Effect of ozone on algal organic matters as precursors for disinfection by-products production.

The effect of ozone dose on algae (Microcystic aeruginosa), algal extracellular organic matters (EOM), humic acids (HA) and four model compounds: bovine serum albumin (BSA), starch, deoxyribonucleic acid (DNA) and fish oil as precursors for disinfection by-products (DBPs) production was investigated. Algae showed the highest DBPs formation (71.8 microg mg-1 total organic carbon (TOC)) than other samples. Only BSA showed lower chloroform yield (5.9 microg mg-1 TOC) than haloacetic acids, HAAs (11.2 microg mg-1 TOC). Algae, EOM, starch, DNA, fish oil and HA all showed higher chloroform yields (46.1, 23.8, 8.9, 37.1, 44.0 and 33.7 microg mg-1 TOC, respectively) than HAAs (25.7, 20.2, 6.3, 10.0, 13.1 and 18.4 microg mg-1 TOC, respectively). Pre-ozonation increased DBPs, especially chloroform, formation from algae and DNA significantly. With the increase in ozone doses, DBPs yields of algae and DNA increased 19.0 and 34.5 microg mg-1 TOC, chloroform yields of algae and DNA increased 15.3 and 30.4 microg mg-1 TOC, respectively. However, pre-ozonation decreased DBPs formation from starch, fish oil and HA, and the corresponding decrease amount was 2.4, 26.9 and 9.5 microg mg-1 TOC, respectively. There are no regular change trends of DBPs formation from EOM and BSA with the increase in ozone doses.