An introduction of a multi‐soil‐layering system: a novel green technology for wastewater treatment in rural areas

Multi‐soil‐layering (MSL) systems are designed for municipal wastewater, livestock wastewater and polluted river water treatments. They are mainly composed of soil mixture block layers and water‐permeable layers (PL). The MSL system overcomes many of the shortcomings of conventional soil treatment systems such as easy clogging, large land requirement and low hydraulic loading rate. This paper summarizes the structure, purification mechanism and practical application of the systems for different kinds of wastewater treatment. The paper also compares MSL systems with other decentralized systems such as wetland and compact filter systems in their respective structures and treatment efficiencies. Finally, the paper gives a rough evaluation of the lifespan and cost of an MSL system based on its material composition.     

Challenges to surface water quality in mid‐sized African cities: conclusions from Awetu‐Kito Rivers in Jimma,south‐west Ethiopia

Rapid urbanization and industrialization, uncontrolled population growth, indiscriminate waste discharge and poor infrastructure are problems that African cities are facing. This paper describes an exemplary case study from Jimma, south‐west Ethiopia. A cross‐sectional study was conducted along the Awetu‐Kito drainage system in Jimma town to assess the level of pollution from urban dwellers and related activities. The study indicates that the Environmental Protection Agency (EPA) norms for biochemical oxygen demand (BOD), dissolved oxygen (DO) and orthophosphates are not met downstream of the major industrial and institutional activities. Small‐scale industries, Jimma University and residential areas contributed 50, 15 and 23% pollution load on the river, respectively. It can be concluded that the pollution effect in Jimma town is mainly as a result of the growing (uncontrolled) industrial activities and not to discharge of household wastewater. Given the same trends of urbanization and population growth, similar development (socio‐economic) indicators and similar climatic conditions, the key findings for Jimma are transferable to other mid‐sized African cities.     

Third‐ and fifth‐order finite volume schemes for advection–diffusion equation with variable coefficients in semi‐infinite domain

In the present paper, a novel numerical model based on the finite volume method is established to predict a time‐dependent, one‐dimensional, advection‐diffusion equation with variable coefficients in a semi‐infinite domain. The third‐and fifth‐order schemes are employed to solve the above‐mentioned equation. Totally, two dispersion problems are used to simulate various conditions as follows: (i) solute dispersion along steady flow through inhomogeneous domain and (ii) solute dispersion along temporally dependent unsteady flow through inhomogeneous domain. The inhomogeneity of the domain is provided by spatially dependent flow. The uniform node distribution is considered to divide the problem domain into a collection of smaller parts. Analytical solutions proposed in the literature are employed to demonstrate the accuracy and reliability of the suggested model. Meanwhile, the results of the aforementioned approaches are compared with the performance of the quadratic upstream interpolation for convective kinetics scheme. Lastly, the accuracy of the implemented schemes in developed model are discussed and evaluated.     

Effects of run‐of‐the‐river hydropower plants on the surface water quality in the Solakli stream watershed,Northeastern Turkey

In recent years, Turkey has turned its attention to alternative energy sources rather than fossil fuels. The Eastern Black Sea Region of Turkey has steep mountains with hilly topography and has large potential in terms of energy production with run‐of‐the‐river hydropower plants (RHPPs). In this study, the effects of two RHPPs on some water quality parameters were examined in the Solakl? stream watershed. This research was conducted over the course of 12 months (January–December 2014). In total, 12 sampling points were selected and various water quality parameters, such as temperature, pH, dissolved oxygen, total suspended solids, electrical conductivity, total dissolved solid, chloride and salinity, were monitered at each point. Statistically, significant changes occured in water quality parameters such as total suspended solids, pH and temperature. In particular, total suspended solids ranged from 10 to 440 mg/L.These results suggest that the RHPP negatively effect water quality and quantity in the main stream in both the operational and constructional phases.     

Application of surrogate artificial intelligent models for real‐time flood routing

Developing a robust flood forecasting and warning system (FFWS) is essential in flood‐prone areas. Hydrodynamic models, which are a major part of such systems, usually suffer from computational instabilities and long runtime problems, which are particularly important in real‐time applications. In this study, two artificial intelligence models, namely artificial neural network (ANN) and adaptive neuro‐fuzzy inference system (ANFIS), were used for flood routing in an FFWS in Madarsoo river basin, Iran. For this purpose, different rainfall patterns were transformed to run‐off hydrographs using the Hydrologic Engineering Center (HEC)‐1 hydrological model and routed along the river using HEC river analysis system RAS hydrodynamic model. Then, the simulated hydrographs with different lag times were used as inputs for training of ANN and ANFIS models to simulate flood hydrograph at the basin outlet. Results showed that the simulations obtained from ANN and ANFIS coincided with the results simulated by the HEC‐RAS, and application of such models is strongly suggested as a backup tool for flood routing in FFWSs.     

Flow measurement with multi‐instrumentation in a tidal‐affected river

Flow measurements in a tidal‐affected river provide important information of cyclic flow pattern characteristics in temporal and spatial variations. Reliability and accuracy of measured flow data can provide for numerical model calibration and verification. In the present study, we measured tidally affected river flow in the Danshui River of northern Taiwan during the 2008 summer and fall. The measured flow data, produced by both state of the art and conventional instruments including particle tracking velocimetry (PTV), acoustic Doppler profiler (ADP), horizontal acoustic Doppler current profiler (H‐ADCP) and Price‐type current metre (PCM) were compared and correlated during several tidal cycles. The mean flows by ADP were similar to that by PCM and highly correlated with those by PTV and H‐ADCP. Index velocity rating between ADP and H‐ADCP separately computed during the flood and ebb tides shows good correlation for the ebb tide and poor correlation for the flood tide due to subsurface maximum velocity in the middle‐ to near‐bottom layers.     

Evaluation of the water quality in the Guadarrama river at the section of Las Rozas‐Madrid,Spain

The variation of the water quality of the Guadarrama river and its tributaries in a section of Las Rozas‐Madrid, Spain, was studied during the time period between January 2003 and January 2008. The parameter water quality index (WQI) was used to determine the water quality based on the conventional parameters of pollution. It was found that the WQI was slightly affected in the section evaluated. The value of the WQI was in the range of 56–64, which corresponded to the classification of ‘good quality’. It was determined that 64.3% of the organic matter present in the river was removed in the section of Las Rozas‐Madrid. The river acted as a plug flow reactor and a first‐order kinetics governed the ultimate biological oxygen demand (BOD₅) (BOD_U) decay. The value of the first‐order constant demonstrated the river's high self‐purification capacity. In addition, a high linear relationship was found between the WQI and the dissolved oxygen deficit (D). Therefore, a quick determination of WQI may be carried out if the values of D are known. These are easily obtainable by field measurements.     

Monitoring,river restoration and the Water Framework Directive

Monitoring is an important aspect of any procedure that seeks to determine whether a technique has worked effectively. The river restoration process is no different. Unfortunately, monitoring is often not undertaken due to constraints on time and resources, as well as the commonly held belief that river restoration is inherently a good thing and, as a result, monitoring is unnecessary. There are many reasons to monitor projects and among the most important is the need to learn from experiences and for regulatory compliance. This paper examines the issues associated with the monitoring of river restoration schemes. In particular, it details monitoring selection models focusing on those associated with ecology and geomorphology. The paper also considers the requirements of monitoring schemes that will help deliver the goals of the Water Framework Directive (WFD).     

STRATEGIC AND PROJECT LEVEL RIVER RESTORATION PROTOCOLS — KEY COMPONENTS FOR MEETING THE REQUIREMENTS OF THE WATER FRAMEWORK DIRECTIVE (WFD)

The number of river restoration projects undertaken in the UK has increased rapidly over the last five years. However, schemes are still largely undertaken on an ad-hoc basis rather than part of a co-ordinated, strategic, catchment restoration strategy. Additionally, project level restoration is rarely initiated through a systematic approach that involves all stages from baseline studies through to design, installation, monitoring and post-project appraisals. The need for both strategic and project levels to be undertaken effectively is necessary if the requirements of the Water Framework Directive (WFD) are to be met. This directive has the potential to significantly increase the number of schemes, as restoration of surface water bodies has become a key duty of member states. There exists, therefore, a need for a holistic catchment scale approach to restoration to be adopted to maximise benefit to the fluvial systems and ensure compliance. This paper outlines key components of strategic and project level protocols for river restoration from a UK perspective.     

A dimensional analysis‐based model for the prediction of nitrogen concentrations in Laborec River,Slovakia

During the past decades, several models that predict the concentration profiles after a discharge of pollutants in a river have been developed. A model that predicts nitrogen concentrations in a river has been developed and is presented in this paper. The developed model that determines nitrogen concentrations in a water stream is based on a dimensional analysis. Fundamentals of the modelling of the pollutant predictions in a water stream consist of a derivation of function dependency from expressed non‐dimension arguments. Non‐dimension arguments are stated from variables, which influence the occurrence of pollutants. The model for the prediction of nitrogen concentrations in water streams has been developed for the Laborec River (eastern Slovakia). The differences between the nitrogen concentrations predicted from developed models and measured concentrations in the river are also discussed here.     

Disturbance of water‐air temperature synchronisation by dam reservoirs

A thermal regime of aquatic ecosystems determines the possibility of survival and development of aquatic biota. Thermal stratification of river water impounded by dam reservoirs can cause a permanent disturbance in the naturally existing water‐air temperature relationship downstream of reservoirs. This article aims at determining the role of dam reservoirs in the disturbance of naturally shaped synchronous behaviour of water‐air temperatures. The object of the analysis is the Carpathian river Dunajec downstream of a reservoir complex built in 1994–1997. Results of spectral analysis indicate that the annual scale is the main scale of water temperature (WT) variation, and this scale corresponds to the main frequency of phase synchronisation. However, following the reservoirs construction, the definite synchronous behaviour of interacting air and WTs was apparently distorted, because the response time of WT to changing atmospheric conditions has considerably increased in comparison with the predam period.     

Comparative experimental study of full‐scale H‐subframe using a new industrialized building system and monolithic reinforced concrete beam‐to‐column connection

Industrialized building system (IBS) is a construction process that uses techniques, products, components or building systems that involve prefabricated components and on‐site installation. The structural behaviour of a prefabricated frame structure is widely affected by the specifications of the beam‐to‐column connection. The understanding on the real behaviour of a connection can be assessed by conducting full‐scale experimental tests. In this study, a new IBS hybrid steel–concrete connection in a full‐scale H‐subframe under monotonic loading is investigated. This innovative connection system, consists of precast concrete beam‐and‐column elements with embedded steel end connectors, is patented as Smart IBS. This paper reports the testing procedures and results of this semi‐rigid IBS beam‐to‐column connection to obtain the important attributes of the connection as well as its comparison with monolithic cast‐in‐place reinforced concrete model. The height of both H‐subframes is 3.3 m while the free length of the beam is 3.2 m. The incremental loads were applied as two point loads in one‐third and two‐third of the beam length. The characteristic relationships of the connection such as load to mid‐span deflection, strength, stiffness, ductility, failure modes and crack patterns are studied and compared between both structural systems. Copyright © 2012 John Wiley & Sons, Ltd.     

Dual‐steel frame consisting of moment‐resisting frame and shape memory alloy braces subjected to near‐field earthquakes

In this paper, concentric braced frames are combined with moment‐resisting frame (MRF) as a dual system subjected to near‐field (NF) pulse‐like and far‐field ground motions. The braced frame in this system configuration consists of steel buckling‐restrained braces (BRB model), braces with shape memory alloy (SMA model), or combination of BRB and SMA braces (COMBINED model). Some prototype structures of the proposed systems are designed according to the code recommendations. Then, the nonlinear models of the considered structures are developed in SeismoStruct software, and nonlinear time history analysis (NLTHA) is implemented. NLTHA is performed subjected to earthquake record sets at maximum considered earthquake (MCE) and design base earthquake (DBE) levels, and responses of the systems are investigated and compared with each other. Among the examined models, the SMA and COMBINED models exceed the CP level subjected to NF‐MCE record set. Therefore, more investigation is needed for using short‐segment SMA braces in the dual‐steel frames in NF area.     

Developing a new method for spatial assessment of drought vulnerability (case study: Zayandeh‐Rood river basin in Iran)

The paper presents an approach to spatially representative depiction for assessing the vulnerability of central Iran's Zayandeh‐Rood river basin to drought using multiple indicators. Drought conditions prevailed in the study basin from 2002 to 2007, with an annual rainfall deficiency of 45 to 55%. Multi‐attribute decision making (MADM) methods develop a framework to evaluate the relative priorities of drought assessment based on a set of preferences, criteria and indicators. The proposed MADM process uses well‐known techniques for product weights analytic hierarchy process (AHP) and order preference (TOPSIS). These indicators include the Standard Precipitation Index (SPI), water demand, the Palmer Drought Severity Index (PDSI) and the Groundwater Balance and Surface Water Supply Index (SWSI). Indicators' spatial information was categorised in layers prepared in the spatial domain using a geographic information system (GIS). The alternatives were ranked and presented using TOPSIS. Results show that the proposed method was highly effective in representing assessments of drought vulnerability.     

Analysis of outrigger‐braced reinforced concrete supertall buildings: Core‐supported and tube‐in‐tube lateral systems

This study is primarily focused on the approximate analysis of reinforced concrete outriggers which are commonly used in the design and construction of supertall buildings subject to distributed horizontal loads. Existing global analysis formulae that provide preliminary results for lateral deflections and moments are reviewed for two lateral load resisting systems, namely, core‐supported‐with‐outrigger (CSOR) system and less frequent tube‐in‐tube‐with‐outrigger (TTOR) system. These formulae are only applicable for CSOR and neglect the reverse rotation of the outrigger actually suffered due to the propping action from the outer columns and give rather high predictions of the deflections compared with advanced numerical finite element (FE) models. An improved model is proposed which overcomes this issue and provides more consistent results to FE predictions. The same can also be extended to TTOR. Several case studies are investigated to verify the accuracy of the proposed methodologies. The global analysis is followed by the local analysis of reinforced concrete outrigger beams using strut‐and‐tie modelling and non‐linear FE analysis to obtain optimized reinforcement layouts (reduction of quantities of reinforcement). The results highlight the different challenges in detailing such structural members which are heavily loaded (high congestion of reinforcement), and the behaviour at failure can be brittle.     

Development of a re‐aeration equation for the simulation of dissolved oxygen in degraded streams

Discharge of domestic and industrial wastewater into the water bodies is the prime source of degradation of the freshwater ecosystem. Re‐aeration of the river allows the rejuvenation of river water quality by absorbing oxygen from the atmosphere at the air‐water interface. An accurate estimation of the re‐aeration coefficient helps to determine the assimilative capacity of streams and wastewater management also. This paper aims to develop the re‐aeration equation and its validation by modelling dissolved oxygen of the Yamuna River. Predictive re‐aeration equations are used to identify their applicability to the study area and the new equation is designed using multivariate statistical regression techniques. QUAL2Kw model is used to validate the equation by modelling dissolved oxygen. Results indicate that the developed equation performs better than the predictive re‐aeration equations for the prediction of water quality.     

A multi‐time‐delay compensation controller using a Takagi–Sugeno fuzzy neural network method for high‐rise buildings with an active mass damper/driver system

An active mass damper/driver (AMD) control system with a single mass has such problems as the excessive weight of the auxiliary mass and the insufficient capacity of its driving equipment. It is necessary to work through multiple subsystems to achieve effective control of high‐rise buildings. However, the time‐delay effect in each subsystem impedes its application in engineering practices. In the paper, an augmented system based on a zero‐order hold is proposed for discrete‐time systems with multiple time delays, and then the system is designed according to the compensation strategy using a classical linear quadratic regulator algorithm. After that, the sample data obtained from the zero‐order hold compensation controller is trained through a Takagi–Sugeno fuzzy neural network method. Finally, a new simplified compensation controller is designed to further shorten the time consuming calculation on the premise of guaranteeing its control effects and parameters. To verify its effectiveness, an AMD system in a high‐rise building is regarded as an example, and the proposed methodology is also applied to an experiment of a four‐story frame. Both results demonstrate that the method can enhance the performance of an AMD system with multiple time delays.     

Protecting water and wastewater utilities from cyber‐physical threats

Recent events have highlighted the need to address cybersecurity threats to systems supporting critical infrastructure and federal information systems which are evolving and growing. These threats have become ubiquitous in the United States, and throughout the world. Many information and communications technology (ICT) devices and other components are interdependent so that disruption of one component may have a negative, cascading effect on others. In the United States, the Federal role in cyber‐security has been debated for more than a decade but creating a policy is complicated because in the United States, State and local governments are the major institutions responsible for providing services to their populations. It is important that critical infrastructure such as Publically Owned Treatment Works (POTWs) and Public Water Systems (PWSs) adopt suitable countermeasures to prevent or minimise the consequences of cyber‐attacks. This paper discusses both technological and procedural techniques that can be used to protect against cyber‐threats.     

Parametric study and design approach of off‐center bracing systems

This paper presents an effective approach for the seismic design of off‐center bracing systems (OBSs). The nonlinear behavior of an OBS can be specified by evaluation of two yielding stages representing tensile yielding of different bracings. This can be achieved when stiffness of the corner brace member is deliberately considered less enough to act as a fuse‐like component. An accurate two‐dimensional finite element modeling for the geometric and material nonlinearity of such systems considering buckling behavior of the brace members is developed. Through an extensive parametric study, the optimal ratios of the influential parameters of OBS are obtained, and their effects on the nonlinear performance of OBS are evaluated. Next, a number of design graphs for determining the trilinear behavior model of different types of the OBS are presented. The aforementioned diagrams are included of non‐dimensional force and stiffness parameters that can be used for other frames with the same properties. Then, by extracting an equivalent bilinear model from the trilinear approximated behavior, an effective design algorithm based on the calculation of system's ductility under desired earthquake is presented, and finally, applicability of the proposed design approach is well demonstrated through an example problem.     

Experimental investigation of a self‐centering precast concrete beam‐to‐column connection with top and bottom friction energy dissipaters

The new friction material, non‐asbestos organic, and Belleville springs are applied to the friction energy dissipaters (FEDs) to improve its friction performance. The new high‐performance FEDs are placed in the top and bottom parts of the self‐centering precast concrete (SCPC) beam‐to‐column connections, which have inherently reduced residual deformation caused by posttensioned tendons, to enhance energy dissipation efficiency. Besides, the reasonable design of the connection between FEDs and backbone members makes it easy for the disassembly of all members, which significantly enhances the repair efficiency after a major earthquake. Theoretical analyses and 14 tests were performed on a full‐scale specimen, which were assembled two times, and the friction pads were replaced one time, to investigate the effects of various parameters on the performance of such FED‐SCPC beam‐to‐column connections. The influence of key design parameters on the hysteretic behaviors, such as stiffness, loss of posttensioned tendons force, self‐centering capacity, and energy dissipation capacity, has been analyzed. The test results indicate that the FED‐SCPC beam‐to‐column connections can achieve significant and reliable energy dissipation levels while maintaining self‐centering capabilities. The experimental and theoretical results can provide certain references for the seismic design and assembly of such structures.