Frontiers in Water-Energy-Nexus—Nature-Based Solutions, Advanced Technologies and Best Practices for Environmental Sustainability

Biogas production within wastewater treatment plants plays a decisive role in the water–energy nexus. Biogas obtained from sewage sludge digestion can be converted into biomethane as CO2 emissions are reduced. Techno-economic assessment of the process is presented. Anodic valorization through chlorine production is performed. Potential impacts of this technology in a wastewater treatment plant are discussed.

The Persian/Arabian Gulf plays a critical role in the sustenance of its surrounding countries, home to over two-thirds of the world’s proven oil reserves. With minimal rainfall and natural water sources, these countries rely heavily on desalination of the Gulf for potable water. A new industry is now emerging in the region: nuclear power. This adds another layer of complexity to the preservation of the already stressed Gulf water.

Projects aimed at reducing water and/or energy consumption present technical and economic complexity profiles that require the analysis of the many components of investment risk. Risk analysis is essential to express judgements on the economic convenience of projects in the water-energy sectors. It is important to study actions for the mitigation of investment risk, so as to report the residual risk within tolerability limits. The integration of the as low as reasonably practicable (ALARP) logic with the cost-benefit analysis allows to define a protocol for the acceptance of the residual investment risk.

In the cost-benefit analysis (CBA), the declining discount rate (DDR) certainly allows to assign the right weight for the long-term effects of investment projects. The DDR gives the opportunity to properly evaluate projects for sustainable development in the water and energy sectors. The estimation model of the DDR based on probabilistic logic solves the problem of the excessive contraction of the project cash flows that occur in temporal instants that are distant from the evaluation one.

Resilience-informed decision-making is crucial for infrastructure interdependencies management; infrastructure interdependencies management requires shared interventions; resilience-informed interdependency management will support investments’ prioritization for infrastructure improvement.

Urban water demand forecasting is a powerful supporting tool for specific water utility decision making problems. Among the others, ARIMA is one of the possible approaches to achieve an efficient short-term forecasting.

Energy consumption for water withdrawal is the main contribution to energy consumption in drinking water supply systems. Energy consumption in large Italian WWTPs should be lower than about 25 kWh PE−1 y−1. Energy recovery in Italian WWTPs takes place mostly by the exploitation of biogas from anaerobic digestion of sewage sludge.

Water and energy are two essential resources for our future since these two resources are strongly interconnected. The identification of the future scenarios and the evaluation of the possible impact on the water sector due the production of electricity are essential actions to be performed in order to obtain a picture of possible developments that could affect the national and the international energy scenarios.

Hydraulic fracturing of shale plays requires large quantities of water and could pollute water resources, which is especially problematic in the water-scarce North African context. This study investigates the potential impacts of fracking on regional water stress in Tunisia by forecasting shale development and water stress for two key regions. To also understand the political economy of shale gas in Tunisia, experts from different backgrounds were interviewed. The results show that fracking could add important volumes to regional water demand, especially in peak drilling years. However, water concerns are of secondary importance to decision-makers, and the promise of economic benefits weighs heavier, increasing the likelihood of shale gas development.

Relationships between energy consumption and characteristic data of the urban water system in Italy have been researched.

Evaluation of water-retentive block and normal block to derive the net benefit of green infrastructure.

Skills for water efficiency and water–energy nexus in building construction and retrofit; skill upgrading of construction and green professionals on water efficiency and water–energy nexus.

A Water-Energy-Food Nexus Simulation Model (WEFSiM) is proposed to quantify the nation-wide resources sustainability. WEFSiM considers the feedback connections between water, energy, and food sectors in a single framework. The optimization module provides more alternatives for resource management planning. The effect of a new energy plan in South Korea (Energy 2030) is simulated in a nexus perspective.

Three different scenarios for meeting domestic water demand in a small island in Greece were examined and compared. Life-cycle cost analysis was performed in order to evaluate each scenario from an economic point of view.

There appears to be little agreement on the precise meaning of the nexus, whether it only complements existing environmental governance approaches or how it can be enhanced in national contexts. Technical solutions for improving coherence and governance within the nexus may have unintended and negative impacts in other policy areas, such as poverty alleviation. The nexus is yet to be extensively grounded, into national policies and practices, and broad-based local demand for nexus-framed policies is currently limited. Through a mini-case study in Nepal, this article seeks to analyse what is the local understanding and practice around the relationship between food, energy and water to inform nexus thinking and practice. These mini-case studies will inform us on the interaction between formal and informal institutional arrangement and how these interactions form the basis of a nexus system.

In this short paper, we show how solutions for mitigating resource security in one sector can be found in another. We demonstrate—by means of a case study in Burkina Faso and Ghana—how investing in the electricity grid in the south leads to increase food security in the north. A new nexus framework was developed (‘MAXUS’) which was built to understand, simulate and optimize intersectoral (and international) development strategies in the water, food and energy sectors. We believe this new type of geospatial integral resource management, supported by the exponential increase of data availability of the twenty-first century, could finally turn nexus models into decision support tools.

The electricity use is a significant part of human’s environmental footprint. Fossil energy is still used as the major energy resource for power generation. Policy makers seek a remedy to mitigate carbon emissions of fossil fuels. A virtual carbon emission tracing method is discussed in this paper. This paper facilitates allotting carbon obligation in power systems.

The use of genetically modified (GM) varieties represents the best strategy to adapt to climate change. The use of quality function deployment (QFD) provides a simple tool for decision taking. The characteristics of water, soil, chemical fertilizers, pesticides, and herbicides are indispensable criteria in the selection of adaptation alternatives.

A combined electrodialysis and photo-electro-chlorination process was evaluated. The current efficiency of the chlorine evolution reaction increased with the [Cl−]. UV/Chlorine boost the oxidation rate of recalcitrant organic compounds.

Reduction of organic and nutrient compounds. Membrane fouling control through the decrease of membrane fouling precursors and quorum sensing. Energy production in terms of hydrogen.

The iron- and copper-based Fenton (-like) reactions produce high-valent metal species (ferryl and cupryl ions). Ferryl and cupryl ions as reactive oxidants are capable of oxidizing refractory organic compounds in water. Ferryl and cupryl ions can be used for the inactivation of microorganisms in both planktonic and biofilm states.

A visible light-responsive photocatalyst (g-C3N4-AQ) has been synthesized. g-C3N4-AQ produces hydrogen peroxide with the response to visible light. g-C3N4-AQ in combination with Fe(III) produces hydroxyl radical by Fenton-like reaction. Fe(III) accelerates the hole oxidation reaction at the valence band (VB) by capturing electrons at the conduction band (CB).

Microalgae provide a low-cost and environmentally friendly oxygenation. Enhanced nutrient recovery as a result of the dual photoautotrophic and heterotrophic metabolism. Microalgae can turn the energy balance of conventional wastewater treatment into positive. Microalgae-based processes can be engineered into multiple configurations. Wastewater treatment and biogas upgrading can be combined in algal-bacterial photobioreactors.

A resourceful and continuously operating ozonation-biofiltration column experimental set-up was built and tested. The set-up is useful for predictions on the fate of ozonation products under different conditions and process configurations. Computational fluid dynamics (CFD) modelling helps to better understand and quantify the membrane-facilitated mass transfer of ozone into water. Modelling and experimental approaches provide the basis for establishing more efficient membrane ozonation processes.

Groundwater availability in Egypt and its quality. RO pretreatment of groundwater to secure drinking water. Large-scale production of flat sheet UF membranes and its evaluation. Spiral wound 4040 modules preparation and its application in the real continuous system.

Results of an energy audit on a large wastewater treatment plant (wwtp) are shown; critical issues related to the use of energy resources in this plant are identified; parasitic inflows negatively affect the plant performances and a distinction between organic and hydraulic load is a useful tool in describing this problem.

Successful persulfate activation by iron was achieved. Amberlite was demonstrated to be a suitable support for obtaining an efficient iron catalyst. Electro-activation of peroxymonosulfate in the presence of iron-based minerals as catalyst was developed. Reusability of heterogeneous catalysts was demonstrated. Lissamine Green B and 1-butyl-1-methylpyrrolidinium chloride removal through sulfate radicals was accomplished.

Electro-Fenton generation of ·OH is more efficient and significant than the ·OH produced in the anode surface by anodic oxidation. Electro-Fenton process was optimised determining the relationship among key variables as electrodes surface and stirring rate. At optimal conditions, the combination of fluoxetine and pirimicarb was easily degraded with high mineralisation level.

Microbial diversity in acid mine drainage from eMalahleni, Mpumalanga, South Africa. Enrichment of SRB improves its performance in sulphate reduction. Microbial community shows synergy between SRB Proteobacteria and facultative Bacilli. Sulphate reduction of 85% and cadmium reduction of 98% were observed within 7 days of continuous operational mode. The microbial community showed wider substrates utilisation.

Nanoscale ferrihydrite incorporated biopolymeric composites prepared for arsenic removal from water. Composite shows excellent adsorption capacities for both arsenite and arsenate (overall >100 mg/g). Low dosage of the composite shows very fast kinetics over a wide pH range of water sample. The green synthesis yields a thermally stable composite with very high mechanical strength. This robust nanocomposite is industrially viable and offers an affordable and sustainable solution to arsenic contamination.

This paper presents self-forming dynamic membrane (SFDM) process as a promising alternative to membrane technology. A stable dynamic membrane (DM) is mainly composed of gel layer and cake layer which are responsible for filtration and biodegradation. An understanding of the formation mechanism and impact of operating conditions, support mesh, sludge properties and configuration on the formation, and characteristics of the dynamic membrane is essential to optimize the efficiency and reduce fouling propensity of this technology. The paper thus aims to promote its applicability on wastewater treatment. Review of the influence of mesh support properties, different operating conditions and sludge properties on SFDM performance, and cost comparison between MBR and SFDMBR technologies.

This paper focused on the combination of membrane ultrafiltration, adsorption and ultrasound processes in one hybrid process called USAMe for improving membrane wastewater treatment performance and membrane fouling control. Different tests were conducted at different ultrasound frequencies and recycle ratio. Improved permeate quality in the USAMe process. Membrane fouling reduction with the combined application of ultrasound and activated carbon. Influence of ultrasound frequency, membrane flux and recycle ratio on treatment performance.

Climate change mitigation in the integral water cycle. WWTPs as energy producers. Use of the plant intrinsic energy. Integration of renewable energies in WWTPs. Water–energy nexus as greenhouse gas emissions reduction tool.

The results show that compared with Escherichia coli promoting corrosion and Pseudomonas fluorescens inhibiting corrosion, in mixed bacteria, the average corrosion rate of carbon steel is reduced by 25.66%. Corrosion current density (Icorr) decreases and the diameter of Nyquist plots increases with time. Meanwhile, the dominant bacteria in mixed condition is verified with different phases. Extracellular polymeric substances (EPS) of E. coli promote the growth of P. fluorescens, and EPS of P. fluorescens can inhibit the growth of E. coli at 400 mg L−1. Scanning electron microscope (SEM) and X-ray diffraction (XRD) demonstrate that the transformation of corrosion products makes the biofilm-corrosion products film formed on the surface of carbon steel more compact in mixed bacteria.

High-density TiO2 epoxy grains for easy gravitational separation after treatment ends. Passive aeration for maintaining high DO levels. Degradation rate constant and reactor throughput as benchmarks for reactor performance. Water turbidity indicator for photocatalyst resistance to abrasion. Promising for scale-up: modular design, integrated storage, no UV transmitting parts.

Microalgae co-cultured with certain filamentous fungi form biopellets. Biopellets can be used in microalgae harvesting and in water treatment. White-rot fungi producing laccase are of interest for water treatment. In suitable environmental conditions, certain white-rot fungi can form biopellets with microalgae.

Event scale analysis of green roofs hydrological performances in a Mediterranean environment. Different green roofs constructive technologies are investigated. Different hydrological models are applied to identify pros and cons of empirical and physically based models.

Exploitation of synthetic aperture radar satellite data. Monitoring of surface water resources with high resolution in time and space. Low-cost technic for freshwater monitoring. Appropriate technology for developing countries. Retrieval of river features: active channels, sediment bars and wet channels.

Tanning industry is receiving a lot of attention due to its pollution levels and discharge legislations toward the environment. Tanerry wastewater treatment by using electrochemical oxidation with SnO2/Ti and PbO2/Ti anodes. The tannery wastewater was pretreated using biological method with aerotank process. SnO2/Ti and PbO2/Ti anodes effectively treated COD and total nitrogen over 85% after 90 min of electrolysis. The treatment efficiency in tannery wastewater of SnO2/Ti anode is greater than PbO2/Ti anode.

OMBR is a recently developed technology for wastewater treatment. OMBR-NF hybrid system was numerically modelled. Influence of process variables on system performance indicators was investigated.

Analysis of event scale hydrological performances of green roofs in a Mediterranean environment. Different green roofs constructive technologies are investigated. Observed soil water contents help describe the impact of cumulative rainfall depth and duration on green roofs hydrological performances.

The acidification in the process of ammonia nitrogen oxidation must be prevented. The superiority of orthophosphate versus bicarbonate was demonstrated. Ammonia nitrogen removal rate in the presence of $${{\text{HPO}}_{4}}^{ = } /{\text{H}}_{2} {{{\text{PO}}_{4}}^{ - }}$$ increased by 15%. Nitrate generation in the presence of $${{\text{HPO}}_{4}}^{ = } /{\text{H}}_{2} {{{\text{PO}}_{4}}^{ - }}$$ decreased by 50%. Presence of $${{\text{HPO}}_{4}}^{ = } /{\text{H}}_{2} {{{\text{PO}}_{4}}^{ - }}$$ limited the generation of bromate to 0.04% of the bromate yield.

Hybrid fluidized bed ceramic membrane reactor was developed using low-cost pyrophyllite/alumina composite membrane with GAC particles as fluidized media to treat real metal-plating wastewater. With GAC fluidization, both uncoated and coated ceramic membranes achieved more than 90% of COD removal efficiency. There was no occurrence in membrane fouling under GAC fluidization during one-day of system operation for both membranes.

Low temperatures produce more biopolymers, leading to severe biofouling. Moving QQ sheets mitigate biofouling under cold weather conditions. QQ activities drop sharply with decreasing water temperatures. QQ sheets remain active during long-term field tests using real wastewater. QQ sheets have no impact on activated sludge treatment performance.

Chemical modification of different morphologies of ZnO nanoparticles (spherical, flowers). Modification of thin-film composite (TFC) using ZnO nanoparticles by surface coating. Measured flux, NaCl rejection and hydrophilicity. Fouling resistance studies on unmodified and modified membrane. Best membrane performance was observed with 0.02 wt% ZnO-S-modified membrane.

Immobilized cells of Chlorella vulgaris in alginate–chitosan matrix achieved faster growth rates and produced more biomass than their free cell counterpart in synthetic aquaculture wastewater. Higher (89.8%) nitrate-N removal was achieved by immobilized cells than by the free cells (45.9%). Phosphate-P removal was both high at 98.9 and 99.5% by immobilized and free cells, respectively. The alginate–chitosan matrix was found suitable for growth, nutrient removal, and biomass production in synthetic aquaculture wastewater.

In this study, treatment of synthetic printed circuit board wastewater containing copper and nickel ions was done through fluidized-bed homogeneous granulation process (FBHGP). The treatment occurred in a single reactor, removing and granulating both copper and nickel ions at the same period of time. The effect of total carbonate loading (10, 12, 15, 17, 20 mM) on the treatment of Cu2+ (6.3 mM) and Ni2+ (3.4 mM) was evaluated in this study with initial precipitant flow rate of 15 mL/min and initial operating pH of 6.5 and shifted to 8.5 pH on the given period of time. The synthetic wastewater containing copper and nickel ions had better result in terms of size of recovered granules, removal and granulation efficiencies when 17 mM of CO3 was employed in the system, resulting to copper removal of 97.5%, copper granulation of 93.1% and nickel removal and granulation efficiencies of 81.2 and 73.6%, respectively. The granules recovered were >0.42 mm in size with rough surface and EDX analysis identified the presence of oxygen, copper and nickel.

Simple synthesis procedure for biochar-supported Fe3-xMnxO4 was conducted. Synthesis conditions were examined for optimal metal impregnation yield. Kinetics of adsorption was investigated for imidacloprid removal.

Fluidized-bed technology had been greatly employed to treat wastewater by removal of heavy metals, nutrients, and dissolved minerals through granulation or crystallization. This work focuses to imply the technology of fluidized-bed homogeneous granulation process to remove hardness from raw and tap waters. The paper investigated the granulation kinetics of CaCO3 through fluidized-bed homogeneous granulation (FBHG) process during the homogenous nucleation stage. The mechanism followed the pseudo-second-order (PSO) kinetics, that calcium cation attracts to carbonate anion to form particle of CaCO3 through double displacement chemical reaction. The calcium-to-carbonate molar ratio ([Ca2+]/[ $${{\text{CO}}_{3}}^{2 - }$$ ]) was varied into 1.25, 1.50, 1.75, 2.00, 2.25, and 2.50, with constant values of operating pH = 10 ± 0.2, influent carbonate concentration ([ $${{\text{CO}}_{3}}^{2 - }$$ ]) = 10 mM and total influx flow rate (QT) = 60 mL min−1.

The presence of pharmaceuticals’ residual in water is considered as a serious environmental problem. Two of them, i.e., paracetamol and diclofenac were treated with peroxydisulfate activated with ferrous ions and copper oxide. The degradation rates of both compounds versus type activators applied were evaluated by the means of changes of pharmaceutical concentration as well as observed changes of nitrite and nitrate concentrations in the reaction mixtures during the oxidation processes. The results clearly show that paracetamol was relatively easily decomposed independently from the type of PDS activator applied, contrary to the diclofenac, which was more resistant to the oxidation, especially, when CuO activation was used.

Fouling is considered the bottleneck of membrane systems. In this study, the fouling occuring in different membrane processes and configurations was studied by using Optical Coherence Tomography (OCT). Fouling formation in membrane system was assessed and quantified non-invasively during operation. The use of the OCT enabled monitoring fouling evolution and correlating it to the membrane performance decline.

TiO2-based commercial membranes were coated with SiO2 nanoparticles using solgel dip coating. Membranes were characterized using FTIR, SEM, contact angle and were also tested for the COD removal efficiency. Membrane coating was confirmed from FTIR spectra. SiO2 coating enhanced membranes hydrophilicity.

Multicriteria evaluation based on technical, economic and environmental assessment shows the benefits and limitations of novel PAC-NF systems versus conventional UF-RO (50%) systems.

A marginal increase in operational costs led to a 45% reduction in carbon footprint. Life cycle assessment and multivariable analysis allow identifying an economic and environmentally friendly operational condition. Photo-Fenton in raceway reactors increases biodegradability of recalcitrant effluents at a low cost (0.33 US$/m3).

Optimization of Energy consumption in activated sludge plants. Selection approach of the best observation that will be used in a supervised deep learning model. The model was applied to learning and validation period in order to show its performance.

A paper-based electrochemical sensor has been developed as a green tool for analysis of diclofenac. The electrochemical behaviour of diclofenac has been studied on carbon-paper-based electrodes. A miniaturized device combining paper electrodes and reusable connections allows to perform decentralized analysis. The employment of a paper-based electrode allows simple on-site preconcentration of the analyte improving the sensitivity of the methodology.

This paper outlines a multi-objective, integrated approach to analyse various possibilities for increasing energy efficiency of the largest Italian wastewater treatment plant (WWTP) at Castiglione Torinese. In this approach, wastewater and sludge treatment units are thoroughly investigated to find the potential ways for improving the energy efficiency of the system. Firstly, a multi-step simulation-based methodology is proposed to make a full link between treatment processes and the energy demand and production. Further, a scenario-based optimization approach is proposed to find the non-dominated and optimized performance of the WWTP. The results prove a potential to save up to 5000 MWh of the annual energy consumption of the plant, in addition to improve the effluent quality through operational changes only. Even for what concerns the sludge line a model was proposed for the optimization of the energy recovery from the processes that in a WWTP are devoted to the management of sewage sludge. The obtained results show that the introduction of an advanced thickening stage and sludge pre-treatment, together with the optimized production and use of biomethane, would have a positive impact on the energy and greenhouse gas balance of the plant. The preliminary tests were conducted with microalgae, under different light intensities (3 and 5 fluorescent lamps equal to 44 and 76 μmol/m2/s), that had shown a total CO2 reduction of 80 and 70%, respectively.

The potential of microalgae, bacteria, and a microalgae–bacteria consortium for the removal of Pseudomonas aeruginosa and Escherichia coli during domestic wastewater treatment was investigated; P. aeruginosa was removed mainly by microalgae action when in the microalgae–bacteria consortium; E. coli was removed by both microalgae and bacterial action; The effect of the LEDs was higher on E. coli than P. aeruginosa removal; The symbiotic system is more advantageous than just microalgae system, because the biomass productivity is higher and pathogens removal is almost similar for both systems.

The whey is a by-product rich in organic substances; the system, as conceived, is self-learning.

Electro-Fenton technology was able to decrease zebrafish embryotoxicity of fluoxetine and pirimicarb, when single or in mixture.

Photocatalytic disinfection of Escherichia coli was assessed. Removal of natural organic matter by advanced oxidation processes more specifically photocatalysis was considered. Application of first-, second- as well as third-generation photocatalysts was evaluated. Photocatalytic degradation process was evaluated for drinking water quality aspects.

Increasing need for clean potable water around the world, have led researchers to focus on water disinfection using natural and/or artificial sunlight for the inactivation of a wide range of microorganisms. In this study solar light-initiated photoinactivation of pathogenic bacteria i.e. Escherichia coli (E. coli). The effect of natural organic matter (NOM) type and water matrix was evaluated. Both NOM and bacteria removal by solar irradiation was followed by UV-vis and fluorescence spectroscopic analysis to characterize NOM and reveal inactivation data of E. coli to kinetics.

Photolytic/photocatalytic degradation of synthetic ROC samples was evaluated. Role of various photocatalysts on ROC degradation was evaluated. Molecular size fractionation was performed following photodegradation/photocatalytic degradation. Advanced fluorescence techniques used for detecting changes in fluorophores.

Preparation of undoped and Cu-doped TiO2 photocatalysts using sol–gel method. Characterization of photocatalysts using XRD, SEM, XPS, UV-DRS, BET and FTIR techniques. Visible light photocatalytic degradation of humic acid in drinking water. Investigation of degradation pathway using humic acid fluorescence excitation emission matrix contour plots. Evaluation of adsorption characteristics of TiO2 photocatalysts on humic acid solution.

Constructed wetlands are an efficient technology for wastewater treatment; environmental monitoring via the analysis of hyperspectral data has a huge potentiality; vegetation indices make it possible to synthesize reflectance characteristics related to health state.

Water one of the most important vital source for the survival of living forms on earth. In the last two decades, a rapid increase in population has given a tremendous increase in uncontrolled development activities leading to the destruction of all major water bodies on earth. River Ganga System, covering 2525 km from the Himalayas to the Bay of Bengal nourishing millions of peoples of India and one of the major source of water and other use in India. With its tremendous use and importance, it is very much important to monitor it on regular basis and categorize its water quality on the basis of water quality indexing. This categorization will help to aware mass depended on the water body for various uses and to policy makers to improve the decision-making system for the betterment of the River Ganga System for its conservation and rejuvenation.

MBR CAPEX is higher than CAS+coagulation CAPEX; MBR OPEX is lower than CAS CAPEX; MBR may be economically competitive with CAS+coagulation systems.

This review paper focuses on discussing SnO2-based electrodes with regard to the stability, their application to water treatment. The approaches have been based on developing new doping routes, new fabrication routes, or combining TiO2 nanotubes with SnO2 catalyst. Operation parameters also need considering thoroughly when SnO2 electrodes are applied to treat wastewater. More effort should be put on optimizing the catalysts and the preparation routes. SnO2-based electrode is a very promise electrode material for electrochemical wastewater treatment.

Analysis of the distribution of the water quality indicators of the Danube River during the period 2010–2012 for the surface water in Chiciu area (km 375). Analysis of the correlation of the quality indicators at the observation points. Similarity and dissimilarity studies of the parameters’ series at the observation points. Mathematical modeling of the indicators series.

This study presents a longitudinal analysis of pollution profiles of rivers in India. Pollution profiles of 40 in India are created based on the levels of the biochemical oxygen demand (BOD). The cluster analysis has been used to represent groups of rivers with similar levels of pollutants. The longitudinal analysis has been used to reveal how the profiles change over six years from 2007 to 2012. The analysis is used for detecting rivers which remained polluted throughout.

Dark fermentation of textile wastes is discussed in the paper. The fermentation was carried out under the following conditions: load 5 g/L, pH was varied in the range 6.23–7.8, and oxygen in small quantities was added. The oxygen flow rates (OFR) were between 1 and 4.6 mL/h. The highest volumes of methane were obtained under anaerobic conditions (pH 6.23 and 7.8), while production of hydrogen was larger under oxygen flow rate 4.6 mL/h and pH value 6.23.

Efficiency of simulated blackwater treatment by UASB was analyzed. Removal of N, P, and DOC by Chlorella sorokiniana was evaluated. Total ammonia removal was obtained.

Starting from an extremely important territory from an ecological and socioeconomic point of view but subject to a strong constraint linked to anthropic pressures. We show in this work how global change has the potential to affect human health through the deterioration of water quality.

The heating sector is a key energy sector in the European Union. Wastewater contains significant amounts of thermal energy. Heat recovery from wastewater can support the energy transition. Wastewater heat recovery concerns a multitude of different disciplines.

The closure of the coal mines originates underground water reservoirs. The stored water can be used to produce energy. The water is at a temperature between 20 and 25 °C. A potential use consists in the production of thermal energy with heat pump.

Polychlorinated biphenyls (PCBs) were wildly used in electrical equipment of various types in the industry, power engineering and other branches of National Economy. Being absorbed from water and accumulated in media and tissue to concentrations greater than those found in surrounding water, PCBs bioaccumulate and increase up the food chain. The greatest danger to environment and people originates from lack of information about the related hazards among owners of PCB and PCB-filled equipment. Monitoring study was performed on surface waters, bottom sediment, foodstuffs, and soil samples. PCBs accumulation occurred from the lower to the higher trophic level.

Orange peel waste (OPW) is a promising substrate for anaerobic digestion. The problems related to the presence of d-Limonene in OPW need to be overcome. Alkaline pretreatment of OPW and addition of granular activated carbon are promising remedies.

Nonwoven wet wipes can be hazardous substances for wastewater systems. The study investigates the composition of physical constituents in the wastewater. The solid fractions per m3 wastewater are determined. The amount of nonwoven wet wipes in the sewer samples ranges from 0 to 116 g/m3. The accumulation of wet wipes along the path of wastewater transport is shown.

The effect of granular size distribution and temperature on the performance of UASB reactors treating municipal wastewater was studied. Larger granular size distribution favours stable methane production. Increase in temperature increases UASB performance. SMA of sludge decreases with increasing height along the reactor.

The CO2 sequestration potential of the green microalga Chlamydomonas reinhardtii was investigated with different CO2 dosing strategies. A gas mixture containing 30% CO2 and 70% N2 was used in these experiments in order to simulate the treatment of flue gases from various industries containing high concentrations of CO2. Alongside the CO2 sequestration, the results suggest that the microalgal biomass was rich in carbohydrates and lipids, and thus suitable to be used for biofuel production.

Source separated human urine is a renewable alternative source of fertilizers. Plant nutrients therein may be concentrated upon clinoptilolite to be made available to plants in due course. The remaining liquid phase is a saline solution containing appreciable amounts of organics which may be converted into biogas to be used as energy while it is treated anaerobically. The preliminary results reveal that in addition to high levels of nutrient recovery and considerable organics removal, the remaining liquid waste may possibly be treated using anaerobic processes and that the outcomes can be improved especially after determining the best choices for process variables.

Climate change and future depletion of resources are two of the most important environmental challenges that humankind have ever faced. This chapter aims to give a second chance to contaminated water and recalcitrant carbon dioxide (CO2) streams by putting forward a resilience and sustainable technology-based electron-driven microbial reactions.

Ultrasonication with water recirculation slightly enhanced the removal of toluene compared to water recirculation alone due to conjunction of pyrolysis and hydroxyl radical oxidation with absorption. On the other hand, the addition of ozone with ultrasonication decreased the removal efficiency due to scavenging of hydroxyl radicals. The reaction rate for ozone and OH radicals produced during the US process was faster compared to the rate for ozone and toluene.

Chlorination is the process of adding chlorine to drinking water to disinfect it prior to transmission and distribution to the receiving community. In order to maintain the drinking water quality, the chlorine level must remain within certain minimum and maximum values. This paper aims at applying GANetXL optimization tool to a real-world water network to best determine where and how much disinfectant should be injected. GANetXL is a software module that relies on the use of a genetic algorithm (GA) interfaced with EPANET 2.0. The results clearly demonstrate the positive performance of GANetXL to optimize both the disinfectant dosage value as well as the dosing location (i.e., the proper nodes to which the chlorine should be injected).

This study established a combined culture system for microalgae, wastewater, and flue gas. The microalgae growth rate could be greatly enhanced by feeding with CO2 of flue gas. The maximum carbon sequestration and average carbon sequestration rate were 1.203 g/L and 0.225 g/(L·d).

An integrated system for sewage sludge drying and electricity production is proposed. The system is powered by waste vegetable oil from separate collection. The system significantly reduces the sludge to be disposed of and the electricity to be supplied by the grid.

This work presents a novel methodology for sustainability assessment of biological wastewater treatment systems (Bio-WWTs) promoting the energy valorization of their by-products (e.g. biogas). The methodology combines analytical identification of principles-criteria of sustainability (PCS), life cycle assessment (LCA) and energy analysis (EmA) to obtain a set of sustainable development indicators (SDIs). Synergy among single SDIs is required to confirm an overall sustainable condition.

Phosphorus and nitrogen were recovered as struvite in an FBC reactor. Nutrients recovery performance was optimized by using synthetic swine wastewater. Upflow velocity of 20 cm min−1 and influent PO43− of 162.32 mg L−1 yield the best nutrient recovery conditions. Model validation proved that RSM-generated models are robust.

Chicken manure is an important substrate for biogas production. Enzymatic pretreatment of chicken manure was investigated. A higher biodegradability of chicken manure was the primary aim. Batch anaerobic digestion tests were conducted after pretreatment. Enzymatic pretreatment provided higher biogas yields.

The liquid-liquid membrane contactor (LLMC) is an innovative and eco-friendly technology for ammonium salts production; Electrodialysis (ED) can concentrate efficiently ammonium salts; Concentrated ammonium salts can be obtained by means of integration processes (LLMC and ED); Ammonium salts produced can be used as liquid fertilizers.

Charcoal from vegetable wastes showed good adsorbent properties for lead-contaminated water. Adsorption capacity at equilibrium was about 10 and 20 mg/g at 50 and 100 mg/L Pb, respectively. Breakthrough curves highlighted longer operation times of column plant filled with charcoal mixed sand than with sand only.

Normalized root mean square error (NRMSE) results from calibration and validation phases confirmed the model robustness and stability; kd calibrated values were consistent with the initial faster process kinetic observed in the anaerobic digestion (AD) configuration; α values from model calibration step further confirmed the beneficial effects of F210 and ARF on the hydrolysis step enhancement of wheat straw (WS).

Cycles of dissolved oxygen perturbation can affect emerging contaminants removal. The nitrification process can also be enhanced by oxygen perturbations. Perturbation frequency is a sensitive parameter.

Adsorption was the main removal process of PFOS and PFOA in activated sludge reactors at laboratory scale. Some biodegradation of the two tested contaminants was also detected, after adsorption. Respirometric tests showed inhibition of the nitrifying bacteria up to 30% due to the presence of PFOS and PFOA. COD removal was not affected by the presence of PFOS and PFOA.

SED is an innovative technology for metallurgical effluents treatment; IEX resin is an efficient methodology for metal separation and concentration steps; Cu and Zn were recovered by means of integration processes (SED and IEX resins).

This study evaluated the potential of microalgae Scenedesmus abundance for pretreatment of pharmaceutical wastewater in photobioreactor (PBR) associated with photosynthetic microbial fuel cell (PMFC). At the end of pretreatment process, the removal efficiency of COD of 75 % along with nitrate and phosphate of 78 and 83 % was obtained, respectively. In continuation of treatment process, the pretreated wastewater was used as a substrate for further treatment in PMFC and was succeeded to achieve maximum COD removal of 87.8 % calculating the total (combined of PBR and PMFC) removal efficiency of 95 %. A maximum voltage of 740.13 mV and power density of 838.68 mW/m2 was achieved. A maximum biomass of 0.71 g/L from PBR after pretreatment and 0.78 g/L from PMFC process was obtained.

Embryos and larvae exposed to FLX showed higher mortality rates at 32 hpf than those exposed to NFLX. At 80 hpf gross malformations, mainly in pigmentation, were higher in NFLX exposed larvae than in FLX exposed larvae. In general, strong positive correlations were found between the expression of 34 target genes. Negative correlations were associated with opposite patterns of gene expression in NFLX and FLX larvae. Adrenergic receptors, and some correlated genes, can be responsible for anomalies in pigmentation.

This paper highlights the use of the combined culture system in municipal wastewater treatment. Removal of nutrients was significantly increased in properly inoculated combined culture system. Release of organic matter from Chlorella biomass decreased the COD removal performance.

Fouling occurred on the ion-exchange membranes under practical condition, Reversible fouling occurred on the CEM, Irreversible fouling occurred on the AEM.

Through composting, biosolids can be converted to a soil conditioner provided pathogen control is ensured. Carbonized rice hull is a promising bulking agent for composting, while OFMSW can provide more organic matter needed for achieving higher peak temperatures. Augmenting with T. harzianum improves quality of compost product, thereby providing resistance to plant diseases and promotes growth.

The organic solvent pretreatment promotes the bioconversion of the organic solid waste. A low acid concentration increases the hydrogen production. Lactate production is favoured by high acid concentration and temperature of the pretreatment.

NF membranes reject divalent ions ( $$ {{\text{SO}}_{4}}^{2 - } $$ ) at much higher rate than monovalent ions (Cl−); Electrodialysis showed higher removal efficiency of $$ {{\text{SO}}_{4}}^{2 - } $$ and Cl−; Sulfate coexists with calcium- and aluminum-enhanced ettringite precipitation.

Treatment of hydrometallurgical effluents by nanofiltration membranes for acid recovery. Application of Solution-Electro-Diffusion Model to determine membrane permeances.

86% of the total water consumed for fuel production in Africa corresponds to oil. 74% of the water consumption for power plant operations is for coal power plants and 60% of the water withdrawals is for natural gas power plants. Renewable energies represent 2% of water consumption and 0.06% of water withdrawals in electricity production in Africa.

Achieving sustainable water–energy relationship is especially important for semi-arid regions. Water consumption due to electricity generation can reach up to 8.4% of the total water potential in the study area. Between 659 and 2851 m3 of water is found to be consumed per GWh of electricity generated at cooling systems.

Ground-source heat pumps (GSHPs) reduce CO2 emissions compared to conventional heating and cooling systems. The thermally altered zone (thermal plume) is a key aspect for land management of GSHPs.

Current desalination technologies present certain limitations associated with brine management. CDI operational conditions similar to EDL capacitors might become a solution for brine volume reduction. Innovative operating procedure utilizes a concentrated brine stream as a washing solution during the salt desorption phase. A high energy efficiency in the adsorption–desorption cycle was obtained using the electrolyte replacement procedure. A coupled RO-CDI system integration was proposed as a method to reduce the volumetric flow of brine.

The synergy between anions and cations is understood for their enhanced antimicrobial activity. Up to thousandfold enhancement of antibacterial and antiviral activity in drinking water by this technique. Enhancement makes disinfection of water affordable, compact and adaptable to multiple purification systems. A decrease in consumption of inorganic ions reduces health risks caused by disinfection by-products (DBPs). Thus DBPs and bioaccumulation related issues can be handled efficiently. This understanding of synergy helps to speed up the disinfection process.

Harnessing the photochemistry of chloramines can provide a promising approach for water reuse and treatment.

Photo(cata)lytic membrane bioreactors (pMBR) were investigated for bacterial disinfection and fouling control. The pMBR achieved >2.5 log removal in total bacterial count under optimum condition. The signal molecules were significantly inactivated by the photo(cata)lytic treatment. Biofouling was well inhibited during continuous pMBR operation.

Water facilities consume a large amount of electrical power. The components of water networks (mostly pumps and tanks) represent an incomparable opportunity for joint operation of water networks and power systems. These components are well suited for being responsive loads to power systems because water is storable

PES/GO mixed matrix membranes were fabricated and characterized. Water permeability tests, hydrophilicity, and surface morphology characterizations were conducted. A max of 2870 L/m2 h water flux and contact angle of 64.5° were achieved.

Ayun Mousa springs area is the most important religious and historical sites in Sinai. The water quality of the exposed springs (seven springs) indicates brackish water suitable for medical purposes. Air quality indicates some pollution next to the highway.

Demand shedding through aeration control can exploit the wastewater treatment plant (WWTP) flexibility to help maintain the power system grid balance and reduce operational costs. The reactions and settling process combination is not considered in traditional WWTP models, but it could play an important role in the modelling of demand response (DR) strategies and their effects on the plants.

Miscanthus is a suitable alternative for energy biomass. Particularly, in cultivation area that is prone to flooding. Current commercial Miscanthus can survive in the winter-flooded environment. There is no significant difference in yield and other physiological development. Observed height and tiller number have no differences between winter flooded and non-flooded ground.

Superior performance of phosphorous removal was achieved by ion exchange process with respect to chemical precipitation. The ion exchange resins required a lower dosage to ensure compliance with the effluent limit. The ion exchange process was less costly due to the lower energy consumption and sludge production.

eMBR is recently developed technology for wastewater treatment. Nanoporous hollow fiber PES membranes were fabricated and tested for eMBR post-treatment. α-MnO2/TiO2 inorganic membranes were fabricated, characterized, and tested for eMBR post-treatment. PES-fβCD mixed matrix membranes were fabricated, characterized, and tested for eMBR post-treatment.

Different pre-treatment processes were applied to investigate the removal of chemical oxygen demand (COD) from paper mill effluent. The objective of this paper is to find the optimal operating conditions for coagulation process. The effect of key operational parameters, including the type of coagulant, initial pH, temperature, and coagulant dose, on the percent removal of COD was investigated. Under the optimal operational conditions, the treatment of wastewater from paper industries by coagulation has led to a reduction of fee paid for wastewater discharged.

The article analyzes water purification and methods for the purpose. Types of sensors and appliances used for wastewater treatment are considered. The scheme and the principle of operation of a sewage treatment plant in Gabrovo, Bulgaria are presented.

Sustainable Development Calculator Application—Innovating tool for Sustainable Development WEN—A Platform for applying WEN Concepts—Integration Between Business Model and WEN—Mobile Application for Water Energy Nexus.

Soil and water bioengineering works can improve water quality. Soil and water bioengineering works are nature-based methods. Stakeholder inputs can improve soil and water bioengineering works. Case studies in soil and water bioengineering from the Mediterranean. New protocols and a template for soil and water bioengineering work for the Mediterranean.

Choice of optimum desalination technology is posited as a multi-criteria decision-making (MCDM) problem. Formulation considers technical, economic, environmental and social criteria. MCDM is an effective tool for selecting the best practice technology. Seawater reverse osmosis was found to consistently outperform thermal desalination technologies.

Different leachate feeding strategies were tested and compared based on BSM1 framework. Leachate co-treatment adversely effected nitrogen removal efficiency and increased aeration energy costs. Shock loading at noon resulted in the worst treatment performance by overloading the plant. Drip feeding based on ammonia control ensures a higher degree of flexibility by adjusting the leachate flow.

Biogasdoneright™ is an innovative agricultural model aimed at achieving a sustainable agricultural intensification. The microfiltration of the by-product from biogas production, the digestate, is among technology innovations supporting the implementation of best practices in the Biogasdoneright™ system. Digestate microfiltration tests were carried out under different operating conditions, to fine tune the best working conditions of the equipment. Then it was possible to distribute the microfiltered digestate in fertigation on growing maize through drip lines without causing blockage. Microfiltered digestate to fertigation has proven to be a best practice to improve nutrients, water and energy efficiency in the context of Biogasdoneright™.

To achieve a robust and optimal design of water distribution networks, both hydraulic constraints and reliability concerns must be met. This paper aims at employing multi-objective particle swarm optimization (MOPSO) algorithm for reliability-oriented design of a water distribution network. We use Pareto-front analysis to make a compromise between cost and reliability satisfaction. Two criteria, referred to as Todini’s resilience index ( $$I_{r}$$ ) and network resilience index ( $$I_{n}$$ ), are used to evaluate the resilience of the network under study. The simulation results clearly show that MOPSO is capable of being used in optimal design of water distribution networks and $$I_{n}$$ is an effective criterion for water networks’ reliability evaluation.

Energy and water nexus stress drives innovation in technology, financing models, business models, and partnerships. There are new platforms to accelerate nexus innovation that leverage the skills and experience of successful entrepreneurs from outside the energy and water sectors. New business and financial models are needed to solve energy and water nexus stress challenges. New partnership models are emerging to foster cross-industry and entrepreneurial platform collaboration.

Darwin Scheduler model based on fast messy genetic algorithm is utilized to best schedule the operation of the pump stations. Van Zyl, which is a well-known water network, is used to simulate the aforesaid model. FMGA reduces energy costs and the number of start/stop of the pumps. FMGA leads to the reduction of the maintenance costs.

Membrane-aerated biofilm reactor (MABR) is an energy efficient biological wastewater treatment process, based on passive aeration: by diffusion of oxygen through membranes, which also support an aerobic biofilm. The theoretical energy savings of MABR over that of conventional activated sludge (CAS) process were calculated to 86.8%. The paper analyzes two case studies of MABR implementation: one treating 25,000 GPD (95 m3/day) of municipal wastewater at US Virgin Islands and the second treating 125 m3/day of concentrated wastewater at Ha-Yogev WWTP in Israel. Energy consumption was measured and averaged over 2 months of operation. The results show the energy consumption for operation of the secondary treatment with MABR amounts to 0.212 kWh/m3 at the first case, while removing 98.9% BOD, 94.8% of NH4, and 96.8% of TSS. In the second case, the energy consumption for operation of the secondary treatment was below 0.4 kWh/m3 for the biological treatment achieving the required removal rates. By consuming very low energy at small treatment capacities, MABR supports the most important principles in water and energy efficiency: reduced energy for treatment and local water reuse.

To date, there is no standardised test available, which assesses the actual performance of a pump for wastewater (especially its clog resistance) as well as providing references about its efficiency. The developed testing procedure presented in this paper can display the different levels of performance for different pumps. The functionality of the pump, together with its efficiency is aggregated to the Function Efficiency Index (FEI). The FEI is thus a holistic parameter to describe a wastewater pump and enables a revaluation of the technologies available on the market.

Native macroalgae were used as an inexpensive and efficient biosorbent. Mercury (Hg), nickel (Ni) and cobalt (Co) were removed from synthetic wastewater. The algal biomass was pretreated with 0.1 HCl, 0.2 HCl, CaCl2 NaOH Na2CO3 and hot water. NaOH pretreatment was most suitable for the removal of Hg. Na2CO3 pretreatment was the best technique for the removal of Ni and Co.

Wastewater pumping plants represent important energy consumers. A real case study in Italy is analyzed. A model-based approach is proposed. Optimization of pumps start/stop number is performed. The approach can be easily extended to different case studies.