Comparison of the disinfection by-product formation potential of treated waters exposed to chlorine and monochloramine

Abstract

The formation of disinfection by-products (DBPs) from chlorination and monochloramination of treated drinking waters was determined. Samples were collected after treatment at 11 water treatment works but before exposure to chlorine or monochloramine. Formation potential tests were carried out to determine the DBPs formed by chlorination and monochloramination. DBPs measured were trihalomethanes (THMs), haloacetic acids (HAAs), halonitromethanes (HNMs), haloacetonitriles (HANs), haloaldehydes (HAs), haloketones (HKs) and iodo-THMs (i-THMs). All waters had the potential to form significant levels of all the DBPs measured. Compared to chlorine, monochloramination generally resulted in lower concentrations of DBPs with the exception of 1,1-dichloropropanone. The concentrations of THMs correlated well with the HAAs formed. The impact of bromine on the speciation of the DBPs was determined. The literature findings that higher bromide levels lead to higher concentrations of brominated DBPS were confirmed.

Effects of operating conditions on trihalomethanes formation and speciation during chloramination in reclaimed water

“…In addition, monochloramine (NH 2 Cl) and its derived reactive products such as hypochlorous acid (HOCl) dominate the process of microbial inhibition (Lu et al 2009). However, the formation of other DBPs such as iodo-THMs (i-THMs), nitrogen-DBPs (N-DBPs), and haloacetonitriles (HANs) could be increased during chloramination (Bougeard et al 2010). It is well known that THMs formation is depended on the water quality and DOM properties (Ma et al 2013a, b) and that THMs formation potential increases at high DOM concentration.…”

Enhanced formation of bromate and brominated disinfection byproducts during chlorination of bromide-containing waters under catalysis of copper corrosion products

“…In brief, 10 mM ethylenediamine was spiked into a water sample as a masking ligand to inhibit the interference of Cu 2þ ; 1 mM bathocuproine was added to form an orange complex with Cu þ ; and the orange complex was measured by light absorbance at 484 nm on a Hach DR6000 spectrophotometer (Hach, USA). Brominated trihalomethanes (Br-THMs), brominated haloacetic acids (Br-HAAs), and brominated haloacetamides (Br-HAcAms) were extracted according to Bougeard et al (2010), and then analyzed with a gas chromatograph and an electron capture detector (GC/ECD) (Agilent 7890A) coupled with a DB-5ms separation column (30 m  0.25 mm, 0.25 mm). The instrumental conditions for the analysis of Br-THMs and Br-HAcAms were as follows: injection volume of 2.0 mL (splitless), helium carrier gas with a flow rate of 2.0 mL min…”

The effectiveness of removing precursors of chlorinated organic substances in pilot water treatment plant

“…In operating water treatment systems, increasing the oxidation time is most often impossible, which is compensated by increasing chemical oxidant dosages. In the case of using free chlorine, and to a lesser degree when using ClO2, the above solution unfortunately results in increasing chloroorganic compound concentrations in water [15][16][17].…”