Disinfection of Membrane Bioreactor Permeate Using Free Chlorine: Virus Inactivation and Disinfection Byproducts Formation

The aim of this study was to investigate some aspects of the performance of electrochemical process as an alternative disinfection strategy, while minimising DBPs, for water purification. The study of electrochemical processes has shown free chlorine to be produced, but smaller amounts of stronger oxidants, such as ozone, hydrogen peroxide and OH radicals (•OH), were also generated. The formation of mixed oxidants increased with increasing electric conductivity, but was limited at conductivities greater than 0.6 mS/cm. Using several microorganisms, such as E. coli and MS2 bacteriophage, inactivation kinetic studies were performed. With the exception of free chlorine, the role of mixed oxidants, especially OH radicals, was investigated for enhancement of the inactivation rate. Additionally, the formation and reduction of DBPs was studied by monitoring the concentration of haloacetic acids (HAAs) during the process.

Download Full-text

Degradation of Aqueous Polycyclic Musk Tonalide by Ultraviolet-Activated Free Chlorine

Processes ◽

10.3390/pr7020095 ◽

2019 ◽

Vol 7 (2) ◽

pp. 95 ◽

Cited By ~ 3

Author(s):

Lili Wang ◽

Xiaowei Liu

Keyword(s):

Disinfection Byproducts ◽

Free Chlorine ◽

Water Disinfection ◽

Side Chain ◽

Product Analysis ◽

Direct Photolysis ◽

Reaction Rate Constants ◽

Water Matrix ◽

First Order Kinetics ◽

Drinking Water Disinfection

Chlorine-incorporating ultraviolet (UV) provides a multiple barrier for drinking water disinfection. Meanwhile, post-UV employment can promote the degradation of micropollutants by radical production from chlorine residual photolysis. This work studied the degradation of one such chemical, tonalide (AHTN), by low-pressure UV-activated free chlorine (FC) under typical UV disinfection dosage of <200 mJ·cm−2 and water matrix of filtered tank effluent. AHTN was rapidly degraded by UV/FC in accordance with pseudo-first-order kinetics. The reaction rate constants of AHTN with reactive chlorine species and hydroxyl radical (HO•) were estimated. Mechanistic exploration evidenced that under UV/FC, AHTN degradation was attributable to direct photolysis, ClO•, and HO•. The carbonyl side chain of AHTN served as an important attack site for radicals. Water matrices, such as natural organic matter (NOM), HCO3−, Cu2+, PO43−, and Fe2+, showed noticeable influence on the UV/FC process with an order of NOM > HCO3− >Cu2+ > PO43− > Fe2+. Reaction product analysis showed ignorable formation of chlorinated intermediates and disinfection byproducts.

Download Full-text

Pilot-scale comparison of microfiltration/reverse osmosis and ozone/biological activated carbon with UV/hydrogen peroxide or UV/free chlorine AOP treatment for controlling disinfection byproducts during wastewater reuse

Water Research ◽

10.1016/j.watres.2018.12.062 ◽

2019 ◽

Vol 152 ◽

pp. 215-225 ◽

Cited By ~ 31

Author(s):

Yi-Hsueh Chuang ◽

Aleksandra Szczuka ◽

Farzaneh Shabani ◽

Joline Munoz ◽

Roshanak Aflaki ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Activated Carbon ◽

Reverse Osmosis ◽

Wastewater Reuse ◽

Pilot Scale ◽

Disinfection Byproducts ◽

Free Chlorine ◽

Biological Activated Carbon

Download Full-text

Metals releases and disinfection byproduct formation in domestic wells following shock chlorination

Drinking Water Engineering and Science Discussions ◽

10.5194/dwesd-3-177-2010 ◽

2010 ◽

Vol 3 (1) ◽

pp. 177-198

Author(s):

M. Walker ◽

J. Newman

Keyword(s):

Trace Metals ◽

Contact Time ◽

Disinfection Byproducts ◽

Oxidation Potential ◽

Free Chlorine ◽

Haloacetic Acids ◽

Background Concentrations ◽

Disinfection Byproduct ◽

Byproduct Formation ◽

By Products

Abstract. Shock chlorination is used for rapid disinfection to control pathogens and nuisance bacteria in domestic wells. A typical shock chlorination procedure involves adding sodium hypochlorite in liquid bleach solutions to achieve concentrations of free chlorine of up to 200 ppm in the standing water of a well. The change in pH and oxidation potential may bring trace metals from aquifer materials into solution and chlorine may react with dissolved organic carbon to form disinfection byproducts. We carried out experiments with four wells to observe and determine the persistence of increased concentrations of metals and disinfection byproducts. Water samples from shock chlorinated wells were analyzed for Pb, Cu, As, radionuclides and disinfection byproducts (haloacetic acids and trihalomethanes), immediately prior to treatment, after sufficient contact time with chlorine had elapsed, and at intervals determined by the number of casing volumes purged, for up to four times the well casing volume. Elevated concentrations of lead and copper dissipated in proportion to free chlorine (measured semi-quantitatively) during the purging process. Trihalomethanes and haloacetic acids were formed in wells during disinfection. In one of two wells tested, disinfection byproducts dissipated in proportion to free chlorine during purging. However, one well retained disinfection byproducts and free chlorine after four well volumes had been purged. Although metals returned to background concentrations in this well, disinfection byproducts remained elevated, though below the MCL, likely because purging volume was insufficient. Simple chlorine test strips may be a useful method for indicating when purging is adequate to remove metals and disinfection by-products mobilized and formed by shock chlorination.

Download Full-text

Disinfection by-products and microbial contamination in the treatment of pool water with granular activated carbon

Water Science & Technology ◽

10.2166/wst.2005.0229 ◽

2005 ◽

Vol 52 (8) ◽

pp. 71-76 ◽

Cited By ~ 9

Author(s):

W. Uhl ◽

C. Hartmann

Keyword(s):

Activated Carbon ◽

Water Treatment ◽

Organic Carbon ◽

Disinfection Byproducts ◽

Free Chlorine ◽

Swimming Pool ◽

Pool Water ◽

Swimming Pool Water ◽

Removal Efficiencies ◽

Filter Bed

For swimming pools, it is generally agreed that free chlorine levels have to be maintained to guarantee adequate disinfection. Recommended free chlorine levels can vary between 0.3 and 0.6mg/L in Germany and up to 3mg/L in other countries. Bathers introduce considerable amounts of organic matter, mainly in the form of such as urine and sweat, into the pool water. As a consequence, disinfection byproducts (DBPs) are formed. Regulations in Germany recommend levels of combined chlorine of less than 0.2mg/L and levels of trihalomethanes (THMs) of less than 20μg/L. Haloacetic acids (HAAs), haloacetonitriles (HANs), chloropicrin and chloral hydrate are also detected in considerable amounts. However, these compounds are not regulated yet. Swimming pool staff and swimmers, especially athletes, are primarily exposed to these byproducts by inhalation and/or dermal uptake. In Germany, new regulations for swimming pool water treatment generally require the use of activated carbon. In this project, three different types of granular activated carbon (GAC) (one standard GAC, two catalytic GACs) are compared for their long time behaviour in pool water treatment. In a pilot plant operated with real swimming pool water, production and removal of disinfection byproducts (THMs, HAAs, AOXs), of biodegradable substances (AOC), of bacteria (Pseudomonas aeruginosa, Legionella, coliforms, HPC) as well as the removal of chlorine and chloramines are monitored as function of GAC bed depth. Combined chlorine penetrates deeper in the filter bed than free chlorine does. However, both, free and combined chlorine removal efficiencies decrease over the time of filter operation. The decreases of removal efficiencies are also observed for parameters such as dissolved organic carbon, spectral absorption coefficient, adsorbable organic carbon and most of the disinfection byproducts. However, THMs, especially chloroform are produced in the filter bed. The GAC beds were contaminated microbially, especially with P. aeruginosa. The contamination was not removable by backwashing with chlorine concentrations up to 2mg/l free chlorine.

Download Full-text

Metals releases and disinfection byproduct formation in domestic wells following shock chlorination

Drinking Water Engineering and Science ◽

10.5194/dwes-4-1-2011 ◽

2011 ◽

Vol 4 (1) ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

M. Walker ◽

J. Newman

Keyword(s):

Trace Metals ◽

Treatment Time ◽

Disinfection Byproducts ◽

Oxidation Potential ◽

Free Chlorine ◽

Haloacetic Acids ◽

Background Concentrations ◽

Disinfection Byproduct ◽

Byproduct Formation ◽

By Products

Abstract. Shock chlorination is used for rapid disinfection to control pathogens and nuisance bacteria in domestic wells. A typical shock chlorination procedure involves adding sodium hypochlorite in liquid bleach solutions to achieve concentrations of free chlorine of up to 200 mg L−1 in the standing water of a well. The change in pH and oxidation potential may bring trace metals from aquifer materials into solution and chlorine may react with dissolved organic carbon to form disinfection byproducts. We carried out experiments with four wells to observe and determine the persistence of increased concentrations of metals and disinfection byproducts. Water samples from shock chlorinated wells were analyzed for Pb, Cu, As, radionuclides and disinfection byproducts (haloacetic acids and trihalomethanes), immediately prior to treatment, after sufficient treatment time with chlorine had elapsed, and at intervals determined by the number of casing volumes purged, for up to four times the well casing volume. Elevated concentrations of lead and copper dissipated in proportion to free chlorine (measured semi-quantitatively) during the purging process. Trihalomethanes and haloacetic acids were formed in wells during disinfection. In one of two wells tested, disinfection byproducts dissipated in proportion to free chlorine during purging. However, one well retained disinfection byproducts and free chlorine after 4 WV had been purged. Although metals returned to background concentrations in this well, disinfection byproducts remained elevated, though below the MCL. This may have been due to well construction characteristics and interactions with aquifer materials. Simple chlorine test strips may be a useful method for indicating when purging is adequate to remove metals and disinfection by-products mobilized and formed by shock chlorination.

Download Full-text

1,3,5-Trimethoxybenzene (TMB) as a new quencher for preserving redox-labile disinfection byproducts and for quantifying free chlorine and free bromine

Environmental Science Water Research & Technology ◽

10.1039/c8ew00062j ◽

2018 ◽

Vol 4 (7) ◽

pp. 926-941 ◽

Cited By ~ 6

Author(s):

Stephanie S. Lau ◽

Ryan P. Dias ◽

Kayla R. Martin-Culet ◽

Nicholas A. Race ◽

Marella H. Schammel ◽

...

Keyword(s):

Disinfection Byproducts ◽

Free Chlorine ◽

Residual Chlorine ◽

Free Bromine

1,3,5-Trimethoxybenzene can be used to quench residual chlorine and bromine without altering disinfection byproducts that are reactive toward traditional quenchers.

Download Full-text

Correlations between surrogate nitrogenous organic precursors and C-, N-DBP formation

Water Science & Technology ◽

10.2166/wst.2011.823 ◽

2011 ◽

Vol 64 (12) ◽

pp. 2395-2403 ◽

Cited By ~ 2

Author(s):

H. H. Chang ◽

G. S. Wang

Keyword(s):

Organic Compounds ◽

Chlorine Dioxide ◽

Benzalkonium Chloride ◽

Product Formation ◽

Disinfection Byproducts ◽

Free Chlorine ◽

Haloacetic Acids ◽

Source Water ◽

Organic Precursors ◽

Different Characteristics

Nitrosamines have been emerging as disinfection byproducts in drinking water using source water impacted with domestic wastewaters. Nitrogenous organic compounds are suggested as precursors of nitrosamines, but many of them have not been identified. This study investigated the correlations between nine selected nitrogenous organic compounds with different characteristics and corresponding disinfection by-product formation potentials (nitrosamines, trihalomethanes (THMs), and haloacetic acids (HAAs)) from their reactions with free chlorine, chlorine dioxide and monochloramine. Besides dimethylamine, the well-known precursor of nitrosamines, 3-(N,N-dimethyloctylammonio)propanesulfonate (3-N,N-DAPSIS) inner salt and benzyldimethyltetradecylamine (benzalkonium chloride, BKC) were suggested as important nitrosamine precursors. 3-N,N-DAPSIS could form about 1,000 ng/L of N-nitrosodimethylamine (NDMA) and more than 1,000 μg/L of THMs. More than 150,000 ng/L of NDMA were observed when BKC was treated with monochloramine, and high levels of THMs (up to 2,700 μg/L) were also yielded. As expected, free chlorine produced higher levels of THMs and HAAs, and chlorine dioxide generated minor levels of traditional DBPs. Nitrosamines were mainly formed when the precursors were treated with monochloramine.

Download Full-text