Environ. Sci. Proc., 2020, EWaS-4 2020

This paper expands on the results of the technical and economic feasibility analysis of substituting existing pressure reduction valves (PRVs) with pumps used as turbines (PaTs) in two real Italian water distribution networks (WDN), chosen as case studies, aiming at effective energy recovery. Water demand variability makes complex the selection of the right pump to be used as a turbine in a WDN maximizing its annual electric energy yield. Hence, this study describes an effective approach that permits us to identify the most suitable pumps, starting from the definition of the best efficiency points at which they should operate in reverse mode. Full article

Lake Karla (Thessaly, Greece) drainage and morphological alterations affected all water-related ecosystem services (ES). The lake is restored as a multipurpose reservoir, whose inflows are boosted with pumping from Pinios River. The Soil and Water Assessment Tool (SWAT) simulated the watershed’s hydrology and the reservoir’s function, under a climate change scenario to assess water related ES. Official timeseries were used for five different scenarios with simulation period until 2100. The results suggest that the reservoir’s water quality is impacted by summer irrigation and by the water volume from the Pinios during winter. As for the selected ES, in almost all scenarios, they seem negatively affected. Full article

An analysis of a 40-year long wave time series was performed, along the coasts of Italy, in order to identify ongoing trends of two synthetic parameters, significant wave height (H_s) and energy period (T_e), and of the wave power (P). First, wave data were deduced from the global atmospheric reanalysis ERA-INTERIM by the ECMWF and checked to verify their consistency. Then, a trend analysis was performed on mean values evaluated at annual and seasonal scales through the non-parametric Mann–Kendall test for three different significance levels equal to 90%, 95% and 99%. The obtained results could be useful for analyses linked to beach morphodynamics and on the identification of field installations of Wave Energy Converters (WECs). Full article

The selection of an appropriate coastal protection structure using multi-criteria analysis method AHP (analytic hierarchy process) was presented by a case study of a beach reconstruction in the Kostanj Bay (north-western part of Croatia). The newly designed beach (about 300 m long) will be formed on the western part of the bay by the additional filling of the natural rocky coastline with gravel and building reinforced concrete seawalls towards the sea. The beach will be protected by a submerged breakwater. Five different alternatives were analysed and defined by a different design of the protective breakwater. The first alternative, without the submerged breakwater, was considered as the baseline alternative. An additional four alternatives were examined based on four criteria and five sub-criteria, which considered the technical, economic, social and environmental impacts. The sensitivity of the ranking for the considered alternatives was analysed using five criteria importance scenarios. Full article

Hydrological predictive models represent the most recently developed tools in the field of water simulation. In this study, the Soil and Water Assessment Tool (SWAT) model was applied in the Aspio basin in central Italy. After a calibration and validation procedure based on daily streamflow-observed data, the sediment erosion rate from the basin was estimated in the 4 years of simulation. The years of 2016 and 2018 were characterized by a higher amount of transported sediment, which coincided with the run-off peaks events. Regarding the land-use classification, this study shows how the agricultural and artificial areas provide a higher contribution to the transported sediments. This study shows that SWAT can be used for land management in highly urbanized watersheds. Full article

In this work, a gridded database was obtained from a rainfall dataset of 129 monthly series collected for the period 1951–2016 in the Calabria region (southern Italy). The Inverse Distance Weighted (IDW) interpolation method was applied to build 603 rainfall grid series with a spatial resolution of 5 km × 5 km. In order to detect possible trends, for each grid point, the seasonal and annual rainfall series were analyzed with the Mann–Kendall non-parametric test and the Theil–Sen estimator. Results showed a decreasing trend for the annual and winter–autumn rainfall and an increasing trend for the summer one. Full article

Residential water consumption data can be important for sizing and operation rules in a water distribution network (WDN) if well compiled. This study aims to evaluate the impacts of a smart metering program in the city of Brasília, Brazil, by means of comparisons between costs and benefits obtained. Two groups of costs were evaluated: (i) the implementation costs, which were obtained from a public database of the Environmental Sanitation Company of Brasília (Caesb) and (ii) the maintenance costs obtained from both interviews and internal research with Caesb’s water managers. To analyze the benefits of the smart metering system, three factors were observed: (i) the water demand reduction with possible lower consumption patterns, (ii) the increased revenues from more accurate measurements, and (iii) the costs reduction when comparing the visual water meter reading with the smart metering. Furthermore to promote an economic viability analysis, this study examined the project payback time considering costs, benefits and a minimum attractiveness rate. Full article

Leakage in water distribution systems is an important issue and of major interest for water utilities. In this study, the Minimum Night Flow (MNF) method to quantify the amount of water lost and the equations representing the relationship between pressure and leakage in power and FAVAD (Fixed and Variable Area Discharge) forms were applied to a District Metered Area (DMA) located in Gorino Ferrarese (FE, Italy) equipped with smart meters. The analysis carried out by exploiting the collected time series of user water consumption, DMA inflow, and pressure highlighted that: (a) the MNF method can lead to significant inaccuracy in leakage estimation in the presence of users with irregular consumptions, when based on literature values, and (b) the estimation of the parameters of the power and FAVAD equation is highly affected by the number and types of observed data used. Full article

Acanthamoeba spp. are widely distributed in the environment and have been reported to be causative agents of lethal encephalitis and keratitis. In this study, thirty water samples from the Caspian Sea were collected during 2018. Water samples were filtrated and the filtrate used for culture. The positive samples were subjected to Polymerase Chain Reaction (PCR) and nucleotide sequencing. Free-living amoebae were identified in 50% (15/30) of the seawater samples. DNA sequencing revealed the presence of T2 and T4 genotypes. The results of the present study confirmed the presence of potentially pathogenic strains in seawater in this area. This awareness should be raised among environmental and public health professionals. Full article

The role of water in Cryptosporidium transmission is now well recognized. In the present study, 19 water samples were collected from the river contaminated with wastewater in Guilan, Iran. This province lies along the Caspian Sea and has a Mediterranean-like climate. The species of Cryptosporidium were identified by polymerase chain reaction (PCR) assay using two set primers: (CPB-DIAGF/R and N-DIAGF2/R2) and (Xiao F1/R1 and F2/R2). A total of 10/19 water samples were positive for Cryptosporidium species (C. parvum, C. muris and C. hominis). The use of sewage-contaminated river water for the irrigation of agriculture farms is a threat of infection to the local population. Full article

The Dutch drinking water distribution network consists roughly of 25% (around 30,000 km) asbestos cement pipes. This pipe material has a relatively high priority to be renewed and therefore received quite some attention when it comes to the development of condition assessments that help water utility experts to prioritize which of these pipes to replace first. In the presented work, X-ray computed tomography (CT) was used to measure the degradation of the asbestos cement (AC) pipes taken out of the field. The CT scans provide a highly detailed view of the pipe degradation. The insight provided by these images poses several questions with respect to some of the core assumptions of the condition models currently in use. Moreover, the comparison of CT results to those of non-destructive, in-line inspection techniques will provide a new avenue for the validation of these techniques and their usefulness for the Dutch water utilities. Full article

The approach applied in methodology development and application in stakeholder management that contributes to sustainable cross-border drinking water supply and integrated water resources management within the Adriatic region is presented. It was developed through the strategic project Networking for Drinking Water Supply in the Adriatic Region (DRINKADRIA), where eight countries across the Adriatic region contributed in implementation to assess and evaluate the framework for sustainable cross-border drinking water resources management given the constraints and challenges within the project area. The interlinkage among stakeholders’ inputs and pertinent Sustainable Development Goal 6 (SDG6) indicators puts into perspective the added value of stakeholders’ contribution in addressing relevant issues and options for sustainable cross-border drinking water resources management and SDG6 targets reinforcement. Full article

Cryptosporidium species have been detected in fish, in a wide range of geographical regions. Currently, three species are genetically characterized as piscine-host-specific: C. molnari, C. scophthalmi, C. huwi. One potential novel species, 23 additional piscine genotypes, other non-piscine-host-specific Cryptosporidium species (C. parvum, C. hominis, C. scrofarum, C. xiaoi) and the rat genotype III have been genetically characterized in fish. The pathology of cryptosporidiosis is very important for the aquaculture industry, causing mortalities in farmed fish, while the presence of Cryptosporidium zoonotic subtypes in edible fish increases the fish-borne zoonotic potential risk, which is of major importance from a public health point of view. Full article

The concept of Circular Economy, although not entirely new, has in recent years gained traction due to growing concern with regards to the Earth’s natural reserves. In this context, Sewer Mining, a wastewater management method based on extracting wastewater from local sewers for reuse applications, presents an interesting option that lies in the interplay between reuse at a household scale and centralized reuse at a wastewater treatment plant. As part of the EU-funded program NextGenWater, a new unit is being prepared for operation in Athens’s Plant Nursery, in Goudi. This paper examines the water flow within the proposed installation, using the Urban Water Optioneering Tool (UWOT). Further research is focused on the economic viability of Sewer Mining and the proposed investment. The results produced are promising regarding Sewer Mining’s capabilities and benefits, as well as its future prospects, in the hopes that this technology can provide an attractive alternative to conventional water sources within the urban water cycle. Full article

We illustrate recent findings on the upriver propagation of long waves entering the mouth of the Misa River (Senigallia, Italy). Such a microtidal environment has been recently studied to understand river–sea interactions: it has been found that the river forcing dominates over the marine actions in winter, especially during storms. However, upriver wave propagation is not negligible with low-frequency waves propagating upriver for distances of the order of kilometers. With the aim to better understand the behavior of low-frequency waves propagating upriver, the analysis of the present work builds on field data collected by instruments installed close to the mouth and along the final reach of the Misa River: a tide gauge, two hydrometers and an acoustic Doppler sensor. It has been here observed that the tidal forcing (periods of the order of hours/days) is significantly strong at a distance of more than one kilometer from the river mouth, while shorter waves, like seiches (periods of some hours), are less important and are supposed to largely dissipate at the estuary, although their role could be of importance during relatively short events (e.g., floods). Full article

Cross border areas face common challenges on water management, such as monitoring water demands and quality, because they share a common water basin for covering their water needs. This paper presents the first results of a new, accurate, sensitive and functional tool for assessing water quality, taking under consideration legislation and expert’s opinion, created in frame of the SAVE-WATER, Interreg IPA II Cross-border Cooperation Programme Greece-Albania 2014-2020. The project addresses the open problems and challenges by promoting a transnational common strategy for drinking water management and a shared management policy among three Greek and two Albanian cross border regions. Full article

A very important part of water cycle monitoring is observing atmospheric energy balance (AB) which describes an interaction between atmosphere and land. The AB can be computed as a difference between precipitation (P) and evapotranspiration (EV). In this paper, trends and correlations between the groundwater level in an unconfined aquifer from the National Hydrogeological Service database and values of precipitation and evapotranspiration are part of the assimilation models. Based on the research, it is concluded that, groundwater level changes measured in wells are correlated with P and EV values. Full article

A new set of local performance indices has recently been introduced within a mathematical framework specifically designed to promote a local–global analysis of water networks. Successively, some local indices were also set up and implemented on WaterNetGen to better exploit their potential. In this paper, after a very brief overview of tools and main notations, Santarém’s (Portugal) water distribution network (WDN) is examined, applying to it the mentioned set of local indices, as a new real case study. The paper also focuses on the Hypotesis required to assess these indices in a pressure driven analysis (PDA) approach, analyzing and discussing the results obtained from such a simulation. Full article

Measurements of stream discharge, bed load transport rate and suspended sediment concentration in the Nestos River (northeastern Greece) were conducted by the Section of Hydraulic Engineering, of the Civil Engineering Department, Democritus University of Thrace. In addition to those measurements, the total sediment concentration was calculated by means of the formulas of Yang. The comparison between the calculated and measured total sediment concentration was achieved by means of several statistical criteria and the results were deemed satisfactory. Full article

Disaggregation techniques are useful to separate data aggregated into single end-use categories, and they are becoming of great interest in the water sector due to the technological innovation in metering systems that has made water consumption data available. However, in order to apply disaggregation methods, high-resolution data at the end-use level are needed. To face this problem, the paper presents an Internet of Things water end-use monitoring system that is able to read real-time end-use consumption in a residential apartment equipped as a pilot site. Moreover, the paper describes preliminary consideration of the dataset and the potentiality of end-use consumption measures to apply disaggregation techniques and profile users’ behaviors. Full article

One of the most important natural processes responsible for soil loss is rainfall-induced erosion. The calculation of rainfall erosivity, as defined in the Universal Soil Loss Equation, requires the availability of rainfall data, either continuous breakpoint, or pluviograph, with sampling intervals on the order of minutes. Due to the limited temporal coverage and spatial scarcity of such data, worldwide, alternative equations have been developed that utilize coarser rainfall records, in an effort to estimate erosivity equivalently to that calculated using pluviograph data. This paper presents the application of generalized additive models (GAMs) to estimate erosivity utilizing daily rainfall records. As a case study, pluviograph data with a time step of 30 min from the Water District of Thrace in Greece were used. By applying GAMs, it became possible to model the nonlinear relation between daily rainfall, seasonal periodicity, and rainfall erosivity more effectively, in terms of accuracy, than the application of two well-known nonlinear empirical equations, both on a daily and an annual basis. Full article

In this article, an adjustment of the extreme theoretical probability distributions upon the sample is proposed, based on the conventional fuzzy linear regression model of Tanaka [1], where all the data must be included within the produced fuzzy band. This is achieved by using the quintile approach, which relates the observed return period with the theoretical cumulative probability. A new contribution of this work is the use of the fuzzified maximum likelihood, as a measure of goodness of fit. The model is applied for real data from the Strymonas River, regarding the annual maximum flow, and finally, useful conclusions are made. Full article

The present study aims at comparing the two most promising water treatment technologies for selenium removal. A techno‐economical comparison of Se(IV) uptake between the laboratory synthesized iron oxy hydroxide (FeOOH/2.5) with the highest positive surface density of 3.25 mmol [OH⁻]/g and adsorption capacity 4.3 μg Se(IV)/mg FeOOH/2.5 at pH 7, and coagulation/precipitation with the use of Fe(III) presenting an uptake capacity 3.2 μg Se(IV)/mg Fe was attempted based on the laboratory scale results. The evaluation showed that coagulation/precipitation treatment appears to be economically advantageous in comparison to adsorption process that was applied in Rapid Small Scale Column Tests (RSSCTs) with the FeOOH/2.5. It must be pointed out that for selection of the optimum removal method, other criteria should also be considered, such as post treatment requirements, water flow, labor cost, and maintenance requirements. Full article

The present study evaluates micropollutant degradation from water by catalytic ozonation in a pilot scale unit comprising of a hydrophobic membrane for ozone dilution and a column filled with granules of the catalyst. The catalysts examined are alumina, calcite, dolomite, goethite, pearlite, polyethylene terephthalate (PET) and zeolite. Experimental results revealed zeolite as the most effective material achieving complete degradation of benzotriazole and carbamazepine, as well as 70% degradation of atrazine and about 50% of p-chlorobenzoic acid (p-CBA). The rest of the catalysts tested presented a moderate performance in micropollutant removal, reaching 30%–50% for atrazine, 25%–35% for p-CBA, more than 90% for benzotriazole and complete degradation of carbamazepine. Adsorption capacity of all materials examined did not exceed 5%. Full article

Chromium occurs in nature mainly in its trivalent or hexavalent form. Hexavalent chromium Cr(VI) is particularly toxic to humans, animals, and plants. The extensive pollution of groundwaters with Cr(VI) necessitates the complete understanding of natural chromium oxidation and reduction mechanisms, both for assessing the risk of hexavalent chromium formation and for the development of techniques for the reduction and removal of Cr(VI) from contaminated water bodies. In this work, the possibility of hexavalent chromium reduction by discarded or low-cost materials, which contain reducing compounds, is investigated regarding the creation of a compact, pump-and-treat filter for Cr(VI) removal from groundwater. Full article

Catalytic ozonation is an Advanced Oxidation Process (AOPs) based on the production of hydroxyl radicals, which are very reactive oxidative species. The aim of this study is to evaluate the catalytic activity of calcite on the ozonation of four different typical micropollutants (atrazine, benzotriazole, carbamazepine, and p-CBA) at pH 7 and for low initial concentrations (4 μΜ) by performing batch mode experiments. These compounds have different physico-chemical characteristics, as well as different rate constants, when reacting with ozone and hydroxyl radicals (•OH), being in the range of <0.15 − 3 × 10⁵ M⁻¹s⁻¹ and 2.4 − 8.8 × 109 M⁻¹s⁻¹, respectively. It was found that most of these micropollutants can be sufficiently removed by the application of heterogeneous catalytic ozonation, using calcite as the catalyst, except for the case of atrazine, which was the compound that was most difficult to degrade, when compared to the application of single ozonation. Carbamazepine with k_O3 = 3 × 10⁵ M⁻¹s⁻¹ can be easily removed even by single ozonation after the first minute of the reaction time, and the addition of the catalyst eliminated the oxidation/reaction time. The application of catalytic ozonation resulted in 50% and 68.2% higher removals of benzotriazole and p-CBA, respectively, in comparison with single ozonation, even during the first 3 min of the reaction/oxidation time, due to the higher production of hydroxyl radicals, caused by the catalytic ozonation. For the case of atrazine, the addition of calcite did not enhance the micropollutant degradation, and its removal reached 83% after a 30 min application of catalytic ozonation, whereas during the single ozonation, the removal under the same reaction time was 90%. Full article

The purpose of the present work was to study the corrosion protection that relatively low-cost magnesium hydroxide coatings offer to concrete by stabilizing the surface pH. To facilitate the material’s adhesive ability, methyl-cellulose and carboxymethyl-cellulose were used as environmentally friendly additives in three different concentrations, 1, 0.4 and 0.1 wt.% of solids, respectively. The coatings were applied on the surface of concrete blocks, in two different coating thicknesses. A sulfuric acid solution was used to simulate the biologically produced acid in sewer pipes. Sulfuric acid was sprayed on the specimens, while the total amount of acid sprayed was calculated, in order to correspond to a specific reaction’s stoichiometry daily. The surface pH of coated specimens was monitored daily with a surface pH meter. The gypsum production was studied with X-ray diffraction, to evaluate the coatings’ protection. The experimental time period that coatings were consumed was compared with the theoretically consumption time. Full article

The current analysis attempts to quantify the interlinkages between the water, energy and food sectors of California covering the period 2002–2015. The results reveal that 25% (60,696 GWh) of the annual energy consumption is attributed to agriculture, while 75% (174,709 GWh) is used for water supply purposes. The agricultural sector consumes 77% (32,629 m³) of the irrigation water, and the energy sector is vulnerable to water availability fluctuations, because many hydroelectric facilities are connected to its grid. Considering the water scarcity and the uneven geographical distribution of water in the state, its central role in California’s water–energy–food (WEF) Nexus becomes apparent. Full article

To research the reasons for the unsatisfactory hydraulic conditions of the reciprocating baffled flocculation tank, this paper investigates its flow field through PIV (Particle Image Velocimetry) laboratory experiment tests and numerical simulation. Three numerical schemes, the standard model, RNG model and realizable model, are calibrated and validated with the experimental data gained in this study. They are adopted for comparative study of their validity and accuracy for modeling the effect of the hydraulic characteristics of the flow field on flocculation. The best validated model is then applied to explain the reasons for the low flocculation efficiency and is applied to improve the structure of the reciprocating baffled flocculation tank. Full article

In mountain areas, natural hazards, e.g., flooding, snow avalanches, droughts, and landslides are triggered by climate change, anthropization, and economic development. Nature-Based Solutions (NBSs) are attracting increasing interest as they are able to couple technical solutions against natural hazards with ecological and socio-economic resilience. On this matter, the four-year H2020 Innovation Action “PHUSICOS—According to Nature” (Grant Agreement nr. 776681) project aims to assess the effectiveness of NBSs and hybrid solutions to hinder hydro-meteorological events in rural and mountainous areas in Europe. Among the ongoing activities within the project, a multi-criteria tool was implemented to assess the effectiveness of NBSs measures from the technical, environmental, and socio-economic perspectives. In this work, the preliminary application of the assessment tool to the Isar River (DE) PHUSICOS concept case is discussed, with reference to an ex-post analysis of the flood risk management plan, comparing the performances of the implemented NBS project scenario against a potential grey solution. Full article

The production of water in a drinking water supply system (WSS) comprises all drinking water enter in the net, while the consumption of water generally comprises all billed amounts of water in a WSS. The production and consumption of water in a drinking WSS depend on different factors. Consumption rates depend on the consumer structure and habits, industrial demand, time of year, water pricing, climatic variables, secondary water losses and many other factors. One of the interesting factors is air temperature. It is especially important in the frame of climate change and global warming. Temperature impact on water consumption in a WSS is not uniform temporally (particularly throughout the year) and spatially (different climate regions and countries, different habits and different conditions in each WSS). Obtained correlations for the two biggest cities in Serbia (Belgrade and Niš) are presented in the paper and compared with some examples worldwide. Full article

Water distribution networks are expected to fulfill the water demand by all consumers and at all times, even during critical scenarios, such as pipe failures. In this work, a methodology is proposed to maximize the quality of service during pipe failures by operating valves. The selection of the valves to operate is done by solving an optimization problem using Gondwana, a generic optimization tool for drinking water distribution networks. Different objective functions and different failure scenarios are investigated, considering a real-life water distribution network. The analysis is performed considering the peak demand condition. The proposed methodology is useful for water companies in managing the operation of their networks during critical scenarios. Full article

The operational management of tanks for urban water distribution networks is usually a critical element due to the dynamic nature of the water demand and the age of the distribution networks themselves. Today, in a context of water resource scarcity, optimal management is a key point for the sustainable management of urban systems. For this purpose, it is useful to implement predictive tools, able to provide short-term forecasts to inform urban water managers on the most suitable procedure to be applied in the case of routine or critical events. A possible approach is to use autoregressive integrated moving average (ARIMA) models, which combine the autoregression and the moving average approaches, with the possibility to work on a differenced series of the data. They can further embed a seasonal- component (Seasonal ARIMA models), to account for possible periodic patterns in the observed data. In this study, the data of water levels measured from May 2018 to 10 January 2019 in a water storage tank in the area of Benevento, Campania region (Italy), were considered as a case study. The standard ARIMA techniques were applied to find the best model for this dataset, according to “Deviance Information Criterion” (DIC) and “Bayesian Information Criterion” (BIC) optimization. The results are discussed, shedding light on the behaviour of the time series with reference to the management of the infrastructure and the dataset. The residual analysis, carried out to check if the autocorrelation was still present and if the residuals were normally distributed, revealed a narrow distribution. Small values were found throughout the dataset, except for a few periods, corresponding to the imputed data. This application represents a preliminary step of more detailed research that will be carried out to detect the best model for forecasting tank levels for the case study to help to manage the urban water supply. Full article

Soil contamination is an issue of paramount importance to assess human health (HHRA) as well as ecological (ERA) risk assessment. To analyze risk scenarios related to contaminated soils, the identification of sources, either of primary or secondary type, as well as the assessment of propagation and fate processes is needed. Although many studies refer to the transport of pollutants in fully saturated porous media, little efforts have been made concerning the case of partially saturated soils so far. The matter is of interest as the contamination in the fully saturated region may take place as a result of the percolation in the vadose zone. Governing equations ruling fate and transport processes in partially saturated soils are here solved numerically by means of a finite element method approach. Richards equations are adopted to describe flow dynamics through the hydraulic conductivity coefficient K_s, while contaminant fate is mainly described by the sorption coefficient K_p. As for the boundary conditions, we consider a local and continuous spill of contaminant at the upper ground of variable thickness. Precipitations are given as step functions whose intensity is derived by considering pluviometric data at the station of Gròmola, Campania Region, Italy. Benzene and tetrachloroethylene (PCE) are taken into account. A comparative analysis is carried out for permeability K_s and distribution K_d coefficients in the range [10⁻⁶, 10⁻⁴] m/s and [10⁻⁵, 10⁻³] m³/kg. Results are then compared and discussed. Full article

Flood caused by a dam-breaking flow may be catastrophic for the downstream area due to the sudden discharge of large volumes of water. Besides the complex flow of the propagating dam-break wave, the presence of structures such as bridges and buildings yield free surfaces which can be accurately reproduced by means of three-dimensional Computational Fluid Dynamics (CFD) software. The prediction of the dam-break flow main features in the presence of obstacles has a crucial role in decreasing the damage. In this study, small-scale laboratory experiments were conducted to examine the problem with a single obstacle. Five ultrasonic sensors were used as measurement devices. Measurements were compared with the numerical results obtained with the FLOW-3D software, solving RANS equations with the k- turbulence closure model. A good agreement was observed. Full article

Wastewater treatment, as a crucial component of the urban water environment, consists of several energy-consumptive stages, therefore efficiency and energy savings measures are essential to maintain them as environmentally sustainable and economically viable. Operational and technical data from WWTPs in Greece have been collected as well as a sample from 61 facilities with key energy profile components. Energy consumption was assessed by specific key performance indicators (KPIs); specific energy consumption expressed per population equivalent (from 3 to 150 kWh/PE), per cubic meter treated (from 0.2 to 2.0 kWh/m³) and per unit of organic load removed (from 0.03 to 7.13 kWh/COD_removed). Full article

The drinking water supply of the city of Nikšić, the second largest city in the Republic of Montenegro, is secured from a nearby karstic groundwater resources. Water is transported from two different directions (two sources) into the distribution system. At the end of the distribution system, on the opposite side of water resources, there is a counter tank, as the only storage capacity for leveling the inflow and consumption in the system. However, the interplay of the three vital water supply capacities (two water sources and counter tank) does not meet the requirements of regular supply, to the point where it is necessary to disconnect the tank, from regular operation. The existing system, which operates without leveling space, is fraught with numerous problems, ranging from the appearance of significant temporal and spatial pressure variations, to the inability of delivering the needed quantities to the peripheral parts of the system, in seasonal peaks of consumption. During International project Drinkadria (2013–2016), efforts for solving numerated problems were done. This paper provides an overview of activities on system operation analysis, based on simulation modeling and definition of technical solution, proposed in the form of subzoning. Realization of proposed subzones will put all capacities in the full operation state, with the realization of stable pressures in the system, and with a regular supply of all parts of the system in all predictable modes of consumption. Full article

Extreme weather conditions, attributed to climate change, include the increase in floods. The only available and appropriate response to the impacts of climate change already shown is adaptation. Adaptation is defined as the process of adjusting to climate change by taking appropriate action to prevent or minimize the damage it may cause. Within this framework, the EU 2007/60/EC Floods Directive foresees that the member states shall undertake preliminary flood risk assessments, taking into account inter alia the impacts of climate change on the occurrence of floods. The present paper aims at the identification of the existing legislative gaps in the Floods Directive taking into consideration the adaptation need regarding climate change. Full article

Membrane fouling still remains a drawback for membrane bioreactors; there is nevertheless a natural promising solution which is the growth of filamentous microorganisms in moderate concentrations. In this project, an innovative 25 L membrane bioreactor is used, consisting of two aerated tanks and a membrane tank. The first tank is supplied with high Food/Microorganism (F/M) loading and the second tank with very low loading. The aerated tanks were constantly provided with dissolved oxygen (DO) 2.5 ± 0.5 mg/L. Finally, it is concluded that the imposed aeration conditions contribute to the growth and control of filaments in moderate concentrations having a filamentous index = 2 and therefore reducing membrane fouling for more than 1.5 months, maintaining the trans-membrane pressure at 1.4 ± 0.11 kPa. Full article

This paper presents a practical application of a sensitivity matrix-based methodology for determining optimal pressure sensor locations for leak detection in a water distribution network (WDN). The optimization is formulated as multi-objective, exploring the tradeoff between the minimization of the number of sensors to be installed and the maximization of the detection coverage. The methodology is applied to a real-life WDN serving the area of Seppe in the Netherlands. Close collaboration with the water utility enabled us to explore alternative designs, fine-tune the optimization problem and obtain results that are ready for practical implementation. Full article

Water leakages are one of the most significant uncertainties affecting water supply system (WSSs) modelling. Due to the dependence between water losses and pressure, the WSSs characterised by high values of pressure in the distribution network are strongly affected by this problem. High-pressure conditions are typical of WSSs in the mountain areas. In this study, a real WSS of the Alpine region is analysed through simultaneous calibration of water losses and pressure-reducing valves with a genetic algorithm. The demand is represented by a uniformly distributed along the network pipes scheme, dealing with the water request separately from the losses. Full article

The use of zeolite-rich tuffs is a valid method for recovering nitrogen from wastewaters. This paper aims at describing the NH₄⁺ adsorption processes of an Italian chabazite zeolite tuff used for the treatment of raw liquid swine manure. The effects of temperature, grain size and contact time were investigated. The isothermal analysis showed a multilayer adsorption behavior, well explained by the Harkins–Jura model, while kinetics was explained by pseudo-second-order, Elovich and intraparticle diffusion models. This study highlighted the complexity of the adsorption process from raw liquid manure, as well as the significant differences between tested particle sizes of the same zeolite tuff. Full article

Private cisterns or underground tanks may be at risk for certain types of contamination associated with adverse health effects. This first and preliminary study evaluated the parasitological quality of drinking water stored in home-based cisterns in rural areas in seven delegations of the Kairouan Governorate in the center of Tunisia. The practices of water management and hygiene were also surveyed in addition to details related to the age and the kind of material used to make these home-based tanks. To achieve this purpose, 39 samples from five different sources—(i) rain water, (ii) truck cisterns, (iii) a mix of these two, (iv) wells, and (v) stored tap water—were collected and examined for the presence of parasites using the Bailenger modified technique. Microscopic/morphological analysis showed the presence of three gastrointestinal protozoa: Giardia duodenalis (10–380 cysts/L), Entamoeba histolytica/dispar/moshkovskii (30–400 cysts/L), and Entamoeba coli (20–200 cysts/L). These protozoa were prevalent in all the five water sources examined. One species of helminths was also detected (Ascaris spp.). The high concentrations of the protozoa cysts found could be correlated with the lack of hygiene, sanitation practices, and education. No statistical correlations were demonstrated with the age or kind of water. Thus, the current situation highlights the need for the frequent monitoring of water microbiological quality in these rural areas. Further studies are needed to determine the true prevalence and pathogenic potential of these and other pathogenic species. Full article

Cryptosporidium is an intracellular protozoan parasite and is increasingly gaining attention as a human and an animal pathogen, mainly due to its predominant involvement in worldwide waterborne outbreaks. This paper reviews the current knowledge and understanding of Cryptosporidium spp. in terrestrial and aquatic animals in Azerbaijan. The diagnosis of cryptosporidiosis relies on the identification of oocysts in faecal samples released by the infected host. Stool specimens were processed using the modified acid-fast staining method (Ziehl-Neelsen) and microscopically examined for Cryptosporidium oocysts. Thirteen species of Cryptosporidium (C. fragile, C. ducismarci, C. serpentis, C. varani, C. baileyi, C. meleagridis, C. muris, C. parvum, C. ubiquitum, C. andersoni, C. bovis, C. hominis, C. suis) from amphibians, reptiles, birds and mammals have been identified as a result of studies conducted between 1987 and 2019 on the structural features of Cryptosporidium oocysts in Azerbaijan territory. Full article

In the context of this paper, the term “price of water” refers to the charges for drinking water supply and sewage services. The current price of water in Serbia is generally set at an affordable level and does not reflect the real costs. It varies from approximately 0.4 €/m³ in smaller settlements of less developed regions of the country, to approximately 1.0 €/m³ in some cities of more developed regions. Lower prices in some cases are the result of fact that these settlements do not provide sewage services (SS). The average price of water in the country is currently about 0.7 €/m³. This paper presents the current and economic price of water in Serbia, and its structure, from a sample of 34 public utility companies (PUC), which perform water supply (WSS) and sewerage services (SS). Full article

The study of the water–energy–food (WEF) nexus has received increasing attention by the science community and related stakeholders on a worldwide scale, focusing on how these three elements can interact sustainably. Even though many research papers, indices and tools have been recorded, the understanding of interconnection among the elements of the WEF nexus still remains elusive. The aim of this research is to investigate the progress that has been made in the development of methods and tools studying the interconnection between the three resources, namely, water, energy and food. A concise and focused review is carried out, highlighting the parameters and the key stakeholders as evidenced by various approaches. In addition to the optimisation methods and tools that have already been applied in specific problems, special focus is also given to the indicators used in reference to their spatial and temporal dimensions. Full article

Water network partitioning (WNP) represents an efficient strategy to improve management of water distribution networks, reduce water losses and monitor water quality. It consists in physically dividing of a water distribution network (WDN) into districted metered areas (DMAs) through the placement of flow meters and isolation valves on boundary pipes between DMAs. In this paper, a novel methodology for designing DMAs is proposed that provides districts with quite similar node elevations and minimizes the number of boundary pipes in order to simplify pressure management and reduce the number of devices to place into the network. Full article

EPANET uses a demand-driven approach to compute pressures and flows in the water distribution system. The demand-driven approach (DDA) assumes that the required demand is always fully satisfied no matter the existing pressure. In scenarios of pressure-deficient conditions the DDA results are not accurate, and a pressure-driven approach (PDA) is needed. Frequently, the PDA is accomplished by using equations that compute the available demand/leakage as a function of the current pressure. However, embedding such equations into the solver introduces convergence problems. This paper details the actions taken in WaterNetGen—an EPANET extension—to bring numerical stability to the pressure-driven solver, namely, by smoothing the pressure–demand/leakage relationship and the pump curve. Full article

A new shape for the external surface of the Crossflow turbine blades is proposed, which allows for the preservation of hydraulic efficiency in spite of a significant maximum blade thickness providing mechanic robustness and reliability. The final shape of the blades is assessed using an iterative solution for two uncoupled models: a 2D computational fluid dynamic (CFD) and a structural 3D finite element method (FEM) analysis of a single blade. Application of the proposed methodology to the design of a power recovery system (PRS) turbine, a new backpressure Crossflow-type inline turbine for pressure regulation, and energy production in a real Sicilian site follows. Full article

In Skiathos Island the water is not potable due to mercury contamination and salinization. The mercury’s origin is natural due to the existence of cinnabar in the Skiathos aquifer as a mineral in the Earth’s crust. The possibility of mercury contaminants ending up in the coastal area was investigated through a field experiment. Mussels (Mytilus galloprovincialis) were employed as mercury monitoring biomarkers at the outflow of the wastewater treatment of the island. Using the RNA:DNA ratio, it was revealed that the organisms were stressed after three months of exposure to Skiathos’ coastal waters. The mercury concentration was directly measured at the bulk mussels’ tissue showing differences between the station located at the outflow of the WWT and the reference station. Although the results may imply mercury contamination in the coastal area of the island, the precise origin of the mercury in mussels is difficult to define. Full article

Water distribution networks suffer from high levels of water losses due to leaks and breaks, mainly due to high operating pressure. One of the most well-known methods to reduce water losses is pressure management. However, when the operating pressure in a water distribution network reduces, the time the water stays within the network (called water age) increases. Increased water age means deteriorated water quality. In this paper, water pressure in relation to water age is addressed in a water distribution network in Greece. Using simulation and optimization tools, the optimum solution is found to reduce water age and operating pressure at the same time. In addition, District Metered Areas are formed and water age is optimized. Full article

The aim of the research is the re-assessment of the flood risk when the sensitivity criteria used to evaluate the vulnerability are enhanced with adaptive-recovery capacity criteria and the exposure. Hence, in the proposed methodology, the vulnerability to flooding is addressed as a synthesis between the adaptive-recovery capacity, the exposure, and the sensitivity. To do so, a multicriteria ranking is proposed. The multicriteria ranking is based on the fuzziness in order to interpret the multicriteria synthesis of the widely-used multicriteria technique for order preference by similarity to ideal solution (TOPSIS) method. The case study areas are the Greek parts of the Nestos and Strymonas transboundary river basins. Full article

A drinking water supply system is an extraordinarily complex system—consisting of kilometers of pipes and various tanks, valves, pumps, and other equipment. This complexity makes it extremely vulnerable to physical, chemical, and/or biological hazards. Therefore, the vulnerability assessment of a drinking water supply system to identify the critical control points is absolutely necessary. This paper assesses the vulnerability of the drinking water supply systems. The assessment is elaborated in systems using water from surface water bodies and groundwater bodies. The critical control points are identified using a risk assessment methodology (identifying the probability of the hazard occurrence and its effect or severity) where the monitoring parameters, and the corrective actions are determined. Full article

The Athens Water in the Circular Economy demo case examines all three of the following as associated with Circular Economy (CE) in wastewater streams: water, energy and materials. The application area is the Athens Urban Tree Nursery, which is located in the center of Athens, in order to address real world problems in water-scarce cities. The Athens demo application includes sewer mining, a technology first pioneered in Australia related to mobile wastewater treatment units in containers that are able to treat and provide reused water at the point of demand in dense urban environments. The installed pilot unit consists of a membrane bioreactor unit (MBR) and a UV disinfection unit. The sewer mining is achieved with a prefabricated pumping statiοn that will be demonstrated in the main sewer network for feeding the sewer mining unit with wastewater. The unit will produce fresh water that will be used for irrigation needs, and also during the winter for aquifer discharge. The Athens Tree nursery also has significant amounts of pruning materials that, until now, have remained untapped resources. The excess sludge produced from the unit along with the green and wood waste will go through a rapid composting process in order to produce fertilizer. The first stage will be a pre-treatment unit that includes the shredding, homogenizing and sorting of the pruning materials. The second stage is rapid composting that will last approximately 2 weeks. The last stage is the compost that will be used again on-site as a fertilizer full of nutrients as part of a renewable energy solution for the area to support more complete autonomy. Full article

Although disinfection is a crucial process for the safety of drinking water, it is responsible for the formation of disinfection by-products (DBPs) being accused of severe health problems. The present study presents the development of models predicting trihalomethanes (THMs) in a drinking water supply system in Greece. Although some of the developed models can be used for the prediction of THMs, they are site-specific and cannot be used extensively. Full article

The experimental study of vegetated walls and their effects on humidity, air temperature and CO₂is essential. This paper presents an experiment on a green wall to apprehend its thermal and hydrological behavior and its impact inside the building. The experiment is based on a living wall set up in a classroom. Monitoring of temperature, humidity and CO₂ variations within the living wall and a reference case enabled us to analyze the effects of green walls. Measurements were performed in Košice, a city in Slovakia. During the measurements, a set of questions were answered. The data from the respondents were used to achievethe goal of this interdisciplinary research, which was to identify the effect of green walls on the well-being of people. It can be stated that women are more sensitive to changes than men. Following the measurements, it can be stated that the green wall is very favorable for indoor environments. The optimum relative air humidity in rooms such as classrooms, hotels and theaters is from 30% to 70%. From a relative humidity perspective, green walls appear to be beneficial for indoor buildings. Full article

Water distribution networks are low-energy efficiency systems, due to the high energy consumption, as well as the large amount of water leakage, which are caused by high pressures in the networks. In this study, the optimal location of pumps as turbines (PATs) within a water distribution network is investigated in order to maximize the production of energy and water savings, as well as minimize installation costs. A literature mathematical model has been employed as reference model and the weaknesses of this previous study have been overcome by new constraints. The main preliminary results of the new optimization procedure will be presented and compared with the literature results. According to the results, the new optimization ensures a good solution, in term of water and energy savings, with low investment cost and a fast return in investment. Full article

In this work, the optimal regulation of variable speed pump (VSP) was solved by means of two optimization algorithms: a mixed-integer optimizer based on the BONMIN (Basic Open-Source Nonlinear Mixed Integer Programming) package, and an original hybrid genetic algorithm (GA) called GA–Powell’s direction set method (PDSM), which employs a derivative free inner optimizer, that is, the Powell’s direction set method (PDSM). The obtained results show how the use of a strategy based on the optimal regulation of VSP allows to obtain huge energy cost savings. The analysis of the results shows that the regulation of the plant does not apparently follow a general rule. Full article

Leakage in water distribution networks (WDN) is still a major concern for water companies. In recent years, the scientific community has dedicated some effort to the leakage calibration issue to obtain accurate models. But leakage modelling implies the use of a pressure-driven approach as well as specific data to define the pressure/leakage relationship. This paper presents the calibration process of a real case study WDN model. The process started with pressure step tests, the model was built in WaterNetGen and the leakage calibration process was performed by a simulated annealing algorithm. As illustrated, after calibration the model was able to produce accurate results. Full article

The EPANET 2.0 is a public domain software used to model water distribution networks. The last main release dates to 2000. Recently, the Open Source EPANET Initiative has fixed some bugs and has brought new features to the EPANET solver, such as improved convergence or pressure-driven simulation, and has released it under a new version: EPANET 2.2. Although the legacy Graphical User Interface (GUI) still works with the updated Dynamic Link Library (DLL) (backward compatibility), it does not access the new features. This paper proposes and explores a GUI extension that takes advantage of the new pressure-driven features (such as pressure deficit or demand deficit). The paper also discusses some implementation aspects of the new solver that should be revisited in future releases. Full article

Infections caused by parasites affect millions of people around the world and cause human death worldwide. Most of the protozoan exists as free-living species in different aquatic environments as well as some of the species living in association with host organisms and can infect the host. The aim of this narrative review is to provide an overview of the available information concerning infectious parasitic diseases in Cyprus. Data on protozoan parasitic infections/carriage prevalence in Cyprus is limited, possibly due to the unknown levels of pathogens contamination in the water supplies and in the ecosystem, which could relate to tourism on the island—a major pillar in the Cypriot economy. Tourists and immigrants represent a melting pot of many human activities that brings many people from all over the world together and potentially serves as a source for contamination that can cause endemic infectious diseases on the island. Full article

Marathon Lake is an artificial reservoir with great environmental, ecological, social, and economic significance because it was the main source of water for Athens, the capital of Greece, for many years. The present study details the first attempt to map sedimentation in Marathon Lake in detail, using bathymetric mapping and soil erosion field surveying of the torrent watershed areas. First, the results of a bathymetric survey carried out in 2011 were compared with topographic maps that pre-date the construction of the dam. Based on this comparison, an estimated 8.34 hm³ of sediment have been deposited in the 80 years since the dam’s construction. In the current survey, the Revised Universal Soil Loss Equation (RUSLE) was used to estimate soil loss in the watershed area of the streams that end in Marathon Lake. The estimated value from the RUSLE was substantially lower (3.02 hm³) than that calculated in the bathymetric survey. Full article

In this study, lock-exchange experiments in a tank of rectangular upper cross section and a lower valley of trapezoidal shape are performed. This is a realistic model of the valleys, which occur in nature. The experiments are performed for equal depths of heavy and light fluid on both sides of the lock gate. Density difference between salt water and clear water is varied between 0.5% and 0.9%. This density difference exists in liquid waste whose spreading is an environmental problem. The release of pollutants into rivers, oil spills in the ocean and the outflow of desalinations plants are examples of man-made gravity currents that cause negative environmental impacts. The aim of this study is to contribute to a better understanding of the propagation and process of mixing of a gravity current with large density difference with water. The movement of the gravity current is monitored with a digital video of high definition, the front velocity is measured and the height of the front is captured. Twenty experiments were performed, ten inside the trapezoidal section (H = 5 or 10 cm) and ten over the trapezoidal section (H = 17.5 or 25 cm). Results are compared with those of gravity currents in lock-exchange experiments, which were performed by other researchers. Full article

Effective mixing between contaminated water and nanoparticles is of great importance in various purification applications of microfluidics, especially when heavy metals are involved. Electromagnetic and shear mixing is combined here to explore optimization mixing strategies. A contaminated water stream is confined between two fresh-water streams loaded with nanoparticles and their mixing is studied numerically. The magnetic mixing is superimposed here with a time-modulated gradient external magnetic field. Results show that as velocity ratio increases, mixing between the heavy metals and nanoparticles grows more efficient, mainly due to increased shear, however, magnetic field action is catalytic to homogenise the mixture as water streams move away from the inlets. The present findings may shorten the path to purifying water and reduce its shortage. Full article

Drinking water distribution networks are among the most resilient infrastructure systems to disasters, specifically hazards such as accidental pollution, floods, droughts, earthquakes, and pandemics. Water operators experiencing these kinds of hazards should focus on the establishment of more effective response systems. The paper presents the outputs and results of improving response time and effectiveness of the capacity developed by national, bilateral, and EU Civil Protection mechanisms. The methodology used for the hazard risk assessment procedures and the analysis of the Water Safety Plans (WSPs) lead to improved preparedness mechanisms. The results showed that water use efficiency is a key component in resiliency. Full article

The change of the hydrologic cycle is one of the biggest concerns related to global warming effects. Larger intensities of rainfall events greater in magnitude are foreseen in the coming years, strongly affecting Waste Water Networks (WWNs), leading to higher flowing rates and reaching the limit of the hydrologic cycle’s capacity or even exceeding it. In this field, the proper modeling of a WWN is a useful and economical approach to detect the networks’ critical issues. This work presents a procedure to model a WWN, including different infrastructures and controls and testing different conditions using the EPA-SWMM 5.1 hydraulic solver. The proposed method was applied to a simplified WWN located in Asturias Region (Spain). Full article

Chios Island undergoes scarcity of freshwater, forcing local authorities to establish a sea-water desalination plant to cope with island’s water needs. Karyes village is plentiful with freshwater springs, augmented every year by the rainfall occurring over this particular district, supplying, in turn, some high-quality freshwater obtaining spots into the capital of Chios, thus establishing an important freshwater origin of the entire Chios Island itself. The present study administers the Box–Jenkins method, utilizing SARIMA (Seasonal Autorregressive Integrated Moving Average) model to achieve short term predictions of monthly rainfall in Karyes village, modeling past rainfall time series and forecasting future ones. The model which best fits to both interpretations of the past rainfall data is selected, assessed by several statistical model evaluation criteria. Full article

Acoustic survey methods have been used in recent years in Greece due to rapid growth of technology for leakage detection in water distribution networks. The application of the latest methodologies and technologies allowed water authorities to improve the efficiency of their water supply networks. Thessaloniki’s water distribution network is an aging and inefficient one so the use of these methods in the last fifteen years has considerably improved the utility’s capability to reduce the losses of drinking water. The use of acoustic loggers on network fittings that record leakage noise in fixed time steps has a considerable effect in Thessaloniki’s water distribution network, which is characterized by a high level of complexity. A major challenge facing Thessaloniki Water Supply and Sewerage CO S.A. (EYATH S.A.) is how to deal with high levels of water loss, and acoustic survey methods are now seen as having an increasingly wide range of benefits, not only including environmental and water conservation benefits of reducing leak flow rate but also improving its performance in water loss management. The paper presents the implementation of the acoustic survey method for leakage detection and reduction in various field areas of Thessaloniki and the interconnected municipalities. Key parameters have been taken included, such as the complexity of water distribution network, the reliability of available mapping, the established zones with respective flow metering, and the existence of high background noise. Results are analyzed in order to examine the efficiency of the acoustic logging technology. Full article

Only a few scientific research studies referencing extremely low flow conditions have been conducted in Greece so far. Forecasting future low stream flow rate values is a crucial and decisive task when conducting drought and watershed management plans by designing construction plans dealing with water reservoirs and general hydraulic works capacity, by calculating hydrological and drought low flow indices, and by separating groundwater base flow and storm flow of storm hydrographs, etc. The Artificial Neural Network modeling simulation method generates artificial time series of simulated values of a random (hydrological in this specific case) variable. The present study produces artificial low stream flow time series of part of 2015. We compiled an Artificial Neural Network to simulate low stream flow rate data, acquired at a certain location of the entirely regulated, urban stream, which crosses the roads junction formed by Iokastis road and an Chrisostomou Smirnis road, Agios Loukas residential area, Kavala city, Eastern Macedonia & Thrace Prefecture, NE Greece, during part of July, August, and part of September 2015, until 12 September 2015, using a 3-inches conventional portable Parshall flume. The observed data were plotted against the predicted one and the results were demonstrated through interactive tables by providing us the ability to effectively evaluate the ANN model simulation procedure performance. Finally, we plotted the recorded against the simulated low stream flow rate data by compiling a log-log scale chart, which provides a better visualization of the discrepancy ratio statistical performance metrics and calculated further statistic values featuring the comparison between the recorded and the forecasted low stream flow rate data. Full article

The project CLIM2POWER aims at developing a climate service including state-of-the art seasonal climate forecasts in the planning of the operation of the power systems. This work presents part of the project, addressing the forecasting of the hydropower generation in a case study area, the Portuguese part of the transboundary Douro River basin. Rainfall-runoff modelling was performed on a daily scale using three ensemble members of seasonal climate data (six months) for Portuguese territory crossed with three daily inflow scenarios from Spanish territory defined according to historical observed data. The obtained results reflect the fact that seasonal climate forecast present a wide variation of scenarios and also the fact that hydropower production in Portuguese territory is highly dependent on transboundary inflows. On the other hand, the implemented approach successfully produced consistent runoff and hydropower production results although improvements on the identification of the most probable scenarios are yet required. Full article