Influence of chlorine on algae as precursors for trihalomethane and haloacetic acid production.

Two species of freshwater algae were isolated from Nile River water. These species represent the green algae (Scenedesmus obliquus) and the blue-green algae (Anabaena flos-aquae). Contribution of the algal cells of both species in the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) during chlorination in the laboratory was investigated. The results showed that the predominant disinfection by-products (DBPs) generated were chloroform, monochloroacetic acid, dichloroacetic acid and trichloroacetic acid. The yields of all DBPs were insignificantly higher upon chlorination of S. obliquus than in case of A. flos-aquae. The amount of algal cells in both species (measured as chlorophyll "a" content) was significantly influenced on the formation of HAAs only. The concentrations of all DBPs were increased as the reaction time was extended. However, 60 % of the chloroform was formed during the first five minutes of the reaction, while 57 -71 % of HAAs was formed during the first 30 minutes of the reaction. Generally, the current study elucidated that the cellular biochemical composition of both algal species may have contribute as DBPs precursors.