Yield of trihalomethanes and haloacetic acids upon chlorinating algal cells, and its prediction via algal cellular biochemical composition Hua Chang Hong a , Asit Mazumder b , Ming Hung Wong a , Yan Liang a, * a Croucher Institute for Environmental Sciences and the Department of Biology, Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Hong Kong, PR China b Water and Aquatic Sciences Research Program, University of Victoria, Canada article info Article history: Received 15 March 2008 Received in revised form 23 June 2008 Accepted 16 September 2008 Published online 1 October 2008 Keywords: Algae Carbohydrates Chlorination HAAs Lipids Proteins THMs abstract The major objective of the present study was to investigate the contribution of major biomolecules, including protein, carbohydrates and lipids, in predicting DBPs formation upon chlorination of algal cells. Three model compounds, including bovine serum albumin (BSA), starch and fish oil, as surrogates of algal-derived proteins, carbohydrates and lipids, and cells of three algae species, representing blue-green algae, green algae, and diatoms, were chlorinated in the laboratory. The results showed that BSA (27 mg mg 1 C) and fish oil (50 mg mg 1 C) produced more than nine times higher levels of chloroform than starch (3 mg mg 1 C). For the formation of HAAs, BSA was shown to have higher reactivity (49 mg mg 1 C) than fish oil and starch (5 mg mg 1 C). For the algal cells, Nitzschia sp. (diatom) showed higher chloroform yields (48 mg mg 1 C) but lower HAA yields (43 mg mg 1 C) than Chlamydomonas sp. (green algae) (chloroform: 34 mg mg 1 C; HAA: 62 mg mg 1 C) and Oscil- latoria sp. (blue-green algae) (chloroform: 26 mg mg 1 C; HAA: 72 mg mg 1 C). The calculated chloroform formation of cells from the three algal groups, based on their biochemical compositions, was generally consistent with the experimental data, while the predicted values for HAAs were significantly lower than the observed ones. As compared to humic substances, such as humic and fulvic acids, the algal cells appeared to be important precursors of dichloroacetic acid. ª 2008 Elsevier Ltd. All rights reserved. 1. Introduction Algae have been shown to produce disinfection by-products (DBPs) following chlorination, such as trihalomethanes (THMs) and haloactetic acids (HAAs) (Plummer and Edzwald, 2001; Nguyen et al., 2005). The major concern lies in the fact that algal-derived organic matter increases coagulant demand and is less easily removed by coagulation and filtration (Cheng and Chi, 2003). Algal cells can also penetrate filters and lead to DBPs formation from chlorination within the water treatment plant (Ma and Liu, 2002). It is known that protein, carbohydrates and lipids are the major constituents of the algal cells, and their relative portions vary with algal species (Brown et al., 1997). Generally, blue-green algae have been shown to have more protein contents (41–69%) than diatoms (12–50%), while diatoms appear to accumulate more lipids in the cells (5–43%) than blue-green algae and green algae (2–30%) (Whyte, 1987; Brown, * Corresponding author. Croucher Institute for Environmental Sciences, Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Hong Kong, PR China. Tel.: þ852 3411 7751; fax: þ852 3411 7743. E-mail address: yliang@hkbu.edu.hk (Y. Liang). Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/watres 0043-1354/$ – see front matter ª 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.watres.2008.09.019 water research 42 (2008) 4941–4948