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Partitioning a water distribution network into several district metered areas is beneficial for its management. Partitioning a network according to its node features and connections remains a challenge. A recent study has realized water network partitioning based on node features or pipe connections individually. This study proposes an unsupervised clustering method for nodes based on a graph neural network, which uses graph attention technology to update node features based on the connections and a neural network to cluster nodes. The similarity between nodes located in each area and the balance of the total water demand between areas are optimized, and the importance of the boundary pipes is calculated to determine the installation position of flowmeters and valves. Three water distribution networks with different structures and sizes are used to verify the proposed model. The results show that the average location differences (LocDiffs) within the areas of the three networks completed by partitioning are 0.12, 0.07, and 0.06, and the total demand differences (DemDiffs) between areas are 0.13, 0.27, and 0.29, respectively. The LocDiff and DemDiff of the proposed method decreased by 6% and 55%, respectively, when compared to the traditional clustering method. Additionally, the proposed method for calculating the importance of boundaries provides an objective basis for boundary closure. When the same number of boundaries are closed, the comprehensive impact of the proposed method on the pipe network decreases by 17.1%. The proposed method can be used in practical applications because it ensures a highly reliable and interpretive water distribution network partitioning method.

Agriculture has significantly aided in meeting the food needs of growing population. In addition, it has boosted economic development in irrigated regions. In this study, an assessment of the groundwater (GW) quality for agricultural land was carried out in El Kharga Oasis, Western Desert of Egypt. Several irrigation water quality indices (IWQIs) and geographic information systems (GIS) were used for the modeling development. Two machine learning (ML) models (i.e., adaptive neuro-fuzzy inference system (ANFIS) and support vector machine (SVM)) were developed for the prediction of eight IWQIs, including the irrigation water quality index (IWQI), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), potential salinity (PS), residual sodium carbonate index (RSC), and Kelley index (KI). The physicochemical parameters included T°, pH, EC, TDS, K+, Na+, Mg2+, Ca2+, Cl−, SO42−, HCO3−, CO32−, and NO3−, and they were measured in 140 GW wells. The hydrochemical facies of the GW resources were of Ca-Mg-SO4, mixed Ca-Mg-Cl-SO4, Na-Cl, Ca-Mg-HCO3, and mixed Na-Ca-HCO3 types, which revealed silicate weathering, dissolution of gypsum/calcite/dolomite/ halite, rock–water interactions, and reverse ion exchange processes. The IWQI, SAR, KI, and PS showed that the majority of the GW samples were categorized for irrigation purposes into no restriction (67.85%), excellent (100%), good (57.85%), and excellent to good (65.71%), respectively. Moreover, the majority of the selected samples were categorized as excellent to good and safe for irrigation according to the SSP and RSC. The performance of the simulation models was evaluated based on several prediction skills criteria, which revealed that the ANFIS model and SVM model were capable of simulating the IWQIs with reasonable accuracy for both training “determination coefficient (R2)” (R2 = 0.99 and 0.97) and testing (R2 = 0.97 and 0.76). The presented models’ promising accuracy illustrates their potential for use in IWQI prediction. The findings indicate the potential for ML methods of geographically dispersed hydrogeochemical data, such as ANFIS and SVM, to be used for assessing the GW quality for irrigation. The proposed methodological approach offers a useful tool for identifying the crucial hydrogeochemical components for GW evolution assessment and mitigation measures related to GW management in arid and semi-arid environments.

Mathematical models are useful for predicting the reactions of watercourses such as rivers due to the entry of contaminants. Some of these models are able to simulate the effects of present and future loadings as well as aid managers and officials in making decisions even if the data are sparse. In other words, river water quality preservation requires more investment in wastewater treatment and/or the installation of collection and control systems; it may also limit activity expansion in the river basin. The conservation of watersheds such as the Maroon and Jarahi basin, which provide water for drinking and for industrial and agricultural use, is socio-economically vital. Therefore, the first stage of managing the conservation of water resources is understanding their qualitative changes. For this purpose, the QUAL2KW mathematical model was utilized to simulate the river water quality in this example region. According to the reported values of water quality parameters and pollutants at monitoring stations, it was established that the river is at a critical condition in terms of biochemical oxygen demand (BOD) pollution due to the discharge of urban and industrial wastewater, as well as high electrical conductivity (EC) due to the drainage of agricultural lands. Based on the statistics calculated during the validation step, the authors concluded that the QUAL2KW water quality model is reliable in the simulation of qualitative parameters and the pollution data of the study area; namely the Maroon and Jarahi river basin located in the south-west of Iran. This will help stakeholders to better manage watersheds with sparse data. This region has been suffering from climate change which has led to droughts and the construction of several dams to retain water. For the second and third stations, the NASH (named after the mathematician John Forbes Nash) values were 0.96 and 0.92, respectively, indicating a relatively high model accuracy. The evaluation using the root mean square errors (RMSE) and NASH showed that the quality of water at the second station was better than the other two stations based on the coefficient of determination R2. Since there were three drains at station number 3, the wastewater entering the Maroon River had a higher level of contamination.

Investigating the spatiotemporal distribution of climate data and their impact on the allocation of the regional aridity and meteorological drought, particularly in semi-arid and arid climate, it is critical to evaluate the climate variability effect and propose sufficient adaptation strategies. The coefficient of variation, precipitation concentration index and anomaly index were used to evaluate the climate variability, while the Mann-Kendall and Sen’s slope were applied for trend analysis, together with homogeneity tests. The aridity was evaluated using the alpha form of the reconnaissance drought index (Mohammed & Scholz, Water Resour Manag 31(1):531–538, 2017c), whereas drought episodes were predicted by applying three of the commonly used meteorological drought indices, which are the standardised reconnaissance drought index, standardized precipitation index and standardized precipitation evapotranspiration index. The Upper Zab River Basin (UZRB), which is located in the northern part of Iraq and covers a high range of climate variability, has been considered as an illustrative basin for arid and semi-arid climatic conditions. There were general increasing trends in average temperature and potential evapotranspiration and decreasing trends in precipitation from the upstream to the downstream of the UZRB. The long-term analysis of climate data indicates that the number of dry years has temporally risen and the basin has experienced succeeding years of drought, particularly after 1994/1995. There was a potential link between drought, aridity and climate variability. Pettitt’s, SNHT, Buishand’s and von Neumann’s homogeneity test results demonstrated that there is an evident alteration in the mean of the drought and aridity between the pre- and post-alteration point (1994).

Remediation of contaminated soil and sediment is important for improving the eco-environmental quality. Electro-kinetic remediation (EKR) is an environmentally friendly technology to migrate and remove pollutants from the soil and sediment matrix. This paper analyses the mechanism and performance of EKR of heavy metals, organic pollutants, and compound pollutants. Moreover, the effect of optimizing individual EKR through soil and sediment pre-treatment (adding acid/oxidant/co-solvent/surfactant, stirring, heating, etc.), electrode optimization (exchange electrode, anode approximation, electrode matrix, etc.), and applying multi-technology combination (electro-kinetic permeable reaction barrier/Fenton/ion, exchange membrane/ultrasonic/electrolyte enhancement, etc.) was evaluated. Factors including incomplete separation of pollutants, variation in physico-chemical properties and microstructure of soil/sediment, and difficulties in in situ practice have restrained the field application of EKR. To solve the above technical challenge, an integrated EKR technology based on pollutant in situ separation, followed by separated contaminant treatment, and subsequent valuable elements recovery is proposed.

The aim of this article is to determine how human interventions in upstream countries coupled with drought events are affecting the flow regime of downstream countries using the Nile River basin for illustrative purposes. This has been addressed by assessing climate change in the study area through analyses of precipitation data obtained from the Global Precipitation Climatology Centre (GPCC) and detecting if there is a trend, and subsequently calculating drought events in the main basins impacting on the downstream flow. Then river discharge data were analysed using different hydraulic indices at key stations in the downstream country and measuring the alterations occurring in the flow. The degree of alteration is a function of the number of civil engineering projects being in operation and classified by time windows; pre-alteration is between 1900 and 1925, while the alteration period is between 1933 and 2012. The alteration period was classified into three periods based on the degree of alteration. The findings revealed that there are changes in the river flow regime caused by both changes in the rainfall pattern in addition to the regulation in the upstream countries. There is a direct relationship between the interventions in the upstream countries and changes in the flow regime especially when coupled with drought events. By increasing the water usage upstream, there is an increase in the alteration of the flow downstream. The years between 2000 and 2012 were linked to the highest alterations between the modified years.

This study investigates and challenges the capability of standard and hybrid soft computing models of fuzzy c-means clustering adaptive neuro-fuzzy inference system (ANFIS), wavenet and artificial neural networks (MLPNN and RBFNN) to estimate the spillway aerator air demand in dams. For the learning process, four different meta-heuristic optimization methods (particle swarm optimization (PSO), genetic algorithm (GA), firefly algorithm (FA) and biogeography-based optimization (BBO)) are considered as alternatives to the classical optimization algorithms of the data-driven models. In addition to the data-driven models, the multiple linear regressions and some empirical relations are used to evaluate the performance of the models. Evaluation of the models is assessed with five different statistical parameters as well as the diagnostic tool of the Taylor’s diagram. Analysis of the models’ outcome reveals that the ANFIS-GA has the best performance associated with a standard root mean square error of 0.309 and a coefficient of determination (R 2 ) of 0.93.

The authors conducted a socio-technical cost–benefit analysis (CBA) in Alexandra Township (Alex for short) by combining three water loss control investment strategies: (i) pipeline and infrastructure upgrades, (ii) repair and maintenance, and (iii) socio-domestic retrofitting capital. The researchers performed the CBA using sensitivity analysis methodologies such as marginal cost of capital (MCC), weighted average cost of capital (WACC), coefficient of variance (CV), the net present value (NPV) ratio, and cumulative and total cost methods. The findings for socio-domestic retrofitting capital investment showed that at an average investment cost of USD 5735 per household, consumption was reduced from 1369.4 m3/year to 301.99 m3/year, whereas a projected water savings average of 521.05 m3/household/year was achieved. The results show that the cumulative cost of water losses equaled USD 43.9 million per year, and that, if the water loss trend continues beyond the year 2026, almost 100% of the system input volume (SIV) will be non-revenue water (NRW) in the water balance. Using the MCC method, the integrated results for the socio-technical strategy showed that the economic level of leakage (ELL) was achieved at a WACC of 16.2, a CV of 0.66, and an NPV ratio or net capital risk of 0.246. This study demonstrates that the socio-technical approach is a viable alternative for water loss control and may be adopted in various parts of the world.

Urgent water and food security challenges, particularly in continental and boreal regions, need to be addressed by initiatives such as the Horizon 2020-funded project WATer retention and nutrient recycling in soils and streams for improved AGRIcultural production (WATERAGRI). A new methodological framework for the sustainable management of various solutions resilient to climate change has been developed. The results indicate that the effect of the climate scenario is significantly different for peatlands and constructed wetlands. The findings also highlight that remote-sensing-based yield prediction models developed from vegetation indices have the potential to provide quantitative and timely information on crops for large regions or even at the local farm scale. Verification of remotely sensed data is one of the prerequisites for the proper utilization and understanding of data. Research shows that current serious game applications fall short due to challenges such as not clarifying the decision problem, the lack of use of decision quality indicators and limited use of gaming. Overall, WATERAGRI solutions improve water and food security by adapting agriculture to climate change, recycling nutrients and providing educational tools to the farming community. Farmers in small agricultural catchments benefit directly from WATERAGRI, but over the long-term, the general public does as well.

Currently, it is important to develop strategic frameworks to support the selection of sustainable resource recovery solutions. This study applies a new framework for planning, implementation, and assessment of resource recovery strategies for a full-scale wastewater treatment plant (WWTP) in S&atilde, o Paulo megacity. The framework comprises several steps based on case study-specific data and information from current literature. Data were collected from various sources: a survey with a wastewater treatment utility, national and regional databases, and review of local regulations and international literature. Treatment configuration, wastewater and by-products composition, potential demand (for water, energy, and phosphorus), stakeholder identification, and local legislation were thoroughly discussed regarding decision-making on resource recovery. Scenario analysis was used to explore suitable nutrient and energy recovery measures based on indicators. Biogas recovery and sewage sludge composting showed more favorable conditions due to similar experiences in the area and robust legislation. The proposed framework is a simplified tool, and its application can support managers to get information on resource recovery and how to plan such initiatives in easier ways to facilitate wiser decision-making, and better operation and management. The results on framework use and refinement can guide potential applications in other contexts and stimulate public policy formulation and further research.

Water is a finite resource and should be given the attention it deserves to reduce its depletion through leakages in pipe systems. The authors implemented pressure management strategies linked to fixed and variable discharge (FAVAD), the burst and background estimate (BABE), and orifice principle methodologies to analyze a two-phased comparative method for applying optimal pressure management and its efficiency indexes in measuring volumetric cost performance, consumption, leakage flowrate, linear leakage reduction, infrastructural leakage and leakage cost indices. Using time-modulated smart control pressure reducing valve (PRV) simulation processes, the authors selected Alexandra Township in Johannesburg, South Africa as a case study. The results showed a reduction in head pressure, a reduction in the system input volume (SIV) from 26,272,579 m3 to 21,915,943 m3 and a reduction in minimum night flow (MNF) from 14.01% to 12.50%. The annual estimated nodal system output (NSO) was reduced from 14,774.62 m3 to 12,787.85 m3. The monthly average linear system repairs were reduced from 246 to 177, while the efficiency index percentages of leakage frequency/km/pressure were reduced from 8.31% to 5.98%. At a unit cost of $3.18/m3, the cost of leakages declined from $4,009,315.54 to $2,862,053.10 per month, while average household consumption (AMC) reduced from 36.33 m3 to 24.56 m3. Finally, the linear reduction value R2 for the percentage of the total leakage flowrate (TLFR)/SIV declined from 0.58 to 0.5, whereas the infrastructure leakage ratio (ILI) increased from 4 to 4.3. The results fully demonstrated that optimal pressure management is an alternative way to simulate, estimate, quantify and understand where and how water is lost in a distribution system. The authors propose that the implementation of proactive leakage management and domestic background leakage repair could further assist in reducing the frequency and cost of water leakages.

Data and literature related to water quality as well as nutrient loads were used to evaluate the Changjiang River (also Yangtze or Yangzi) Basin with respect to its hydrological regime, sediment transport, and eutrophication status. Waterbodies exhibited different eutrophic degrees following the ranking order of river &lt, reservoir &lt, lake. Most of the eutrophic lakes and reservoirs distributed in the upstream Sichuan Basin and Jianghan Plain are located in the middle main stream reaches. During the past decade, the water surface area proportion of moderately eutrophic lakes to total evaluated lakes continually increased from 31.3% in 2009 to 42.7% in 2018, and the trophic level of reservoirs rapidly developed from mesotrophic to slightly eutrophic. Construction and operation of numerous gates and dams changed the natural transportation rhythm of runoff, suspended solids (SS), and nutrients, and reduced flow velocity, resulting in decreased discharge runoff, slow water exchange, and decreased connectivity between rivers and lakes as well as accumulated nutrient and SS, which are the main driving forces of eutrophication. To mitigate eutrophication, jointly controlling and monitoring nutrient concentrations and flux at key sections, strengthening water quality management for irrigation backwater and aquaculture wastewater, and balancing transportation among runoff, SS, and nutrients is recommended.

Storage of greywater is controversial for environmental and health reasons. Artificial greywater was assessed after 2 and 7 days of storage time. Two different greywater pollutant strengths were statistically compared at each storage time. A negative significant (p

A baseflow separation methodology combining the outcomes of the flow–duration curve and the digital filtering algorithms to cope with the restrictions of the traditional procedures has been assessed. Using this methodology as well as the monitored and simulated hydro-climatologic data, the baseflow annual variations due to climate change and human-induced activities were determined. The outcomes show that the long-term baseflow index at the upstream sub-basin is nearly half of that at the downstream from October to April, whereas, they are close to each other for the remaining months. Some of the groundwater reacts to precipitation and an evident rise in the groundwater contribution has been detected for the hydrological years 1998–2001 and 2006–2008. The contrary has been recorded for 1987. The water released from the reservoir in the dry periods lead to distinctions in the detected baseflow index between the pre-damming and post-damming periods of the river.

This paper evaluates six soft computational models along with three statistical data-driven models for the prediction of pan evaporation (EP). Accordingly, improved kriging—as a novel statistical model—is proposed for accurate predictions of EP for two meteorological stations in Turkey. In the standard kriging model, the input data nonlinearity effects are increased by using a nonlinear map and transferring input data from a polynomial to an exponential basic function. The accuracy, precision, and over/under prediction tendencies of the response surface method, kriging, improved kriging, multilayer perceptron neural network using the Levenberg–Marquardt (MLP-LM) as well as a conjugate gradient (MLP-CG), radial basis function neural network (RBFNN), multivariate adaptive regression spline (MARS), M5Tree and support vector regression (SVR) were compared. Overall, all the applied models were highly capable of predicting monthly EP in both stations with a mean absolute error (MAE) &lt, 0.77 mm and a Willmott index (d) &gt, 0.95. Considering periodicity as an input parameter, the MLP-LM provided better results than the other methods among the soft computing models (MAE = 0.492 mm and d = 0.981). However, the improved kriging method surpassed all the other models based on the statistical measures (MAE = 0.471 mm and d = 0.983). Finally, the outcomes of the Mann–Whitney test indicated that the applied soft computational models do not have significant superiority over the statistical ones (p-value &gt, 0.65 at α = 0.01 and α = 0.05).

There is scientific evidence of accelerated sea level rise and saline intrusion. Some impacts, such as stratification and estuarine circulation, are subtle; others are dramatic including shifts in salt-sensitive habitats and limited water availability of suitable quality for industrial and municipal uses. These results have become a remarkable reality resulting in a set of integrated surface water organisation issues. Tremendous population increases overwhelming many coastal areas have expanded the problem. These challenges have been studied from many perspectives using various objectives and methodologies, and then arriving at different findings. However, all research assured that significant rises in sea level have influenced estuaries and tidally affected rivers, and these observations are expected to become rapidly worse in the future. This study introduces, categorises, critically investigates, and synthesises the most related studies regarding accelerated sea level rise and challenges of the development associated with the resources of surface water in estuaries and tidally-affected rivers. This critical review reveals that there is a need for research that focuses on the development of sustainable surface water resources.

Climate change and drought phenomena impacts have become a growing concern for water resources engineers and policy makers, mainly in arid and semi-arid areas. This study aims to contribute to the development of a decision support tool to prepare water resources managers and planners for climate change adaptation. The Hydrologiska Byråns Vattenbalansavdelning (The Water Balance Department of the Hydrological Bureau) hydrologic model was used to define the boundary conditions for the reservoir capacity yield model comprising daily reservoir inflow from a representative example watershed with the size of 14,924 km2 into a reservoir with the capacity of 6.80 Gm3. The reservoir capacity yield model was used to simulate variability in climate change-induced differences in reservoir capacity needs and performance (operational probability of failure, resilience, and vulnerability). Owing to the future precipitation reduction and potential evapotranspiration increase during the worst case scenario (−40% precipitation and +30% potential evapotranspiration), substantial reductions in streamflow of between −56% and −58% are anticipated for the dry and wet seasons, respectively. Furthermore, model simulations recommend that as a result of future climatic conditions, the reservoir operational probability of failure would generally increase due to declined reservoir inflow. The study developed preparedness plans to combat the consequences of climate change and drought.

Climate change (CC) and drought episode impacts linked with anthropogenic pressure have become an increasing concern for policy makers and water resources managers. The current research presents a comprehensive methodology but simple approach for predicting the annual streamflow alteration based on drought indices and hydrological alteration indicators. This has been achieved depending on the evaluation of drought severity and CC impacts during the human intervention periods to separate the influence of climatic abnormality and measure the hydrologic deviations as a result of streamflow regulation configurations. As a representative case study, the Lesser Zab River Basin in northern Iraq has been chosen. In order to analyse the natural flow regime, 34 hydrological years of streamflow (1931–1965) prior to the main dam construction were assessed. The Indicators of Hydrologic Alteration (IHA) method has been applied to quantify the hydrological alterations of various flow characteristics. In addition, an easy approach for hydrological drought prediction in relatively small basins grounded on meteorological parameters during the early months of the hydrological year has been presented. The prediction was accomplished by implementing the one-dimensional drought examination and the reconnaissance drought index (RDI) for evaluating the severity of meteorological drought. The proposed methodology is founded on linear regression relations connecting the RDI of 3, 6, and 12 months and the streamflow drought index (SDI). The results are critical for circumstances where an early exploration of meteorological drought is obtainable. Outcomes assist water resources managers, engineers, policy makers and decision-makers responsible for mitigating the effects of CC.

Multi-regression, hydrologic sensitivity and hydrologic model simulations were applied to quantify the climate change and anthropogenic intervention impacts on the Lower Zab River basin (LZRB). The Pettitt, precipitation-runoff double cumulative curve (PR-DCC) and Mann–Kendall methods were used for the change points and significant trend analyses in the annual streamflow. The long-term runoff series from 1979 to 2013 was first divided into two main periods: a baseline (1979–1997) and an anthropogenic intervention period (1998–2013). The findings show that the mean annual streamflow changes were consistent using the three methods. In addition, climate variability was the main driver, which led to streamflow reduction with contributions of 66–97% during 2003–2013, whereas anthropogenic interventions caused reductions of 4–34%. Moreover, to enhance the multi-model combination concept and explore the simple average method (SAM), Hydrologiska Byrans Vattenbalansavdelning (HBV), Genie Rural a Daily 4 parameters (GR4J) and Medbasin models have been successfully applied.

Numerous drought indices with various intricacy have been utilised in several climatic regions. Presently, the reconnaissance drought index (RDI), which is considered as a powerful index of meteorological drought, is acquisitioning approval primarily in semi-arid and arid climatologic areas. Because RDI is based on precipitation (P) and evapotranspiration (ET), it assesses the ET estimation effects on the characterisation of drought severity computed by RDI. The current study sheds light on the impact of the ET methods, and the elevation and climate conditions on the RDI annual results, (particularly, the alpha form of the index (RDIα12)), using three of the most widespread experimental ET estimates with low data requirements. These techniques are known as Thornthwaite, Hargreaves, and Blaney-Criddle, and are utilised in addition to the Food and Agriculture Organization Penman-Monteith reference technique. Data from 24 stations for the period from 1979 to 2014 cover different elevations and climatic conditions. No significant (P > 0.05) impacts on both the standardised (RDIst) and normalised (RDIn) forms of the RDI were detected by applying the considered ET methods at various elevations for various climatic conditions. However, the RDIα12 is directly influenced with a significant (P < 0.05) deviation that has been observed by various ET methods at different elevations and climate conditions. Accordingly, consideration should be paid to the ET estimation methodologies, in particular at high elevations. The use of various approaches may lead to flaws in availability of water resources and water quality forecasts.

Efficient water allocation for sustainable irrigated agriculture has become a growing concern, especially in transboundary river basins where the competition between upstream and downstream countries is substantially increasing. In this paper, the Diyala basin, one of the most water-stressed basins shared between Iraq and Iran, was used as an example case study. The water-stress situation is projected to get worse in the foreseeable future, as climate change adversely altered runoff at a time when demand for water is witnessing remarkable growth. Irrigated agriculture is the greatest consumer of the water supply, having a critical role for the efficiency of water use. The study aims at examining the sensitivity of irrigation demands to a set of potential improvements in irrigation efficiency (between 40 % and 60 %) in the riparian countries under different operational conditions. The investigation of the climate trends discloses that the area tends to be drier, with lower precipitation and higher rates of potential evapotranspiration. The possible impacts of climate change on water availability were examined through the simulation of various climatic scenarios with a rainfall-runoff model. Results show that the annual runoff may be reduced from 14 % to 30 %. It is estimated that such reduction can cause considerable water deficits, especially when there are small improvements in irrigation efficiency. This approach can support the development of a set of plausible scenarios to reduce irrigation water demand while maintaining a healthy agricultural sector.

Due to water scarcity in many arid countries, there is considerable interest in recycling wastewater streams such as treated urban wastewater for irrigation in the agricultural sector. The aim of this study is to assess the contamination of soil and Capsicum annuum (grown in pots) irrigated by domestic wastewaters treated by different wetland types between September 2013 and September 2014. The objectives were to assess (a) the suitability of the irrigation water for growth when using recycled wastewater contaminated by trace minerals and pathogens, (b) the impact of differently treated wastewaters on soil and fruits as a function of the wetland type, and (c) the marketable yield of the harvest as a function of mineral and biological contamination risk. Ortho-phosphate-phosphorus, ammonia–nitrogen, potassium and manganese concentrations in the irrigation water considerably exceeded the thresholds. High contamination levels by total coliforms, Salmonella spp. and Streptococcus spp. were detected. No mineral contamination was observed in the soils due to irrigation with treated wastewater. Results showed that slight to moderate zinc contamination was detected in some vegetables. Potassium accumulation in the yield showed the highest values followed by zinc. In contrast, the lowest mineral accumulation of the yield was observed for iron. No bacterial contamination was detected for fruits harvested from plants irrigated by wetland outflow water. In contrast, fruits harvested from those plants irrigated by preliminary treated wastewater showed high contamination by total coliforms, Streptococcus spp. and Salmonella spp. especially for fruits, which were located close to the contaminated soil surface. However, findings indicate that vegetables receiving wastewater treated with wetlands can be considered as safe compared to those receiving only preliminary treated wastewater. High yields in terms of economic return were associated with tap water and an organic growth medium, and a wetland with a small aggregate size and a low contact time.

The sustainable management of water resources subjected to the joined influence of transboundary basin-wide dry climatic conditions and intensive man-made river regulations in an upper riparian state on the stream flow regime of a downstream country is a serious challenge. This is particularly the case for arid and semi-arid regions where water resources are limited. The Diyala river basin, shared between Iraq and Iran, was used as an example. The study aims to develop a generic approach to isolate the relative effect of upstream man-made interventions from the mutual impacts of basin-wide dry climate environments and upstream human-induced pressures. The proposed method supports water managers in unbiased, timely and spatially relevant decision-making processes. The streamflow drought index and the monthly-based truncation level were utilized to characterize hydrological droughts, while the standardized precipitation index was used for meteorological drought interpretations. Findings revealed that the upstream river regulation schemes noticeably led to a decline in water availability of the downstream country. The relative impact ranged from a minimum value of 5% in February to the highest value of 54% in July. The average proportional impacts between April and October and between November and March were about 46% and 17%, respectively.

Climate change impact, drought phenomena and anthropogenic stress are of increasing apprehension for water resource managers and strategists, particularly in arid regions. The current study proposes a generic methodology to evaluate the potential impact of such changes at a basin scale. The Lower Zab River Basin located in the north of Iraq has been selected for illustration purposes. The method has been developed through evaluating changes during normal hydrological years to separate the effects of climate change and estimate the hydrologic abnormalities utilising Indicators of Hydrologic Alteration. The meteorological parameters were perturbed by applying adequate delta perturbation climatic scenarios. Thereafter, a calibrated rainfall-runoff model was used for streamflow simulations. Findings proved that climate change has a more extensive impact on the hydrological characteristics of the streamflow than anthropogenic intervention (i.e. the construction of a large dam in the catchment). The isolated baseflow is more sensitive to the precipitation variations than to the variations of the potential evapotranspiration. The current hydrological anomalies are expected to continue. This comprehensive basin study demonstrates how climate change impact, anthropogenic intervention as well as hydro-climatic drought and hydrological anomalies can be evaluated with a new methodology.

The aim was to assess if domestic wastewater treated by different vertical-flow wetlands can be successfully recycled to water commercially grown crops. The growth of both Sweet Pepper (California Wonder; cultivar of Capsicum annuum Linnaeus Grossum Group) and Chilli (De Cayenne; Capsicum annuum (Linnaeus) Longum Group 'De Cayenne') fed with different treated and untreated wastewater types were assessed. The overall growth development of Sweet Peppers was poor due to the high concentrations of nutrients and trace minerals. In contrast, chilies did reasonably well but the growth of foliage was excessive and the harvest was delayed. High yields were associated with tap water and an organic growth medium, and a wetland with a high aggregate size, leaving sufficient space for biomass. Low fruit numbers correlated well with inorganic growth media and irrigation water contaminated by hydrocarbons. Findings indicate that nutrient concentrations supplied to the Chillies by a combination of compost and treated waste water are usually too high to produce a good harvest. However, as the compost is depleted of nutrients after about 8 months, the harvest increased for pots that received pre-treated wastewater. Findings will lead to a better understanding of the effects of different wetland treatment processes.

The ambiguity of diverse functions of sustainable flood retention basins (SFRBs) may lead to conflict and risk in water resources planning and management. How can someone provide an intuitive yet efficient strategy to uncover and distinguish the multiple potential functions of SFRBs under uncertainty? In this study, by exploiting both input and output uncertainties of SFRBs, the authors developed a new data-driven framework to automatically predict the multiple functions of SFRBs by using multi-instance multi-label (MIML) learning. A total of 372 sustainable flood retention basins, characterized by 40 variables associated with confidence levels, were surveyed in Scotland, UK. A Gaussian model with Monte Carlo sampling was used to capture the variability of variables (i.e., input uncertainty), and the MIML-support vector machine (SVM) algorithm was subsequently applied to predict the potential functions of SFRBs that have not yet been assessed, allowing for one basin belonging to different types (i.e., output uncertainty). Experiments demonstrated that the proposed approach enables effective automatic prediction of the potential functions of SFRBs (e.g., accuracy &gt, 93%). The findings suggest that the functional uncertainty of SFRBs under investigation can be better assessed in a more comprehensive and cost-effective way, and the proposed data-driven approach provides a promising method of doing so for water resources management.

This study quantified the contributions of different P removal pathways in an integrated constructed wetland (ICW) treating domestic wastewater. Findings over the study period (February 2008 to March 2012) showed average P retention rates of 31 ± 2 mg/m2/day for molybdate reactive phosphate (MRP) and 40 ± 3 mg/m2/day for total P. Near complete P removal was achieved during the first 2 years of operation. Thereafter, effluent concentrations increased slightly. According to the mass balance estimation, assimilation by plants accounted for approximately 16% of the total P retained, while sediment storage contributed nearly 60%. Sediment storage was the major P removal pathway in the ICW. Thus, high effluent concentrations recorded during high effluent flow volumes was due to remobilisation of P from the sediment. Management of ICW systems may therefore require implementing sediment removal schemes. The combination of plants with high biomass production can be beneficial for improving ICW performance.

The aim was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand (COD) loading) variables on the long-term and seasonal performance of vertical-flow constructed wetland filters operated in tidal flow mode before and after a one-off spill of diesel. Ten different vertical-flow wetland systems were planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). Approximately 130 g of diesel fuel was poured into four wetland filters. Before the spill, compliance with secondary wastewater treatment standards was achieved by all wetlands regarding ammonia-nitrogen (NH4-N), nitrate-nitrogen (NO3-N) and suspended solids (SS), and non-compliance was recorded for biochemical oxygen demand and ortho-phosphate-phosphorus (PO4-P). Higher COD inflow concentrations had a significantly positive impact on the treatment performance for COD, PO4-P and SS. The wetland with the largest aggregate size had the lowest mean NO3-N outflow concentration. However, the results were similar regardless of aggregate size and resting time for most variables. Clear seasonal outflow concentration trends were recorded for COD, NH4-N and NO3-N. No filter clogging was observed. The removal efficiencies dropped for those filters impacted by the diesel spill. The wetlands system shows a good performance regarding total petroleum hydrocarbon (TPH) removal.

Due to water scarcity in many arid countries, there is considerable interest in recycling various wastewater streams such as treated urban wastewater for irrigation in the agricultural sector. The aim was therefore to assess if domestic wastewater treated by different wetlands can be successfully recycled to water commercially grown crops. The objectives were to assess variables and boundary conditions impacting on the growth of two different types of peppers fed by domestic wastewater pre-treated by diverse mature constructed treatment wetlands. The growth of both Sweet Pepper (California Wonder; cultivar of Capsicum annuum Linnaeus Grossum Group) and Chilli (De Cayenne; C. annuum (Linnaeus) Longum Group ‘De Cayenne’) fed with different treated and untreated wastewater types were assessed. A few plants suffered from either a shortage and/or excess of some nutrients and trace minerals. The overall growth development of Sweet Peppers was poor due to the high concentrations of nutrients and trace minerals. In contrast, Chilies did reasonably well, but the growth of foliage was excessive and the harvest was delayed. High yields were associated with tap water and an organic growth medium, and a wetland with a high aggregate size, leaving sufficient space for biomass. Low fruit numbers correlated well with inorganic growth media and irrigation water contaminated by hydrocarbons. Findings indicate that nutrient concentrations supplied to the Chillies by a combination of compost and treated waste water are usually too high to produce a good harvest. However, as the compost is depleted of nutrients after about eight months, the harvest increased for pots that received pre-treated wastewater. The project contributes to ecological sanitation understanding by closing the loop in the food and water chain. Findings will lead to a better understanding of the effects of different wetland treatment processes on the recycling potential of their outflow waters.

There is growing concern in Iraq about the inefficiency of reactive drought management practices. Corresponding actions are largely characterized as emergency-based responses that treat the symptoms of drought rather than consider the vulnerability components associated with impacts. The Diyala watershed shared between Iraq and Iran has been used as an example transboundary river basin marked by ineffectiveness of drought management. The standardized precipitation index and the reconnaissance drought index were used to determine the historical meteorological drought episodes and analysis indicated climate change-induced alterations in the area. Spatiotemporal drought maps were drawn, which can be used for the identification of drought prone areas and assist with proactive planning. This paper discusses the underlying causes of the impairments of drought management policies, and the challenges and difficulties accompanying the governance of drought in Iraq. Given the influence of climate change and the upstream anthropogenic pressures, the time has come to adopt a gradual nation-wide transition step to drought risk planning incorporating a management approach at the transboundary scale. Moreover, the institutional and technical water vulnerability components associated with drought management should be considered in an integrated manner. The paper presents a generic technical template to support decision-makers in drought risk management.

Monitoring large-scale treatment wetlands is costly and time-consuming, but required by regulators. Some analytical results are available only after 5 days or even longer. Thus, adaptive neuro-fuzzy inference system (ANFIS) models were developed to predict the effluent concentrations of 5-day biochemical oxygen demand (BOD5) and NH4-N from a full-scale integrated constructed wetland (ICW) treating domestic wastewater. The ANFIS models were developed and validated with a 4-year data set from the ICW system. Cost-effective, quicker and easier to measure variables were selected as the possible predictors based on their goodness of correlation with the outputs. A self-organizing neural network was applied to extract the most relevant input variables from all the possible input variables. Fuzzy subtractive clustering was used to identify the architecture of the ANFIS models and to optimize fuzzy rules, overall, improving the network performance. According to the findings, ANFIS could predict the effluent quality variation quite strongly. Effluent BOD5 and NH4-N concentrations were predicted relatively accurately by other effluent water quality parameters, which can be measured within a few hours. The simulated effluent BOD5 and NH4-N concentrations well fitted the measured concentrations, which was also supported by relatively low mean squared error. Thus, ANFIS can be useful for real-time monitoring and control of ICW systems.

The urgent need for rational use of water resources and the intense competition among most of the riparian countries with respect to the use of shared water sources have raised the importance of examining the contribution of base flow to total stream flow. This paper examines the Diyala transboundary river basin shared between Iraq and Iran. Daily unregulated flow records during the hydrologic years between 1955 and 1982 were considered at the upstream flow gauging station and daily unimpaired flow time series during the water years between 1931 and 1961 were examined at the most downstream hydrometric station. Two digital filtering algorithms and the flow duration curve method were applied to extract the base flow time series and compute its signature to total river flow. A generic methodology, which incorporates the flow duration curve method within digital filtering algorithms, has been introduced to obtain the filter parameter α in the filtering algorithms, and obtain the base flow contribution with a high level of confidence. Findings revealed that the base flow proportion is 38 % for the upper sub-basin and 31 % for the upper and middle combined sub-basins. The computed base flow signatures using the incorporated approach have very strong correlation coefficients of around 0.985. The driest year had the highest annual base flow index. The base flow index values started to increase in April and climbed to a peak by the end of May. A gradual decline between August and September was observed. The proposed methodology should be applied to unregulated watersheds.

Recent increases in human activities in shared river basins have unquestionably raised concerns about potential hydrological impacts, especially impacts of dams and large-scale water withdrawal schemes in the highlands. Anthropogenic pressures twinned with drought impacts have exacerbated water management challenges. This article assesses the cumulative consequences of upstream anthropogenic pressures and drought spells on temporal river flow regimes for the downstream country. The size and complexity of problems confronting transboundary river watersheds makes it necessary to use a representative example basin to study the problems and potential solutions. The Diyala (Sīrvān) river basin, which shares dozens of transboundary watersheds between Iraq and Iran, has been selected as a representative case study. A subset of the Indicators of Hydrologic Alteration (IHA) was utilised and climate variability was considered in assessing the combined effect of various forms of upstream human-river regulations and climatic conditions on natural flow regimes in the downstream state. Findings indicated that the anthropogenic river-regulation coupled with the impact of drought periods have noticeably modified the natural flow paradigm. The yearly average runoffs, which are no longer available for the downstream country, have soared to very high levels, particularly over the last fifteen years. More adverse impacts were detected in the non-rainy season. Findings reveal also that damming and considerable water diversion to large-scale irrigation projects in the upstream state are the main regulations affecting the management of shared water resources in the downstream country.

This article assesses the adverse impact of upstream anthropogenic regulation of a transboundary river watershed on the natural flow regime of the downstream country, by focusing on a case study: the Diyala (Sīrvān) River watershed shared between Iraq and Iran. The article explores transboundary watershed management difficulties in a three-level system called the transboundary three-scalar framework, which helps to sustainably manage water resources. The average rates of reduction in flow between 2004 and 2013 ranged from nearly 24% in February to about 77% in September. The median of the reduction of rates between June and October was 66.4%.

Environmental and water pollution through heavy metals is a growing concern. The recycling of untreated wastewater, which is often contaminated with heavy metals, for agricultural applications is becoming more popular. However, information on the amount of absorption and accumulation of cadmium (Cd) at variable concentrations by different crops is limited. This study aims to analyze the impact of various Cd concentrations (0, 30, 60 and 120 mg/kg) in the root zone on the quantity of its absorption as well as accumulation in various parts of seven different types of common vegetables. The experiments were carried out under laboratory-like controlled conditions. Four treatments and three replicates were selected. Cadmium accumulation exceeded the permissible limits for human consumption, and its accumulation in different plant parts followed this order: Leaves: broccoli > spinach > basil > garlic > carrot > tarragon > dill. Stems: broccoli > spinach > basil > garlic > tarragon > carrot > dill. Roots: broccoli > garlic > basil > spinach > carrot > dill > tarragon. Therefore, the authors recommend the reuse of treated wastewater, which should be virtually free of contaminants such as heavy metals, to irrigate farm lands in the future.

Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h–1 and an adsorption capacity of 42.37 μg/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 μg/L influent loads regardless if planted or not. The presence of P. vittata contributed to no more than 13.5% of the total As removal. In contrast, J. effuses was associated with a 24% As removal efficiency.

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The most significant operational cost in a treatment plant is related to the dewatering and disposal of sludge. In this research, different shapes of mixers (radial, axial, wheel, three-blade and magnetic) have been tested to assess their influence on sludge dewaterability testing. As well as the shape of mixers, different rapid mixing velocities, rapid mixing times and coagulants also have been used as test parameters. The capillary suction time (CST) test apparatus was used as a rapid measure to assess sludge dewaterability. Findings indicate that the use of magnetic stirrers leads to the lowest sludge dewaterability properties tested using the CST. The magnetic stirrer produced greater vortex and turbulence compared with other types of mixers, so rapid contact between the coagulant and the water occurred. The use of the other mixers produced similar results. However, the application of different coagulants results differently regarding the sludge dewaterability, when using different rapid mixing velocities. Different rapid mixing times did not lead to differences in the CST. During rapid mixing, Moringa oleifera produced the highest CST values followed by alum and ferric. This is likely due to the difference in sludge volume that is produced by each coagulant. Only M. oleifera produced contaminant agglomerates. In comparison, alum and ferric produced contaminant agglomerates and coagulant hydrolysis products.

Sustainable water resources management attracts considerable attention in today’s world. Recycling and reuse of both wastewater and greywater are becoming more attractive. The strategy is to protect ecosystem services by balancing the withdrawal of water and the disposal of wastewater. In the present study, a timely and novel synthetic greywater composition has been proposed with respect of the composition of heavy metals, nutrients and organic matter. The change in water quality of the synthetic greywater due to increasing storage time was monitored to evaluate the stability of the proposed chemical formula. The new greywater is prepared artificially using analytical grade chemicals to simulate either low (LC) or high (HC) pollutant concentrations. The characteristics of the synthetic greywater were tested (just before starting the experiment, after two days and a week of storage under real weather conditions) and compared to those reported for real greywater. Test results for both synthetic greywater types showed great similarities with the physiochemical properties of published findings concerning real greywater. Furthermore, the synthetic greywater is relatively stable in terms of its characteristics for different storage periods. However, there was a significant (p

Constructed wetland sediments are frequently contaminated with nitrogen and phosphorus. There is a risk that accumulated pollutants can either be remobilised or reach the groundwater. Five identical mesocosms, which were filled with subsoil collected from full-scale integrated constructed wetland (the first cell receives the most contaminated influent), were set up to examine nutrient removal within sediment layers. The results indicated that accumulated nutrients leached out into inflow water and that the sediment capacity of nutrient retention decreased as the wetlands aged. Furthermore, the mesocosm planted with Phragmites australis achieved better treatment results compared with the one planted with Agrostis stolonifera. The risk of contamination to groundwater does not exist because none of the treated water reached the bottom outlet during the study period. Both the bentonite (clay) and biogeochemical processes taking place within sediments proved to be efficient in preventing polluted water from infiltrating into lower lying soils.

Data collected from five Wildfowl & Wetlands Trust constructed wetland systems offering a range of styles and inflow water types between 2005 and 2009 were examined and compared to identify long-term trends in nutrient removal. Ammonia-nitrogen concentrations were reduced between 31.9 and 96.8%. In contrast, the concentrations of nitrate-nitrogen and total oxidised nitrogen in the effluent exceeded the influent in many of the systems. Reduction in ortho-phosphate-phosphorus and total phosphorous were between −10.5 and 87.6%, and between 6.9 and 92.5%, respectively. Removal efficiencies of biochemical oxygen demand were between 0.0 and 87.3%, and reductions of total suspended solids ranged from −249.3 to 57.6%. Ammonia-nitrogen reduction was effective during summer. Long-term nitrogen removal has been efficient and consistent. However, phosphorous reduction was only sufficient during the early stages of operation, and generally declined as the wetland aged.

This review discusses high impact research in sustainable urban and land management. The focus is on large European projects that have a holistic and multi-disciplinary assessment approach towards the total environment. This paper clearly indicates that many projects propose decision-making tools partly supported by numerical models. Successful projects were identified as applying the following criteria: a communicative and holistic approach involving economic, environmental and social sciences throughout the project; sufficient geographic coverage; engagement of stakeholders from a wide variety of sectors; and plans for dissemination of project outcomes and active knowledge sharing.

Permeable pavement systems (PPS) are frequently associated with high removal efficiencies for water quality parameters. Their effluent can, therefore, be recycled, for example, for sprinkling onto gardens. Nevertheless, some stakeholders fear that potentially pathogenic organisms within the treated run-off could be too high, and therefore they request disinfection before recycling. The aim of this paper is, therefore, to assess the efficiency of a batch flow combined titanium dioxide (TiO2) and ultraviolet (UV) light photocatalytic reactor in removing water-borne microbial contaminants from the effluent of PPS. Combined TiO2 and UV photocatalytic reaction times between 80 and 100 min were required for the complete removal of Escherichia coli, total coliforms and faecal Streptococci, which had mean initial counts of 1.5 × 107, 4.4 × 106 and 6.9 × 105 colony-forming units (CFU) per 100 mL, respectively. In comparison, UV disinfection alone resulted in insignificant microbial removal. Suspended TiO2 powder was more effective than small immobilised TiO2 crystals.

This paper reviews the ecological environment protection measures of Chinese rural hydropower development schemes. China’s rapid economic growth is making great energy demands and developing rural hydropower currently provides 30.4 GW annually. There is a conflict of interest between hydropower development and ecological and environmental protection. Potential problems include changes in hydrological condition, eutrophication, downstream nutrient reduction, sediment deposition, aquatic ecosystem alteration, and ecological water demand variation. Since most of the rural hydropower resources are located in ecologically fragile regions, it is significantly more important that ecological environment protection is being considered. As exploitation of rural hydropower has developed in China, ecological environment protection schemes had to adapt to changing boundary conditions. Due to improvements in environmental protection management, various environmental impact assessment methods have been applied including fuzzy analysis hierarchy process, ecological scheduling, pressure-state-response, and ecological environment evaluation index. The latter index can both qualitatively and quantitatively analyze ecological environment impacts and has become the most frequently used tool in the evaluation of rural hydropower exploitation. To rebalance the interests regarding energy generation and environmental protection, countermeasures originating from different aspects such as engineering design optimization, management improvement, and ecological restoration were recommended to promote ecological environment protection. The review concludes that by taking ecological environment protection into consideration in the whole rural hydropower plan, adopting ecological scheduling to guarantee river ecological water demand and implementing ecological restoration in watershed management are the most effective approaches in furthering sustainable development of rural hydropower.

Four planted (Typha latifolia L.) pilot-scale vertical subsurface flow constructed wetlands were constructed to purify the eutrophic water of the Jinhe River in Tianjin (China) and to determine the...

This paper investigates the role of plants and sediment in removing nutrients from wastewater being treated in a representative integrated constructed wetland (ICW). It discusses the role of plants and sediment in removing nutrients from an ICW treating agricultural wastewater for more than 7 years. More nitrogen and phosphorus were stored in wetland soils and sediments than in plants. The first cell had the highest depth of sediment accumulation (45 cm). Over the 7-year operation period, the accretion rate was approximately 6.4 cm/year. With respect to maintenance, desludging of the first wetland cell of the ICW system appears to be necessary in 2011. An average of 10,000 m3 per year of wastewater entered the ICW. Approximately 74% (780 kg) of the phosphorus and 52% (5,175 kg) of the nitrogen that entered the wetland system was stored in the wetland soils and sediments. Plants stored a small fraction of nutrients compared to soils (

The use of permeable pavement systems with integrated geothermal heat pumps for the treatment and recycling of urban runoff is novel and timely. This study assesses the efficiency of the combined technology for controlled indoor and uncontrolled outdoor experimental rigs. Water quality parameters such as biochemical oxygen demand, nutrients, total viable heterotrophic bacteria and total coliforms were tested before and after treatment in both rigs. The water borne bacterial community genomic deoxyribonucleic acid (DNA) was analyzed by polymerase chain reaction (PCR) amplification followed by denaturing gradient gel electrophoresis (DGGE) and was further confirmed by DNA sequencing techniques. Despite the relatively high temperatures in the indirectly heated sub-base of the pavement, potentially pathogenic organisms such as Salmonella spp., Escherichia coli, faecal Streptococci and Legionella were not detected. Moreover, mean removal rates of 99% for biochemical oxygen demand, 97% for ammonia-nitrogen and 95% for orthophosphate-phosphates were recorded. This research also supports decision-makers in assessing public health risks based on qualitative molecular microbiological data associated with the recycling of treated urban runoff.

The relationships between pH, dissolved oxygen (DO) and chlorophyll a in aquaculture and non-aquaculture waters are assessed in this paper. The research includes the evaluation of field and experimental studies at the Panjiakou Reservoir (between Aug and Oct 2009) and the review of international data covering two decades. The results indicated that typical eutrophic non-aquaculture water had mean concentrations of chlorophyll a of higher than 10 μg L−1, and significant positive correlations were found between pH, DO and chlorophyll a. When the mean concentration of chlorophyll a was less than 10 μg L−1, no correlation was found between DO and chlorophyll a for waters with a high exchange rate or heavily organically polluted natural waters. Diurnal variations were found for both pH and DO. A corresponding significant positive correlation was found between both water quality parameters. In general, when the mean concentration of chlorophyll a was less than 10 μg L−1 within aquaculture waters of low exchange rate, only a weak or no correlation at all was found between pH, DO and chlorophyll a during summer and autumn. On the other hand, a significant positive correlation between pH and chlorophyll a and a significant positive correlation or no correlation between DO and chlorophyll a were found for aquaculture waters with a high exchange rate during summer and autumn. Strong diurnal variations for both pH and DO were identified. A significant positive linear correlation between pH and DO was found for field enclosure experiments.

A low-cost technology for drinking water purification involving plant extracts that are harmful to potentially pathogenic bacteria was developed. The methanolic and aqueous extracts of different parts of the Moringa oleifera vegetable tree were examined for their antibacterial and coagulation properties. The extracts from buds and shoots showed more antibacterial activities against Staphylococcus aureus, Bacillus cereus var. mycoides, Pseudomonas aeruginosa, Klebsiella pneumonia and Shigella flexneri at 37°C than those obtained from leaves and seeds. The lowest minimum inhibitory concentrations and minimum bactericidal concentrations were observed for buds and shoots, and not for seeds and leaves. The seeds were associated with higher coagulation activity in comparison with other parts of the plant and alum. These results suggest that bud and seed extracts can be used for water treatment, avoiding the risk of contamination by water-borne pathogens and promoting an indigenous solution to disease control and environmental management.

The use of sustainable drainage systems (SuDS) or best management practice (BMP) is becoming increasingly common. However, rather than adopting the preferred “treatment train” implementation, many developments opt for end-of-pipe control ponds. This paper discusses the use of SuDS in series to form treatment trains and compares their potential performance and effectiveness with end-of-pipe solutions. Land use, site and catchment characteristics have been used alongside up-to-date guidance, Infoworks CS and the model for urban stormwater improvement conceptualisation to determine whole-lifecosts, land take, water quality and water quantity for different SuDS combinations. The results presented show that the use of a treatment train allows approaches differing from the traditional use of single SuDS, either source or “end-of-pipe”, to be proposed to treat and attenuate runoff. This outcome provides a more flexible solution where the footprint allocated to SuDS, costs and water quality can be managed differently to more comprehensively meet stakeholder objectives.