Effect of Phosphate Loading on the Generation of Extracellular Organic Matters of Microcystis Aeruginosa and Its Derived Disinfection By-Products

Zhang, Ni; Xu, Bingbing; Qi, Fei

Effect of Phosphate Loading on the Generation of Extracellular Organic Matters of Microcystis Aeruginosa and Its Derived Disinfection By-Products

2016

Zhang, Ni | Xu, Bingbing | Qi, Fei

Microcystis aeruginosa is a common cause of algal bloom outbreaks in Chinese lakes. This study investigated the effects of phosphate loading on the algal growth and extracellular organic matter (EOM) production of M. aeruginosa. The cell density was monitored by cell counting, and EOMs were characterized by dissolved organic carbon (DOC), carbohydrate, protein, and excitation/emission matrix fluorescence spectroscopy (EEM). DOC concentration peaked during the stationary phase and was contributed primarily by amino acid- and fulvic-like substances. Carbohydrate was a substantially larger fraction than protein. Phosphate showed positive influence on the cell growth and EOMs. As its concentration increased, the EOMs concentration increased. So did EOM and β-ionone as typical taste and odor compounds. Whatever the phosphate concentration was, the peak of β-ionone concentration exceeded its odor threshold (7.0 ng/L), resulting in a severe fruit-like odor. Additionally, the disinfection by-products involved with EOM were evaluated in both chlorination and chloramination, indicating that trihalomethanes were the dominated toxic by-products and the chloramination showed more significant effect on its formation as an interesting result.

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