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Graphical abstract Highlights • Concentrations of heavy metals were significantly reduced in paper mill sludge by earthworm. • Heavy metals were accumulated by earthworm internal body. • High concentration of paper mill sludge showed the highest incidence of damaged tissues in earthworms. • Vermistabilization is a low-cost eco-friendly technology to combat land pollution. Abstract The present study demonstrates the vermistabilization of paper mill wastewater sludge (PMS) spiked with cow dung (CD) employing indigenous epigeic earthworm Perionyx excavatus Perrier. A total of six treatments were prepared along with a positive control (PC) and negative control (NC). Twenty earthworms were released into each treatment including PC and NC without earthworms. The different proportions viz., T1 (CD – 100%), T2 (PMS:CD – 1:3), T3 (PMS:CD – 1:2), T4 (PMS:CD – 1:1), T5 (PMS:CD – 3:1), T6 (PMS:CD – 2:1), PC (PMS – 100%) and NC (PMS – 100%) and changes in chemical parameters and microbial properties were recorded during the course of 60 days. Vermistabilization caused a significant decrease in the level of heavy metals: Cd (2.9–27.8%), Cu (0.22–42.3%), Pb (1.3–56.3%) and Cr (0.8–46.2%). The bioconcentration factor (BCFs) was also calculated and great amount of heavy metals accumulated in their body (mg kg−1) that ranged from 0.31 ± 0.003–0.45 ± 0.007 for Cd, 0.12 ± 0.005–0.24 ± 0.003 for Cu, 0.15 ± 0.005–0.31 ± 0.006 for Pb and 0.29 ± 0.007–0.56 ± 0.001 mg kg−1 for Cr, accumulation of heavy metals are in the order: Cr > Cd > Pb > Cu. The physicochemical parameters of earthworm treated substrate such as electrical conductivity, total nitrogen, total phosphorus and total potassium were significantly increased; whereas, pH, total organic carbon, C:N ratio (carbon: nitrogen) and C:P ratio (carbon: phosphorus) were reduced after 60 days of vermistabilization. The vermistabilized materials also had a higher population of bacteria (98.90 ± 0.30 CFU × 106 g−1), fungi (43.75 ± 0.55 CFU × 103 g−1) and actinomycetes (67.65 ± 0.45 CFU × 105 g−1) than initial mixtures. Moreover, several histopathological changes were observed in earthworm tissues viz., disintegration of cells, irregular surface of epidermis, cellular debris, irregular cellular compartmentation, and oval-shaped nucleus. Higher level of histopathological abnormalities was recorded in PC (PMS-100%) while none were detected in lower concentrations of PMS. Furthermore, the study concludes that the paper mill sludge in a mixture of cow dung (1:1 ratio) can be a useful proposition for utilizing this hazardous waste through the adoption of vermitechnology. [ABSTRACT FROM AUTHOR]

The largest Phragmites reed field in the world, with a historical area of approximately 1000 km 2 , is located in the Liaohe Delta in northeastern China. The Phragmites wetlands are extensively managed to maximize the production of reed biomass for the paper industry. Based on satellite remote sensing we estimated that the total area of the Phragmites wetlands has decreased from 857 km 2 in 2003 to 786 km 2 in 2009 to accommodate oil field infrastructure and societal developments. However, at the same time the production of Phragmites biomass used for the production of reed pulp has increased to 400,000 metric tons per year. This paper describes the great efforts that have been made to increase the Phragmites yields for the paper industry, including (1) diversion of freshwater from rivers to the Phragmites fields, (2) management of the water table, (3) harvesting and burning for pest control, and (4) seawater irrigation to rehabilitate Phragmites fields infested with weeds. The paper industry has facilitated the conservation of the Phragmites wetlands and their associated ecosystem services. Besides being a source for fiber, the wetlands provide important habitat for wildlife, sequester carbon, and create job opportunities and economic income for the local people. [ABSTRACT FROM AUTHOR]

The present study deals with the bioremediation of potentially hazardous pulp and paper mill effluent by a laccase producing Paenibacillus sp. strain LD-1 (JX499920) isolated from contaminated soil sample by lignin enrichment method. The bacterium effectively reduced pollution parameters (colour 68%, lignin 54%, phenol 86%, BOD 83% and COD 78%) after 144 h of treatment at 34 ± 1 °C and 120 rpm. GC–MS analysis of control and treated samples showed that concentration of most of the low molecular weight phenolic compounds like 2-methoxyphenol, 2,6-dimethoxy phenol, 2-methoxy-4-ethyl-phenol, 3-allyl-6-methoxyphenol, ethanone 1-(-4-hydroxy-3,5-dimethoxyphenyl), benzoic acid, 2-methoxy-4-(1-propenyl) phenol and 4-methoxycinnamic acid present in control untreated effluent were reduced after bacterial treatment. The toxicity assessments were carried out with treated and untreated effluent by studying the growth and germination of seeds of mung bean ( Vigna radiata L.). The mung bean bioassay confirmed the detoxification of effluent after bacterial treatment. [ABSTRACT FROM AUTHOR]

Heavy metal content has become a serious issue with increase in compost application in agricultural land. The bioavailable fraction (water soluble and diethylene triamine pentaacetic acid (DTPA) extractable) is the major concern comparing to the total concentration as it can be taken up by plants which in turn affects the human health. Thus, this study was carried out to determine the variation in bioavailable and leachable fraction of heavy metals (Cd, Cu, Fe, Ni, Pb, Cr, Zn, Hg and Mn) and to assess the influence of temperature, pH, organic matter degradation and humification during rotary drum composting of paper mill sludge (PMS) for 20 days. A total concentration of all the metals as well as nutrients increased during composting. The Hg was not detected in water soluble and DTPA extractable fraction, whereas Pb and Cr were also not detected in water soluble fraction in all the trials. A decreasing trend was observed in leachable quantity for all the metals during composting. Water extractable quantity increased for Fe and Cu during composting. Organic matter degradation and humification during composting influences the variation in bioavailability and leachability of heavy metals, which can be optimized by applying appropriate proportion of cow dung during rotary drum composting of PMS. [ABSTRACT FROM AUTHOR]

The results of physico-chemical analysis of pulp and paper mill effluent sedimented sludge revealed the presence of heavy metals (mg l −1 ) Fe (67.53), Zn (13.90), Cu (2.15), Cr (2.30), Cd (0.255), Mn (11.0), Ni (3.30), and Pb (1.05) along with persistent chlorolignin. The major persistent organic pollutants detected by GC–MS were ethane, 1,1-diethoxy; tetradecanoic acid; furane 2,5-dimethyl; n -hexadecanoic acid; nonacosane, trimethylenebis-1,3-dioxolane; 1,3-dioxolane, 2-(phynylmethyl). Twelve representative native plants were noted based on their population number growing on pulp and paper sludge and evaluated for their phytoextraction potential of heavy metals. The result revealed that Triticum aestivum was found as root accumulator for all metals except Cu. Similarly, the Brassica campestris accumulated all metals maximum in root except Ni, Fe and Pb. While, Eclipta alba accumulated majority of metals in their shoot and leaves, But Solanum nigrum, Rumex dentatus accumulated metals in root and shoot both. Rananculus scleratus accumulated all the tested metals in their aerial parts except Cd and Pb. Cammelina benghalensis accumulated metals in root except Cd, Pd. Similarly the Phragmites cummunis and Ricinus cummunis accumulated majority of metals in their shoot and leaves. It was also noted that several evaluated plant showed bioconcentration factor (BCF) greater than one for accumulated metals i.e. Pb in T . aestivum (1.285), C . benghalensis (5.142), Cannabis sativa (3.466), P . cummunis (7.180), R . cummunis (66.80) was also noted. Furthermore, greater than one translocation factor (TF) for all these plants showed strong evidence for phytoextraction and in situ remediation potential of these plants. The overall order of phytoextraction potential of native wetland plants were C . sativa > P . cummunis > C . benghalensis > T . aestivum > B . campestris > E . alba . [ABSTRACT FROM AUTHOR]

Green roofs provide ecological benefits to urban areas and the use of biodiverse communities enables the vegetation to recover from stress caused by dry conditions. Recycled waste materials are often used as substrates and extensive research on their physical and chemical properties has been carried out. In this study, we evaluated different amounts of deinking sludge pellets as an alternative substrate component in establishing drought-tolerant herbaceous communities on green roofs. Three substrates were prepared aimed at providing decreasing fertility: a commercial substrate composed of tephra and compost (control); an experimental substrate composed of tephra, pellets, and compost, and another one consisting of tephra and pellets. A mixture of 30 species, including native herbaceous species and sedum, of Mediterranean phytocenosis, was transplanted on all the substrates. A physical and chemical characterization of the substrates was carried out. The plant ecological functionality, life forms and richness, and the abundance of flower-visiting insects were studied. The substrate composition affected the plant community cover and richness. The amount of pellets in the two experimental substrates reduced the availability of resources (nitrogen and moisture content) promoting diversity, in terms of the number of species, as well as the hardiness of the vegetation. Our results are of great interest for obtaining a biodiverse mosaic habitat in green infrastructures, by measuring out the quantity of infertile materials in the substrates. [ABSTRACT FROM AUTHOR]

Abstract: This study investigates the predictive ability of gene-expression programming (GEP) in the estimation of methane yield (Y m ) and effluent substrate (S e ) produced by two anaerobic filters. The modeling study was carried out using the data obtained from two upflow anaerobic filters – one mesophilic (35°C) and one thermophilic (55°C) – operated for the treatment of paper-mill wastewater under varying organic loadings. The GEP model was composed of three inputs, hydraulic retention time (T hr ), organic loading rate (R ol ), and influent substrate (S i ), and one output, either S e or Y m . The Stover–Kincannon model was also used for data analysis and to evaluate the prediction ability. Three statistical criteria, root mean square error (RMSE), determination coefficient (R 2), and Akaike''s information criteria (AIC), were the means used for comparison. The results showed that the GEP approach predicted the performance of both anaerobic filters much better than the Stover–Kincannon model. [Copyright &y& Elsevier]

Management of industrial sludge is a big challenge for developing countries. Composting is an economical and viable option to manage and treat an industrial sludge. However, efficient compost production requires nature of materials involved, process understanding and physics behind the process. We investigated the physical parameters during composting of solid pulp and paper mill sludge in 550 L rotary drum composter. Variation in physical parameters such as bulk density, volatile solids, moisture content, free air space, void ratio, ash content and particle density were analyzed over the period of composting. Bulk density was observed increasing, whereas free air space was showed declining trend and observed 52% in end compost. The particle density was observed to be increasing from 610 to 680 kg m −3 . End compost was analyzed for nutritional parameters and seen to be increasing over the period of composting. A strong relationship was found between various physical parameters. Pearson’s correlation coefficient matrix was formed between free air space, bulk density, moisture content and particle density. [ABSTRACT FROM AUTHOR]

Despite growing health concerns and increasing water scarcity, adequate wastewater treatment and reuse remains limited in India. Low-cost, decentralised, and nature-based on-site sanitation systems could play a key role in a circular water approach. This paper evaluates the performance of a Wastewater Fertigated Short Rotation Coppice (wfSRC) system based on willow, poplar, and bamboo species as a potential solution, offering low-cost, efficient water treatment, and high biomass production. Through a full-scale wfSRC pilot plant (250 m3·day−1 municipal wastewater on 6864 m2) established at Aligarh Muslim University, Uttar Pradesh, India, treatment capacities, biomass production rates, and contamination tolerance of different willow, poplar, and bamboo species were investigated. The chemical compositions of incoming wastewater, percolation water, soil, and biomass were monitored regularly. Despite the high load, all plant sections of the wfSRC system showed efficient removal of wastewater-originated pollutants. BOD5 and COD removal efficiencies were up to 99% and 95% respectively. Removal efficiencies for PO4-P reached 93% and for TN 91%. In general, total nitrogen and phosphate loads appear to be the limiting design parameters under the conditions at Aligarh to meet all discharge limits in India. Biomass production was projected to be >225 tDM·ha−1·yr−1 for bamboo, 65 tDM·ha−1·yr−1 for willow, and 206 tDM·ha−1·yr−1 for poplar. The pilot, conducted from March 2022 to June 2023, showcased how these densely planted agroforestry systems can effectively treat wastewater through natural processes such as oxidation, microbial degradation, and plant uptake. The findings demonstrate wfSRC's potential to serve as a nature-based, sustainable approach to wastewater treatment, particularly beneficial for suburban and rural areas in India and similar regions worldwide. This paper also provides recommendations for future implementation of wfSRC systems, emphasizing the need for careful planning regarding plant selection, system design, and operational strategies to maximize treatment efficiency and biomass production. [ABSTRACT FROM AUTHOR]

River water irrigation is used to reduce soil salinity in the reed fields of the Shuangtai Estuary Wetland in Northeast China to improve the reed quality for paper industry; however, quantitative effects of this approach have not yet been investigated. In this study, the effect of irrigation was investigated by conducting comprehensive field observations and numerical simulations, and the necessary irrigation water volume was determined. The field observations included determination of (1) the relation between surface soil salinity and reed yield; (2) vertical profile of soil salinity before and after the irrigation period; and (3) variation of depth and salinity of the standing water during irrigation and the rate of rainwater interception by reed leaves. Our findings suggested that (1) the reed yield decreased remarkably when the surface soil salinity exceeded 5‰ and (2) irrigation could reduce salinity to below this level. From our observations, water budget in the irrigated reed fields was evaluated. A numerical model was constructed to simulate the salinity reduction process by assuming that the salinity flux across the ground surface was proportional to the salinity difference between the standing water and the surface soil. The model parameters were calibrated using the results of observation (3) such that the model successfully reproduced the observed time series of standing water salinity. A series of numerical experiments were performed using the model to determine the irrigation water volume necessary for sufficient soil salinity reduction. The results suggested that soil salinity reduction depended greatly on rainfall during the reed growth period. Further, an initial irrigation depth of about 20 cm was sufficient for lowering the salinity to 5‰ even during rainfall shortage that occurred every 10 years on an average. Replacing the saline standing water before intensive rainfall events with rainwater was found to be an effective approach to lower the surface soil salinity. [ABSTRACT FROM AUTHOR]

Willow is considered an ideal plant species for environmental applications, including phytoremediation. Improving planting efficiency and reducing the costs of phytoremediation have become key steps for increasing its application. This paper reports the most update-to-date information on frequently used techniques for establishing willow, including plant material, planting methods, and the factors influencing the early establishment of trees in the field. The five main types of planting materials (rods, cuttings, billets, micro-cuttings and single-bud short branches), and the seven main planting techniques, especially different vertical and horizontal planting directions, were assessed. Factors affecting willow establishment were also reviewed, including the characteristics of planting materials (i.e., clones, cutting phenology, propagules size, pre-treatments), operation during planting (i.e., timing, orientation and planting depth) and post-planting management (i.e., soil conditions and weed management). New planting approaches with small-sized cuttings (of about 5 cm in length) have been recently proposed showing promising economical and effectiveness characteristics, especially for the establishment of willows in harsh soil and challenging conditions. [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]

This special issue of Ecological Engineering provides an overview of research within the Everglades Stormwater Treatment Areas (STAs) over the past decade to understand the ecology and the biogeochemical processes that affect phosphorus (P) retention in these constructed wetlands. This research was established within the South Florida Water Management District's Restoration Strategies Science Plan (RSSP). The RSSP was developed in 2012, updated in 2018, and produced a total of 21 studies. The goal of RSSP research is improve understanding of the factors contributing to P retention, to support management of the STAs to attain and sustain a stringent outflow total P concentration goal (i.e., the Water Quality Based Effluent Limit or WQBEL) and to maintain the wetland plant communities used to achieve this goal. Compliance with the WQBEL will reduce P loads to the Everglades to support restore and maintain this special ecosystem. This synthesis paper presents an overview of the STAs and their purpose and then summarizes the findings from the publications included in this special issue as well as previous STA related research. From this synthesis, a list of potential management options to enhance P retention in the STAs is presented. • Stormwater Treatment Areas (STAs) built to reduce P in runoff entering the Everglades. • STA discharge must meet strict low P concentration limits. • P biogeochemistry research conducted to support management of the STAs. • P removed by particle settling, biogeochemical processes and plant uptake. • Fauna excretion, bioturbation, and internal loads substantially affect P retention. [ABSTRACT FROM AUTHOR]

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]

Vegetation in front of levees, dikes and seawalls can decrease wave energy and therefore contribute to the safety against flooding. However, wave damping predictions by vegetation are still inaccurate due to measurement and modelling uncertainties. Many studies focused on finding reliable predictive tools using scaled flume tests with vegetation mimics. Scaling down vegetation can however lead to discrepancies with realistic scales, known as scale errors. In this work scaled tests were conducted on 3D-printed elastic replicas of willow trees and compared with real-scale experiments. We identified differences in measured wave dissipation between the scaled hydraulic model (1:10) and its real-scale prototype with 5 m high live willow trees under storm conditions (1:1). The maximum measured wave damping (30%) was roughly 1.5 times higher than the real-scale experiments (20%). Following the same trend of the real-scale experiments, this amount of wave height damping declined for larger water levels. Largest effects are argued to be due to increased viscous damping (smaller branch Reynolds numbers) and non-exact flexibility scaling. These significant deviations illustrate that full-scale experiments, although expensive, are still needed to validate the results of scaled experiments for woody vegetation. Alternatively, accounting for these discrepancies can make scaled experiments more reliable and expensive real-scale experiments less needed for wave damping studies on woody vegetation. • A forest with Froude and Cauchy scaled mimics of real pollard willow trees with detailed multi-scale branch structure was 3D printed. • Wave damping for the specific tested scaled pollard willow forest increased by a factor 1.5 compared to a real-scale 40-m long forest: 30% instead of 20% wave height reduction. • The major scale and model effects are inferred to be viscous effects, and imperfect elasticity scaling, respectively, both having the same order of magnitude. • Branch deflection was observed for the real-scale and scaled tests with the scaled forest appearing too stiff. • For realistic multi-scale trees, turbulence processes are different for the different elements, and dimensionless numbers have a range of values for different parts. In this paper the main dimensionless numbers, Reynolds and Cauchy, were calculated for different parts of the trees. [ABSTRACT FROM AUTHOR]

Abstract: The ability of Kraft lignin, a waste product of paper production, for removing copper, zinc, cadmium and chromium ions from water was investigated. The studies were conducted by a batch method to determine equilibrium parameters. The adsorbed heavy metal ions followed the order: Cr(VI)≫Cd(II)>Cu(II)>Zn(II). The influence of other ions such as Ni(II), Cd(II) and Pb(II), on Cu(II) adsorption by Kraft lignin was evaluated. Obtained results support the idea that adsorption behaviour of heavy metal ions have to be perceived from the aspect of possible influence of interfering ion species. [Copyright &y& Elsevier]

• Control latrine played a typical geochemical behavior of a contaminant source. • Alternative latrine oxidized almost completely ammonium to nitrate. • Nitrate removal efficiency promoted by sawdust layer was of 42% on average. • Isotopes analyses corroborated N-species hydrogeochemistry trends across latrines. • Relative placement of sawdust and BOF slag layers impacted denitrifiers performance. Nutrients, like nitrate and phosphate, and pathogens are the primary contaminants released into groundwater by on-site sanitation systems, which are an effluent disposal outcome for regions not covered by sanitation infrastructure, as periurban communities in developing countries. As appropriate setback distances between pit latrines and supply wells often cannot be met to avoid groundwater contamination, especially in a densely-populated situation, efficient, low-cost and accessible technologies are extremely necessary to protect water resources and surpass critical and persistent public health problems. This paper presents 1-year field-testing of an alternative latrine (AL) that incorporates two waste materials as permeable reactive barriers (PRB) in an irregular settlement at the municipality of São Paulo (Brazil). Basic oxygen furnace (BOF) slag in contact with wastewater effluent increases its pH level, which causes pathogens inactivation and phosphate adsorption. Sawdust under water saturation creates reducing conditions that encourage the growth of denitrifying bacteria that remove nitrate. A control latrine (CL) was constructed 90 m apart from AL with similar hydraulic characteristics and nonreactive materials for hydrochemical comparison. It was evident for AL the formation of well-defined nitrification and denitrification reaction zones, whereas CL overall presented nitrogen in its ammoniacal form, with incipient nitrate production at CL bottom, indicating that nitrification is probably boosted below that. BOF slag had attenuated microorganisms and phosphate almost completely, but nitrate removal average efficiency was 42%. The high pH effluent generated in BOF media may have also affected in the short-term the denitrifying bacteria in sawdust barrier 1 m below. The inverted position of the reactive barriers, i.e., sawdust PRB overlying BOF slag PRB, should be a more suitable design to achieve nitrate and pathogens removal. This kind of sanitation solution employing cheap and accessible waste materials have never been applied in the design proposed in this paper and also was a novelty for Brazilian context, proving to be a suitable technology to meet local needs. [ABSTRACT FROM AUTHOR]

Nitrate pollution of surface water from farms and urban runoff is widespread – impairing drinking water supplies, recreation, and wildlife habitat. The scale of the problem in rivers has overwhelmed most watershed-based best management practices. A new paradigm is needed. In this paper we highlight the 119 ha (294 acres) Prado Wetlands in southern California, USA as an example of a gravity-enabled, free surface flow vegetated wetlands to treat a river – the nitrate-rich, effluent-dominated Santa Anna River. The wetland treats ∼1–2 m3/s of the 7.1 m3/s (250 cfs) flow of the river in 28 wetland cells in two parallel trains (residence time 2–4 d, hydraulic loading rate 10–20 cm/d). The cleaner water is returned to the river and infiltrated downstream into a managed groundwater basin supplying 2.4 million customers. Since 1998, ∼1200 t of nitrate-N have been permanently removed from the river and released as N 2 -gas into the air. Over 24 years, in the warm summers an average of 6.1 mg-N/L entered the wetland and 3.7 mg-N/L flowed out, a removal efficiency of 57%. In the cooler winters, an average of 6.4 mg NO 3 -N/L entered and 2.6 mg NO 3 -N/L flowed out, a removal efficiency of 45%. Individual months varied widely in concentration removal efficiency from 7% (winter) to 98% (high summer). Areal summer removal averaged 137 mg NO 3 -N/m2/d and the apparent "k" was around 46 m/y. All-year rates were 129 mg NO 3 -N/m2/d or 47 g/m2/y, a reasonable performance considering the size of the system and its configuration for both nitrate removal and duck hunting (i.e., more open water). Annual average nitrate removal efficiency increased substantially over time (45 to 72% for 1998–2004 versus 2016–22) and is attributed to an increase in hydraulic residence time, upgraded internal plumbing, and increased winter temperatures (+3C°). Prado Wetlands also removes phosphorus, though not as well as nitrate; average warm season removal efficiency was 23% (inflow 1.20 mg PO 4 -P/L, outflow 0.93 mg PO 4 -P/L). The aerial removal rate was high at 23 mg P/m2/d or 8.5 g/y, probably due to the high inflowing P-concentrations and the hard water. Wildlife was also enhanced. Least Bell's Vireo (Vireo belli pusillus) , an endangered bird in the Prado Basin, increased from 19 pairs (1998) to a recent average of 444 pairs due to habitat improvement and reduction of cowbird parasitism. Results from the Prado Wetlands show that cleaning up rivers via diversion through wetlands benefits both water quality and wildlife. [ABSTRACT FROM AUTHOR]

Most lacustrine deltas are nowadays highly anthropized systems. River training works during past centuries considered rivers mainly as vectors of water and sediments from a point source to a sink. However, numerous problems have been identified by residents and the competent authorities, such as lakeshore erosion near river deltas, land-use conflicts, and loss of biodiversity without efficiently managing flood risks. These human-induced changes on the deltaic environment led to the deterioration of ecosystem services. This paper focuses on the lacustrine deltas as a complex biotope at the interface of aquatic and terrestrial environments. It proposes a restoration strategy based on two simple geometrical parameters. This methodological approach defines the potential to recover a quasi-natural state of the delta using the slope of the upstream water course and the opening angle of the delta. The result of this work is the creation of a diagram like the ones classifying rivers according to their morphology. This chart will allow the design engineer to determine, given the actual slope of the water course, which shape a delta would ideally adopt without accounting for the downstream lacustrine morphogenic parameters. It will also help in determining the space required for the watercourse to fulfill its natural functions. This methodological approach is applied to a case study: The Reuss Delta, where a restoration project took place. This approach can be used as a pre-study to determine, according to the available space, if it will be possible to improve the morphological dynamics of the delta and to recover its non-anthropized state. [ABSTRACT FROM AUTHOR]

Based on the complex population structure of fish species in Songhua River, this paper broke through the present method modeling by the single target species and introduced a developed approach classified by different spawning habits to evaluate ecological flow. Three main spawning periods and two spawning types were respectively analyzed combining with biographical information. For the characteristic of abundant branching channel and wide floodplain in study area, MIKE21 hydrodynamic model was applied to simulate hydrological condition. Combing the habitat preference curves and hydrodynamic results, the composite suitability index for the study reach was attained. At the same time, the lasting time of fish incubation was used to suggest the flow duration. At last, this paper put forward the optimal discharge, flow duration, occurrence time and frequency in April, May and June-July respectively. Using this result, the ecological flow process can effectively support to the management strategies for rational allocation of water resources. [ABSTRACT FROM AUTHOR]

Abstract This editorial describes a 12-paper special issue that began with a symposium at EcoSummit 2016 in Montpellier France in August/September 2016 with a focus on ecological engineering and spatial planning in coastal seascapes. The papers in this issue review ideas around experimental design for testing and application of eco-engineering to reduce the impacts of coastal infrastructure and improve ecological outcomes. Similarly, the need for early integration of ecological principles into engineering designs (eco-design) is highlighted as a key factor in the success of impact mitigation (2 papers). Ideas are presented on spatial planning for coastal infrastructure to mitigate and offset impacts at regional scales (3 papers). At more local scales, empirical evidence is presented to support the manipulation of physical complexity on coastal infrastructure through the addition of artificial rock pools and turf mimics, as well as complex crevice and ledge habitat (3 papers). Chemical manipulations of substrate (concrete) are also explored (3 papers) with the aim of increasing the sustainability of structures and improving specific ecological outcomes. While increasing human pressure has pushed our oceans out of balance, this special issue provides practical solutions, supported by case studies and empirical data to begin helping the “feng shui” of our coastal seascape. Highlights • Modern day seascape comprises a mix of natural and built ecosystems • This special issue is on ecological engineering science of coastal development • Many of the 12 papers began at the EcoSummit 2016, Montpellier France • Authors were from United Kingdom, Australia, United States, France, Hong Kong and Chile • Major advances in ecological engineering need to keep pace with coastal development expansion [ABSTRACT FROM AUTHOR]

Abstract Restoring riparian shade to formerly forested streams in cleared land is an important step in the restoration of stream ecological health. In a companion paper, we validated a numerical model for diffuse non-interceptance (difn) against measurements made in precisely-constructed physical models for two simplified geometries ‘canyon’ and ‘cylinder’ with trees lacking canopy ‘shape’. In this paper, we extend the model to include canopy ‘shape’ by representing trees as ellipses or kites, and quantifying shading from canopy overhang of the channel. The ratio of tree height (h) to stream width (w) strongly influences stream shade and is a key parameter when scoping riparian revegetation. Canopy width, overhang and viewpoint affect stream shade and could profitably be included in water temperature and aquatic plant growth models. Tree shape has a second-order effect on shade, most noticeably near the stream banks. The model predicts shade assuming a sky of uniform radiance (viz., it predicts shade to diffuse radiation) on the premise that difn is a useful index of long-term averaged light exposure. The model successfully reproduced the trajectory of shade reductions following riparian restoration predicted using a published physically-based model, confirming its suitability for scoping riparian shade restoration. While it would be feasible to include direct radiation in the model, this would require additional input data and computational effort. [ABSTRACT FROM AUTHOR]

Graphical abstract This paper examines the scientific evidence underpinning four hypotheses about the role of plants in bioretention systems: (i) Planted systems are more effective than unplanted systems, (ii) Plant species differ in their effectiveness, (iii) Native species are more effective than exotic ones, (iv) Diverse systems are more efficient than monocultures. Highlights • Manuals are often based on hypotheses on plant role in bioretention, not evidences. • Plants have a positive effect on permeability and nitrogen removal. • Right plant species is crucial for nitrogen not TSS, phosphorus, metals removal. • Native plants may help biodiversity, but not hydrologic or treatment performances. • Diverse plantings can be more resilient, but will not necessarily perform better. Abstract Plants are essential components of bioretention systems, with bioretention design-guides around the world providing extensive advice on the role of selection of plants to maximize system performance and sustainability. Four principal hypotheses regarding the role of plants have been identified in bioretention design manuals: (i) Planted systems are more effective than unplanted systems, (ii) Plant species differ in their effectiveness, (iii) Native species are more effective than exotic ones, (iv) Diverse systems are more efficient than monocultures. This paper examines the extent to which these hypotheses are supported by the scientific literature. Comparison of planted and unplanted systems show that increased permeability and hydraulic conductivity, as well as removal of nitrogen, are the main benefits of the presence of plants in bioretention. Knowledge on their positive effect on hydrocarbons remains fragmented, although there is evidence from phytoremediation studies in other plant-based technologies. Choosing the right species makes a difference in hydraulic performance and nitrogen removal, with root traits being identified as important predictors of performance. No scientific results can support the hypothesis that native plants or diversely-planted systems offer better performance than systems planted with fewer species or with exotic species. Questions remain regarding the plant-microbe interaction in the bioretention context, the role of biomacropores in pollutant migration or the differential impact of plant choice on performance. [ABSTRACT FROM AUTHOR]

Highlights • This paper presents the current experience of Polish Sludge Treatment Reed Beds. • 6 Polish reed systems were analyzed. • Sludge Treatment Reed Beds could be economical and useful solution in small and medium-sized wastewater treatment plants. • Sewage sludge utilized in Sludge Treatment Reed Beds can be potentially a good fertilizer. • Proper work of Sludge Treatment Red Beds requires right design and maintenance. Abstract Sludge Treatment Reed Beds (STRBs) is the technology of sludge treatment, which is based on natural processes occurring in the environment, in specially designed and operated facilities to achieve benefits for the environment. Integrated dewatering and stabilization occur in reed systems. For economic and environmental reasons it is an attractive solution, especially in rural areas where there are no appropriate facilities. In the recent years many European countries like Denmark, France or Germany have applied this technology for sewage sludge management. Poland has also some experience in dewatering and stabilization of sewage sludge in STRB systems. The objective of the paper is to present the current experience and lessons learned from the operation and to assess the quality of sewage sludge from STRBs in Poland. The analyzed sewage sludge was treated in STRBs located in five wastewater treatment plants: Darżlubie, Swarzewo, Zambrów, Nadole and Gniewino, Poland. Two from the analyzed systems (Darżlubie and Swarzewo) worked only in a pilot scale and three of them (Darżlubie, Swarzewo and Nadole) did not work any longer. In the collected samples of sludge the evaluation of dewatering and stabilization processes, fertilizer properties, as well as heavy metals concentrations were determined. The average dry matter content in sludge treated in Polish STRBs was from 11.2 to even 53.7%. The degree of mineralization in analyzed systems was from 31.4 to 68.6%. The average nutrient contents was for nitrogen from 1.0 to 10% DM and for phosphorus from 0.2 to 1.0% DM. The conducted research confirms that sludge treated in STRBs is dewatered and stabilized, thus it could be used as a fertilizer in agriculture. [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]

The Stormwater Treatment Areas (STAs) are constructed wetlands used to reduce the total phosphorus (TP) level in water discharged to the environmentally sensitive areas of the Everglades Protection Area. Analysis of high temporal frequency TP data reveals that TP concentrations discharged from selected STA flow-ways exhibit diel and seasonal cyclic patterns and are most affected by discharge rate and water depth. The objective of this paper is to describe the diel TP pattern and evaluate the possibility of using it to reduce TP in STA discharge. The amplitude of diel TP pattern ranged from 0.7 to 1.5 μg L−1 (3–6% deviation from daily mean) at three flow-ways, peaking in the early afternoon and reaching lowest concentrations between midnight and 4 am. To assess the possibility of further reducing TP concentration discharged from the STAs by increasing the proportion of daily flow discharged at night when diel TP is at a minimum, a General Additive Model (GAM) was created with discharge rate, water depth, year, location, day-of-year, and time-of-day as covariates. While time-of-day was a statistically significant factor in the model (p < 0.001), its average marginal effect was smaller than all other significant model covariates: discharge rate, season, and water depth. Modeling suggests that within specific ranges of discharge rate and water depth, the opportunity exists to provide additional TP reduction in STA outflow by discharging a greater proportion of the daily flow at night when TP concentrations are lower. Further research is needed to quantify the effect of increasing nighttime flow on annual flow weighted mean TP. Additionally, an evaluation of the practicality and logistical cost required to redistribute flow is needed before attempting to take advantage of this natural cyclic pattern to improve STA TP retention. • A diel pattern in totla phosphorus (TP) was found in south Florida wetlands. • Peak diel TP occured between noon and 3 pm, a minimum concentration between midnight and 4 am. • Amplitude of diel pattern ranged between 0.7 and 1.5 μg L-1 TP or 3–6% from daily mean TP. • Under certain hydrologic conditions increasing the proportion of overnight flow could reduce TP in wetland discharge. [ABSTRACT FROM AUTHOR]

In agroecosystems, straw return is considered an important agricultural management practice influencing soil respiration. However, the impact of straw return on soil respiration is equivocal and the underlying mechanisms underpinning any responses remain unclear. To address this, we synthesized 86 recently published papers on dryland agroecosystems in China, which comprise approximately 74% of the agricultural land area, using a meta-analysis approach and explored the influence of straw return on soil respiration and the underlying mechanisms involved. Straw return resulted in a 13.5% increase in soil respiration, a 9.4% increase in soil moisture, a 10.4% increase in crop yield, a 18.9% increase in SOC (soil organic carbon), and a 2.6% decrease in soil temperature. Compared to conventional tillage without straw return treatment, the increase in soil respiration in response to straw return was closely related to modifications in soil temperature, soil moisture, SOC, and crop yield (P < 0.05). The contribution of the different drivers to increases in soil respiration in response to straw return showed a trend of crop yield > soil temperature > SOC > soil moisture. In addition, straw mulching, crop planting system, tillage method, and fertilization modified the effect of straw return on soil respiration. The increase in soil respiration was less when straw was used as a mulch (12.9%), compared to when it was incorporated into the soil (18.8%). The cropping system also influenced the effect of straw return on soil respiration and was increased by 21.1% in inter-crops, and by 17.3% and 11.0% in monocultures and rotations treatments, respectively. Our results also showed that the effect of straw return on soil respiration was larger in deep tillage treatments than in shallow tillage treatments (26.9% vs.18.7%). In addition, the effect of straw return on soil respiration was also larger in fertilized treatment compared to unfertilized one (12.7% vs. 0.5%). However, this depended on the amount of nitrogen fertilizer applied rates and was higher (14.8%) with low (<300 kg ha−1) application rates compared to high (≧300 kg ha−1) ones (2.5%). Therefore, in dryland agroecosystems in China, biological factors, especially those related to crop yield, may be a more important factor regulating the effect of straw return on soil respiration. However, straw mulching, crop planting system, tillage method, and fertilization can modify the effect of straw return on soil respiration. [ABSTRACT FROM AUTHOR]

Abstract: Constructed Technosols deliberately combine technogenic materials to obtain specific services (e.g. plant biomass production) in particular contexts (e.g. industrial wasteland reclamation). Their ecological reclamation by key members of the soil fauna, such as earthworms, is a promising way to ensure such services. However, literature which treats these animals as a biological agent of constructed Technosol functioning is very scarce. This work assesses the effects of the composition of a constructed Technosol (i.e. the proportions of the constituent materials) on earthworm (Lumbricus terrestris) surface cast production and composition, and to a lesser extent on earthworm survival and biomass. Earthworms were placed in laboratory microcosms made of different proportions of materials: green-waste compost (GWC) and thermally treated industrial soil mixed with paper mill sludge (TIS/PS), for 30 days. We found that 25% of GWC on the surface and 75% of TIS/PS below was the most beneficial composition in that it gave the highest body mass gain. Furthermore, this composition generated a moderate surface cast production compared to other compositions and an increase in microorganism activity and number compared to non-ingested by earthworm soil. This composition also led to casts with bacteria of diverse morphologies and largest microaggregates compared to compositions without GWC, resulting from the ingestion and mixing of the two materials in the earthworm gut. However, earthworms did not modify the carbon contents of surface casts. This laboratory approach was a necessary step before field assessment of ecological reclamation by earthworms. From a soil engineering point of view, this contributes to better-managed soil construction for ecological reclamation. [Copyright &y& Elsevier]

This paper summarizes 19 papers published in a special issue of Ecological Engineering under the general banner of wetlands and carbon. Many of the papers were presented at a special session at EcoSummit 2016 in Montpellier, France in August-September 2016. The papers are in four general categories: estimating greenhouse gas fluxes with eddy covariance; methane and other greenhouse gas emissions from wetlands; carbon sequestration by wetlands; and organic carbon decomposition in wetlands. Overall, we found that further development and wider use of eddy covariance measuring stations could help clarify long-term annual budgets of CO 2 and CH 4 in wetlands and, while CH 4 fluxes in some coastal wetlands such as mangroves can be negligible, some inland wetlands can be significant sources of CH 4 where hydroperiods are the major determinants of the emission rates. The papers here demonstrated a variety of parameters determining dynamics of methane fluxes and carbon sequestration in different wetlands and lead us to suggest that more attention should be paid to detailed analysis of the impact of environmental and management factors on carbon budgets in wetlands. Carbon sequestration is almost always estimated by soil dating methods such as with 137 Cs and 210Pb isotopes and results continue to show order of magnitude differences among systems but sometimes among laboratories. This is due to the inexact nature of estimating soil dates over relatively short (∼50 year) time horizons. The idea of capping landfills, which are enormous methane sources, with wetlands which could then turn them into carbon sinks is worth investigating further but the design of these systems is still in its infancy. Organic carbon decomposition in wetlands has been investigated extensively for decades and more recently on the biogeochemical processes. ‘Enzymic latches” such as phenol oxidase, which can break down phenolics and therefore speed up decomposition, may be key controllers of organic matter decomposition in waterlogged and submerged soils in wetlands. The best approach for balancing greenhouse gases and carbon sequestration remains an enigma, but the papers in this special issue take us one step closer to providing clarity. [ABSTRACT FROM AUTHOR]

In recent years, large parts of arid and semi-arid areas in the world are dealing with water restrictions. In these areas, wetlands provide habitats for migratory birds and have a critical role in socio-ecological systems. Generally, in these areas, changing water-use patterns because of land-use change and water limitation because of climate change have led to the loss of wide areas of wetlands. Wetland restoration is suggested to restore the functions and values of wetlands that have been destroyed or affected by stresses. In this paper, a new application of wetland restoration prioritizing is introduced; restoration prioritizing to reduce the negative effects of drought. In this method, areas with the highest priority for restoration will be determined in a wetland destroyed because of water limitations. Multicriteria-spatial decision support system (MC-SDSS) was used to plan a scheme for Hamun wetlands restoration prioritizing in order to reduce the negative effects of drought and to restore the wetlands. This prioritization-determined areas that are valuable for Long-term water conservation, reduce the negative effects of dust storms and conserve water bird’s habitats. This method was used in a wetland that is the only water resource in the middle of a wide arid plain. Because of water limitation, it is not possible to restore the hole wetland; therefore, different parts of this wetland were prioritized for restoration. Based on the results, it is possible to produce a model to determine which priority can be restored in each amount of water volume. In this way, it becomes clear for decision-makers to select areas for restoration in different volumes of water. The result of this study shows that since MC-SDSS decreases conflicts between alternatives in a decision-making process and uses their spatial situation, it is a preferred method to balance among conflicting goals. Furthermore, because spatial data are the most important parts of MC-SDSS, this paper shows the ability of remote sensing to be used in MC-SDSS method. It seems that in the future; remote sensing will have the most important role in MC-SDSS. [ABSTRACT FROM AUTHOR]

This editorial describes a 10-paper special issue that arises from the 4th International Conference on Soil Bio- and Eco-Engineering (SBEE2016) ‘The Use of Vegetation to Improve Slope Stability’ held at the University of Sydney, Australia, in July 2016. The conference focused on current topics and progress in slope stability research and the successful application of soil bio-engineering and eco-engineering techniques to stabilizing slopes in a variety of climatic and geomorphic settings. The papers are divided into the following categories: vegetation and slope stability (1 paper); root-soil interactions (5 papers); slope stability modelling (2 papers); eco-engineering and land restoration (2 papers). Most of the papers present case studies documenting bio- and eco-engineering techniques, site-specific investigations or innovative slope stability modelling approaches and two papers are aimed at standardizing data collection and sustainability assessment practices within the discipline. Case studies are presented by scientific researchers, practitioners, geotechnical and civil engineers, biologists, ecologists, geomorphologists, and foresters from North America, Europe, South-East Asia, Australia, and New Zealand. [ABSTRACT FROM AUTHOR]

This editorial describes a 25-paper special issue that began with a symposium at EcoSummit 2016 in Montpellier France in August/September 2016 with a focus on ecological engineering principles applied to the development of large-scale sustainable landscapes and catchments. The papers are divided into the following categories: watershed management (3 papers); wetland creation and restoration (5 papers); monitoring wetlands (3 papers); lake management (2 papers); restoration of wetland and terrestrial landscapes (6 papers); public health (2 papers); and ecotechnological solutions (4 papers). Some of these case studies are purposeful application of ecological engineering principles; others happened or are happening naturally through self-design. Several of the presentations focus on ecological engineering that involves scales of thousands of hectares or even larger catchments to solve ecological and environmental problems. Case studies are presented by scientists and engineering from North America, Europe, and South America. [ABSTRACT FROM AUTHOR]

Green roof is one of the main infrastructures used in Sustainable Urban Drainage Systems (SUDS). Detailed design and the correct choice of materials to be applied in this type of roof are essential to obtain satisfactory hydrological performance. In recent years, numerous papers on this topic have been published. This study aimed to provide a holistic view of the main research trends for the construction of green roofs to control stormwater runoff. A systematic literature review was carried out within scientific publications from the last 5 years in the Web of Science (WoS) database. 67 papers were selected for analysis. Recent types of vegetation and materials for green roofs were listed and hydrological tests were discussed in this review. Extensive substrates were chosen by 78% of the studies due to smaller thickness, tending to be lighter and economically viable than intensive substrates. Succulents of Sedum genus were the most used in the studies due to their physiological characteristics and ability to adapt to different climates. Drainage layer consisted mainly of specific slabs commercially available for green roofs. Other layers, such as filtration, thermoacoustic insulation, and waterproofing, were also applied in many studies. The main parameters to evaluate the hydrological performance were retention capacity and runoff coefficient. In general, results showed that green roofs have considerable capacity to reduce rainwater runoff. However, many factors, such as meteorological indices, substrate antecedent moisture, and materials and plant species used can influence hydrological performance of green roofs. Some gaps were found in studies. Most of them did not compare the performance of green roofs with conventional roofs. In addition, the studies did not present cost and weight analyses, which is very important for the decision to build green roofs. [ABSTRACT FROM AUTHOR]

Understanding the relationship between supply and demand of ecosystem services (ES) is important to achieve sustainable use of natural capital and keep coordination of supply and demand. This paper used spatial analysis of the Geographic Information Science (GIS) method to quantify ecosystem service supply (ESS) and ecosystem service demand (ESD) by constructing the ecosystem services provision index and land development index respectively. Then the spatial-temporal characteristics of ES's supply and demand situation in Hexi Corridor (HC) were analyzed. In addition, the ecosystem service flow (ESF) and the corresponding ecological compensation (EC) for the ecosystem services supply areas (ESSA) and ecosystem services demand areas (ESDA) were quantified. The results showed that the regions with medium and high ESS showed significant growth, and regions with high ESD increase significantly. Besides, the distribution pattern of the ecosystem services supply-demand ratio (ESSDR) was high in the northwest and low in the southeast, which was mainly dominated by ES surplus, and the ESSDR always has spatial autocorrelation and spatial heterogeneity, forming a relatively stable spatial pattern. The High-High cluster areas of ESSDR were mainly distributed in the better ecological area, while the Low-Low cluster was mainly distributed in the economic development area. The supply-demand coordination displayed a balanced trend, and the changing area of supply-demand was mainly concentrated in the population aggregation region in the south of HC. The EC amount paid by ESDA decreased from 2000 to 2020, indicating that the supply capacity of ES was increased. This paper can provide references for regional ecosystem management and restoration. [ABSTRACT FROM AUTHOR]

• A super absorbent polymer was adopted to modify the soil for plants growing in ecological concrete. • Scouring resistance of soil increased with the increase of super absorbent polymer addition. • Survival ratio of plants was greatly enhanced by 1.5 wt% super absorbent polymer. Ecological concrete could protect the slopes along a motorway or on a river bank and prevent water/soil loss and beautify and built the environment compared to ordinary concrete. Overlaying soil, as a key component of ecological concrete, plays an important role in greening rate of ecological concrete. However, natural soil used as overlaying soil cannot meet plants growing demand due to its unsatisfying scouring resistance and water retention properties. In this paper natural super absorbent polymer (SAP) was utilized to modify the natural soil for the preparation of a material with enhanced scouring resistance and water retention performance which are indispensable for growing plants in ecological concrete. Experimental results suggested that 1.5 wt% SAP content in the soil was the most suitable option. At this natural soil replacement level, the scouring resistance increased by 68.9% while its water retention performance improved by 11.1% at the age of 160 h. In addition, other performance improvements of the soil were determined including increasing of the water absorption rate which was tested increasing by up to 69.4% and the cone index of up to 0.39 MPa, and the advancements of perennial ryegrass were measured increasing of the survival ratio which was found increasing by up to 97.9% and the dry weight of up to 2.16 kg/m2. [ABSTRACT FROM AUTHOR]

• Cost for assimilation wetlands averaged $0.60/gallon of treatment capacity. • 2° and 3° treatment costs averaged $4.90 and $6.50/gallon, respectively. • Wetland assimilation is less sensitive to cost increases than traditional systems. In recent decades, water quality standards for wastewater treatment have become more stringent, increasing costs and energy required to reduce pollutants. Wetland assimilation is a low-cost and low-energy alternative to traditional tertiary wastewater treatment where secondarily treated and disinfected municipal effluent is discharged primarily into freshwater forested wetlands in coastal Louisiana. In this paper, costs per gallon of treatment capacity for conventional secondary and tertiary treatment were compared to those for assimilation wetlands. Cost analysis reports were used to determine costs per gallon of treatment capacity for conventional wastewater treatment facilities, including costs for conveyance between the collection system and the assimilation wetland site, and between the treatment and disposal sites if they could not be co-located. Capital and operation and maintenance costs were considered. Because all wastewater treatment plants are required to treat at least to secondary standards, costs for primary and secondary treatment were combined. If necessary, these costs were adjusted for inflation to 2017 dollars using an average inflation rate of 2.19 percent and a cumulative inflation rate of 50.84 percent. To determine costs per gallon of treatment capacity for assimilation wetlands, actual costs provided by the project engineer were used when available. To simulate the future costs of facility construction and compare the replacement costs of conventional secondary and tertiary wastewater treatment facilities and treatment wetlands in the context of energy prices, U.S. Bureau of Labor and Statistics (BLS) data for the price index for inputs to construction were used, as were the Energy Information Administration (EIA) data for the price of crude oil to model future wastewater treatment plant construction and operation costs. The cost for the Mandeville assimilation wetland included $1 million for the price of the land. Future costs of treatment facility construction and operation were modeled relative to average price of construction inputs between 1998 and 2015 using the projected price of crude oil. When treatment costs were compared among secondary, tertiary, and assimilation wetlands, mean cost for assimilation wetlands was $0.60 per gallon (>1 MGD capacity) compared to $4.90 and $6.50 per gallon for secondary and tertiary treatment, respectively. The lower total costs and energy requirements for assimilation wetlands result in lower variability in the price of construction and operation. Wetland assimilation is more economical than conventional wastewater treatment, especially compared to advanced secondary and tertiary treatment. It is likely that energy costs will increase significantly in coming decades. Because conventional secondary and tertiary treatment are energy intensive, increases in energy costs will significantly increase the costs of these treatment systems. Treatment systems that combine lower technology (e.g., oxidation ponds) secondary treatment with wetland assimilation are less likely to be impacted by rising energy costs than traditional wastewater treatment. [ABSTRACT FROM AUTHOR]

The efficiency of active aeration (AE) of constructed wetlands expressed as the ratio between implied oxygen consumption and oxygen delivered to the system is comprehensively reviewed in this paper. The aeration efficiency appears to be rather low with a mean value of 1.73% and median value of 0.48% of oxygen used in the systems for situations with only partial aerobic degradation of the pollutants. For full aerobic degradation, the mean value of AE is 3.74% but median value is much lower 1.08%. For both cases, the standard deviation is higher than the mean value (4.95% and 10.87% respectively), so there is a lot of variability in the data. For systems with the Forced Bed Aeration the results are more uniform and are close to the literature values given for this system, which is an implication that the proposed methodology might be potentially used for rough estimate of the aeration efficiency. [ABSTRACT FROM AUTHOR]

The eco-hydraulic diversity in a tidal reach is obviously enriched after spur dikes built, such as a turbulent rapid around structures head when tide ebbing and a gently dynamic environment in the back during the whole tide process. It would be much beneficial for adult fishes to spawn eggs and the youngs to fatten. Spur dikes have been utilized as channel regulation structures worldwide, especially in the upstream tidal reach of river estuary, where is a superexcellent habitat for resident fish or migratory fish during different life history stages. However, local hydraulic characters will be altered upon spur dikes establishment, resulting in several influence on fish habitat. The purpose of this paper was to reveal the impacts mechanism of spur dikes on fish habitat in a tidal reach through a comprehensive analysis based on some previous neglected aspects, such as fish physiological characters, hydraulic variations and essential factors alterations of the aquatic ecosystem. Hydraulic information around spur dikes was acquired through a 3D hydrodynamic model, and validations of tidal level, velocity and diversion ratio yielded a high accuracy. Turbulent rapid around spur dikes head and mild nearshore environment behind structures have some potentialities to become new spawning grounds, for fish spawning semi-pelagic eggs and fish laying adhesive eggs respectively. Benefitted from effective mixture of water during a tidal cycle, plenty of planktons and organic matters will be brought in and gradually enriched behind structures, thus a favorable feeding ground will appear there. Meanwhile, deflecting flow induced by spur dikes may cause some hazards for survival probability of migratory larval fish. It is drifted off the nearshore into the river middle, where is a higher turbulent intensity and less phytoplankton concentration. In summary, spur dikes possess tremendous ecological effects, i.e. enriching the eco-hydraulic diversity, not only as a velocity shelter. In addition, research result could afford a sufficient basis for environment conservations to restore aquatic ecosystem with spur dikes. [ABSTRACT FROM AUTHOR]

• Flow-vegetation interactions were examined at the real scale in a drainage channel. • Flow resistance and turbulence were analysed for three vegetation scenarios. • Manning's n resulted higher than expected due to dead remnant material at the bottom. Drainage channels are a widespread component of agricultural and urbanized lowland landscapes. Management of instream and riparian vegetation along drainage channels must be planned by reconciling the need to ensure channel hydraulic efficiency with the need to preserve the riparian habitat. The present paper reports the experimental results of a study conducted on a drainage channel colonized by Phragmites australis in undisturbed natural conditions. The impacts of common reed on flow resistance, flow velocity distribution and turbulence parameters were examined with different discharges under three different scenarios of channel vegetation, which were obtained by means of machineries traditionally used in land reclamation areas. Removing either totally or partially the channel vegetation had great effects on streamwise velocity distribution and turbulence patterns, with small differences in global flow resistance. The experimental results suggest that clearing the channel vegetation just in the center of the cross section can improve the channel conveyance to values close to those obtained with the total removal of the vegetation, while maintaining relatively high levels of turbulent intensities. [ABSTRACT FROM AUTHOR]

A fishway is a fish-passing facility that helps migratory fish to cross obstacles. To minimize the considerable time and economic costs associated with fishway structure-optimized experiments, this paper proposes an Active Fish Migration (AFM) model developed based on experimental data of the juvenile Schizothorax prenanti movement and fishway flow fields. The proposed AFM model is a probability-based model in which a fish surrogate randomly determines its next movement behavior according to the computed probability. The AFM model can predict any of the possible paths of fish, making it suitable for describing fish migration in fishway engineering. In addition, the AFM model integrates the random forest and Eulerian–Lagrangian–agent methods to simulate juvenile Schizothorax prenanti migration in vertical slot fishways. The experimental results show that the average precision of the swimming behavior classification is 80.4%, the recall is 79.4%, and the F1-score is 79.8%, while the R2 value of the speed regression exceeds 0.7 (MAE < 0.07). The simulated trajectories are in good agreement with the observation data of the same flow pattern. Finally, the proposed AFM model's results exhibit a high agreement with real fish movement; thus, the AFM model has great application potential in fishway design. [Display omitted] • An AFM model integrating random forest and Eulerian-Lagrangian agent method was proposed. • Juvenile Schizothorax prenanti migration in vertical slot fishways was simulated. • The proposed AFM model exhibits a high agreement with real fish movement. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) for wastewater treatment have been used in the Czech Republic since 1991. Nowadays, there are about 200 full-scale constructed wetlands for treatment of municipal sewage. Most CWS have been designed with horizontal subsurface flow, in the late 2010s and early 2020s, combination of vertical and horizontal flow or two-stage vertical flow CWs have been used. The average number of designed PE is 235 and the average surface area of the Czech CWs is 1132 m2. The average treatment efficiencies are 87.5% for BOD 5 , 78.5% for COD, 85.7% for TSS, 41.8% for N-NH 4 and 41% for TP. The respective average outflow concentrations are (in mg l−1): 12.5, 48.5, 11.2, 16.6 and 3.35. The results from the oldest CWS in the Czech Republic revealed very consistent performance over the period of 30+ years with no refurbishment. The paper also provides information about two CWs which were refurbished after about twenty years of operation from horizontal subsurface flow to hybrid systems. In both CWs, the refurbishment was successful and the treatment efficiency increased. • Constructed wetlands have been used for wastewater treatment in the Czech Republic since 1991. • Most CWs were designed with horizontal subsurface flow. • Treatment efficiency can be consistent for >30 years. • During refurbishment CWs are usually converted into hybrid systems. [ABSTRACT FROM AUTHOR]

Vegetation changes have a significant impact on the runoff and sediment process of rivers in arid areas. Since 2000, the middle reaches of the Yellow River Basin have experienced rapid vegetation restoration, and the sediment transport in this area has also shown a significant decreasing trend. In this paper, we selected 10 rivers from north to south located in the middle reaches of the Yellow River as the research area, and analyzed the temporal and spatial characteristics of vegetation restoration and changes in runoff and sediment, as well as the effects of vegetation restoration on runoff and sediment process. The results show that sediment transport modulus in the middle reaches of the Yellow River are very significantly decreasing (p < 0.001), and the rate of change of the northern rivers is higher than that of the southern rivers. During the periods of 1956–1979 and 1980–1999, the sediment transport modulus showed a very significant decreasing trend from north to south (p < 0.001), but the trend of significantly decreasing the sediment transport modulus from north to south from 2000 to 2020 no longer existed (p = 0.761), after 2000, the middle reaches of the Yellow River underwent a rapid process of vegetation restoration, vegetation restoration significantly reduced the spatial heterogeneity of river sediment transport. Partial correlation analysis and sensitivity analysis show that, there was no significant correlation between vegetation restoration and runoff reduction (R2 = 0.03, p = 0.63), but there was a significant correlation between vegetation restoration and reduced sediment transport modulus (R2 = 0.49, p < 0.05), and a significant correlation between vegetation restoration and decreased sediment concentration (R2 = 0.66, p < 0.01). During the periods of 1981–1999 and 2000 - 2020, the relationship between precipitation and sediment transport modulus was positively correlated. In the 1981–1999 period, NDVI showed a weak negative correlation with sediment transport modulus but in the 2000 - 2020 period, NDVI and sediment transport modulus showed a significant negative correlation. This study provides valuable insights into the natural response of river sediment transport to vegetation restoration, and the findings are critical for soil and water conservation planning in arid area. [ABSTRACT FROM AUTHOR]

The southeastern US coastal plain was originally home to over one million ha of evergreen shrub bogs, locally known as pocosin. More than 70% have been drained for agriculture and forestry. These drained peatlands release GHGs to the atmosphere, mainly as CO 2 , which has resulted in significant concerns about their impact on climate change. Our long-term study at Pocosin Lakes National Wildlife Refuge (PLNWR) and adjacent private peatlands in North Carolina investigates the effect of drainage, and hydrologic restoration on carbon (C) budgets, including GHG losses, C sequestration rates, soil C respiration, and net ecosystem exchange (NEE). Soil CH 4 and N 2 O emissions were negligible as CO 2 emissions made up 99% of their GHG contributions. Carbon budgets indicate that the vast majority of C (>97%) is stored in the peat soil with the drained site having only about 53% of the peat mass found at the restored site. The reference site with the highest biomass produced the highest annual soil GHG loss of 11.3 Mg C ha−1 yr−1 followed by the drained site at 6.8 Mg C ha−1 yr−1 with the restored site having the lowest annual losses at 5.2 Mg C ha−1 yr−1. The drained site exported 0.39 Mg ha−1 yr−1 of TOC through hydraulic transport, a value 15% higher than either the restored or reference site annual mean. Eddy-covariance analyses revealed that restoring peatlands by raising water tables by 30 cm, i.e., by decreasing water table depth (WTD) from −60 to −30 cm, reduces CO 2 losses to the atmosphere by >90%. When annual mean WTDs are deeper than a threshold of -30 cm, the drier peatlands generate an annual C loss and if WTDs are shallower (-20 cm) and wetter the peatlands show annual C gains, thus providing restoration guidelines. • This paper provides new information regarding the effects of hydrologic restoration on C stocks and GHG releases from peatlands known as pocosin. • Our study offers water table restoration guidelines for rewetting drained pocosin to reduce CO 2 and CH 4 releases to the atmosphere. • Restoring water levels to between -20 and -30 cm will greatly reduce GHG losses from pocosin peatlands and foster an increase in C sequestration. • This research provides a C budget for pocosins peatland systems, and guidelines for restoring these ecosystems as C sinks on the landscape. [ABSTRACT FROM AUTHOR]

In recent years, the ecological functions of inland waterways have received much attention. Roughness elements have been used in waterway regulations (WRs) to guard the riverbed and improve physical habitat. However, the response of aquatic organisms to regulations varies widely. It is controversial whether inland waterway regulations can achieve the sustainable function of navigation, flood control and ecological needs.This paper evaluated the influence of WRs on aquatic habitat by using the physical habitat simulation models combining a 2D hydrodynamic model and habitat models. Compared with a reference model with no-engineering, the habitat suitability of zoobenthos, four major species of Chinese carp's spawning ground and the Yangtze finless porpoise at different flow discharges were simulated under different densities of river training structures and types of roughness elements. Results showed that the implementation of the WRs can adjust the distribution of the suitability of aquatic habitats, but does not change the pattern of suitability with discharge. The response of biological habitats to regulation projects varied by species. Regulation can maintain the stable habitat during dry and flood periods, reducing the effect of extreme weather on aquatic organisms. Roughness elements are not suitable for large-scale use in WRs. The "win-win" agreement between economic and ecological issues can be obtained through pre-optimization. [ABSTRACT FROM AUTHOR]

Bioretention systems have proven to be an effective stormwater treatment technology for reducing runoff pollution. However, the accumulation risk of heavy metals and characteristics of the microbial communities in the filter media is still unclear under long-term runoff infiltration. This paper reports on a field study that investigated the ecological impact of common heavy metals and the structures of microbial communities in nine bioretention systems during two seasons. Samples were collected from the filer media to determine the concentrations of heavy metals and the microbial information was obtained by high-throughput sequencing technology. The results indicated that Cr, Ni, Cu, and Zn accumulated significantly in the bioretention system, with mean concentrations 2–3 times higher than the corresponding background values. Heavy metals were mainly trapped in the surface media (0-10 cm) and concentrations varied with season. The comprehensive pollution status of the bioretention systems was at a light to medium level. In particular, Ni accounted for the majority of the potential ecological risk index values, with an ecological hazard of above moderate levels. The results of high-throughput sequencing showed that Actinobacteria (22.51–42.16%) and Proteobacteria (19.67–34.46%) are the dominant phyla in the bioretention media under the long-term pollutants accumulation. Microbial diversity was negatively correlated with the heavy metals content of the media ( p < 0.05). Heavy metals inhibited the growth and reduced the diversity of media microorganisms to varying degrees, with Ni contributing the most to microbial community changes. Our findings are expected to help in controlling the heavy metals pollution in the bioretention systems and provide practical guidance regarding the systems operation and media micro-ecosystem maintenance. [ABSTRACT FROM AUTHOR]

Anthropogenic impacts on marine habitats are a global problem, particularly in coastal areas. While boulder reefs in temperate waters hold high biomass and biodiversity, and may be unable to recover from anthropogenic stressors without restoration efforts, little is known about how to restore and conserve this important marine habitat. Limited knowledge is a serious impediment to projects aimed at restoring boulder reefs that have been degraded or removed by substrate extraction. In 2008, a boulder reef was restored in Kattegat, the transitional waters between the North Sea and the Baltic Sea, using differently sized boulders. The restored reef covered approximately 27,600 m 2 seafloor and included 100,712 tons of boulders added at depths ranging between 4 and 11 m. This paper describes methodology and lessons learned during the restoration project. Before the restoration, geological and geotechnical surveys confirmed that the sea bed could support added boulders, and high resolution bathymetric surveys provided input for the design of the reef, particularly for numerical modelling of the hydrographic and sediment transport conditions. Numerical modelling was used to derive hydrographic design conditions for boulder placements and further, to ensure that the restored reef would not affect the sea bed morphology and hydrographic conditions at a local harbour and at a protected habitat, both situated in the vicinity of the restoration area. Data on the physical structure of the restored boulder reef, collected in 2009, demonstrated that cavernous structures and shallow reef areas were restored. Moreover, data collected in 2012 confirmed the stability of the restored reef. Finally, results highlighted the importance of stakeholder mapping at the outset, appropriate timing of stakeholder involvement and ongoing consideration of stakeholder perceptions. Charting strategy and introducing a checklist for marine restoration projects, this paper outlines important considerations and methodology needed to ensure that restoration of temperate reef structures meet the objectives, without having undesirable effects on existing hydrographic and morphological conditions, including nearby coastal areas and protected marine habitats. [ABSTRACT FROM AUTHOR]

An idea that which zones are the main disturbed areas in mining cities and what are the exact impacts in space concerns re-use and optimal allocation of land. Current research mostly concludes that mining activities impact land use greatly, but there is no definite spatial range of disturbance. To find out the exact range, this paper sets up 12 gradients composed of mineral locations and 11 surrounding gradients with an interval of 3 km. And the “D-C-S” (Disturbance-Continuity- Sustainability) framework was then established to evaluate land use characteristics, including 9 indices in the three layers of disturbance, continuity and sustainability. Here, this paper adopted two approaches − transverse land use profiles and anomalous economic points − to test out the understanding of land use characteristics in mining cities. Our findings show that the areas surrounding mineral locations possibly play a more important role in land use structure and functions, designated to 0–9 km, especially 3–6 km away from mineral locations, where land needs more concerns about optimal allocation for future policy-making to improve the pattern, function and continuity. [ABSTRACT FROM AUTHOR]

Due to the serious nitrate pollution in Northeast China, the in-stream nitrate and its isotopic composition (δ 15 N-NO 3 and δ 18 O-NO 3 ) were analyzed to explore the seasonal nitrate sources and its transformation processes combining with chemical indicators in the Haicheng River during the spring, early summer, late summer, and autumn seasons throughout the year of 2010. The nitrate nitrogen (NO 3 -N) concentrations in riverine water co-varied with the discharge data of the river, showing significant seasonal variations (p < 0.001) based on the one-way ANOVA. The riverine δ 15 N-NO 3 values and chloride (Cl − ) variations suggested that NO 3 -N was mainly contributed by sewage/manure in spring. The NO 3 -N sources in early summer were largely induced by nitrification process from synthetic fertilizers. The combined application of δ 15 N-NO 3 and δ 18 O-NO 3 explained that the NO 3 -N sources in late summer and autumn were derived largely from soil organic matter and sewage/manure. Denitrification process of soil organic matter and sewage/manure in autumn and their nitrification process in late summer mostly controlled the NO 3 -N concentrations in river water. The results will provide useful information on nitrate sources of seasonal variations in isotope compositions of river systems for controlling NO 3 -N concentrations and improving the ecological quality near the Liaodong Bay and Bohai Sea in the near future. [ABSTRACT FROM AUTHOR]

In this special issue, a number of the latest and meaningful research related to riverine wetlands from a variety of fields were presented and discussed, covering investigation and analysis of many studying sites, development of ecosystem service evaluation approaches, propose of ecosystems modeling methods, advancement of wetland restoration and protection techniques and strategies, as well as the applications of these methods and models in several typical wetlands and the associated river systems. In this special issue, 24 papers were selected for a thorough peer review process with at least two rounds of reviews. According to the journal's guideline and requirement, the 24 papers were reviewed by at least two authoritative experts in this field. All papers were related to the topic of “Function, Restoration, and Ecosystem Services of Riverine Wetlands in the Temperate Zone,” offering a good view of relevant issues and research status, techniques, and applications for restoration. The 24 papers can be categorized into four groups: (a) investigation and evaluation of ecosystem services and functions, (b) dynamic modeling and optimal management of ecosystem services, (c) policies and technologies for ecosystem restoration, and (d) practices and application of ecosystems modeling and restoration approaches. [ABSTRACT FROM AUTHOR]

MIKE SHE is one of the most extensively used physically based distributed hydrological models that are capable of credibly interpreting the response mechanism of ecohydrological processes to ecosystem components and organization. However, implementing MIKE SHE in integrated catchment modeling is a complex task requiring an experienced modeling team with skills in a variety of disciplines, making it difficult for scientists without a background in hydrology or computer science to utilize this useful model. This review, from the perspective of ecology and environmental science, illustrates the important role of a physically based distributed model as a solution to issues related to ecohydrological processes, offering a major discussion of issues that received little attention from the previous reviewers and that would interest researchers without a hydrology background. The inevitable and possible difficulties confronting these potential users at the beginning and early stages of utilizing the model are also brought to light, with suggestions for solutions. This paper offers a brief review of MIKE SHE development and elaborates its main merits, key problems, and research on the model's theories and practices implemented by scholars. Lingering problems in current solutions are analyzed, and potential approaches to solutions are proposed. We hope that this paper provides some practical advice to researchers who want to initiate study of water issues related to modeling ecohydrological processes by employing MIKE SHE. [ABSTRACT FROM AUTHOR]