Biodegradation of MIB, geosmin and microcystin-LR in sand columns containing Taihu lake sediment Stephanie L. DeVries, Wenjie Liu, Neng Wan, Pengfei Zhang and Xiqing Li ABSTRACT Lake Taihu, located in southeast Jiangsu Province, China, is an important drinking water resource serving almost 2 million residents nearby. In recent years, eutrophication has led to more frequent cyanobacterial algae blooms whose metabolites, including 2-methylisoborneol (MIB), 1,10-dimethyl- trans-9-decalol (geosmin) and microcystin-LR (MC-LR), can be both toxic and unpalatable. Traditional treatment methods are expensive and often poorly remove these compounds. Since biodegradation has shown promise, the removal of MIB, geosmin and MC-LR in columns containing a mixture of quartz sand and Taihu lake bed sediment was tested. Results show that 24, 38.5 and 100% removal of MIB, geosmin and MC-LR, respectively, can be achieved at a 1 m d –1 flow rate through 30 cm long columns containing 10% Taihu sediment. Biodegradation rates derived from one-dimensional transport modeling were used to predict the performance of 2 m filtration beds of similar composition. The results indicate that satisfactory removal of MIB, geosmin and MC-LR can be achieved by this method. Stephanie L. DeVries Xiqing Li (corresponding author) Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China E-mail: xli@urban.pku.edu.cn Stephanie L. DeVries Pengfei Zhang (corresponding author) Department of Earth and Environmental Sciences, Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY 10016, USA E-mail: pzhang@sci.ccny.cuny.edu Wenjie Liu Neng Wan School of Biological and Food Engineering, Changshu Institute of Technology, Changshu, Jiangsu 215500, China Pengfei Zhang Department of Earth and Atmospheric Sciences, City College of New York, 160 Convent Avenue, New York, NY 10031, USA Key words | biodegradation, geosmin, infiltration gallery, methylisoborneol, microcystin INTRODUCTION Lake Taihu, located on the border between Jiangsu and Zhe- jiang Provinces, is the third-largest fresh water lake in China, with a surface area of approximately 2,400 km 2 . Surrounded by six large cities, Taihu is an economically important fishery and a primary drinking water resource serving over 2 million people. Economic development in this region has flourished in the last few decades, driving a concomitant increase in water pollution and usage, thus rendering the lake prone to eutrophication and seasonal development of large cyanobac- terial algae blooms (Zhang & Qin ) whose metabolites can be toxic and unpalatable. Microcystins (MCs), produced by Microcystis aeruginosa and other blue-green algae, are a class of cyclic hepatotoxins whose most common variant, microcystin-LR (MC-LR), has been linked to both chronic and acute health risks, including tumor growth (Carmichael ), high rates of primary liver cancer (Yu ) and possibly death (Lambert et al. ). Though non-toxic, two common taste and odor compounds, 2-methylisoborneol (MIB) and 1,10-dimethyl-trans-9-decalol (geosmin), are also produced by a range of cyanobacterial species. Each imparts a foul earthy/musky odor and flavor to water (Carmichael ) and are detectable by the human nose at concentrations as low as 2–10 ng L À1 (Per-Edvin ). The presence of MIB and geosmin in drinking water can give the impression of poor quality to consumers, who subsequently seek alternative water supplies, often at higher consumer and environmental cost (Srinivasan & Sorial ). In order to prevent a drinking water crisis in the Taihu region, a low-cost and effective method is needed to remove MC, MIB and geosmin before it reaches the tap. 691 © IWA Publishing 2012 Water Science & Technology: Water Supply | 12.5 | 2012 doi: 10.2166/ws.2012.043