Comparison between hydraulic and hydrologic computational methods is conducted in this study, regarding prismatic open channels under unsteady subcritical flow conditions. One-dimensional unsteady flow continuity and momentum equations are solved using explicit and implicit finite difference schemes for a symmetrical trapezoidal cross section, where the flow discharge and depth are the dependent variables. The results have been compared to those derived from Muskingum-Cunge hydraulic/hydrologic method as well as the commercial software HEC-RAS. The results from explicit and implicit code compare well to those from commercial software and hydraulic/hydrologic methods for long prismatic channels, thus directing the hydraulic engineer to quick preliminary design of prismatic open channels for unsteady flow with satisfactory accuracy. Full article

A mathematical model has been employed to determine the characteristics of Boussinesq round buoyant jets which are injected horizontally or at an angle to horizontal, into a homogeneous, calm ambient. The solution of a system of three conservation first order nonlinear differential equations was obtained with a 4th Runge-Kutta scheme, using an entrainment coefficient which is related to the local Richardson number of the flow. Two types of positively and negatively buoyant jets were investigated (i) those where the buoyancy is a function of salinity henceforth called saline jets, and (ii) those where the buoyancy is a function of the temperature difference between jet and ambient fluid, henceforth called thermal jets. Full article

This study presents the results of laboratory experiments that were performed to simulate the positions of mussel shocks which were selected aiming at the optimization of the quality of mussels’ production in mussel farming areas. The mussel shocks were studied in natural scale. Velocity measurements were taken upstream of two successive mussel shocks and for different positions in relation to the central axis of the channel and different distances between the shocks for three different mean velocities. Based on the results of several numbers of experiments, the main conclusion of this study was that the position and the distance between the mussel shocks play a significant role to the quality of mussels’ production in mussel farming areas. This is due to the fact that the different distances between the mussel shocks influence the velocities and the eddies around them. Full article

Long straight seawalls along the coastal front are quite common, especially in cases of coastal cities. In this study in the middle of a coastal zone, a harbor basin in the form of an orthogonal area recessed to the waterfront is considered. A mole of variable length and position offers protection from waves. The renewal time of the waters and the self-purification capacity of the harbor under the influence of alongshore coastal currents of different intensity were examined. The effect of technical partial closing of the harbor’s entrance to the water renewal rate is examined in the present research. More specifically, the study was based on the use of a two dimensional, depth averaged hydrodynamic model which describes the water circulation along the coastal zone. For the solution of the equations of mass and momentum conservation, the method of finite differences was used. The adjustment and the validation of the reliability of the numerical model at a laboratory level were conducted in a recent research based on the use of PIV measurements which ensured a very good agreement between numerical and experimental results. Full article

Grey, blue and green infrastructure supports socio-ecological processes the city undergoes. Yet, procedures of constructing anthropogenic habitats often undermine the value of natural landscape elements such as urban streams. Thessaloniki’s backbone comprises of urban streams that run from the suburban forest of ‘Seih-Sou’ to the Thermaikos Gulf acting as corridors of the natural urban matrix. Policies of the past have dealt with urban streams through extensive engineering drainage methods, eliminating the risk of flooding, yet resulting in rapid stormwater runoff, water quality problems, disturbed riparian ecosystems, leading to the urban stream syndrome. Furthermore, they have failed to address urban streams as an inseparable part of the landscape and thus to incorporate them in people’s mental map and everyday activities. The paper discusses the case of ‘Polygnotou stream’ which forms the beginning of the large scale engineered peripheral moat of Thessaloniki, constructed in the 60’s, and playing the role of the water recipient for six urban streams in total. It falls unknown to the majority of people living in the area, yet its services as an ecosystem ought to be acknowledged, helping inform decision makers of its socio-ecologic, perceptual and economic value. In addition, Polygnotou stream, adjacent streams and the peripheral moat overall, could be considered as a touristic product of great importance. Full article

A possible solution for water purification from heavy metals is to capture them by using nanoparticles in microfluidic ducts. In this technique, heavy metal capture is achieved by effectively mixing two streams, a nanoparticle solution and the contaminated water. In the present work, particles and water mixing is numerically studied for various inlet velocity ratios and inflow angles of the two streams. The Navier-Stokes equations are solved for the water flow while the discrete motion of particles is evaluated by a Lagrangian method. Results showed that as the velocity ratio between the inlet streams increases, by increasing the particles solution flow, the mixing of particles with the contaminated water is increased. Thus, nanoparticles are more uniformly distributed in the duct. On the other hand, angle increase between the inflow streams ducts is found to be less significant. Full article

Only a few scientific research studies with reference to extremely low stream flow conditions, have been conducted in Greece, so far. Forecasting future low stream flow rate values is a crucial and desicive task when conducting drought and watershed management plans, designing water reservoirs and general hydraulic works capacity, calculating hydrological and drought low flow indices, separating groundwater base flow and storm flow of storm hydrographs etc. 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 both a part of the past year (2016) as well as the present year (2017) considering the stream flow data observed during two different respecting interval period of the years 2016 and 2017. We compiled an Artificial Neural Network to simulate low stream flow rate data, acquired at a certain location of the partly regulated semi-urban stream which runs through the eastern exit of Kavala city, NE Greece, using a 3-inches U.S.G.S. modified portable Parshall flume, a 3-inches conventional portable Parshall flume, a 3-inches portable Montana (short Parshall) flume and a 90° V-notched triangular shaped sharp crested portable weir plate. The observed data were plotted against the predicted one and the results were demonstrated through interactive tables providing us the ability to effectively evaluate the ANN model simulation procedure performance. Finally, we plot the recorded against the simulated low stream flow rate data, compiling a log-log scale chart which provides a better visualization of the discrepancy ratio statistical performance metrics and calculate the derived model statistics featuring the comparison between the recorded and the forecasted low stream flow rate data. Full article

Only a few scientific research studies, especially dealing with extremely low flow conditions, have been compiled so far, in Greece. The present study, aiming to contribute in this specific area of hydrologic investigation, generates synthetic low stream flow time series of an entire calendar year considering the stream flow data recorded during a center interval period of the year 2015. We examined the goodness of fit tests of eleven theoretical probability distributions to daily low stream flow data acquired at a certain location of the absolutely channelized urban stream which crosses the roads junction formed by Iokastis road an Chrisostomou Smirnis road, Agios Loukas residential area, Kavala city, NE Greece, using a 3-inches conventional portable Parshall flume and calculated the corresponding probability distributions parameters. The Kolmogorov-Smirnov, Anderson-Darling and Chi-Squared, GOF tests were employed to show how well the probability distributions fitted the recorded data and the results were demonstrated through interactive tables providing us the ability to effectively decide which model best fits the observed data. Finally, the observed against the calculated low flow data are plotted, compiling a log-log scale chart and calculate statistics featuring the comparison between the recorded and the forecasted low flow data. Full article

A small number of scientific research studies with reference to extremely low flow conditions, have been conducted in Greece, so far. Predicting future low stream flow rate values is an essential and of paramount importance task when compiling watershed and drought management plans, designing water reservoirs and general hydraulic works capacity, calculating hydrological and drought low flow values, separating groundwater base flow and storm flow of storm hydrographs etc. The Monte-Carlo simulation method generates multiple attempts to define the anticipated value of a random (hydrological in this specific case) variable. The present study compiles, correspondingly, artificial low stream flow time series of both the same part of the year (2016) as well as a part of the calendar year (2017), based on the stream flow data observed during the same two different interval periods of the years 2016 and 2017, using a 3-inches U.S.G.S. modified portable Parshall flume, a 3-inches conventional portable Parshall flume, a 3-inches portable Montana (short Parshall) flume and a 90° V-notched triangular shaped sharp crested portable weir plate. The recorded data were plotted against the fitted one and the results were demonstrated through interactive tables providing us the ability to effectively evaluate the simulation procedure performance. Finally, we plot the observed against the calculated low stream flow rate data, compiling a log-log scale chart which provides a better visualization of the discrepancy ratio statistical performance metric and calculate statistics featuring the comparison between the recorded and the forecasted low stream flow rate data. Full article

In this study laboratory experiments and numerical simulations of flow in an open channel with gravel bed of 2 cm thickness are presented and compare. The experimental results were obtained using 2D Particle Image Velocimetry (PIV). For the numerical simulation of gravel bed, a porous layer of thickness 2 cm and appropriate porosity (ε = 0.80, volume of fluid over total porous medium volume) was used. In order to validate the results of the CFX based numerical model, computed quantities are compared with experimental data from PIV measurements. Vertical distributions of velocity above the permeable layer are presented for different total flow depths. The determination of the velocity profiles is of practical importance in the design of open channels. The findings are supported by both laboratory measurements and numerical modelling results and can be useful for engineering applications. In all cases there is a good agreement between experimental and numerical results. Full article

This work presents a platform for efficient representation in the frequency domain of multiple partial blockages in a single pipeline. Blockage detection studies were explored to calibrate the location and size of partial blockages using pressure variation induced by each blockage. To obtain feasible expressions for complicated analytical formulas of multiple partial blockages, an alternative formula is proposed for use in a reservoir pipeline valve system. The validity of the alternative formula was checked by comparing impedance distributions produced by it, with those of existing approaches. The new formula was validated and tested in terms of model parsimony. Full article

This paper studies the potential for drain water heat recovery on a single residence scale, showing its interaction with the space and domestic hot water heating system. The article performs a Monte Carlo simulation based on measured wastewater characteristics, and heat consumption data provided by the Building Energy Ratings database. It shows the necessity of a back-up heating system, on average between 8 and 42% of the demand can be met by recovered heat. This would signify a reduction in GHG emission varying between 7.6 and 22%, but would increase costs ranging from 120 to 130%. Using a hot water reservoir increases the share of recovered heat in the mix, reducing GHG emissions and costs. However at current traditional heating prices, the drain water heat recovery system for a single residence is not financially competitive with traditional systems, showing the need for different strategies. Full article

The design of network blueprints (ideal design of water distribution networks taking into account the existing infrastructure) is optimized considering the minimization of costs while satisfying the required pressure and flow velocities. The optimal transition from the existing infrastructure towards the blueprint is described by the minimization of pipe failures or maximization of hydraulic performance and the number of construction sites, where old pipes are replaced by new ones, in each transition phase. Both problems are solved with Gondwana. An application to the network of Helmond-Mierlo (The Netherlands) shows that the costs for the optimized blueprint are only 64% of those from the currently existing infrastructure, while the hydraulic performance is improved. The optimized transition shows that a larger number of intervention sites allows for a higher reduction of pipe failures and a better hydraulic performance of the network. Full article

Water resources are essential for the economic development and sustenance of human activities belonging to the civil, agricultural and industrial sectors. Increasing water stress conditions, mainly due to climate change and population growth, imply the need to improve the resilience of water supply systems and account for sustainability of water withdrawals. Metabolic modelling approaches represent a flexible tool able to provide a support to decision making in the medium-long term, based on sustainability criteria. Here, these concepts are adopted to analyse part of the water supply network in the Province of Reggio-Emilia (Italy). Different water withdrawals scenarios are considered to account for a potential decrease in water resources availability from a quantitative perspective. As a second step, these scenarios are compared by means of a set of key performance metrics able to identify the most sustainable long-term strategy for a dynamic management of the water supply system. Results of these analysis allow to increase the resilience of the network under future scenarios, while protecting the water resources. Full article

Due to the shortage of clean and fresh water, especially in the coastal regions there is an urgent need to look for alternative water sources to meet people needs and compensate the reduction in groundwater. Desalination is one of such alternative water sources that can solve water shortage problem in Libya and other countries where face the same conditions. Desalination is the main technology that has been developed globally over the past three decades to meet the increasing demand for fresh and clean water. The objective of this paper is to highlight the conventional and non conventional water resources in Libya. In this context, our paper intends to present an overview on seawater desalination technology in Libya and why it should be accommodated as a strategic and ultimate solution for water shortage. Full article

In the present paper, different clustering techniques were applied to detect significant patterns describing single-household water consumption in a residential neighborhood of the City of Naples, basing on hourly time series aggregated at the monthly scale. Comparisons among results were performed by means of a selection of Clustering Validity Indices, that were adjusted to overcome a bias caused by sparsely populated clusters. The most performant cluster solution proved to be the one resulting from the application of a mixed strategy, namely a Self-Organized Map followed by K-means performed on first level cluster centroids. Full article

The sustainable management of water distribution networks is a crucial challenge especially in emerging countries. The distribution networks have very low efficiency with very high levels of leaks. Locating and prioritizing of water leakage areas becomes a main concern for public services, to optimize the use of resources and improve constancy of supply. A decision support approach was proposed to locate areas with higher leakage rate. It is based on the resolution of the FAVAD equation (Fixed And Variable Area Discharge). The determination of FAVAD parameters enables to simulate the quantities and the location of the leaks, through the use of genetic algorithms coupled with hydraulic modeling and the geographical information system (GIS). Full article

Comsima is a mechanical model that calculates stresses and joint rotations in drinking water distribution pipes based upon several loadings on the pipe (soil, traffic, water pressure, differential settlements). Pipe degradation mechanisms (slow crack growth resistance for PVC and calcium leaching for AC) were added to the model. A comparison with failure registration for an area in the Netherlands using satellite data to determine differential settlements shows that pipes with higher stresses or higher joint rotations in general have a higher failure rate. Full article

The aim of this paper is to determine the influence of irregular wall roughness of old pipes to pressure drop and flow velocity in Water Distribution Systems (WDS). Typical calibration of a numerical model of an existing WDS that contains old pipes is usually based on the estimation of roughness of the pipes using nominal pipe diameters. Due to wall build-up the shape of the inner pipe surface can vary temporally and spatially. In this study a series of numerical investigations are carried out using CFD (Computational Fluid Dynamics) software to determine the effect of irregular pipe diameter to pressure drop and flow velocity. Full article

The failure of joints plays an important role in the overall performance of mains. One of the prevalent failure modes at polyvinyl chloride (PVC) joints is the rupture of pipe or joint, which may occur due to high angular deflection of the pipe with respect to the joint, caused by differential soil settlement. The present paper reports the construction and use of a finite element model to determine the maximum angular deflection of a variety of PVC joints in different loading situations. The resulting acceptable deflections vary between 3° and 8° per side, which differs significantly from installation guidelines. The results will support drinking water companies in substantiating the prioritization of maintenance and inspection. Full article

The paper presents results and sensitivity analysis of the results of a real detailed study focused on changes in water consumption and its unevenness with changing pressure conditions in a particular observed office building. The dependence of water consumption on pressure is expressed using the FAVAD equation using the N₃ coefficient. Parameters for sensitivity analysis are number of workers in the building, pulse value from water meter and length of time step for expressing unevenness of water consumption during the day. Full article

This paper presents the results recorded by upgrading and rehabilitating the pumping stations for an urban water network with a primary goal of diminishing the operation and maintenance costs and a secondary goal of reducing the water losses in the water distribution network. The adopted technical solutions within the structural and functional modifications of the pumping stations have led to both the improvement of hydraulic parameters of the pumping stations and also the improvement of registered energy consumption. The undertaken modifications and transformations within the pumping stations led to significant energy savings and at the same time to important water losses reductions within the distribution network. Full article

The allocation of water flowing through a river-with-reservoirs system to optimally meet spatially distributed and temporally variable demands can be conceived as a Network Flow Optimisation (NFO) problem and addressed by Linear Programming (LP). In this paper we present an extension of the strategic NFO-LP model to simultaneously optimise the allocation of water and the location of one or more reservoirs. The applicability of the MILP model has been illustrated by applying it to a hypothetical river network configuration consisting of seven candidate reservoir nodes and seven demand nodes, and by comparing the outcome (water levels in selected reservoir, penalties) with the values obtained by the original LP-model for the same network with six reservoirs present. Full article

Small-scale hydrokinetic (HK) energy systems is a renewable energy source which has never before been explored in South Africa, mainly due to the abundance of low-cost coal-powered electricity. A HK pilot project was implemented in an applicable section on the Boegoeberg irrigation canal in the Northern Cape Province of South Africa and tested for optimum functionality and correct application. This paper describes the HK system development and evaluates the technical viability and resilience of the system. Furthermore, the sustainability of such an installation into existing infrastructure in a developing country is analyzed. Full article

River discharge changes, in addition to natural variability, depend on several factors. Three factors are the most important: climate change (CC), changes in human use of water (HU), and land use changes (LU). River discharge has hydraulic connection with its alluvial sources and both are sensitive to climate and other changes. Alluvial water sources (ALWSs) are often used for water supplying purposes. The question is what could we expect in the future? Are they more or less sensible on climate change and other two factors, compare to river discharge changes, or it differ from case to case? Full article

This paper deals with a comparative analysis and benchmarking of drinking water supply systems and water supply sector in the selected countries of Central and Eastern Europe. These include the Czech Republic, Poland, Romania, and Slovakia. The article provides an analysis of existing benchmarking systems in each country. Methods of supervision and control over the assessment and the functioning of the organizations responsible for the assessment and benchmarking of water utilities are also described. Comparative analysis for the selected performance indicators is carried out. The units, methods of data collection and processing were described. Full article

Optimizing water distribution systems is an essential part of water resources allocation planning. It leads to challenging combinatorial optimization problems, for which meta-heuristics have been applied, notably genetic algorithms and ant colony optimization. The present paper introduces the application of the physarum algorithm, a recent biologically inspired algorithm, utilized hitherto for path finding problems in networks. Direct comparison is presented to ant colony optimization applied to a typical water supply system. Full article

Water losses are in focus of water supply management in last decades. Basic and widely accepted indicator is ILI Index, but is insufficient, when water resources are abundant, treatment costs low and energy consumption miniscule due to gravity. In such situation several authors introduced more detailed analysis defining “Economic Level of Leakage” (ELL) in short run. This analysis provides an insight into shadow market of leakages that is defined by marginal cost of water supplied on supply side and by marginal cost of repairs to mitigate water loss on demand side and provide empirical example based on real water supply system (WSS) data. Full article

The use of traditional risk management systems has proven to be insufficient to safeguard the safety of drinking water. Nowadays, it is preferable to apply preventive instead of corrective systems. Two of the most commonly used systems are the Hazard Assessment and Critical Control Points (HACCP) and the Water Safety Plans (WSPs). The major benefit of their implementation is the improvement of drinking water quality. Of course, the successful implementation of HACCP and WSPs in water utilities can be limited by a number of factors such as the lack of financial resources. However, the importance of implementation’s difficulties is minimal in relation to the benefits that may result from the application of HACCP and WSPs in water utilities. Full article

In the last three decades, the need of achieving a reliable water distribution system has become more eminent for both the consumer’s satisfaction and the efficient management of water sources. The purpose of this paper is to provide an optimal separation of a water distribution network (WDN) into District Metered Areas (DMAs) in order to ensure that the delivered water is of proper age and pressure. At first, the water distribution network is divided into smaller areas via the method of Geometric Partitioning, which is based on Recursive Coordinate Bisection (RCB). Subsequently, Gaussian Mixture Modelling (GMM) solution is applied, obtaining an optimal placement of isolation valves and separation of the WDN into DMAs. The performance of the proposed system is evaluated on two different networks and is compared against the Genetic Algorithm (GA) tool, constituting a very promising approach, especially for sizeable water distribution networks due to the diminished running time and the noteworthy reduction of pressure and water age. Full article

Water use efficiency is a crucial issue in drinking water utilities as it is connected to environmental and economic consequences. WATenERgy CYCLE project aims at developing a methodological approach towards efficient and effective transnational water and energy resources management in the Balkan–Mediterranean area. The paper presents the results of performance evaluation of the water supply systems of the water utilities involved in the project, both at local and national level. The methodology used in the water balance and performance indicators as well as data on the operational status of the water supply systems. The results showed that Non-Revenue Water is one of the major problems addressed. Full article

Drinking water supply safety is of paramount importance for human health. Disinfection is considered as one of the most significant water treatment processes as it inactivates pathogens from drinking water. However, disinfection might have adverse effects in human health, as disinfection by-products, blamed for cancer and reproductive/developmental effects, are formed. Many predictive models and optimization tools are developed in the research. However, an early warning system integrating monitoring, modelling and optimization tools is lacking. The paper reviews the disinfection methods and the models developed so far and presents the basic principles for the development of an early warning system. Full article

New bidirectional technologies for remote access and control of DMAs are introduced into the Advanced Pressure Management field. Using interconnected devices, a controller at the PRV and a logger at the DMA’s Critical Point, it is attempted to reach the optimal performance of the network in terms of pressure, energy consumption, economic parameters, losses and broken pipe events frequency. All manual adjustments are implemented remotely through an integral 2-way web communication system, allowing accessibility from any place, at any time. A case study of a 2-year trial period in Athens, Greece is presented. Full article

Biogas Plant is located in Busan, Korea and it has a facility to produce biogas through the anaerobic digestion of sewage sludge and food waste. But the generated biogas is recovered and used as fuel to increase the temperature in the digester and the rest is burned and dumped at the waste gas incinerator. In this study, we analyzed the performance of a biogas-fueled solid oxide fuel cell (SOFC) system, which is coupled with a Micro gas turbine (MGT) for a target biogas plant. The objective of this study is to clarify the relationship between the scale of a plant and the optimal size. The calculation results of the greenhouse gas emission due to power usage using biogas is decreased. Full article

Yellow water is a segregated domestic wastewater stream resulting from Ecological Sanitation (ECOSAN). It is mainly source separated human urine which is rich in nutrients. The potential contribution of yellow water as fertilizer to food security is considerable. The use of this potential however is related to the acceptance of the consumers towards urine based fertilizers (UBF). This work aims to assess acceptance of consumers towards UBF and urine diverting toilets (UDT) for separation of urine, through questionnaires with 444 participants from Egypt, Iraq and Turkey with different age groups, genders, educational backgrounds and occupations. The overall acceptance for UDTs and UBF was 62% and 56%, respectively. All-in-all, public opinion regarding the use of UDT/UBF is promising. Full article

Nowadays there is an increasing amount of everyday flood incidents around the world, the impact of which poses a challenge on the society, economy and environment. Under the Water Framework Directive (2000/60/EC), green infrastructure provided by sustainable drainage systems (SuDS) is the recommended policy to manage and treat storm water. This paper presents experimental work carried out in the laboratory on a permeable pavement rig, investigating mainly the short-term hydrology of the pavement, and the way that runoff percolates through the structure during simulated rainfall events. Results showed high flood mitigation capacity, encouraging further investigation of this type of SuDS. Full article

A complex hydraulic facility is modelled in EPANET. The system consists in an underground high head Hydro Power Plant (HPP) and a Pumping Station (PS), operating in a pumped-storage hydropower scheme with three reservoirs. The complexity of the system is due to its unusual configuration, where the PS discharges the water directly into the HPP penstock. The PS is equipped with 2 × 10 MW pumps. The HPP is equipped with 2 × 75 MW Francis turbines. The simulations allow assessing the energy production and/or consumption in various scenarios, offering a tool to decision makers, to wittingly choose the operation mode of the facility. Full article

Land, food, energy, water and climate are linked and interconnected into a Nexus, characterized by complexity and feedbacks. An integrated management of the Nexus is critical to understand conflicts/synergies and secure efficient and sustainable use of resources, especially under climate change. The Nexus perspective is applied to Sardinia, as regional case study, to better understand and improve integrated resource management and relevant policy initiatives. Vulnerability of Sardinia Nexus is assessed under several climate projections by articulated balances of resources (water, energy) availability and sustainable development goals, at regional and sub-regional scales, accounting for demands and conflicts among key economic sectors (agriculture, hydro-power, tourism). Full article

The multidisciplinary Legionella research has developed hand in hand with the level of science and technology, health care, and other scientific fields. The primary aim of this paper is to present our research focused on the theoretical and experimental analysis of building water distribution systems from the point of view of microbiological risk in hospitals in the Slovak Republic. To assess the potential public health impact of Legionella colonization in hot and cold water, a study was undertaken to identify and qualify the levels of the microorganism. The measures proved that thermal disinfection is not a systematic solution. By applying preventive measures, physical or chemical treatment and the use of risk management, we can obtain a secure system which eliminates costly solutions. The outputs of our goals will be transformed to the hygienic water audit scheme as a tool in the fight against Legionella contamination in the future. Full article

The present study attempts to examine the comparative performance of seven different WQIs, as they were computed for Polyphytos Reservoir-Aliakmon River in Greece, based on water quality monitoring data for the period between June 2004 and May 2005. The WQIs applied were: Prati’s Index of Pollution, Bhargava’s Index, Oregon WQI, Dinius’ Index, CCME WQI, NSF WQI and the Weighted Arithmetic WQI. Significant discrepancies were observed in classification results between the different methodologies. Among others, it was concluded that NSF and Bhargava indices classify the reservoir in higher quality classes, Prati’s and Dinius indices in medium, while CCME and Oregon in lower quality categories. Full article

Research and development of desalination technologies are becoming highly important because of the rapid increase in freshwater demand. Researchers are continually working on improving the existing desalination technologies and exploring new methods and ideas to desalinate salty water in order to come up with cost-effective systems. Comparisons between different renewable powered desalination technologies were mainly based on different system capacity, energy source system, feed-water salinity and system components. This makes the economical comparison almost impossible. There is an existing gap in having an economical comparison to different renewable energy powered desalination systems with the same basics such as availability of renewable and water resources. This research is an attempt to provide a systematic methodology to obtain the most cost-effective renewable energy powered desalination system. Full article

A Multi-criteria Decision Aid (MCDA) framework based on the combination of Multi-Attribute Utility Theory (MAVT/MAUT) with the Weights Assessment through Prioritization method (WAP) is proposed for decision problems related to agricultural water management in the context of water-energy-land-food (WELF) nexus. The implementation of the framework supports a Decision Maker (DM) to quantify his/her preferences in a structured and rational way, in order to select the best alternative for agricultural water management. Through the use of the Multicriteria Interactive Intelligence Decision Aiding System (MIIDAS), marginal utilities functions for all the criteria are constructed. The criteria are grouped in points of view, which may refer to individual nexus elements and costs for investments or agricultural inputs. The WAP software assists the DM to assess the relative importance of the criteria and estimate their weights. Full article

The urban wastewater treatment plants can be an important part of circular sustainability due to integration of energy production and resource recovery during clean water production. Currently the main drivers for developing wastewater industry are global nutrient needs and water and energy recovery from wastewater. The article presents current trends in wastewater treatment plants development based on Circular Economy assumptions, challenges and barriers which prevent the implementation of the CE and Smart Cities concept with WWTPs as an important player. WWTPs in the near future are to become “ecologically sustainable” technological systems and a very important nexus in SMART cities. Full article

The main objective of the LIFE VERTALIM project is to demonstrate the efficiency of a holistic solution (including technical, legislative, social and environmental aspects) for the controlled integration of food industry wastewater in urban sanitation system with the compliance of all stakeholders. The artisan production of canned tuna is characterized by generating effluents with high organic and saline loads, which complicates their suitable treatment. This work shows two approaches to solve this problem. To begin, low-cost innovative solutions, through clean and eco-efficient production and wastewater pretreatment for the fish canneries. Then, the implementation of a real time control system (RTC) as a remote management system in the sanitation network that will allow the remote management of the urban and industrial discharges, based on the modeling of the collector network and WWTP in different scenarios. Full article

Detection of changes in observed meteorological and hydrological changes are of the great interest for water sector. This paper presents the most recent findings relevant for trend examination in observed datasets for precipitation (P), temperature (T) and river discharge (Q) for selected stations across the Republic of Serbia. In addition, correlations of the observed variations in average Q with detected changes in observed average T are comprehensively evaluated. Similar study were done for period 1949–2006, which was the most convenient period due to data availability during the first research step (2008–2010), and these finding were presented at the EWAS2. The new research phase that includes last 10 years (2007–2016), for annual data sets for T, P and Q is ongoing based on methodology developed in the First step of research. This paper presents the most recent results and discuss does earlier registered T, P and Q trends have the same pattern or some new phenomenon has been observed across Serbia in the last 10 years. Full article

The United Nations Food and Agriculture Organization (FAO) has established the Water-Energy-Food Nexus, implying that the three commodities are inextricably linked forming a complex system of interrelations. Perceiving water, energy and food as a system variable with dependencies rather than a singularity suggests an approach of a more holistic view that can offer a sustainable plan for managing resources. In this article, the already established three-way Nexus is expanded to include two more dimensions, namely land use and climate and a framework for modelling the interlinkages among these dimensions is presented. Full article

Soil erosion on Cephalonia Island, Greece has been identified as a predominating land degradation process and a major threat to the sustainability of the agricultural sector. In the present work, the evolution of soil erosion on the island was estimated for the years 2000 and 2012. A simple empirical model, the Revised Universal Soil Loss Equation (RUSLE) for modeling soil erosion, was applied in a Geographical Information System (GIS). The results indicate that the mean annual soil erosion was estimated to be 12.78 t/ha for the year 2000 and 12.28 t/ha for the year 2012. Further, 38.24% of the area of Cephalonia demonstrated moderate to significantly high soil erosion in the year 2012 compared to 40.55% in year 2000. We can assume that during the period 2000–2012, despite influences on the natural environment including forest fires and overgrazing, the combination of vegetation and other protective soil factors contributed to reducing soil erosion. Full article

Investigations have indicated that in addition to traditional sources, drained peat soils can be considered as a significant source of nitrogen in Estonia. This changes the measures to improve water quality in rivers. At present modelling of nitrogen in rivers has been concentrated on influence of agricultural activity. However, drained peat can increase nitrogen concentrations even without fertilization and farming activities. This investigation describes the attempt to model water quality in the watershed with large share of drained peat soils. A good alignment between measured and modelled nitrate concentrations using the MACRO and the SOILN for MACRO models was shown. Full article

This paper analyses the possibilities to derive drainage density map, a parameter used within Erosion Potential Method (EPM, Gavrilović), for the Dubračina catchment study area in better detail and precision. EPM method is used for erosion assessment in the karstic areas characterized by torrential rivers. In this paper, three different methodologies were used to derive drainage density map each using different assumptions and allowing different spatial variability. The third case of drainage density map provides most realistic spatial variance of the drainage density parameter with lower values along the edges of the catchment and higher values concentrated along the river and tributary intersections. Full article

According to WFD, European countries shall establish monitoring programmes for water quality overview. In EcoSUSTAIN, an Interreg–MED project, Gap analysis, an approach that reveals the difference between current and desired level, was carried out, targeting five Mediterranean hydro-ecosystems covering “Monitoring Practices” and “Water Quality and Pressures”. Our goal is to investigate practicing deficiencies, as long as information lack and distance from desirable status, supporting water uses and WFD goals. Data was collected by literature research supported by questionnaires. The findings on both fields, revealed problematic areas dealing with the compliance with the WFD and several deficiencies in tackling pressures. Full article

A description of hydromorphological pressures is required by the Water Framework Directive, however, there is not a commonly accepted assessment method. This study aims to explore a description tool application, not used before in Greece, for the quantification of the human impact extent on natural environment. Thus, in lakes Kastoria and Pamvotis, the Lake Habitat Survey was applied in the field and remotely to map the pressures, to examine confidence, suitability and ease of applicability through plot quantitative description, to calculate the “Lake Habitat Quality Assessment”, “Lake Habitat Modification Score” and “Alteration of Lake Morphology Score” indices. Full article

Degradation of reservoir dams can lead to water percolation through dam structure. Here, close-range photogrammetry and UAV (Unmanned Aerial Vehicle) thermal imagery can be used to monitor differences in dam moisture. The article presents a study of the dam of Podvinak Fishpond (Czech Republic). The TDR (Time Domain Reflectometry) data (soil moisture), the Theta probe data (soil moisture), and the temperature data of the dam top profile and the grassed area below the dam were compared. Analysis focused on the comparison between sampled data, and UAV data obtained by Optris TIM 450 (Portsmouth, USA) and Flir Tau2 336 (Wilsonville, USA) IR cameras. Based on the study, the spectral resolution, the accuracy of the results, and the reliability of both UAV monitoring systems is similar. Full article

The Programmes of Measures (PoMs) are included in the River Basin Management Plans (RBMPs). They comprise the outputs on the analysis of pressures, impacts and status of the water bodies, by designating those actions that need to be employed for the amelioration of the water quality status. In this research a methodology based on the coupling of hybrid multicriteria methods, namely outranking, in which 6 criteria and 37 alternatives are integrated, with a 0/1 linear programming in which the cost of the measures is induced as a constraint, is proposed for the prioritization of the supplementary PoMs that are included in the RBMP of Central Macedonia, Greece. The results of the research demonstrated the usefulness of the methodology when financial constraints do not permit the implementation of the whole set of measures. Full article

Water resources monitoring traditionally refers to the observation of surface or groundwater as separate entities. However, in one watershed, almost all characteristics of surface water interact with groundwater. This research was done in order to obtain more accurate assumptions about the interaction between groundwater and surface water and establish recharge zones on the example of Banja river catchment area. This research shows the possibility to have both quantitative and qualitative analyses of groundwater–surface water interactions of some river catchment with limited input data in short period of time which can be beneficial, especially on remote locations. Full article

An Integrated Mathematical Model (IMM) is applied at a continuous time scale in Nestos River basin (Macedonia–Thrace border, northeastern Greece). The IMM comprises a rainfall–runoff submodel, a soil erosion submodel, a streambed deposition submodel and a streambed erosion submodel, and computes sediment yields at the outlet of the basin, at fine time steps and for long periods of time. Soil erosion is estimated by means of the Modified Universal Soil Loss Equation (MUSLE), deposition of sediment load is modeled by the formulas of Einstein and Pemberton and Lara, while streambed erosion is estimated through the formula of Smart and Jaeggi. The application of the IMM enables the computation of annual sediment yields, at the outlet of the basin. Full article

In the Second EWaS International Conference (June 2016, Chania, Crete, Greece), the bed load transport formula of Meyer-Peter and Müller (1948) was calibrated with respect to the bed roughness coefficient for Nestos River. The calibration was manual and incremental, taking five measured values of bed load transport rate at a time. In contrast, the present study carries out a nonlinear optimization of two suitable parameters, while utilizing the average value of the roughness coefficient k_st found by the manual calibration. Thus, a uniform calibration is attained, by taking at once the totality of the available 68 measurement points. The results did not show any marked fitting improvement in comparison to the previous study. However, considering moving averages of the measured bed load transport values yields a better adjustment of the model to the measured results. Full article

Recent studies have shown that wave blocking occurs at river mouths with strong currents typically preventing relatively short period sea and swell waves from propagating up the river. However, observations demonstrate that lower frequency waves, so-called infragravity waves, do pass through and propagate up the river, particularly during storm events. We present observations from the Misa River estuary of infragravity wave propagation up the river during storm conditions. A model of the complex nonlinear interactions that drive infragravity waves is presented. The results are discussed in the context of an observed river mouth bar formed in the lower reach of the Misa River. Full article

One of the most evident consequences of global atmospheric warming is the modification of the water cycle. Precipitation plays a crucial role in the process and its variations can affect water resources, natural environments and human activities. In this paper, an investigation of the temporal rainfall variability in the Calabria region (southern Italy) has been carried out using a homogeneous and gap-filled monthly rainfall dataset of 129 rain gauges with more than 50 years of observation in the period 1951–2006. Possible trends in monthly and annual rainfall values have been detected by means of the Mann–Kendall test and of a new graphical technique (Şen’s method), which allows the trend identification of the low, medium and high values of a series. As a result, a different behavior of both the highest and the lowest rainfall values emerged among the five Rainfall Zones (RZs) that were considered in the analysis. Moreover, from the comparison of the trend methodologies, different trends results (increasing, decreasing, or trendless time series) have been identified. In particular, this study shows that the Şen’s method could be successfully used in the evaluation of peak and low values of data for the trend analysis of rainfall values. Full article

One of the main drivers affecting water quality evolution with climate change is temperature. While the effects of climate change on the thermal regimes of surface waters have already been assessed by many studies, there is still a lack of knowledge on the effects on groundwater temperature. Studies of historical changes in river water temperature generally report increases. Even for groundwater, recent studies identify a direct relationship between air temperature and groundwater temperature, especially in shallow alluvial aquifers. The large dataset of the Campania Environmental Agency was analyzed to assess the impact of climate change on the local unconfined aquifer. Full article

Urban stormwater drainage systems (UDS) are severely affected by the changing climate bringing along inter alia more intense rainfall events. The conduits, usually having limited capacity, are unable to cope with these excessive flowrates. Therefore, measures must be undertaken to temporarily accumulate extra flowrates in order to avoid the flooding. There are several options available to tackle this challenge, e.g., low impact development (LID) solutions, best management practices (BMP), stormwater real-time control measures (RTC). In this study the efficiency of in-line and off-line detention tanks are analyzed. Moreover, new concept of smart in-line storage system is created and evaluated. This solution shows significant reduction in peak flow, economic benefit and is particularly suitable for the districts with limited construction space. The concept has been successfully tested in 10 ha dense urban development area in Estonian capital Tallinn. Full article

The aim of this work is to identify and present small scale sustainable urban stormwater management techniques that can be implemented by local authorities into public spaces. We present areas that bioretention and other Sustainable Urban Drainage Systems (SuDS) can be adopted, causing the transformation of public areas into multifunctional spaces. Full article

The paper is a part of ongoing doctoral study focusing on interior green walls and their qualities. The paper describes living wall built in entrance hall in the laboratory of Technical University of Košice, its construction, irrigation and vegetation; the most important segments of every living wall. The research deals with effect of green wall on air temperature and humidity in the room and compares it with air temperature and humidity in the room without green wall. Full article

The scope of this paper is to evaluate the short-term predictive capacity of the stochastic models ARIMA, Transfer Function (TF) and Artificial Neural Networks for water parameters, specifically for 1, 2 and 3 steps forward (m = 1, 2 and 3). The comparison of statistical parameters indicated that ARIMA models could be proposed as short-term prediction models. In some cases that TF models resulted in better predictions, the difference with ARIMA was minimal and since the latter are simpler in their construction, they are proposed for short-term prediction. Artificial Neural Networks didn’t show a good short-term predictive capacity in comparison with the aforementioned models. Full article

Flood frequency estimation for the design of hydraulic structures is usually performed as a univariate analysis of flood event magnitudes. However, recent studies show that for accurate return period estimation of the flood events, the dependence and the correlation pattern among flood attribute characteristics, such as peak discharge, volume and duration should be taken into account in a multivariate framework. The primary goal of this study is to compare univariate and joint bivariate return periods of floods that all rely on different probability concepts in Yermasoyia watershed, Cyprus. Pairs of peak discharge with corresponding flood volumes are estimated and compared using annual maximum series (AMS) and peaks over threshold (POT) approaches. The Lyne-Hollick recursive digital filter is applied to separate baseflow from quick flow and to subsequently estimate flood volumes from the quick flow timeseries. Marginal distributions of flood peaks and volumes are examined and used for the estimation of typical design periods. The dependence between peak discharges and volumes is then assessed by an exploratory data analysis using K-plots and Chi-plots, and the consistency of their relationship is quantified by Kendall’s correlation coefficient. Copulas from Archimedean, Elliptical and Extreme Value families are fitted using a pseudo-likelihood estimation method, verified using both graphical approaches and a goodness-of-fit test based on the Cramér-von Mises statistic and evaluated according to the corrected Akaike Information Criterion. The selected copula functions and the corresponding joint return periods are calculated and the results are compared with the marginal univariate estimations of each variable. Results indicate the importance of the bivariate analysis in the estimation of design return period of the hydraulic structures. Full article

Classical linear regression has been used to measure the relationship between rainfall data and altitude in different meteorological stations, in order to evaluate a linear relation. The values of rainfall are supposed as dependent variables and the values of elevation of each station as independent variables. It has long been known that a classical statistical relationship exists between annual rainfall and the station elevation which in many cases is linear as the one examined in this article. However classical linear regression makes rigid assumptions about the statistical properties of the model, accepting the error terms as random variables, and the violation of this assumption could affect the validity of the classical linear regression. Fuzzy regression assumes ambiguous and imprecise parameters and data. For this reason it may be more effective than classical regression. In this paper we evaluate the relationship between annual rainfall data and the elevation of each station in Thessaly’s meteorological stations, using fuzzy linear regression with trapezoidal membership functions. In this possibilistic model the dependent measured elevations are crisp, and the independent observed rainfall values as well as the parameters of the model are fuzzy. Full article

The selection of an appropriate spillway has a significant effect to the construction of a dam and several procedures and considerations are needed. In the past, this selection of the type of the spillway was arbitrary and sometimes with bad results. Recently the Multiple Criteria Decision Making theory has given the possibility to make a decision about the optimum form of a spillway under complex circumstances. In this paper, the above method is used and especially the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method for the selection of a spillway for a dam in the district of Kilkis in Northern Greece—‘Dam Pigi’. As the criteria were fuzzy and uncertain, the Fuzzy TOPSIS method is introduced together with the AHP (Analytic Hierarchy Process), which is used for the evaluation of criteria and weights. Five types of spillways were selected as alternatives and nine criteria. The criteria are expressed as triangular fuzzy numbers in order to formulate the problem. Finally, using the Fuzzy TOPSIS method, the alternatives were ranked and the optimum type of spillway was obtained. Full article

Integrated water resources management at the catchment scale, considering the full water cycle as manageable, is a primary approach to improve water use efficiency and promote sustainable water management solutions. To this purpose, advanced modelling tools are required to quantify the physical and economic effects of alternative land management options. This work presents an application of a spatially distributed physically based hydrological model to the Bonis experimental watershed located in the mountain area of Sila Greca (southern Italy). Different infiltration models were tested to better reproduce discharge observations at basin outlet. The model will be used for evaluating different land use/management scenarios, combined with climate change forcing, to quantify the effect of alternative management options on the land-water cycle. This work is part of the INNOMED project (Innovative Options for Integrated Water Resources Management in the Mediterranean) funded by ERA-NET COFUND WATERWORKS 2015 call. Full article

This paper presents preliminary analyses carried out in order to assess the possibility to treat a small simple catchment as linear reservoir when modeling the runoff from a precipitation event. This analysis was carried out for the catchment of Černá Desná stream to the profile Jezdecká. The applicability of linear reservoir concept was tested by calculating the recession constant values for hydrographs falling limbs which were then evaluated in a statistical way. Specifically, five events were selected for the detail analysis. The results indicate that the linear reservoir concept can be applied in this case to predict relatively well the discharges in next 48 h. However, the results also show that there are limitations in the application of linear concept and that the introduction of non-linear reservoir could improve the prediction results. Full article

The present work aims at quantifying the benefit of Low Impact Development (LID) practices in reducing peak runoff and runoff volume, and at comparing LID practices to conventional stormwater solutions. The hydrologic-hydraulic model used was the Storm Water Management Model (SWMM5.1). The LID practices modeled were: (i) Green roofs; and (ii) Permeable pavements. Each LID was tested independently and compared to two different conventional practices, i.e., sewer enlargement and detention pond design. Results showed that for small storm events LID practices are comparable to conventional measures, in reducing flooding. Overall, smaller storms should be included in the design process. Full article

The present research work uses Residual Kriging to estimate the groundwater level of an unconfined alluvial aquifer, as well as the trend function. The ground surface elevation is used as auxiliary variable in the trend model. Indicator Kriging is applied to detect potential vulnerable locations. Classical variogram functions are applied to determine the spatial correlation of the measurements. The risk of hydraulic head to lie below a threshold value is significant, mainly at the South and North parts of the aquifer, where the lower values of groundwater level are estimated, indicating that these areas require intense monitoring to ensure the water resources availability. Full article

Chloride concentration and salinity tend to vary spatially in depth within the unsaturated zone, according to the local hydrologic conditions; and therefore are widely used as naturally occurring environmental tracers. In this study, undisturbed material from the unsaturated zone was collected at regular intervals of 50 cm down to a maximum depth of 300 cm in 17 different locations. Vacuum filtration has been used for extraction of soil water from 75 soil samples, and chemical analyses showed that the chloride concentrations in soils range from 0.4 to 79 meq/L indicating the existence of soluble salts, also verified by elevated electrical conductivity values. Full article

The consideration of a theoretical probability distribution regarding the annual cumulative discharge will provide a significant opportunity to characterize the intensity of the hydrological drought. However, the matching between the observed probabilities and the adopted theoretical probability distribution can not be identical. Hence, in this work this matching is achieved by using a fuzzy regression based methodology and the attributes of the log-normal distribution. Finally, an ascending procedure to classify the intensity of hydrological drought is proposed and it is applied in case of the Evros River. Full article

This paper describes the synergetic use of earth observation satellites optical and radar data to detect flooded areas and explore the impacts of the flood event. A flash flood episode took place in May 2016, in the central-eastern part of West Thessaly (Central Greece). A Landsat-7 ETM+ and a Sentinel-1 SAR image were acquired. For Landsat-7 several water indices were applied and for the Sentinel-1 a threshold method was implemented. Furthermore, Sentinel-2 images were utilized so as to record the land use/cover of the flooded area. The inundated areas and the affected cultivations were delineated with high precision, and the financial effects were evaluated. Full article

This work presents an innovative approach on aerobic activated sludge (AS) wastewater treatment plants’ (WWTP) design and operation towards more efficient wastewater treatment, minimization of sludge accumulation and significant reduction of excess sludge, with relatively low specific energy consumption. This approach, which is called complete solids retention activated sludge (CRAS) process, was applied on a slaughterhouse’s WWTP and on a fruit processing industry’s WWTP, characterized by high organic and volumetric load respectively, as well as on a municipal WWTP located in Paralimni, Cyprus. The results showed without using sophisticated technologies and processes a more sustainable WWTP operation can be achieved. Full article

Sulphide was adopted as odorous compound in a simulation of AS Diffusion, an interesting process to treat odors at wastewater treatment plants by diffusing odorous air into aerobic basins. Its behaviour were experimentally evaluated along with its effects on the biomass and the biological processes supposed by some author in an AS diffusion test. Two bench scale sequencing batch reactors (SBRs) were fed in parallel on real primary sewage and monitored after adding increasing concentrations of sulphide to one of them. In this reactor, an average sulphide removal of 94% was measured. Microbial biochemical activity and composition did not show relevant variations after the addition of sulphide, and the good features of activated sludge flocs were maintained also in terms of sludge settleability. Full article

Removal of mercury (II) from aqueous phase is of utmost importance, as it is highly toxic and hazardous to the environment and human health. A promising method for the removal of mercury (II) ions from aqueous solutions is by using adsorbents derived from coal fly ash (CFA), such as synthetic zeolites. In this work we present the hydrothermal production of synthetic zeolites from CFA followed by a modification for impregnation of silver nanoparticles, in solid concentrations from 0.15 to 4.71 wt.%. All produced zeolites and parent materials are characterized by XRD, XRF, BET and PSA to obtain morphological and microstructural data. Moreover, mercury (II) ions removal from aqueous solutions with initial concentration of 10 ppm is studied. According to results, zeolites and Ag-nanocomposites demonstrate much higher removal than parent CFA (up to 98%). In addition to this, we could observe a distinct adsorption behavior depending on the loading of Ag NPs in nanocomposites. A possible removal mechanism for both zeolites and Ag-nanocomposites is discussed. Full article

The article investigated the effects of ultrasound pretreatment on biological treatment of landfill leachate. Leachates with and without conditioning were combined with municipal wastewater at different ratios. The study showed that the implementation of a pretreatment step prior to biological treatment not only results in higher pollutant removal efficiency but may also allow for an increased leachate volume share in the influent stream entering the reactor by up to 20% (quality of effluents meets national regulation requirements) which in scenarios without pretreatment cannot exceed 5% due to poor quality of the effluents. Full article

The (RSM) is a useful method for optimizing analytical methods and it has been applied to evaluate independent variables in FPs. In this study, the removal of dimethoate (DMT) which is a commonly used pesticide and has a toxic effect on the environment, was evaluated in terms of oxidation and mineralization efficiency using response surface methodology (RSM) in the Fenton-like process (FLP). The obtained optimum conditions for DMT oxidation and mineralization using the FLP included DMT/Fe⁺³/H₂O₂ ratio of 0.018 mM/0.03 mM/0.15 mM and reaction time of 65 min. DMT oxidation efficiency was 78% and mineralization efficiency was 18%. The initial DMT concentration was the most significant variable affecting both the oxidation and mineralization efficiency of DMT. Full article

Wastewater treatment plants (WWTPs) highly contribute to the transmission of antibiotic resistance genes (ARGs) in the environment. In this work, the diversity of ermF, ermB, sul1 and int1-enconding genes was examined in the influent, the mixed liquor and the effluent of a full-scale WWTP. Based on the clones analyzed, similar genotypes were recorded at all process stages. However, distinct genotypes of int1 were responsible for the expression of sul1 and ermF genes in Gammaproteobacteria and Bacteroidetes, respectively. Due to the detection of similar ARGs profiles throughout the biological process, it is concluded that additional treatment is needed for their retention. Full article

Sludge disposal is becoming an issue at the municipal solid waste incinerator (MSWI), especially for environmental and economic reasons. This paper describes a case study of the optimization of the sludge management (SM) system at the MSWI in the Czech Republic. The original concept of SM at MSWI was designed as waste-free. However, the present operation indicates that there is a need to carry out regular extraction and disposal of sludge settling at the bottom ash tank and the bottom of the retention basin. The current status of SM causes problems not only in terms of operation but it also entails significant financial costs given the necessary regular cleaning of tanks. The aim of the applied research presented in this paper is SM optimization by a mobile sludge dewatering (DW) press unit with optimal polymer combination for DW. Full article

In the present study, activated carbons (PAC) were hydrothermally prepared with an environmental friendly preparation route after pyrolysis from biomass (specifically from agricultural (potato) peels). The prepared biochars were activated with potassium hydroxide (chemical activities). The preparation route had a strong impact on the pore structure of PAC. In addition, surface chemistry was also affected by the preparation and activation process. The adsorbent materials were also characterized by Scanning Electron Microscopy. The prepared activated carbons were used as adsorbents for the removal of lead ions. Batch experiments were performed to investigate the effect of physico-chemical parameters, such as pH, contact time, initial metal concentration and temperature. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The thermodynamic parameters such as the change of enthalpy (ΔH⁰), entropy (ΔS⁰) and Gibb’s free energy (ΔG⁰) of adsorption systems were also determined and evaluated. Full article

Use of Membrane Bioreactor (MBR) technology for municipal wastewater treatment has been increased in recent years, as it successfully overcomes the disadvantages of the conventional activated sludge process. Membrane fouling is the major disadvantage of MBRs and leads to decreased membrane performance and expanded operational expenses. In this study, fouling was monitored in a pilot-scale submerged MBR system fed with municipal wastewater. TMP was directly measured on the membrane module during the operation. To control TMP increase owing to biosolids accumulation on membrane surface, successive backwashes and air-cross flow velocity increase were applied. These measures lowered TMP and improved flux. Full article

Nonylphenol (NP) and octylphenol (OP) are considered as endocrine disrupting compounds and they restrict the reuse potential of wastewater. Therefore, innovative and reliable technologies are required for elimination of these compounds from waste streams. In this study, we consider use of iron nanoparticles (nZVI) (0.1 mM; 2 mM) and also a composite of nZVI/fullerene nanoparticles (aq-nC₆₀) (0.1 mM nZVI/2.5 ppm aq-nC₆₀; 2 mM nZVI/2.5 ppm aq-nC₆₀) for the removal of 25 μg/L NP and OP concentrations. The nano-composite was synthesized according to chemical reduction method and was characterized using XRD, particle size distribution and zeta potential measurements. NP and OP concentrations were quantified with a GC-MS. The results demonstrated that 0.1 mM nZVI alone resulted in 6% and 17% decrease in NP and OP concentrations, respectively. However, when the nZVI concentration was increased to 2 mM, the removal efficiency increased to 59% for NP and 32% for OP. When compared with NP, lower removal rates were achieved for OP regardless of the nZVI concentration. Although NP and OP have similar chemical structures, OP has a branched arrangement and this structure is anticipated to cause a decrease in the active adsorption sites and lower removal efficiency for OP. Highest removal was obtained with 0.1 mM nZVI/2.5 ppm aq-nC₆₀ for both NP and OP. Our results show that nZVI/aq-nC₆₀ holds a potential for elimination of NP and OP from wastewater sources. Full article

In this research the adsorption of organic matter onto calcium carbonate (CaCO₃) nanoparticles was studied. CaCO₃ nanoparticles were prepared by purging CO₂ gas into lime slurry. Progress of the reaction was monitored by online measurement of pH and conductivity. Prepared particles were contacted with organic matter synthetic solutions. Organic matter removal rates during adsorption were higher in samples with a high initial organic matter concentration. This result would be a promising solution strategy for the problem of management of flows collected in the treatment concentrates of membrane filtration plants. Full article

The construction of irrigation reservoirs is a technical global solution for enhancing the agricultural production especially in arid and semi-arid areas. These water bodies are treated as technical projects and not as freshwater ecosystems. Eutrophication in new reservoirs becomes a hot issue in the world. The aim of the present study is to present the assessment of the key-eutrophication parameters in seven reservoirs located in the catchment area of Lake Karla. We suggest that the studied artificial ecosystems are sensitive in nutrients concentrations especially in the warm-dry period, influenced mainly by agricultural activities in the watershed. Full article

The main goal of this study is to evaluate the short-term and long-term inhibitory effects of Cu (II) on Anammox process. To investigate the short-term inhibition level, four different concentrations (1, 2.5, 5 and 10 mg L⁻¹ as Cu²⁺) were tested in batch reactors. IC50 levels for short-term exposure deduced as 4.57mg L⁻¹ (R²: 0.97) from the modified non-competitive inhibition model. Lab-scale continuous flow up-flow fixed bed reactor with Kaldness biofilm carriers was operated 240 days with gradually increased Cu concentrations (from 0.2 to 8 mg L⁻¹). To identify the IC50 levels in case of prolonged exposure of Cu(II), experimental data were fitted with a modified non-competitive inhibition model, and calculated as 6.77 mg L⁻¹ (R²: 0.95). The results show that the IC50 level for copper in long-term exposure was higher than in short-term exposure and the possible reason for that is the self-adaptation of Anammox bacteria. Full article

Textile wastewaters are characterized by high chemical oxygen demand (COD) concentration, strong color, high pH and temperature, and low biodegradability. Conventional treatment methods are considered to be inefficient to comply with the discharge limits. Recently, nano zero-valent iron (nZVI) technology has received increasing attention of the scientific community as an emerging technology for treatment of polluted streams. Due to smaller particle size, larger surface area and higher surface reactivity of iron nanoparticles, the removal of pollutants occur very rapidly. In this work, we synthesized nZVI employing green chemistry principles in a chemical reduction reaction. Iron precursor solution (FeSO₄) was reduced by plant extracts that contain polyphenols. Plant polyphenols are known to possess strong reducing agent properties and act as effective metal chelators. The objective of this study was to characterize the green synthesized iron nanoparticles in terms of size and zeta potential parameters under various synthesis conditions (pH, precursor concentration and precursor/extract volume ratio) and compare the reactivity of the engineered nanoparticles for textile wastewater treatment. Green tea leaves-GT and Rose leaves-R were selected as the plant sources. Plant extracts were examined in terms of their Total Phenolic Content (TPC) expressed as Gallic Acid Equivalent (GAE). Rose leaves were found to possess 2062 mg/L TPC whereas, Green Tea leaves were found to have 1882 mg/L in grinded powder form. Results showed that 74% color removal along with 18% TOC removal could be achieved with 5 ppm of GT-ZVI nanoparticles synthesized at a 2/1 ratio (v/v) of precursor to extract. With the same concentration of R-ZVI nanoparticles, 78% color removal and 40% of TOC removal were observed. Full article

Initially an area-differentiated modelling of groundwater recharge in River Pinios Basin (Greece) was carried out for the reference period 1971–2000 based on the mGROWA model. Subsequently, the model was applied to assess the impacts of climate change on groundwater recharge and irrigation need. For this purpose one bias-corrected RCM–GCM combination from the EURO-CORDEX ensemble of climate models for two emission scenarios (RCP 4.5 and RCP 8.5) have been used as input data for the projected periods 2011–2040 and 2040–2070 and 2700–2100. Results of the mGROWA model runs for the projected periods and the two emission scenarios indicate a different evolution of groundwater recharge and a general increase in irrigation need, however with different degrees of intensity. Full article

Disc infiltrometer experiments were conducted in the laboratory on two disturbed soils, a loam and a silty clay loam soil, in order to investigate the relationship between three- and one-dimensional infiltration using the proposed equation of Smettem et al. A mini disc infiltrometer of a radius of 45 mm with suction ranged from −5 mm to −70 mm was used. Three- and one-dimensional infiltration tests were performed on repacked cores by applying pressure heads −70, −40 and −10 mm for loam soil, and −30 and −10 mm for silty clay loam soil. Analysis of the results showed that the difference between the three- and one-dimensional infiltration is linear with time confirming the equation of Smettem et al. [1]. Also, this difference is used to calculate the value of an additional infiltration parameter. Full article

The standard methodology for the soil salinity assessment is provided through the determination of the electrical conductivity (EC) of the soil saturated paste extract, EC_e. This approach is cumbersome and tedious. Instead of this, it appears easier to measure the EC of various soil over water mass ratios, (soil:water), such as 1:1, 1:5. In the present study an attempt is made to compare the EC_e methodology with the methods providing the EC_1:1 and EC_1:5. EC_e, and EC_1:1 or EC_1:5 values were obtained from 198 soil samples from 5 different locations in Greece. It was shown that the methods providing EC_1:1 and EC_1:5 values are linearly correlated to the EC_e methodology with a high correlation coefficient (R² > 0.93). Full article

The aim of this research was to study the effects of full and limited irrigation on the growing and productive characteristics of organically cultivated “Mountain Tea” (Sideritis raeseri). The research took place at the University of Thessaly farm in Velestino, Magnesia-Central Greece, during the year 2016, which was the second growing season. The experiment consisted of three treatments in three replications. Two of the treatments were irrigated: one treatment was irrigated with a supplied amount of water equal to the 75% of the daily water needs, while the other one was fully irrigated (100% of the daily water needs). Irrigation water was provided with a surface drip irrigation system. The third treatment was rainfed (no irrigation–0%). The results showed that limited irrigation compared to the full one, can save a significant amount of irrigation water while having the same results regarding the crop’s characteristics. Full article

Methodology for determining priorities in implementing irrigation plans using multicriteria analysis method DEXi is applied on the specific case study area in the sub-catchment area of river Orljava in Požega-Slavonia County, Croatia. Five potential irrigation areas are analyzed according to five selected criteria: environmental protection, water-related (4 sub-criteria), social, economic and time criteria with different criteria importance (weight). The aims of this paper are: confirm the adequacy of using DEXi method when determining priorities in fulfilling irrigation plans; present the model for preparation of the input data; apply the method and give feedback on the application. Full article

Small earth dams usually lack the detailed seepage monitoring system that would provide high resolution data on changes in seepage flow. Alternative solution is monitoring of the temperature and electrical resistivity in the body of the dams. Geophysical methods are useful techniques for a non-destructive exploration of the subsurface. We have utilized the combination of electrical resistivity tomography (ERT), ground penetrating radar (GPR) and multi-depth electromagnetical conductivity meter (CMD) techniques to observe the inner structure, especially internal failures, of the historical earth-filled dams. Longitudinal and transversal profiles of four typical fishpond dams in the Czech Republic were measured within this research. The dams were constructed as early as in the 15th century, some of them went through minor reconstruction. The aim of the application of geophysical methods for investigation of old fishpond dams was to detect and localize the boundary of the dam foundation, new earth material from the reconstruction works, cone of water depression, technical objects location, potential internal erosion, cavities, inhomogeneity in the water content pattern and any other anomalies. The primary results show that the ERT is suitable to observe the dam stratification, dam foundation, bedrock below the dam and large anomalies. GPR is suitable for small objects and anomalies detection in the shallow depths. Full article

Un-managed surface and groundwater exploitation in coastal areas usually leads to deterioration of such sensitive ecosystems by means of water resources degradation and/or increased salinity. The coastal partof Marathon is a typical Mediterranean hydro-environment that hosts a naturally occurring coastal wetland linked to a typical coastal and today degraded hydrogeological system of a semi-arid region. A smart engineered Subsurface-Water-Solution (SWS)system composed ofan optimised Pump & Treat componentintegrated with an Aquifer Storage and Recovery (ASR) scheme in this area is envisagedcontribute to the remediationof the groundwater system and the wetland. Full article

A physical model of a pond dam was constructed at the Czech Technical University for the conducting of various related experiments including the application of sprayed bentonite. Importantly, the model allowed for the real-scale testing of a bentonite sealing layer which was applied in such a way as to provide protection against leakages along the concrete wall. The model of the dam will be carefully monitored so as to identify potential leakages once the reservoir of the experimental dam has been filled with water. The particle size distribution of the bentonite material and initial testing indicated that granulated “Bentonite 75” exhibits very good properties for the given purpose. Full article

The paper proposes an integrated modeling system consisting of a surface hydrology model, a water reservoir model, a Lake-Aquifer Interaction model, aground water model, and a transport and dispersion model to study ground water quality through two different operational management scenarios. The first scenario is examining the existing condition of groundwater quality without the reservoir operation while the second scenario is assessing the impact of the reconstruction of Lake Karla in the groundwater quality. The study highlights the importance of using an integrated hydrological modeling approach to investigate the groundwater quality in a region which is characterized by extensive agricultural activity. Full article

In recent years, mercury (Hg) concentration that exceeds the Maximum Contaminant Level Standard set by the World Health Organisation for drinking water has been detected in the groundwater of Skiathos Island in Greece. The island single source of urban water is groundwater; as a result, tap water has been characterised as unsafe for drinking and people rely on bottled water for their everyday needs. The origin and speciation of Hg in the aquifer is investigated with the use of the Pourbaix diagram, while the possible correlation with groundwater salinization due to seawater intrusion is examined. Full article

Climate change as a phenomenon of the recent years highly concerns scientists and governments. Global warming is the beginning of a domino effect with a lot and often huge consequences on the anthropogenic and natural environment. The present study aims at analyzing and understanding the driving factors, the impacts and the consequences of the climate change, while in parallel actions and policies are presented regarding its prevention. Additionally, an attempt is made to analyze data from 67 meteorological stations (Aegean Sea, Ionian Sea, Crete) to examine the occurrence and frequency of extreme weather phenomena and their consequences on the Greek Island region. Finally, conclusions are drawn and measures are proposed, aiming at the adjustment of the climate change planning on the Greek Island Area. Full article

Water network protection from accidental and intentional contamination is one of the most critical issues for preserving the citizen health. Recently, some techniques have been proposed in the literature to define the optimal sensor placement. On the other hand, through the definition of permanent DMAs (District Meter Areas), water network partitioning allows significant reduction in the number of exposed users through the full isolation of DMA. In this paper, the optimal sensor placement is coupled with water network partitioning in order to define the best location of isolation valves and control stations, to be closed and installed respectively. The proposed procedure is based on different procedures, and it was tested on a real water network, showing that it is possible both to mitigate the impact of a water contamination and simplify the sensor placement through the water network partitioning. Full article

The present paper illustrates some of results obtained in the GST4Water project concerning the development of appropriate metrics, methods and tools for the assessment of economic and environmental sustainability of urban water systems at different scales for a variety of stakeholders. At the household scale and based on data and algorithms to represent residential water demand, we reconstruct the behavior of domestic users and develop a suite of indicators accounting for consumption performances and sustainability, and a software tool geared at the needs of water consumers. Considering multiple scales ranging from household to urban, we develop a model based on urban metabolism, able to evaluate several performance indicators for both sustainability assessment and benchmark, comparing the impact of different management options for water demand and reuse. Full article

The correct management of Water Distribution Networks (WDNs) allows to obtain a reliable system. When a pipe failure occurs in a network and it is necessary to isolate a zone, it is possible that some nodes do not guarantee service for the users due to inadequate heads. In these conditions a Pressure Driven Analysis (PDA) is the correct approach to evaluate network behavior. This analysis is more appropriate than the Demand Driven Analysis (DDA) because it is known that the effective delivered flow at each node is influenced by the pressure value. In this case, it is important to identify a subset of isolation valves to limit disrupting services in the network. For a real network, additional valves must be added to existing ones. In this paper a new methodological analysis is proposed: it defines an objective function (OF) to provide a measure of the system correct functioning. The network analysis using the OF helps to choose the optimal number of additional valves to obtain an adequate system control. In emergency conditions, the OF takes into account the new network topology obtained excluding the zone where the broken pipe is located. OF values depend on the demand deficit caused by the head decrement in the network nodes for each pipe burst considered. The results obtained for a case study confirm the efficiency of the methodology. Full article

this study proposes the results of a research activity devoted to the analysis and development of methodologies, models and strategies, which allow integrating decentralized solutions such as rainwater harvesting, greywater reuse systems, and green technologies in buildings. A methodology based on a hydraulic/hydrological model developed by means of SWMM is presented. It allows estimating the optimal size of the storage tanks, considering the overall efficiency of the system, and calculating the wastewater overflows reduction. This study is carried out within the Work Package three (WP3) of the GST4Water project funded by the Emilia-Romagna Regional Council (Italy) through the European Regional Development Fund 2014–2020 ERDF—ROP. Full article

In this study an analysis of the water supply variability for three towns in Puglia (Southern Italy), Roccaforzata, Palagianello and Palagiano was carried out, based on a time series continuously recorded over three years. The towns’ population ranges between 1800 and 16,000 inhabitants and the flow data, collected with time steps of 10 min, are referred to drinking water in urban environment. In particular the frequency analysis on the series of daily maximum hourly peak coefficients, calculated using the observed dataset, was conducted in order to assess the stochastic behavior of the hourly peak water demand at local scale. Full article

This paper presents some of the results achieved within the framework of the GST4Water project concerning the development of a real time monitoring and processing system for water consumption at individual user level. The system is based on the most innovative technologies proposed by the ICT sector and allows for receiving consumption data sent by a generic smart-meter installed in an user’s house and transfer them to a cloud platform. Here, the consumption data are stored and processed in order to characterize leakage at district meter area (DMA) and at individual user level. Finally, the processed data, on the one hand, are returned to the Water Utility and can be used for billing, on the other hand, they provide frequent feedback to the user thus gaining full awareness of his consumption behaviour. Full article

To support their Integrated Water Supply Grid, Wessex Water recognized the need for a sophisticated control system. The Servelec Technologies pump optimization system OptiMISER was identified as the best tool for this function and has been in use in the Control Room since September 2014. Since then it has been controlling pumps and valves across the Warminster area, ensuring pro-active optimal management of that part of the network, as a precursor to full implementation over the Grid. Full article

The potential of micro-hydropower generation has been evaluated in seven community-owned rural water supply networks (CORWSN) in Ireland. The replacement of the existing infrastructure in place to reduce pressure in the networks with micro-hydropower turbines (Scenario 1) was considered. New potential locations for additional pressure reduction were also considered (Scenario 2). An assessment of the energy potential and economic viability of each site was carried out, including quantification of leakage reduction impacts. While only one of the seven CORWSNs showed two potential sites with power higher than 1 kW, the power generated can still have significant impacts on local energy demands. The estimated total energy saved in Scenario 2 ranged from 0.63 MWh year⁻¹ to 84.5 MWh year⁻¹ according to the micro-hydropower potential in each CORWSN. Furthermore, water savings from 4348 € m⁻³ to 73,264 € m⁻³ were estimated due to the reduction of leakage volume after installing micro-hydropower turbines at the potential sites detected in Scenario 2. Thus, the water cost saving associated to the reduction of leakage volume makes the incorporation of this element in the networks feasible. Full article

Pumps As Turbines (PATs) are a class of unconventional hydraulic turbines consisting of standard water pumps working in reverse mode as the prime mover. Such devices can be well suited for either in-pipe energy recovery or small-scale hydropower, but their practical application is hampered by the lack of comprehensive guidelines able to assist the designer in the determination of the optimal plant layout and the choice of equipment. In fact, the performances of a PAT will depend on factors such as its construction type, its size and the flow conditions under which the machine is expected to operate. Ultimately, the design of a PAT-based hydro scheme is a matter of trade-offs which are in most cases not trivial. An innovative software was developed in order to assist hydro designers and provide a visual aid when choosing between different layouts of the analyzed hydro scheme (e.g., more than one PAT in series/parallel, different shaft speeds), and has been applied to a real case study of energy recovery in a water network. Full article

The agricultural sector is one of the most significant users of water resources worldwide. Irrigation infrastructure has been modernized in recent years in many regions dedicated to agriculture, transitioning from traditional open channels to more efficient on-demand pressurized irrigation networks. Despite improvements in water efficiency, the modernization of these networks has led to increased energy demands of the irrigation sector. Several negative consequences have been linked to additional energy requirements of pressurized networks, such as the rising cost of irrigation water. Other consequence linked has been the excess pressure in certain locations that could be used to recover energy from these networks. This paper studies the excess pressure in pressurized irrigation networks and the conversion of this excess to usable energy by means of small-scale hydropower turbines. Twelve irrigation networks located in the South of Spain have been modelled, quantifying the excess pressure available for power generation. Over 1 GWh per annum has been estimated that could be recovered. Full article

In this paper preliminary results of the numerical assessment of PAT erosion, caused by the impingement of solid particles in the water flow, are provided and discussed. A CFD model was developed by the Università degli Studi di Napoli Federico II to investigate the fluid dynamics of a PAT and coupled with the in-house E-CODE developed by the Politecnico di Milano for wear estimation. The erosion simulations were performed to assess the wear of PAT components, namely inlet, impeller, volute and outlet pipe, for abrasive particles with different size, aiming at estimating the relation between the fluid dynamics of the slurry flow and the development of the erosion process. Full article

Pumps as turbines (PaTs) are becoming more and more attractive in Small Hydropower. PaTs are considered a cost-effective alternative to conventional turbines as long as their turbine characteristic curves can be predicted. Indeed, manufacturers need of a tool that could support them to predict the turbine mode performance from the knowledge of pump characteristics, in order to be competitive on the market. In this framework, a new 1-D prediction model is proposed for manufacturers in order to predict the entire characteristic of a PaT, by taking into account detailed geometrical information of the machine, hydraulic losses and the influence of the flow deflection with respect to the outlet blade angle of the runner during turbine operation. Full article

Nowadays Pumps working as Turbines (PaT) are devices widely used to perform energy recovery in hydraulic grids, thus improving their overall efficiency, and to build small hydropower plants. In this work, a centrifugal pump has been numerically investigated in turbine operating mode by means of the open-source CFD code OpenFOAM with emphasis on the flow field at the runner outlet. Due to the reduced number of blades in a PaT, the mean outlet relative velocity angle differs from the blade angle. In order to account for this phenomenon, the slip factor is introduced. The slip factor is investigated and its application to a 1D model is shown in order to highlight the improvement in predicting the characteristic curve of a centrifugal pump used in reverse mode as a turbine (PaT) especially at its part-load. Full article

In recent years, recovering energy while managing excessive pressure in water distribution networks (WDNs) has gradually taken hold through the use of Pumps as Turbines (PATs). Therefore, algorithms commonly used for the optimizations of WDNs require modifications to incorporate these devices. Within this study, an intermediate step toward a new Hybrid Genetic Algorithm (HGA) for the optimal placement and setting of PATs within WDNs is proposed. The described methodology is based on a non-linear optimization algorithm, the Powell Direction Set (PDS) method. For each WDN configuration with PATs, a non-linear univariate function, namely the energy production subjected to pressure and technical constraints, is maximized by the PDS method. The promising capabilities of the algorithm are demonstrated with a case study. Full article

Pumps As Turbines (PATs) can be installed in Water Distribution Networks (WDNs) to couple pressure regulation and small-scale hydropower generation. The selection of PATs in WDNs needs proper knowledge about both the performances of machines available in the market and the operating conditions of the network. In this paper, a procedure for the preliminary selection of a PAT is proposed, based on the design of the main parameters (the head drop and the produced power at the Best Efficiency Point, the impeller diameter and the rotational speed) to both maximize the producible power and regulate the exceeding pressure. Full article

This work shows the results of an experimental investigation on a domestic hydropower model assembled at the Laboratory of Environmental and Maritime Hydraulics of the Department of Civil Engineering, University of Salerno, Italy. Hydropower offers the opportunity to create a clean renewable source of energy, reducing carbon footprint and having a minimal impact on the environment. Small-scale hydropower plants in the domestic context are suitable for buildings with heights and roof surfaces that, in conjunction with a proper storage system, may yield capacities of up 100 kW. The device here adopted, mimicking the vertical part of a drain serving a flat complex, is composed of a storage tank of 60 l connected to a pressurized system fitted in the final downstream section with a nozzle. The available kinetic energy is converted in electricity thanks to a microturbine which drives a generator. The system is analyzed by: using different nozzles obtained by a 3D printer, varying the flowrate and attack angle at the microturbine and changing the number of blades. Full article

The nexus of food, energy, and water is one of the most complex issues that face society. By 2050 the Earth’s population is expected to exceed 9 billion and most of the population increase will occur in developing countries. In addition, water scarcity will be particularly pronounced in the Middle East/North Africa and the South Asia regions and is likely to worsen as a result of the climate change. Within this framework, we revised the use of the hydraulic ram as a possible solution to supply water in remote areas. Experimental results of a preliminary investigation carried on a hydraulic ram pump assembled at the Laboratory of Environmental and Maritime Hydraulics of the Department of Civil Engineering, University of Salerno, Italy showed that geometric parameters as well as material properties affect its operating efficiency. The effect of the impulse valve on the pressure temporal trend is assessed by processing video recordings taken with high-speed digital cameras with a sampling rate of 1 KHz. Most of its effect is produced when the percentage of valve opening is in the range 0–20%, where correspondingly the valve coefficient K_v varies of about 80%. Unsteady pressure profiles were detected by means of pressure transducers with an acquisition of up to 1 kHz. The system of acquisition revealed the existence of a family of transient shock waves which intensity depends on the system’s features. Full article

The urban water cycle spends energy to provide communities drinking water and to treat produced wastewater. The same cycle can also provide energy by exploiting the kinetic energy of water flowing into the network to turn turbines and generate electricity. In this framework, this work focuses on the hydropower potential arising from the installation of a water turbine at the end of the pipeline of the water supply system “New Aqueduct”, managed by the “Ausino S.p.A. Servizi Idrici Integrati” in the Campania Region, Italy. The plant allows to reach—in some circumstances—a minimum power level at which the return of the investment occurs in a reasonable time period. In facts, the supply system exhibits somewhere pressure heads of up to hundreds meters, a matter which has been seen of a certain relevance as attenuation systems such as pressure relief valves were adopted to reduce pressure levels. Today, this related 'waste of available potential energy’ can be conveniently avoided by installing proper energy recovery apparatuses as detailed in this study. Full article

South Africa is acknowledged to be not particularly endowed with the best hydropower conditions as it might be elsewhere in Africa and the rest of the world, however, large quantities of raw and potable water are conveyed daily under either pressurized or gravity conditions over large distances and elevations. There exists conduit hydropower generation potential in the water supply and distribution systems belonging to municipalities, water supply utilities and mines. Bloemwater, a water utility, constructed a stand-alone turbine, based on the available pressure and flow which generates a constant output ranging between 55 and 96 kW and when sufficient, supplies the head-office. Initially a manual changeover was utilized to switch between the hydropower and the local electricity supplier when the hydropower was insufficient to meet the demand i.e. switching of the full load from the one source to the other. To maximize the utilization of the hydropower, an automatic change over panel was developed to deal with the variable electricity demand from the office. The office building’s electrical distribution was divided into different distribution boards to allow each sector to be supplied and switched individually with 6, PLC controlled, motorized change-over switches. The PLC constantly evaluates and subsequently executes switching actions so that Bloemwater can utilize the maximum renewable hydropower, but also limits power interruptions to a minimum because of these switching actions. This technical paper describes the development of this conduit hydropower plant by evaluating the interrelationship of water supply, electricity demand and operating cycles, providing Bloemwater with the optimum solution with increased resiliency and sustainability. Full article

Measurements of Cryptosporidium and Giardia in water have been compiled from over 50 references comprising data from over 20 countries throughout Europe from Scandinavia to the Mediterranean, from the Atlantic to the Urals. Data predominantly reported after 2000 and mostly by IMS-IFA based analysis clearly demonstrate the distribution of these waterborne pathogens across all parts of the continent. The presence of these organisms at readily detectable levels in surface water used for public water supply corresponds to epidemiological evidence describing the prevalence of cryptosporidiosis and of giardiasis in all countries of Europe. Where the extent of data from individual references has permitted, cumulative frequency analysis has been used to describe typical (median) concentrations and variability (standard deviation). These estimates are presented with accompanying data from elsewhere showing the relation of occurrence levels and degrees of variation as part of a global spectrum. Full article

Public health implications of Cryptosporidium and Giardia (C&G) in surface water depend on the characteristics of their occurrence at locations relevant to public water supplies. Recent detailed multi-location and long-term data sets have provided an accurate and complete understanding of occurrence features not previously available. Poisson statistics describe oocyst and cyst concentrations that are characteristically low with respect to the limit of detection of best available analytical methods. The IMS-IFA based analytical methods (e.g., ISO 15553, USEPA 1622/1623) provide reliable data on levels of both C&G in water. Recovery efficiency varies widely and must be measured to give concentration data that can be compared between disparate locations and sampling times. Analysis of samples at a minimum monthly frequency using sufficient sample volumes, e.g., 50 L, has shown that C&G are virtually universal in surface water, continuously, and at levels consistent with catchment conditions. Some basic rules of monitoring and data analysis derived from this background information will ensure that monitoring effort and cost are applied in the most efficient and effective manner. Full article

Free-living amoebae (FLA) can be found both in natural aquatic environments and in artificial, man-made aquatic environments. For a long time, (naked) FLA were considered to be harmless protozoa of soil and water. However, research since the 1960s has demonstrated that FLA can be pathogenic to humans and animals with nearly 100% morbidity from some strains. As etiological agents of the so-called Acanthamoebiasis, the Acanthamoebae can trigger several specific diseases (or symptoms) in humans. The amoebiasis of the central nervous system is called granulomatous amebic encephalitis (GAE), when Acanthamoebae are the etiological agents, showing subacute to chronic progress. GAE differs clinically from the primary amoebic meningoencephalitis (PAM(E)), which is caused by Naegleria fowleri. The Acanthamoeba keratitis is not necessarily associated with an immune suppression, but rather with a trauma, exposure to contaminated water or, particularly, the improper handling of contact lenses, which promotes infection. The clinical picture of GAE by Balamuthia mandrillaris is characterized by headache and neck stiffness. The infection is chronic and the time between infection and appearance of neurological symptoms may range from one month to about two years. The prevalence of FLA in water networks is associated with biofilms, where the amoebae live within a biocoenosis sympatric with other microorganisms. These biofilms serve as feeding grounds for the FLA and provide protection to a certain degree while the FLA adhere to the surfaces. In such a biocoenosis there are multiple interactions between FLA and other microorganisms: In addition to their role as pathogens, FLA are known to serve as host of and vehicles for diverse intracellular organisms (bacteria, viruses, eucaryonts), some of them being natural human pathogens. They act as reservoir or vehicle for various microorganisms such as various Legionella sp., Listeria monocytogenes, Pseudomonas aeruginosa and some Mycobacterium sp. In the cyst-stage of the FLA these intracellular organisms (endocytobionts) are protected to a high degree against any adverse environment (FLA as “Trojan horse”). This host-endocytobiont relationship may further lead to health risks in terms of the development of pathogenicity/virulence and antibiotic resistance (FLA as “Trainings ground”). Full article

The aim of this study was to gather information on the spread of antibiotic resistance in Escherichia coli isolates from wells, boreholes and untreated drinking water in islands of Greece. We analyzed for antibiotic resistance 235 E. coli strains isolated from untreated drinking water of small rural communities, and ground water from 4 islands. Resistance was tested against Norfloxacin, Ciprofloxacin, Levofloxacin, Amoxicillin and Cefaclor. More than half (54.9%) were resistant to at least one of the antibiotics tested. Of these 26.3% showed multiple resistance (to two or more antibiotics). Strains from drinking water sources were overall more sensitive. Frequent resistance was observed for Amoxicillin (38.3%) and Levofloxacin (28.5%), low for Norfloxacin (5.5%). Full article

Water and energy are two inextricably linked resources of great importance, as they are the key for satisfying basic human needs. In this study a water–energy nexus analysis is conducted in order to achieve a sustainable supply and effectively manage water and energy at city level. Different electricity uses such as domestic, agricultural and commercial are compared and tested on how they correlate with water use. Moreover, time series of water and energy consumption for the island of Skiathos are analyzed using specific distance metrics. The results of the analysis show that water and energy are intimately related. Full article

To enable effective decision-making at the entire city level, both surface water and groundwater should be viewed as part of the extended urban water ecosystem with its spatiotemporal availability, quantity, quality and competing uses being taken into account. The Water4Cities project aims to build an ICT solution for the monitoring, visualization and analysis of urban water at a holistic urban setting to provide added-value decision support services to multiple water stakeholders. This paper presents the main stakeholders identified, the overall approach and the target use cases, where Water4Cities platform will be tested and validated. Full article