Avoiding Chlorite: Chlorine and CIO₂ Together Form Fewer DBPs

Abstract

This article discusses how dosing chlorine and chlorine dioxide concurrently provides excellent disinfection inactivation and limits chlorite formation. This was done when Aurora (Colorado) Water's 80‐mgd Griswold Water Treatment Facility was rebuilt in 1999. A 2002 needs assessment indicated that a similar strategy should be implemented during expansion of Aurora Water's 80‐mgd Wemlinger Water Treatment Plant (WTP). However, at the Wemlinger WTP, ClO2 formation rose higher than expected during startup, forming at up to 85 percent of the ClO2 dose. Chlorine dioxide also decayed more rapidly than expected. The article discusses how this situation was addressed along with other lessons learned at the Wemlinger WTP, the importance of monitoring and reporting, and the power of coapplication.

Disinfection by-product formation during seawater desalination: A review

“…Chlorine dioxide (ClO 2 ) does not form appreciable levels of chlorinated DBPs such as THMs and HAAs under typical water Mayankutty et al, 1995. treatment conditions (Aieta and Berg, 1986;Hua and Reckhow, 2007). Many drinking water utilities have been using ClO 2 as an alternative disinfectant to chlorine for pre-oxidation and postoxidation to reduce the formation of THMs and total organic halide (TOX) due to its strong oxidizing capacity (Lykins and Griese, 1986;Linder et al, 2006). Even in the presence of high bromide, ClO 2 is a good disinfectant.…”

Disinfection by-products of chlorine dioxide (chlorite, chlorate, and trihalomethanes): Occurrence in drinking water in Qatar

“…The chlorite concentrations in all the samples were less than 1000 and 700 mg L À1 , which are the maximum values regulated by the USEPA (1998 andupdated in 2006) and WHO (WHO, 2004, GSO 149/2009and KM (KM, 2012, respectively. The EU guidelines are more stringent than guidelines for the KM and WHO since the maximum allowable chlorite ion concentration in drinking water in Italy is 200 mg L À1 (Linder et al, 2006).…”

“…Parts of the EU and North America have more stringent regulations for chlorite ions. For example, the maximum allowed concentration in drinking water in Italy was 200 mg L À1 in 2006 (Linder et al, 2006;Chu et al, 2011). Despite the intensive work conducted on DBP formation in disinfected water around the world, the potential hazards of DBPs and the scarcity of this type of data in Qatar make this type of research essential.…”

“…DBP formation during ClO 2 pretreatment has been studied (Linder et al, 2006;Lee et al, 2007;Yang et al, 2013). ClO 2 oxidation prior to chlorination can reduce the formation of THMs and total organic halogens (TOX) (Linder et al, 2006). A recent study reported that ClO 2 pre-oxidation reduced THMs and other by-products (Yang et al, 2013).…”

“…Chlorite and chlorate are the primary byproducts (Korn et al, 2002). DBP formation during ClO 2 pretreatment has been studied (Linder et al, 2006;Lee et al, 2007;Yang et al, 2013). ClO 2 oxidation prior to chlorination can reduce the formation of THMs and total organic halogens (TOX) (Linder et al, 2006).…”