Assessment of THMs Formation Potential in Treated Water

Abstract

Raw water in the Saidabad water treatment plant is treated by chlorination. Water samples were collected in February, March, July and September from the six locations of DND canal and treated by chlorine dose. Higher chlorine dose is required in dry season. The treated samples are tested for dissolved organic carbon (DOC), chloride and bromide ions. Using the test results, Trihalomethane (THM) predictive models are developed. Total THM formation is related to the DOC concentration; where DOC is higher, THM is also higher. This may be due to the muddy bottom which could consist of organics in combination with the shallower depth. DOC provided better correlations than UV absorbance as a precursor parameter. Due to their collinearity, only DOC was included in the models. As the models for total THM and for individual THM species are developed by using different data, sum of individual THM species and total THM are not equal.

Keywords – Water treatment, chlorination, THMs formation, raw water