scholarly journals Removal of cyanobacteria from a water supply reservoir by sedimentation using flocculants and suspended solids as ballast: Case of Legedadi Reservoir (Ethiopia)

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249720
Author(s):  
Hanna Habtemariam ◽  
Demeke Kifle ◽  
Seyoum Leta ◽  
Maíra Mucci ◽  
Miquel Lürling
Keyword(s):  
Water Supply ◽  
Moringa Oleifera ◽  
Suspended Solids ◽  
Aluminium Chloride ◽  
Reservoir Water ◽  
Massive Growth ◽  
Toxic Cyanobacteria ◽  
Cyanobacterial Species ◽  
Mitigation Methods ◽  
Water Supply Reservoirs

The massive growth of potentially toxic cyanobacteria in water supply reservoirs, such as Legedadi Reservoir (Ethiopia), poses a huge burden to water purification units and represents a serious threat to public health. In this study, we evaluated the efficiency of the flocculants/coagulants chitosan, Moringa oleifera seed (MOS), and poly-aluminium chloride (PAC) in settling cyanobacterial species present in the Legedadi Reservoir. We also tested whether coagulant-treated reservoir water promotes cyanobacteria growth. Our data showed that suspended solids in the turbid reservoir acted as ballast, thereby enhancing settling and hence the removal of cyanobacterial species coagulated with chitosan, Moringa oleifera seed, or their combination. Compared to other coagulants, MOS of 30 mg/L concentration, with the removal efficiency of 93.6%, was the most effective in removing cyanobacterial species without causing cell lysis. Contrary to our expectation, PAC was the least effective coagulant. Moreover, reservoir water treated with MOS alone or MOS combined with chitosan did not support any growth of cyanobacteria during the first two weeks of the experiment. Our data indicate that the efficacy of a flocculant/coagulant in the removal of cyanobacteria is influenced by the uniqueness of individual lakes/reservoirs, implying that mitigation methods should consider the unique characteristic of the lake/reservoir.

scholarly journals Toxic Cyanobacteria in Four Brazilian Water Supply Reservoirs

2012 ◽  
Vol 03 (01) ◽  
pp. 68-73 ◽  
Author(s):  
Viviane Piccin-Santos ◽  
Maria do Carmo Bittencourt-Oliveira
Keyword(s):  
Water Supply ◽  
Toxic Cyanobacteria ◽  
Water Supply Reservoirs

Source characterization of disinfection byproduct precursors in two Arkansas water-supply reservoirs

Fact Sheet ◽  
1997 ◽  
Author(s):  
Michael L. Pomes ◽  
W.R. Green ◽  
E.M. Thurman ◽  
W.H. Orem ◽  
H.T. Lerch
Keyword(s):  
Water Supply ◽  
Source Characterization ◽  
Disinfection Byproduct ◽  
Water Supply Reservoirs

Enhanced rapid gravity filtration and dissolved air flotation for pre-treatment of river thames reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 35-42 ◽  
Author(s):  
M. J. Bauer ◽  
R. Bayley ◽  
M. J. Chipps ◽  
A. Eades ◽  
R. J. Scriven ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Supply ◽  
21St Century ◽  
Reservoir Water ◽  
Dissolved Air Flotation ◽  
Lowland Rivers ◽  
Air Flotation ◽  
Pre Treatment ◽  
Counter Current ◽  
Dissolved Air

Thames Water treats approximately 2800Ml/d of water originating mainly from the lowland rivers Thames and Lee for supply to over 7.3million customers, principally in the cities of London and Oxford. This paper reviews aspects of Thames Water's research, design and operating experiences of treating algal rich reservoir stored lowland water. Areas covered include experiences of optimising reservoir management, uprating and upgrading of rapid gravity filtration (RGF), standard co-current dissolved air flotation (DAF) and counter-current dissolved air flotation/filtration (COCO-DAFF®) to counter operational problems caused by seasonal blooms of filter blocking algae such as Melosira spp., Aphanizomenon spp. and Anabaena spp. A major programme of uprating and modernisation (inclusion of Advanced Water Treatment: GAC and ozone) of the major works is in progress which, together with the Thames Tunnel Ring Main, will meet London's water supply needs into the 21st Century.

Susceptibility of Water Supply Reservoirs to Drought Conditions

1998 ◽  
Vol 3 (2) ◽  
pp. 140-148 ◽  
Author(s):  
Antonino Cancelliere ◽  
Alessandro Ancarani ◽  
Giuseppe Rossi
Keyword(s):  
Water Supply ◽  
Drought Conditions ◽  
Water Supply Reservoirs

Evaporation from water supply reservoirs: An assessment of uncertainty

2009 ◽  
Vol 376 (1-2) ◽  
pp. 261-274 ◽  
Author(s):  
Lisa D. Lowe ◽  
J. Angus Webb ◽  
Rory J. Nathan ◽  
Teri Etchells ◽  
Hector M. Malano
Keyword(s):  
Water Supply ◽  
Water Supply Reservoirs

scholarly journals Impact of Changes in Land Use and Land Cover in the Contribution Basin of Doutor João Penido Water Supply Reservoir of Juiz de Fora, MG, Brazil

2021 ◽  
Vol 11 (1) ◽  
pp. 108
Author(s):  
Juliana Nazareth de Lana ◽  
Márcio de Oliveira ◽  
Vanessa Romario de Paula ◽  
Cézar Henrique Barra Rocha
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Land Cover ◽  
Water Supply ◽  
Quality Parameters ◽  
E Coli ◽  
The City ◽  
Water Supply Reservoirs ◽  
Limnological Parameters

Changes in the land use and land cover in areas adjacent to water reservoirs directly affect the quality of this water. This research presents a study on the water quality in the basin of one of the most important public water supply reservoirs in the city of Juiz de Fora, Minas Gerais. The main objective of this study was to analyze the behavior of limnological parameters and the correlation with land use and land cover in the contribution basin of the Doutor João Penido reservoir (CBJPR). The methodology was based on the analysis of water quality parameters, related to water samples collected from 2012 to 2015. Six sampling points were chosen from different locations: spring, medium course, main tributaries of the reservoir and the reservoir catchment. The parameters analyzed were turbidity, total solids (TS), oxygen consumed (OC), dissolved oxygen (DO), electrical conductivity, total nitrogen (TN), total phosphorus (TP), E. Coli, temperature, pH and total dissolved solids (TDS). The Kendall’s tau test was used to analyze the correlations between the parameters of water quality, land use and land cover in the CBJPR. In general, measured parameters showed better results in spring and in reservoir catchment, showing a worse quality of the water along the tributaries and the dilution power of the reservoir. The correlations pointed to the need for protection and preservation of forests in strategic locations to ensure good water quality.

Occurrence and Significance of Toxic Cyanobacteria in Southern Africa

1991 ◽  
Vol 23 (1-3) ◽  
pp. 175-180 ◽  
Author(s):  
W. E. Scott
Keyword(s):  
South Africa ◽  
Southern Africa ◽  
Single Species ◽  
Practical Significance ◽  
Toxic Species ◽  
Toxic Cyanobacteria ◽  
Cyanobacterial Species ◽  
Wide Range ◽  
Toxic Blooms ◽  
Different Parts

A comprehensive list is provided of more than forty cyanobacterial species and genera reported to have toxic properties. In South Africa the majority of animal poisonings since 1927 have been caused by a single species Microcystis aeruginosa. Although other toxic species also occur in southern Africa, to date they have been of little practical significance. The widespread distribution of M. aeruginosa throughout southern Africa indicates a tremendous potential for toxic blooms to develop with increasing eutrophication. Using HPLC techniques up to six different toxin variants have been quantified in natural blooms of M. aeruginosa collected in different parts of South Africa. The amounts and proportions of the different toxins in the different samples varied over a wide range. Several additional unidentified toxins were detected.

scholarly journals Study on Production, Domestic and Ecological Benefits of Reservoir Water Supply Based on Emergy Analysis

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1435
Author(s):  
Xinjian Guan ◽  
Pengkun Jiang ◽  
Yu Meng ◽  
Haidong Qin ◽  
Hong Lv
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
Evaluation Model ◽  
Emergy Analysis ◽  
Reservoir Water ◽  
Water Users ◽  
Ecological Benefit ◽  
Analysis Theory ◽  
Regulation Function ◽  
Current Water

As an important water conservancy project, it is necessary to evaluate its water supply benefit. Based on the emergy analysis theory, a reservoir water supply benefits evaluation model (RWSBEM) was established. Firstly, the emergy transformity of natural and engineering water body was calculated. Secondly, the water resource values (WRV) of different water users (industrial, agricultural, domestic, ecological) were calculated. Finally, combined with the water supply situation of the reservoir, the various water supply benefits of the reservoir were calculated. Taking Hekoucun reservoir as an example, its ecological water supply benefit is the largest and agriculture is the smallest, followed by industry and life. The results showed that the trend of WRV was domestic > industry > ecology > agriculture, which reflected the contribution and utility of water resources in different industries. Under the condition of current water resources, the planned water supply benefits of the reservoir can be guaranteed in the wet and normal years, but in the dry years, the ecological benefit will be reduced. Therefore, the industry water-saving needs to be further strengthened, and the interannual regulation function of the reservoir should be applied more effectively to maximize the comprehensive benefits of reservoir water supply.

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