A Review on the Removal Technologies of Nickel(II) Ion from Aqueous So-lution

The need of disinfecting potable water to eliminate potential health risks associated with waterborne pathogens, however inevitably resulting in leaving elevated toxicity in water by forming disinfection by-products (DBPs) is being considered as one of the primary threats to human well-being. Bromate is a carcinogenic DBP mainly formed during ozonation of bromide-containing water. The current maximum contaminant level (MCL) of bromate in the US national primary drinking water standard is set at 10 μg/L. With continuous improvements in analytical instrumentation and removal technologies, a lower MCL for bromate is expected in the future. Current researches on bromate control strategies involve minimizing bromate formation (like ammonia addition) or removing bromate after formation (like carbon adsorption), however have their own limitations. Seeking for alternative bromate control strategies that can be used alone (or in combine with others) is of great value and in urgent need when water quality standards are getting more stringent. This paper reviews the occurrence of bromate in water supply and evaluates the effectiveness of bromate removal technologies applied, to advance our understanding of bromate fate and degradation in water supply system for future study.

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Arsenic Speciation: Reduction of Arsenic(V) to Arsenic(III) by Fulvic Acid

Environmental Chemistry ◽

10.1071/en05095 ◽

2006 ◽

Vol 3 (2) ◽

pp. 137 ◽

Cited By ~ 17

Author(s):

Tsanangurayi Tongesayi ◽

Ronald B. Smart

Keyword(s):

Fulvic Acid ◽

Arsenic Removal ◽

Research Effort ◽

Arsenic Speciation ◽

Inorganic Arsenic ◽

Stripping Voltammetry ◽

Reduction Reaction ◽

Cathodic Stripping Voltammetry ◽

Suwannee River Fulvic Acid ◽

Removal Technologies

Environmental Context.Most technologies for arsenic removal from water are based on the oxidation of the more toxic and more mobile arsenic(iii) to the less toxic and less mobile arsenic(v). As a result, research effort has been focussed on the oxidation of arsenic(iii) to arsenic(v). It is equally important to explore environmental factors that enhance the reduction of arsenic(v) to arsenic(iii). An understanding of the redox cycling of arsenic could result in the development of cheaper and more efficient arsenic removal technologies, especially for impoverished communities severely threatened by arsenic contamination. Abstract.The objective of this study was to investigate the reduction of inorganic arsenic(v) with Suwannee River fulvic acid (FA) in aqueous solutions where pH, [FA], [As(v)], [As(iii)], and [Fe(iii)] were independently varied. Samples of inorganic As(v) were incubated with FA in both light and dark at constant temperature. Sterilisation techniques were employed to ensure abiotic conditions. Aliquots from the incubated samples were taken at various time intervals and analysed for As(iii) using square-wave cathodic-stripping voltammetry at a hanging mercury drop electrode. The study demonstrated the following important aspects of As speciation: (1) FA can significantly reduce As(v) to As(iii); (2) reduction of As(v) to As(iii) is a function of time; (3) both dark and light conditions promote reduction of As(v) to As(iii); (4) Fe(iii) speeds up the reduction reaction; and (5) oxidation of As(iii) to As(v) is promoted at pH 2 more than at pH 6.

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Virtual special issue: Sour gas reservoirs and sulfur-removal technologies

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2015.08.006 ◽

2015 ◽

Vol 26 ◽

pp. 1506-1507 ◽

Cited By ~ 3

Author(s):

Zhien Zhang ◽

David A. Wood

Keyword(s):

Sulfur Removal ◽

Special Issue ◽

Gas Reservoirs ◽

Removal Technologies ◽

Sour Gas

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Conditions and technologies of biological wastewater treatment in Hungary

Water Science & Technology ◽

10.2166/wst.2012.062 ◽

2012 ◽

Vol 65 (9) ◽

pp. 1676-1683 ◽

Cited By ~ 4

Author(s):

G. M. Tardy ◽

V. Bakos ◽

A. Jobbágy

Keyword(s):

Wastewater Treatment ◽

Carbon Source ◽

Nitrogen Removal ◽

Wastewater Treatment Plants ◽

Treatment Temperature ◽

Low Carbon ◽

Biological Phosphorus Removal ◽

Wastewater Quality ◽

Removal Technologies ◽

Biological Nitrogen

A survey has been carried out involving 55 Hungarian wastewater treatment plants in order to evaluate the wastewater quality, the applied technologies and the resultant problems. Characteristically the treatment temperature is very wide-ranging from less than 10 °C to higher than 26 °C. Influent quality proved to be very variable regarding both the organic matter (typical COD concentration range 600–1,200 mg l−1) and the nitrogen content (typical NH4-N concentration range 40–80 mg l−1). As a consequence, significant differences have been found in the carbon availability for denitrification from site to site. Forty two percent of the influents proved to lack an appropriate carbon source. As a consequence of carbon deficiency as well as technologies designed and/or operated with non-efficient denitrification, rising sludge in the secondary clarifiers typically occurs especially in summer. In case studies, application of intermittent aeration, low DO reactors, biofilters and anammox processes have been evaluated, as different biological nitrogen removal technologies. With low carbon source availability, favoring denitrification over enhanced biological phosphorus removal has led to an improved nitrogen removal.

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