scholarly journals Comparing the effect of tailwater replenishment at different time intervals on eutrophic surface freshwater: a mesocosm simulation study

Author(s):  
Haibin Tang ◽  
Yanran Dai ◽  
Yaocheng Fan ◽  
Deshou Cun ◽  
Xiaoyong Song ◽  
...  

Abstract Tailwater is becoming the main water source supplied to surface freshwater worldwide. However, few studies have been compared the effect of tailwater replenishment at different time intervals on eutrophic surface freshwater. In this study, we investigated the changes of water quality, sediment, and submerged macrophytes in eutrophic water in an outdoor mesocosm in response to different tailwater replenishment time intervals [every 7 days (TW7), 14 days (TW14) and 28 days (TW28)]. An 84-day simulation experiment demonstrated that there were only significant differences in total nitrogen (TN) concentration of overlying water, with the lowest mean value occurring in TW28. Nevertheless, the sediment TN was lowest in TW7 with a denitrification rate of 102.9 μmol/m2/h. Tailwater replenishment also increased the nitrogen content and total biomass of Vallisneria spiralis, and TW7 had the highest total biomass of 20.19 g. Additionally, tailwater replenishment also affected plant enzyme activity, causing an increase in superoxide dismutase, peroxidase, and catalase, coupled with a decrease in malondialdehyde concentration in the leaves. Overall, TW28 can be adopted as a tailwater replenishment strategy to ensure water quality, whereas TW7 can be applied without a strict water quality requirement for TN.

2017 ◽  
Vol 7 (3) ◽  
pp. 477-484 ◽  
Author(s):  
K. Ghodeif ◽  
R. Wahaab ◽  
S. Sorour

The present work was conducted to document the problems raised regarding low-flow in the Rosetta branch, Egypt and to develop management options to protect drinking water sources. The water quality was monitored during low-flow periods at four drinking water intakes. Results showed an increase in electric conductivity (EC), ammonium (NH4), nitrite (NO2), phosphate (PO4), and total organic carbon (TOC) during the low-flow period. EC ranges from 454 to 1,062 μS/cm and the mean value is 744. Ammonium ranges from 0.38 to 18.5 mg/L and the mean value is 5.45. NO2, PO4, and TOC have mean values of 0.73, 1.85, and 6.71 mg/L, respectively. Statistical evaluation revealed the association of NH4, EC, and PO4 that are good indicators for the load of wastewater. High ammonium often refers to a bad situation regarding oxygen while high nitrite indicates the first oxidation for wastewater through microbiological processes. The low-flow action has a serious impact on drinking water source. A high content of ammonium has delayed coagulation, enhanced algae growth, and prevented the breakpoint being reached during chlorination processes. Potential management options to deal with water scarcity and low-flow, meanwhile reducing the contaminant load in the source drinking water were proposed.


2021 ◽  
Vol 25 (9) ◽  
pp. 1671-1675
Author(s):  
B.O. Ekute ◽  
E.U. Etim

The effect of industrial effluents on surface water quality of Oruku River was investigated in this study by analyzing selected water quality indicators such as pH, dissolved oxygen (DO) and total dissolved solids (TDS) were examined amongst other physicochemical parameters using standard methods. Results show that, average pH of the surface waters ranged from 5.53±0.31 to 6.23±0.45 with SR3 having the highest value. This indicates that all the water sources were alkaline. The effluents had an average pH range of 5.95 ± 1.12 to 6.40 ± 0.48. A comparison of these average pH values with effluent quality standards indicated that the effluents pH were below limit (6.5-9.5). The average BOD levels in surface water ranged from 1.94 ± 0.95 for SR-4 to 3.78 ± 1.61 for SR-1. DO average values in surface water was found to be higher at SR-1 with a mean value of 5.36 ± 1.55 and lower at SR-2 with a mean value of 3.05 ± 0.68. The mean COD value for surface water ranged from 108.66 ± 73.03mg/L to 232.81 ± 155.46mg/L. SR-3 had the highest COD average value of 232.81 ± 155.46mg/L while there was a reduction at SR-5 to an average value of 108.66 ± 73.03mg/L. The high COD value in the surface water indicates that gross-organic pollution of the water source may be from other sources such as agricultural and urban run-offs.


Author(s):  
P. Bykova ◽  
I. Egorova ◽  
A. Strelkov ◽  
L. Talovyria ◽  
O. Nesterenko ◽  
...  

При изучении качества воды источника водоснабжения г. Самары Саратовского водохранилища особое внимание было уделено основным показателям, влияющим на выбор реагентной обработки: мутность, перманганатная окисляемость и цветность. Сезонные изменения качества воды водохранилища требуют постоянной корректировки дозы реагентов с целью достижения нормативных требований к качеству очищенной воды. Приводятся результаты производственных исследований изменения качества воды Саратовского водохранилища в створе водозаборов г. Самары за 20172019 годы по мутности, перманганатной окисляемости и цветности. В связи с аномальными температурными перепадами и наступлением осеннего паводка (конец декабря 2019 г. и январь 2020 г.) резко изменилось качество воды водохранилища по цветности и перманганатной окисляемости. Отмечено, что увеличение указанных показателей потребовало повышения дозы реагентов при очистке исходной воды. Оптимальная доза реагентов постоянно коректируется в зависимости от состава исходной воды на флокуляторе Lovibond ЕТ-750 . Регулярное проведение пробного коагулирования позволило поддерживать качество очищенной воды в соответствии с нормативными требованиями СанПиН 2.1.4.1074-01 Питьевая вода. Контроль качества , кроме цветности и железа общего, так как превышение этих показателей наблюдалось в пределах погрешности методов измерения.While studying the water quality of the water source of the city of Samara the Saratov water reservoir, special attention was paid to the main indicators that influence the choice of chemical treatment: turbidity, permanganate index and color. Seasonal changes in the water quality of the water reservoir require constant adjustment of the chemical dose in order to meet the regulatory requirements to the quality of treated water. The results of the studies of changes in the water quality of the Saratov reservoir at the water abstraction points of the city of Samara for 20172019 by turbidity, permanganate index and color are presented. Due to the abnormal temperature differences and onset of autumn flood (end of December 2019 and January 2020), the water quality in the water reservoir dramatically changed in color and permanganate index. It was noted that an increase in these indicators required an increase in the dose of chemicals during the source water purification. The optimal dose of chemicals is selected with Lovibond ET-750 flocculator depending on the composition of the source water. Regular test coagulation allowed maintaining the quality of purified water in accordance with the regulatory requirements of SanPiN 2.1.4.1074-01 Drinking water. Quality control , except for color and total iron since the values of these indicators were increased within the measurement accuracy.


1993 ◽  
Vol 28 (7) ◽  
pp. 197-201 ◽  
Author(s):  
Dunchun Wang ◽  
Isao Somiya ◽  
Shigeo Fujii

To understand the algae migration characteristics in the fresh water red tide, we performed a field survey in the Shorenji Reservoir located in Nabari City, Japan. From the analysis of the field data, it is found that the patterns of vertical distributions of the indices representing biomass are very different in the morning and the afternoon. Since some water quality indices have reverse fluctuations between the surface and the bottom layer in respect of the time series changes and the total biomass of the vertical water column is relatively constant, it is concluded that vertical and daily biomass variation of red tide alga is caused by its daily migration, that is the movement from the bottom layer to the surface in the morning and the reverse movement in the afternoon.


1999 ◽  
Vol 40 (4-5) ◽  
pp. 43-50 ◽  
Author(s):  
Marcelo Juanico ◽  
Eran Friedler

Most of the water has been captured in the rivers of Israel and they have turned into dry river-beds which deliver only sporadic winter floods. In a semi-arid country where literally every drop of water is used, reclaimed wastewater is the most feasible water source for river recovery. Two topics are addressed in this paper: water quality management in rivers where most of the flowing water is treated wastewater, and the allocations of reclaimed wastewater required for the recovery of rivers and streams. Water quality management must consider that the main source of water to the river has a pollution loading which reduces its capability to absorb other pollution impacts. The allocation of treated wastewater for the revival of rivers may not affect negatively the water balance of the region; it may eventually improve it. An upstream bruto allocation of 122 MCM/year of wastewater for the recovery of 14 rivers in Israel may favor downstream reuse of this wastewater, resulting in a small neto allocation and in an increase of the water resources available to the country. The discharge of effluents upstream to revive the river followed by their re-capture downstream for irrigation, implies a further stage in the intensification of water reuse.


2015 ◽  
Vol 8 (1) ◽  
pp. 38-42
Author(s):  
Pengfei Si ◽  
Xiangyang Rong ◽  
Angui Li ◽  
Xiaodan Min ◽  
Zhengwu Yang ◽  
...  

As a realization of the energy cascade utilization, the regional energy system has the significant potential of energy saving. As a kind of renewable energy, river water source heat pump also can greatly reduce the energy consumption of refrigeration and heating system. Combining the regional energy and water source heat pump technology, to achieve cooling, heating and power supply for a plurality of block building is of great significance to reduce building energy consumption. This paper introduces a practical engineering case which combines the regional energy system of complex river water source heat pump, which provides a detailed analysis of the hydrology and water quality conditions of the river water source heat pump applications, and discusses the design methods of water intake and drainage system. The results show that the average temperature of cold season is about 23.5 °C, the heating season is about 13.2 °C; the abundant regional water flow can meet the water requirement of water source heat pump unit; the sediment concentration index cannot meet the requirement of river water source heat pump if the water enters the unit directly; the river water chemistry indicators (pH, Cl-, SO42-, total hardness, total iron) can meet the requirement of river water source heat pump, and it is not required to take special measures to solve the problem. However, the problem of sediment concentration of water must be solved.


Author(s):  
Wen ◽  
Wu ◽  
Yang ◽  
Jiang ◽  
Zhong

Nutrients released from sediments have a significant influence on the water quality in eutrophic lakes and reservoirs. To clarify the internal nutrient load and provide reference for eutrophication control in Yuqiao Reservoir, a drinking water source reservoir in China, pore water profiles and sediment core incubation experiments were conducted. The nutrients in the water (soluble reactive P (SRP), nitrate-N (NO3−-N), nitrite-N (NO2−-N), and ammonium-N (NH4+-N)) and in the sediments (total N (TN), total P (TP) and total organic carbon (TOC)) were quantified. The results show that NH4+-N was the main component of inorganic N in the pore water. NH4+-N and SRP were higher in the pore water than in the overlying water, and the concentration gradient indicated a diffusion potential from the sediment to the overlying water. The NH4+-N, NO3−-N, and SRP fluxes showed significant differences amongst the seasons. The NH4+-N and SRP fluxes were significantly higher in the summer than in other seasons, while NO3−-N was higher in the autumn. The sediment generally acted as a source of NH4+-N and SRP and as a sink for NO3−-N and NO2−-N. The sediments release 1133.15 and 92.46 tons of N and P, respectively, to the overlying water each year.


2012 ◽  
Vol 66 (5) ◽  
pp. 1103-1109 ◽  
Author(s):  
Zenghu Qin ◽  
Mingwei Tong ◽  
Lin Kun

Due to the surface water in the upper reaches of Yangtze River in China containing large amounts of silt and algae, high content of microorganisms and suspended solids, the water in Yangtze River cannot be used for cooling a heat pump directly. In this paper, the possibility of using Yangtze River, which goes through Chongqing, a city in southwest China, as a heat source–sink was investigated. Water temperature and quality of the Yangtze River in the Chongqing area were analyzed and the performance of water source heat pump units in different sediment concentrations, turbidity and algae material conditions were tested experimentally, and the water quality standards, in particular surface water conditions, in the Yangtze River region that adapt to energy-efficient heat pumps were also proposed. The experimental results show that the coefficient of performance heat pump falls by 3.73% to the greatest extent, and the fouling resistance of cooling water in the heat exchanger increases up to 25.6% in different water conditions. When the sediment concentration and the turbidity in the river water are no more than 100 g/m3 and 50 NTU respectively, the performance of the heat pump is better, which can be used as a suitable river water quality standard for river water source heat pumps.


1976 ◽  
Vol 3 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Thomas W. Constable ◽  
Nicholas Kouwen ◽  
Shully I. Solomon

A mathematical model has been developed which can aid in assessing the effect of the modification of land use patterns on the water quantity and water quality regime of a watershed. The basin under study is divided into a number of elements using a square grid technique. The hydrologic and water quality components are evaluated at each element in the basin at successive time intervals, and flows are routed through the elements by use of a streamflow network system. The model can be used to assist in evaluating the effects of alternative land use configurations in a watershed, such as urbanization, the removal or growth of forests, the construction of dams, etc., on water quantity and water quality. It can also be used in the preliminary design of an urbanized area to estimate the size of storm sewers, artificial ponds, etc.


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