ESTW4 reactor with 200000 particles/kg the worst organic matter removal and sludge stability. The plant height, root length and chlorophyll growth of the ESTW4 reactor were significantly inhibited, and the yield of catalase (CAT) increased significantly, which proved that a large number of MPs had noticeable side effects on plants. The number of MPs (35.21particles/kg) and small size MPs (62.6%) in earthworm casts reached maximum, CAT (38.1U/mg prot) and acetylcholine esterase (AChE) (14.3U/mg prot) have the same trend in ESTW4. A large number of MPs during the ESTW reactor lead to an obvious oxidative stress reactions and lasting neurotoxicity of earthworm. Additionally, the type and quantity of bacteria in the ESTW reactor could reduce when the MPs adding too much. © 2021 Elsevier Ltd