scholarly journals Optimizing NOM Removal: Impact of Calcium Chloride

2021 ◽  
Vol 13 (11) ◽  
pp. 6338
Author(s):  
Alfredo Gonzalez-Perez ◽  
Kristofer Hägg ◽  
Fabrice Duteil
Keyword(s):  
Water Treatment ◽  
Calcium Chloride ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Adverse Health Effects ◽  
Surface Water Treatment ◽  
Treatment Processes ◽  
Aluminum Sulphate ◽  
Adsorption Processes ◽  
Sedimentation Processes

Understanding the character of natural organic matter (NOM) and assessing its impact on water quality is paramount for managers of catchments and water utilities. For drinking-water producers, NOM affects disinfectant demand and the formation of by-products which can have adverse health effects. NOM content in raw waters also has an impact on water treatment processes by increasing required coagulant dosages, reducing the effectiveness of adsorption processes and fouling membrane systems. This study investigated the effects of calcium chloride (CaCl2) as a co-coagulant in Al3+ and Fe3+ assisted coagulation, flocculation and sedimentation processes for NOM-removal from raw water collected from Lake Bolmen, in southern Sweden. Jar tests were conducted at Ringsjö Water Works (WW), a surface water treatment plant (WTP), to investigate the potential reduction in primary coagulants aluminum sulphate (Al2(SO4)3) and ferric chloride (FeCl3). This work shows that CaCl2 can, in certain situations, reduce the need for primary coagulants, which would reduce the environmental impact and costs associated with primary coagulant consumption.

scholarly journals Characterization of Disinfection By-Products Levels at an Emergency Surface Water Treatment Plant in a Refugee Settlement in Northern Uganda

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 647 ◽  
Author(s):  
Syed Ali ◽  
Matt Arnold ◽  
Frederick Liesner ◽  
Jean-Francois Fesselet
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Standard Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Northern Uganda ◽  
Surface Water Treatment ◽  
Treatment Processes ◽  
By Products ◽  
Rapid Treatment

The reliance on chlorination in humanitarian operations has raised concerns among practitioners about possible health risks associated with disinfection by-products; however, to date, there has not been an evaluation of disinfection by-product (DBP) levels in an emergency water supply intervention. This study aimed to investigate DBP levels at a surface-water treatment plant serving a refugee settlement in northern Uganda using the colorimetric Hach THM Plus Method. The plant had two treatment processes: (1) Simultaneous clarification–chlorination (“rapid treatment”); and (2) pre-clarification and chlorination in separate tanks (“standard treatment”). For both standard (n = 17) and rapid (n = 3) treatment processes, DBP levels in unique parcels of water were tested at 30 min post-chlorination and after 24 h of storage (to simulate what refugees actually consume). DBP levels after 24 h did not exceed the World Health Organization (WHO) guideline limit of 300 ppb equivalent chloroform, either for standard treatment (mean: 85.1 ppb; 95% confidence interval (C.I.): 71.0–99.1 ppb; maximum: 133.7 ppb) or for rapid treatment (mean: 218.0 ppb; 95% C.I.: 151.2–284.8; maximum: 249.0 ppb). Observed DBPs levels do not appear to be problematic with respect to the general population, but may pose sub-chronic exposure risks to specifically vulnerable populations that warrant further investigation.

Practical Guide to Determine the Impact of Radon and Other Radionuclides on Water Treatment Processes

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1255-1264
Author(s):  
K. L. Martins
Keyword(s):  
Activated Carbon ◽  
Water Treatment ◽  
Environmental Protection Agency ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Packed Tower ◽  
Treatment Processes ◽  
Radioactivity Exposure ◽  
The Impact ◽  
Percent Removal

During treatment of groundwater, radon is often coincidentally removed by processes typically used to remove volatile organic compounds (VOCs)-for example, processes such as liquid-phase granular activated carbon (LGAC) adsorption and air stripping with vapor-phase carbon (VGAC). The removal of radon from drinking water is a positive benefit for the water user; however, the accumulation of radon on activated carbon may cause radiologic hazards for the water treatment plant operators and the spent carbon may be considered a low-level radioactive waste. To date, most literature on radon removal by water treatment processes was based on bench- or residential-scale systems. This paper addresses the impact of radon on municipal and industrial-scale applications. Available data have been used todevelop graphical methods of estimating the radioactivity exposure rates to facility operators and determine the fate of spent carbon. This paper will allow the reader to determine the potential for impact of radon on the system design and operation as follows.Estimate the percent removal of radon from water by LGAC adsorbers and packed tower air strippers. Also, a method to estimate the percent removal of radon by VGAC used for air stripper off-gas will be provided.Estimate if your local radon levels are such that the safety guidelines, suggested by USEPA (United States Environmental Protection Agency), of 25 mR/yr (0.1 mR/day) for radioactivity exposure may or may not be exceeded.Estimate the disposal requirements of the waste carbon for LGAC systems and VGAC for air stripper “Off-Gas” systems. Options for dealing with high radon levels are presented.

Selection of the surface water treatment technology – a full-scale technological investigation

2014 ◽  
Vol 71 (4) ◽  
pp. 638-644 ◽  
Author(s):  
Alina Pruss
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Full Scale ◽  
Treatment Technology ◽  
Surface Water Treatment ◽  
Second Stage ◽  
Third Stage ◽  
Water Treatment Technology

A technological investigation was carried out over a period of 2 years to evaluate surface water treatment technology. The study was performed in Poland, in three stages. From November 2011 to July 2012, for the first stage, flow tests with a capacity of 0.1–1.5 m3/h were performed simultaneously in three types of technical installations differing by coagulation modules. The outcome of the first stage was the choice of the technology for further investigation. The second stage was performed between September 2012 and March 2013 on a full-scale water treatment plant. Three large technical installations, operated in parallel, were analysed: coagulation with sludge flotation, micro-sand ballasted coagulation with sedimentation, coagulation with sedimentation and sludge recirculation. The capacity of the installations ranged from 10 to 40 m3/h. The third stage was also performed in a full-scale water treatment plant and was aimed at optimising the selected technology. This article presents the results of the second stage of the full-scale investigation. The critical treatment process, for the analysed water, was the coagulation in an acidic environment (6.5 < pH < 7.0) carried out in a system with rapid mixing, a flocculation chamber, preliminary separation of coagulation products, and removal of residual suspended solids through filtration.

Removal of cyanobacteria, cyanotoxins, heterotrophic bacteria and endotoxins at an operating surface water treatment plant

2006 ◽  
Vol 54 (3) ◽  
pp. 23-28 ◽  
Author(s):  
J. Rapala ◽  
M. Niemelä ◽  
K.A. Berg ◽  
L. Lepistö ◽  
K. Lahti
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Treatment Process ◽  
Heterotrophic Bacteria ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Bacterial Isolates ◽  
Sand Filtration ◽  
Surface Water Treatment ◽  
Guide Value

The removal of cyanobacteria, hepatotoxins produced by them (microcystins), phytoplankton, heterotrophic bacteria and endotoxins were monitored at a surface water treatment plant with coagulation, clarification, sand filtration, ozonation, slow sand filtration and chlorination as the treatment process. Coagulation–sand filtration reduced microcystins by 1.2–2.4, and endotoxins by 0.72–2.0 log10 units. Ozonation effectively removed the residual microcystins. The treatment process reduced phytoplankton biomass by 2.2–4.6 and heterotrophic bacteria by 2.0–5.0 log10 units. In treated water, the concentration of microcystins never exceeded the WHO guide value (1 μg/L), but picoplankton and monad cells were often detected in high numbers. The heterotrophic bacterial isolates from the treated waters belonged to genera Sphingomonas, Pseudomonas, Bacillus, Herbaspirillum and Bosea.

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