Significant Water Loss Research Articles

Start-up strategies for nitrification and manganese oxidation on a single stage RSF for drinking water production

Abstract In drinking water production from groundwaters, biological rapid sand filters (RSFs) can be used for ammonium and manganese removal in aerobic conditions. However, in some boreholes, a start-up duration of several months is required to reach the required removal capacity, leading to significant water losses. Moreover, in specific industrial cases, no exogenous biomass under the form of backwash water or activated sludge can be added to accelerate the process, and different approaches are seldom considered in the literature. With the aim of saving water, start-up strategies coupling water temperature increase and substrate dosing were studied to accelerate the installation of biological activities in a pilot plant fed with borehole water. These set-ups enabled a substantial acceleration of nitrification but no improvement of manganese oxidation in the experimental conditions, although the experiments showed no clear negative influence of nitrification, through nitrite accumulation, on biological manganese oxidation. To further save energy and reduce water loss, outlet water recirculation at a rate of 75% during the start-up phase was validated. The proposed start-up strategy enabled the complete installation of active biofilms with a mean start-up time reduction of 36% and water use reduction of 84% compared to the reference natural conditions.

GPS Constraints on Drought‐Induced Groundwater Loss Around Great Salt Lake, Utah, With Implications for Seismicity Modulation

AbstractGreat Salt Lake (GSL), Utah, lost 1.89 ± 0.04 m of water during the 2012–2016 drought. During this timeframe, data from the Gravity Recovery and Climate Experiment mission underestimate this mass loss, while nearby Global Positioning System (GPS) stations exhibit significant shifts in position. We find that crustal deformation, from unloading the Earth's crust consistent with the observed GSL water loss alone, does not explain the GPS displacements, suggesting contributions from additional water storage loss surrounding GSL. This study applies a damped least squares inversion to the three‐dimensional GPS displacements to test a range of distributions of groundwater loads to fit the observations. When considering the horizontal and vertical displacements simultaneously, we find a realistic distribution of water loss while also resolving the observed water loss of the lake. Our preferred model identifies mass loss up to 64 km from the lake via two radial rings. The contribution of exterior groundwater loss is substantial (10.9 ± 2.8 km3 vs. 5.5 ± 1.0 km3 on the lake), and greatly improves the fit to the observations. Nearby groundwater wells exhibit significant water loss during the drought, which substantiates the presence of significant water loss outside of the lake, but also highlights greater spatial variation than our model can resolve. We observe seismicity modulation within the inferred load region, while the region outside the (un)loading reveals no significant modulation. Drier periods exhibit higher quantities of events than wetter periods and changes in trend of the earthquake rate are correlated with regional mass trends.

A green MXene-based organohydrogel with tunable mechanics and freezing tolerance for wearable strain sensors

Conductive hydrogels have attracted considerable attention owing to their potential for use as electronic skin and sensors. However, the loss of the inherent elasticity or conductivity in cold environments severely limits their working conditions. Generally, organic solvents or inorganic salts can be incorporated into hydrogels as cryoprotectants. However, their toxicity and/or corrosive nature as well as the significant water loss during the solvent exchange present serious difficulties. Herein, a liquid-like yet non-toxic polymer-polyethylene glycol (PEG) was attempted as one of the components of solvent for hydrogels. In the premixed PEG-water hybrid solvent, polyacrylamide (PAAm) was in situ polymerized, overcoming the inevitable water loss induced by the high osmotic pressure of the PEG solution and achieving tailored water capacity. Interestingly, the mechanical strength (“soft-to-rigid” transition) and anti-freezing properties of organohydrogels can be simultaneously tuned over a very wide range through adjusting PEG content. This was due to that with increasing PEG in solvent, the PAAm chains transformed from stretching to curling conformation, while PEG bonded with water molecules via hydrogen bonds, weakening the crystallization of water at subzero temperature. Additionally, a highly conductive Ti3C2Tx-MXene was further introduced into the organohydrogels, achieving a uniform distribution triggered by the attractive interaction between the rich functional groups of the nanofillers and the polymer chains. The nanocomposite hydrogels demonstrate high electrical conductivity and strain sensitivity, along with a wide working temperature window. Such a material can be used for monitoring human joint movement even at low temperature and has potential applications in wearable strain sensors.

Analysis of a vapor compression refrigeration system using a fog-cooled condenser

Traditional vapor compression refrigeration system with a water-cooled condenser involves the use of a cooling tower, which leads to significant water losses and higher power consumption. In the proposed work, an attempt has been made to eliminate this water loss by doing away with cooling towers, their related water treatment, and pumping systems while improving the cooling efficiency. The current work involves analysis, testing and performance validation for a 1-ton vapor compression refrigeration system using a fog-based condenser. Here, tiny fog droplets are spread onto the hot surface of the condenser which evaporate quickly. The formed water vapor is recovered further in a water recovery heat exchanger resulting in zero water loss. This trend of water conservation is expected to continue for large-scale cooling because water is recovered in a closed system. The thermal properties were measured under given operating conditions. An analysis of performance parameters was done experimentally, on the air side; and theoretically, on the refrigerant side. The results obtained were as follows: 4.7 Coefficient of performance, 16 Energy Efficiency Ratio, and 844 W/ton consumption. Further, the heat transfer area obtained for the fog-based system is 3.5 times more than that of a water-cooled condenser for the same heat exchanger. For a 1-ton capacity of refrigeration, around 50% increase of COP was observed with the fog-based condenser compared to an air-cooled condenser (which is expected to be higher for larger capacities). Also, the effects of supersaturation and inlet fog temperature on the system performance were studied.

Environmental and economic issues concerning the use of wet scrubbers coupled to bagasse-fired boilers: a case study in the Brazilian sugarcane industry

For decades, wet scrubbers have been used to control particulate matter (PM) emitted by bagasse-fired boilers in the sugarcane industry. This choice was justified by their acceptable performance in meeting environmental standards, the abundance of water resources, and the fact that their operation was simpler and less expensive than other dry cleaning operations. However, the progressive tightening of PM emission limits, as well as the need for more rational water and wastewater management in these applications, has changed this aspect of the industry. Despite the extensive technical literature on wet scrubbers, the lack of up-to-date indicators of their performance in sugarcane industries has prevented the optimization of wet scrubbing processes. This paper clearly shows that the use of wet scrubbers can result in significant water and heat losses, as well as high operating costs for wastewater treatment stations (WTSs). Mass and energy balances were determined for a typical ethanol-sugar plant operating in Brazil, which is the world's largest sugarcane producer. The key boiler and scrubber performance indicators were evaluated experimentally over the course of a crop season and were compared to the legal particulate emission and water quality requirements in Brazil. The boiler processed an average of 114.8 t/h of bagasse containing 46.8% moisture and generated 4.75 t of gas and 28.2 kg of PM for each ton of dry burned bagasse. Of the total PM (ash and soot), 68% was collected as dry material in the grate, heat exchangers, and multicyclone; 25% was collected in the wet scrubber; and 7% was emitted to the atmosphere, in compliance with the Brazilian standards. The operation of the WTS linked to the gas cleaning system was inefficient, using 70% of the water to convey the dry PM retained in the boiler, heat exchangers, and multicyclone and only 30% to operate the wet scrubber. Evaporation caused the loss of 10.5% of the scrubbing water to the atmosphere. The transportation of moist cake (7.9 t/h, 78% wb) for disposal in fields resulted in significant fuel costs and water losses. The operation of the WTS accounted for 62% of the total capital expenditure of the cleaning system, while the wet scrubber accounted for only 38%. This work provides updated performance indicators and alternatives for optimizing a gas cleaning system to promote more rational water and wastewater management and savings for the sugarcane sector.Graphic abstractRequired collection efficiency for bagasse boilers based on the inlet PM concentration and emission limits imposed in Brazil, China, and most countries

Penurunan Kepadatan Eceng Gondok (Eichhornia crassipes (Mart.) Solms) di Danau Rawapening dengan Memanfaatkannya sebagai Bahan Dasar Kompos

High sedimentation and the entry of organik and inorganik pollutants, especially P and N, have led to the eutrophication of Rawapening Lake waters. These conditions triggered an uncontrolled booming of water hyacinth aquatic weed (Eichhornia crassipes (Mart.) Solms). The presence of water hyacinth triggers a significant loss of water compared to local weeds through evapotranspiration. The invasion of water hyacinth causes various problems, including depletion of water oxygen content which has an impact on decreasing fish production, damaging natural beauty, and also affecting public health. Many efforts to control water hyacinth in Rawapening Lake have been carried out both physically and by utilizing biological agents. One of the efforts to control the density of water hyacinth in Rawapening Lake is to use it as compost raw material. Water hyacinth contains various elements that are useful for making quality compost, including calcium (Ca), sodium (Na), potassium (K), iron (Fe), copper (Cu), and others. Water hyacinth root contains sulfates and phosphates, the leaves contain carotin and the flowers contain delphinidin-3-diglucosida. The various nutrients contained in water hyacinth make quality compost capable of meeting the nutritional needs of cultivated plants. This article aims to review the use of water hyacinth as a basic material for making compost which is useful for fertilizing agricultural cultivation activities

Phosphates-Containing Interpenetrating Polymer Networks (IPNs) Acting as Slow Release Fertilizer Hydrogels (SRFHs) Suitable for Agricultural Applications.

Novel, phosphorus-containing slow release fertilizer hydrogels (SRFHs) composed of interpenetrating polymer networks (IPNs) with very good swelling and mechanical properties have been obtained and characterized. It was found that introducing organophosphorus polymer based on a commercially available monomer, 2-methacryloyloxyethyl phosphate (MEP), as the IPN’s first component network results in much better swelling properties than for a terpolymer with acrylic acid (AAc), 2-methacryloyloxyethyl phosphate (MEP) and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) when the same weight ratios of monomers are employed. The procedure described in this paper enables the introduction of much larger amounts of phosphorus into polymer structures without significant loss of water regain ability, which is crucial in the application of such materials in the agricultural field.

Assessing Climate Change and Land-Use Impacts on Drinking Water Resources in Karstic Catchments (Southern Croatia)

The Mediterranean freshwater resources, mostly represented by groundwater, are under increasing pressure due to natural and anthropogenic factors. In this study, we investigated possible negative effects of climate change and land-use practices on water quality and availability from five springs in the karstic catchments in southern Croatia. The investigated springs are used in the regional public water supply system. Firstly, we employed hydrogeochemical field and laboratory analyses to detect possible traces of anthropogenic activity originating from specific land use. Additionally, we performed hydrological and climate modeling to detect changes in the air temperature, precipitation, and runoff. In particular, we used three regional climate models (Aladin, RegCM3, and Promes). The results estimated an increase in the mean annual air temperature, changes in the precipitation patterns, and reductions in runoff in the study area. Hydrochemical analyses showed standard ion concentrations for karst groundwaters, elevated sulfates due to evaporite deposits in the hinterland, surprisingly low nitrate levels which disproved expected agricultural pollution, and high microbiological activity. Significant water losses are expected in the near future which require immediate attention in order to develop adaptation strategies that focus on sustainable utilization and resilience of freshwater resources. This paper was based on the Interreg Central Europe PROLINE-CE project research in the South Dalmatia.

Impact of economic activity on geoecological transformation of the basin of the Zhovtenka River (Ukraine)


 
 
 The article presents the results of the study on the current geoecological condi- tion of the basin of the Zhovtenka River. The study object corresponded to the criteria of a small river, having the length of 42 km and the area of the drainage basin of 293 km2. According to the geographic peculiarities and the level of anthropogenic impact it is a typical small river of the Ukrainian Steppe zone. At the current stage of water management, the river and its tributaries are significantly regulated by artificial aquatic objects – ponds and a water reservoir. The total number of hydrotechnical facilities that form the water bodies is 34 levees. On the river itself, average density of water bodies equals 1 pond per every 2 km of the river length. Such regula- tion contradicts the norms of the current water protection legislation of Ukraine. As a result of fragmentation, the river has turned into a cascade of evaporation ponds. Special ecological threat to water use is the quality of water in the ponds. We determined that due to absence of current and low water exchange, the saline content in water undergoes significant changes. During the field surveys, we collected samples and determined the parameters of mineralization, content of chlorides and sulfates in 10 water bodies. Sampling was carried out during the year in different seasons. We determined that the averaged parameters of mineralization level change within the range of 9.000 mg/dm 3 in spring to 13.000 mg/dm 3 in summer and autumn. The content of chlorides varies within 2.600-3.600 mg/dm 3, sulfates – 4.000-4.800 mg/dm 3 according to the similar seasonal dependence. Due to changes in the climatic conditions and current tendencies of warming and dry climate, decrease in the water resources heightens the risks of irreversible geoecological degradation of the river. Significant regulation and evaporation-caused loss of water leads to rapid shoaling of the water bodies and growth of aquatic-marsh vegetation. The authors suggest an approach to assessment of the level of geoecological transformation of the river basin based on determining quantitative parameters of the constituents of the elements of natural ecosystems and elements of negative anthropogenic impact. We proposed calculation of various coefficients (indicators) which alter the natural condition of water ecosystems, particularly: coefficients of fragmentation, coefficients of urbanization, coefficients of alienation, etc. We present a pos- sibility of using them in relation to the length of the river and hydrographic network, as well as the area of drainage. We determined that percentage parameter of geoecological impact was seen in 94.3% of the area of the drainage basin or 87.4% of the river length. We suggest approaches that would minimize the deleterious impact of economic activity and gradually restore the condition of aquatic ecosystem of the river. The article provides recommendations of using coefficients of geoecological transformation of river ecosystems.
 
 

Modern approaches to the prevention and rehydration therapy of antibiotic-associated diarrhea affected by ARI in children

The use of antibiotic drugs (ABDs) has significantly reduced the number of severe bacterial infectious diseases and mortality in children, especially in infants. But the widespread and unnecessary use of ABDs, including reserve antibiotics (the use of carbapenems increased by 45%, polymyxins – by 13%), to treat uncomplicated acute respiratory infections is open to many hazards, such as increased antibiotic resistance of pathogens. Antibiotic-associated diarrhea is one of the common complications of antibiotic therapy. According to various authors, the incidence of antibiotic-associated diarrhea is 6–80% among patients treated with antibiotics, on average 35% of patients (approximately every third patient) receiving antibiotics report symptoms of antibiotic-associated diarrhea. Disruptive changes in the qualitative and quantitative composition of the intestinal microbiota are accompanied by a decrease in the protective functions of the intestinal mucosa and contribute to the growth of pathogenic and opportunistic microorganisms (Clostridium spp., Candida spp., Salmonella spp., Staphyloccus aureus). The findings of most studies obtained on a large sample of paediatric population, as well as the clinical guidelines of the World Association of Gastroenterologists recommend the use of L. rhamnosus GGprobiotic strain (level of evidence 1) to prevent antibiotic-associated diarrhea in children. L. rhamnosus GGpresents chromosomal resistance to a range of antibiotics, which varies with species and strain. They do not contain plasmid DNA, which is dangerous for the spread of antibiotic resistance among other bacteria, which enables their wide therapeutic and prophylactic use. Clinical case studies of the course of antibiotic-associated diarrhea in children are presented to demonstrate the variability of clinical symptoms. Fever in children with ARI, particularly in tender-age infants, requires special attention from parents and doctors, as its main risk lies with a dehydration due to significant water loss during breathing, and especially increased sweating (including sweating induced by antipyretics). Therefore, oral rehydration therapy is an important method for treating infectious diseases in children. Complications that develop in patients, especially in children, after administration of antibiotics, diseases that can lead to water and electrolyte imbalance are life-threatening conditions that require immediate medical attention. Correction of water and electrolyte balance, timely restoration of intestinal microflora improve prognosis in such patients and promote faster recovery.

МОНИТОРИНГ ТЕХНИЧЕСКОГО СОСТОЯНИЯ КРЮКОВСКОЙ ОРОСИТЕЛЬНОЙ СИСТЕМЫ АБИНСКОГО РАЙОНА С ПРИМЕНЕНИЕМ МЕТОДОВ ЛАЗЕРНОГО СКАНИРОВАНИЯ

At this stage of agricultural development, Russia is in many ways inferior to other countries. This is manifested, first of all, with the underdevelopment of industry and shortcomings in the technologies for the development of agriculture. Considering one of the activities in agriculture, namely rice growing, it is worth noting that relatively recently, in the 80s of the last century, the Kuban, as one of the constituent entities of the Russian Federation, achieved maximum success in the development of irrigation systems for rice cultivation. But at this time, there is enough area for rice cultivation to meet both internal and external needs, which is good news, but at the same time another problem arises related to the constant decrease in water resources. Accordingly, the timely elimination of problems in the irrigation system will lead to the improvement of the irrigation system. The challenge is to reduce unnecessary water loss during irrigation in rice cultivation. The economic support for the maintenance of irrigation system technology in Russia leaves much to be desired. Because of this, in numerous cases, individual parts of the irrigation system are subject to repair, but not the reconstruction of the main canals, or even the construction of new systems. The article deals with modern issues of monitoring the technical condition of the Kryukovskaya irrigation system of the Abinsk region using laser scanning methods. The results of the use of unmanned aerial vehicles to improve the monitoring of the technical condition of the elements of irrigation systems are presented. Today, the Federal State Budgetary Institution "Kubanmeliovodkhoz Administration" does not have the technical capabilities and resources as in the 70-80s of the last century, but at the same time, responsibility has only increased over the years, both pumping stations, mechanical equipment, partitioning structures, as well as inter-farm and on-farm channels. Many elements need to be replaced, as they have exhausted their operational resource, designed for thirty years of operation. Irrational organization of water management leads to significant losses of water, energy and material and technical resources. The stages of using modern unmanned aerial vehicles for examining the elements of irrigation systems are considered.

Obtaining carbohydrate biopolymers (prebiotics) from brown algae

The article discusses the issues of obtaining prebiotic food additives - an actual area of research in modern food technology. The test results determined the safety of the brown algae Ascophyllum nodosum and Fucus vesiculos growing on the littoral of the Barents Sea. Fucus algae contain significant the amount of alginic acid in terms of absolutely dry weight (a.d.w.) which proves the possibility of using them as raw materials for the production of sodium alginate. It was shown in the work that it is preferable to use Fucus vesiculosus for this purpose, since the content of alginic acid in it and the yield of finished products are higher. Studies of frozen algae in storage revealed a significant loss of water even after a month of storage of raw materials, while during storage of dried algae, the qualitative composition of the product remains constant. The properties of sodium alginate samples obtained from different types of fucus algae were studied. It was found that sodium alginates in appearance represent a free-flowing substance in the form of small thin plates, from light to dark brown in color, without taste and odor. Fucus sodium alginate can be used as a prebiotic, since it is a highly viscous biopolymer and belongs to natural dietary fiber.

Significance of Hypernatremia Due to SARS-CoV-2 Associated ARDS in Critically Ill Patients.

Background and ObjectivesSARS-CoV-2-induced ARDS is a new entity that should be characterized as it appears to be different from standard ARDS. Hypernatremia is a biological alteration that seems to occur very often in this population without any clear cause. The present study aims to clarify the possible causes of hypernatremia and evaluate its impact on patient outcome.Patients and MethodsWe conducted a retrospective one-day prevalence study in 2 intensive care units, which only treated COVID-19 patients with moderate to severe ARDS. We measured blood and urine electrolytes in all the patients. Patients with chronic renal failure or renal replacement therapy were excluded from the study. Hypernatremia was defined as plasma sodium levels above 145 mmol/L.ResultsInclusion criteria were met in 17 out of 24 patients. Hypernatremia was present in 52% patients. All had a natriuresis higher than 20 mmol/L and a urine osmolality above 600 mOsm/L. Hypernatremia was acquired in ICU as all the patients had a normal serum sodium level at admission.ConclusionThe incidence of hypernatremia was elevated and appears to be linked to significant insensible water losses. This should trigger us to optimize the maintenance fluid therapy in critically ill patients with SARS-CoV-2-induced ARDS.

Problems of technical exploitation and ecological safety of hydrotechnical facilities of irrigation systems

In this work, we analyzed and studied the Ukrainian typical hydrotechnical structures of the ameliorative complex on soil materials. On the examples of such objects in Dnipropetrovsk oblast, we carried out research and determined the technical condition of the transporting (main irrigation canals) and regulating (retention ponds) hydrotechnical structures (HTS). The main factors and the reasons for the negative engineering-geological processes occurring in those structures and affecting the ecological balance of adjacent territories were determined. The study revealed that the long period of exploitation and absence of corresponding technical care have led to significant losses of irrigation water from the canals and retention ponds. Due to the systemic absence and low use of monitoring researchers, we have proposed the use of prompt and low-cost methods and means of technical diagnostics. The article presents the possibility of using a complex of geophysical methods of natural impulse magnetic field of the Earth and vertical electrical sounding for the purposes of technical diagnostics. The possibility of recording plots and parameters of zones of seepage deformations in the body and at the base of the structures was visually determined and instrumentally proven. This allows identifying the amounts of technical and material resources, stages and order of implementation of repair-restoration works. It was determined that share of the damaged zones accounts for 20 to 35% of the total length of the hydrotechnical structures dependingon their type and parameters of the constructions. In such conditions, the estimated losses of water equal 17-22% of the total amount of the delivery. The surveys showed that further operation of HC poses an ecological threat because of significant worsening of quality of water resources. The article presents disturbing dynamics of change in the irrigated areas involving the danger of secondary salinization, sodification, alkalinization, and toxification as a result of watering. We indicated threatening changes in the structures of the areas irrigated with low-quality water, which, according to various indicators of danger, increased by 1.4 times regarding threat of secondary salinization and by 2 times regarding threat of sodification. We proposed and substantiated approaches to improving the general technical and technological level of functioning of ameliorative structures in the context of maintaining ecological balance and economic practicability of their further use, based on the principles of systemic optimization of complex technical-natural ecosystems.

Merging Fluid Transient Waves and Artificial Neural Networks for Burst Detection and Identification in Pipelines

AbstractThe occurrence of bursts in water pipelines can not only prevent the system from functioning properly, but it can also produce significant water loss that disrupts activities in urban areas...

Innate local response and tissue recovery following application of high density microarray patches to human skin

The development of microarray patches for vaccine application has the potential to revolutionise vaccine delivery. Microarray patches (MAP) reduce risks of needle stick injury, do not require reconstitution and have the potential to enhance immune responses using a fractional vaccine dose. To date, the majority of research has focused on vaccine delivery with little characterisation of local skin response and recovery. Here we study in detail the immediate local skin response and recovery of the skin post high density MAP application in 12 individuals receiving 3 MAPs randomly assigned to the forearm and upper arm. Responses were characterised by clinical scoring, dermatoscopy, evaporimetry and tissue viability imaging (TiVi). MAP application resulted in punctures in the epidermis, a significant transepidermal water loss (TEWL), the peak TEWL being concomitant with peak erythema responses visualised by TiVi. TEWL and TiVi responses reduced over time, with TEWL returning to baseline by 48 h and erythema fading over the course of a 7 day period. As MAPs for vaccination move into larger clinical studies more variation of individual subject phenotypic or disease propensity will be encountered which will require consideration both in regard to reliability of dose delivery and degree of inherent skin response.

ANALISA KEHILANGAN AIR IRIGASI DI DESA KOTA NEGARA KECAMATAN MADANG SUKU II KABUPATEN OKU TIMUR

In the irrigation water network in the city village of Negara sub-district of Madang, Suku II, East Oku Regency experienced a significant loss of irrigation water. From the observation site, it is caused by the number of channels that have broken and broken conditions, the growth of wild plants in the walls of the channel and a lot of garbage that has accumulated in the channel and evaporation in the summer. The purpose of this research is to find out how much the loss of irrigation water in the secondary channel starting from the building tapping BGT1 to BGT4 In the liquid that flows in the channel made of concrete over time the channel will be damaged, overgrown with a lot of wild plants because of damage and the other channel will cause water loss during drainage. The source of the data is obtained based on the results of the field survey, primary data and secondary data are obtained.Based on the analysis results, the largest irrigation water loss on the first day in the morning was 0.325 m³ / s, on the sixth day in the afternoon it was 0.332 m³ / s, on the seventh day in the afternoon it was 0.184 m³ / s. The smallest irrigation water loss on the fifth day in the morning was 0.128 m³ / s, the fifth day in the afternoon was 0.129 m³ / s, and the first day in the afternoon was 0.02 m³ / s. The average water loss occurred on the second day with results obtained in the morning of 0.297 m³ / s, in the afternoon amounting to 0.322 m³ / s, and in the afternoon amounting to 0.184 m³ / s.

Simulation and evaluation of agricultural water distribution and delivery systems with a Hybrid Bayesian network model

Regular appraisal performance of the irrigation water distribution systems from the adequacy, equity, and sustainable operation perspectives are essential due to the significant water losses that has been led by the improper adjustments of the hydraulic structures. Appropriate operational strategies could be adapted when the irrigation district authorities have a pragmatic approach to assess the hydraulic behavior of the system. This study develops an intelligent model for i) hydraulic simulation and ii) operational performance evaluation of the agricultural water distribution systems by employing a Hybrid Bayesian Networks (HBNs). The developed model was tested on a real test case located in Iran and under the different operational scenarios. In this regard, firstly, a hydrodynamic model of the test case was developed, calibrated, and validated to simulate the hydraulic condition of the irrigation canal based on a wide range of the canal inflow variations, called operational scenarios. Then, performance assessment was conducted for the scenarios based on adequacy, equity, and efficiency of water distribution perspectives. The results were employed for the training of the HBNs model. The HBNs model configuration was selected based on the irrigation district manages expectations, where the performance indicators of "adequacy," "efficiency" and "equity" of water delivery, needs to be calculated for the canal inflow variations in different operational scenarios. Validation of the developed HBNs model reveals that Mean Absolute Percentage Error (MAPE) and Coefficient of Determination (R2) of the superior model within the entire output nodes are 17.31% and 0.96, respectively. The results indicated the ability of the HBNs Model for the "Simulation/Performance Appraisal" of any operating systems in the irrigation districts. The developed model is a useful tool for i) periodic appraisal performance of the distribution system, ii) operational personals and ditch-riders, and iii) regionalization of the district to facilitate the recurrent inspections and field visiting.

Numerical simulation on mass transport in a passive vapor-fed direct methanol fuel cell operating with neat methanol

A direct methanol fuel cell (DMFC) operating with neat methanol is a promising power candidate for electronic and portable devices because of its high specific energy. But complex mass transport continues to hinder the reliability of such a DMFC. In this work, a two-dimensional isothermal model for a passive vapor-fed DMFC operating with neat methanol is developed to explore the triple-phase (gas, liquid and dissolved phases) mass transport and phase change. The simulation results indicate that the addition of water management layer at the cathode effectively facilitates the water recovery to the anode, especially under lower relative humidity condition. The increase of the methanol vapor supply rate alleviates the concentration polarization at high current densities, but the aggravated methanol crossover by an excessive fuel supply decreases the cathode performance. The elevated operating temperature enhances the electrochemical kinetics and mass transport, while excessively high temperature leads to the degradation of the cell performance due to significant water loss. The present work provides an effective theoretical guidance for the design and operation of a passive vapor-fed DMFC operating with neat methanol.

Cooling tower water treatment using a combination of electrochemical oxidation and constructed wetlands

A substantial part of the freshwater used in the industry is consumed in cooling towers. Cooling towers discharge saline cooling tower blowdown (CTBD), and the reuse of CTBD in the cooling tower can lower the industrial freshwater footprint. This reuse requires CTBD desalination and a pre-treatment that removes organic chemicals before physico-chemical desalination technologies to be applied efficiently. In the present study, the pre-treatment of CTBD by a combination of electrochemical oxidation (EO) with a boron-doped diamond (BDD) or mixed-metal oxide (MMO) anode and a vertical flow constructed wetland (VFCW) was assessed in both possible configurations. The integrated VFCW-EO systems removed more organic chemicals, such as COD, TOC, and the corrosion inhibitor benzotriazole than the EO-VFCW systems. However, the EO resulted in highly toxic effluent to Vibrio fischeri and the plants in the VFCW. This toxicity was the result of the production of unwanted chlorinated organic compounds and ClO3− and ClO4− by both the BDD- and MMO-anode during EO. These toxic EO by-products were removed substantially in the VFCW during EO-VFCW treatment but did impact the removal efficiency and viability of the VFCW. Moreover, significant water loss was observed in the VFCW due to evapotranspiration. In conclusion, the negative impact of EO effluent on the VFCW and evapotranspiration of the VFCW should be considered during application.