Performance and Design of a Stepped Spillway Aerator

Stepped spillways are frequently limited to specific discharges under around 30 m2/s due to concerns about potential cavitation damages. A small air concentration can prevent such damages and the design of bottom aerators is well established for smooth chutes. The purpose of this study is to systematically investigate the performance of a deflector aerator at the beginning of stepped chutes. Six parameters (chute angle, step height, approach flow depth, approach flow Froude number, deflector angle and deflector height) are varied in a physical model. The spatial air concentration distribution downstream of the aerator, the cavity sub-pressure, water discharge and air discharges are measured. The results describe the commonly used air entrainment coefficient, the jet length, as well as the average and bottom air concentration development to design an aerator. The lowest bottom air concentration measured in all tests is higher than the air concentration recommended in literature to protect against cavitation damages. And, unlike smooth chutes, there appears to be no significant air detrainment downstream of the jet impact. One deflector aerator seems therefore sufficient to provide protection of a stepped spillway.

The specific features of the thermal radiation of lake Kenon during freeze-up in the infrared band

This work is the study of the infrared images of Lake Kenon located in the city of Chita. The images were obtained from a satellite Lansat-8. The images revealed the thermal anomalies of the said internal water body. The anomalies consisted in the fact that areas of open water having negative temperature are formed in the lake in the winter period. The phenomenon may be caused both by surface supercooling of the lake water and by formation of water aerosol at the temperature below 0°C. The emergence of areas with supercooled water may be, paradoxical as it may sound, due to the impact of the thermal power plant located near the lake. Its functioning prevents formation of the ice cover, especially at the locations of warm water discharge. Analysis of the satellite images in the IR-band obtained over the recent five years has shown the area of the higher water temperature on the lake surface not to exceed 10% of the total area of the lake. The time before the freeze-up in the absence of wind, October – November, is the best time for revealing the maximum temperature difference.

Simulation for water quality management using system dynamics modeling in the Bedadung Watershed, East Java, Indonesia

The potential for pollution of rivers is influenced by river-water discharge and the distribution of pollution sources. This research aimed to examine recommendations for water quality management in the Bedadung River segment of the Patrang, Sumbersari, and Kaliwates Districts as an urban area of Jember Regency refer to simulations of the total pollution load capacity for 10 years (2016-2026) using a system dynamics modeling. The preparation of a system dynamics modeling used Powersim 5.0 software. It could represent holistic environmental management modeling. The input data were total suspended solid (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and the streamflow of the Bedadung River. The model scenarios were the business of usual, moderate, and optimistic scenarios involving environmental and socio-economic aspects. The medium-term and long-term recommendations for water quality management of the Bedadung River based on system dynamics simulation were respectively moderate scenario and optimistic scenario. The strategies of the moderate scenario were application of the best management practice method in agricultural cultivation, improving sanitation and domestic wastewater treatment, implementing clean production in the field of livestock and industry, as well as waste management on riverbanks. These alternative strategies for river water quality management can be used as consideration for protecting surface water sources in urban areas.

The modell ing study of flow in Vasishta Godavari estuary

The v as islua branch of the Godavari estuary open s into the Bay of Bengal at Antarvedi,Conditions in the estuary arccharacterized by a seasonally varying fresh water discharge and salt water intrusionfrom the Bay resul tingfrom the flow as~oc ia ted with the se.ni- diu rnal t ide. A numerica l model is applied to simulatethe flow and sali nity structures which have also been documented m the literature. The observations duringmonsoon and post-monsoon seasons arc used in a comparison with the theor etical results which are derived froma model in which turbulenceclosure scheme is used.

Treatment Technologies for Cooling Water Blowdown: A Critical Review

Cooling water blowdown (CWBD) generated from different industries and district cooling facilities contains high concentrations of various chemicals (e.g., scale and corrosion inhibitors) and pollutants. These contaminants in CWBD streams deem them unsuitable for discharge into surface water and some wastewater treatment plants. The pollutants present in CWBD, their sources, and the corresponding impacts on the ecosystem are discussed. The international and regional (Gulf states) policies and regulations related to contaminated water discharge standards into water bodies are examined. This paper presents a comprehensive review of the existing and emerging water treatment technologies for the treatment of CWBD. The study presents a comparison between the membrane (membrane distillation (MD), reverse osmosis (RO), nanofiltration (NF), and vibratory shear enhanced membrane process (VSEP)) and nonmembrane-based (electrocoagulation (EC), ballasted sand flocculation (BSF), and electrodialysis (ED)) technologies on the basis of performance, cost, and limitations, along with other factors. Results from the literature revealed that EC and VSEP technologies generate high treatment performance (EC~99.54% reduction in terms of silica ions) compared to other processes (membrane UF with reduction of 65% of colloidal silica). However, the high energy demand of these processes (EC~0.18–3.05 kWh/m3 and VSEP~2.1 kWh/m3) limit their large-scale applications unless connected with renewable sources of energy.

Analisis Kebutuhan Debit Air Di Gedung C RSUD Kota Bukittinggi

In the Bukittinggi City Hospital building which has 6 floors, there is a water pump and a reservoir used to supply clean water for daily needs. Based on the reality in the field where there is no secondary data to determine the type of pump and reservoir. The purpose of this analysis is to obtain clean water discharge requirements, obtain the type of pump and ensure that the reservoir used for building C RSUD Kota Bukittinggi is in accordance with the type of pipe and reservoir installed in building C, floor 6. By using field studies and interviews and applying the formulas related to pump calculations. In determining the type of pump to be used in the building, it includes the required water discharge, determining the capacity of the components to be used such as pipe diameter, water tank capacity on the ground floor and roof of the building and the total head on the pipe. Based on the calculation results, the required water discharge is 0.08333 m 3 /min, the upper reservoir has a capacity of 150,000 liters, the bottom reservoir is 5,000 liters and the Hot that occurs is 18.429 m. Then the required pump specifications are 40 x 32B2 -51.5 Grundfos CM 10-3. The pump specifications are not much different from those that have been applied in the field.

STATE OF BOTTOM SEDIMENTS OF THE VORONEZH RESERVOIR IN THE PLACES OF WATER DISCHARGE FROM THE TREATMENT FACILITIES OF THE CITY OF VORONEZH

Рассмотрена проблема загрязнения Воронежского водохранилища в пределах Воронежской городской агломерации, в местах сброса вод с очистных сооружений предприятий левого берега. В работе использованы результаты количественного химического анализа донных отложений, выполненных на базе эколого-аналитической лаборатории факультета географии, геоэкологии и туризма Воронежского госуниверситета, а также данные мониторинга, предоставленных Федеральной службой по надзору в сфере природопользования и Департаментом природных ресурсов и экологии Воронежской области. База данных включает результаты наблюдений с 2000 по 2021 год. По составу осадков прослежена история аккумуляции загрязнителей, выделены проблемные зоны водоема в каждом исследуемом периоде. Выполнен пространственно-временной анализ содержаний загрязняющих веществ, рассчитаны «кларки концентрации» тяжелых металлов, по которым для каждой точки наблюдения в порядке возрастания значения признака построен ранжированный ряд. На основании лабораторных исследований и результатов их статистической обработки с применением корреляционного анализа сделаны выводы о перспективах существования и развития Воронежского водохранилища. Проверены корреляционные связи между «кларками концентрации» и суммой выпавших осадков за календарный и за гидрологический год. По содержаниям сероводорода в различные годы, сделаны выводы о диапазоне колебания концентраций и формировании цикличного процесса. Выделена зона устойчивой деградации водоема. Ее формирование происходит выше и ниже сброса с городских очистных сооружений левого берега города. Результаты многолетних наблюдений за качеством донных отложений указывают на значительную техногенную нагрузку со стороны Воронежской городской агломерации. Недостаточная очистка воды, медленная скорость течения и турбулентность природной воды ускоряет процесс естественного эвтрофирования водоема. The author considers the problem of pollution of the Voronezh water reservoir within the Voronezh urban agglomeration, in places of discharge of water from the treatment facilities of enterprises of the left bank. The paper uses the results of quantitative chemical analysis of bottom sediments performed on the basis of the ecological and analytical laboratory of the Faculty of Geography, Geoecology and Tourism of Voronezh State University, as well as monitoring data provided by the Federal Service for Supervision of Nature Management and the Department of Natural Resources and Ecology of the Voronezh Region. The database includes the results of monitoring from 2000 till 2021. On the basis of the composition of precipitation the author detected the history of accumulation of pollutants; as well she identified problem areas of the water reservoir in every study period. The author performed a spatio-temporal analysis of the contents of pollutants, calculated the "concentration clarkes" of heavy metals, according to which she created an ordered series for each observation point in ascending order of the attribute value. Based on laboratory studies and results of their statistical processing using correlation analysis the author draws some conclusions concerning the prospects for the Voronezh water reservoir existence and development. The correlations between the "concentration clarkes" and the amount of precipitation for the calendar and hydrological year have been verified. Based on the hydrogen sulfide content in different years, the author concludes about the range of concentration fluctuations and the formation of a cyclic process. She identified the zone of stable degradation of the water reservoir. Its formation occurs above and below the discharge from the municipal sewage treatment plants of the left bank of the city. The results of long-term observations of the quality of bottom sediments indicate a significant anthropogenic load on the part of the Voronezh urban agglomeration. Insufficient water purification, slow flow velocity and turbulence of natural water accelerate the process of natural eutrophication of the water reservoir.

Impact of Climate Change on the Hydrology of the Forested Watershed That Drains to Lake Erken in Sweden: An Analysis Using SWAT+ and CMIP6 Scenarios

Precipitation and temperature around the world are expected to be altered by climate change. This will cause regional alterations to the hydrological cycle. For proper water management, anticipating these changes is necessary. In this study, the basin of Lake Erken (Sweden) was simulated with the recently released software SWAT+ to study such alterations in a short (2026–2050), medium (2051–2075) and long (2076–2100) period, under two different climate change scenarios (SSP2-45 and SSP5-85). Seven global climate models from the latest projections of future climates that are available (CIMP 6) were compared and ensembled. A bias-correction of the models’ data was performed with five different methods to select the most appropriate one. Results showed that the temperature is expected to increase in the future from 2 to 4 °C, and precipitation from 6% to 20%, depending on the scenario. As a result, water discharge would also increase by about 18% in the best-case scenario and by 50% in the worst-case scenario, and the surface runoff would increase between 5% and 30%. The floods and torrential precipitations would also increase in the basin. This trend could lead to soil impoverishment and reduced water availability in the basin, which could damage the watershed’s forests. In addition, rising temperatures would result in a 65% reduction in the snow water equivalent at best and 92% at worst.