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Membrane Water Treatment Volume 9, Number 3, May 2018 , pages 147-153 DOI: https://doi.org/10.12989/mwt.2018.9.3.147 |
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Flocculation of microalgae using extracellular polymeric substances (EPS) extracted from activated sludge |
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Dandan Dong, Dongmin Seo, Sungkyu Seo and Jae Woo Lee
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| Abstract | ||
| This study investigates the role of microbial extracellular polymeric substances (EPSs) as bioflocculants to harvest microalgae (water-microalgae separation). The EPS extracted from waste activated sludge (WAS) by heat extraction were fractionated into soluble EPS (S-EPS), loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS) forms. All the EPSs facilitated the flocculation of microalgal cells from stable growth medium. Of those EPSs, the TB-EPS showed the highest flocculating activity (FA) resulting in the substantial decrease in the amount of EPS added in terms of total organic carbon (TOC) during flocculation. The FA of microalgae was improved with the increase in TB-EPS dose, however, excessive dose of TB-EPS adversely affected it due to destabilization. Both LB- and TB-EPS could be utilized for flocculating microalgae as a sustainable option to the existing chemical-based flocculants. In addition to the conventional assessments, the effectiveness of the two bioflocculants for floc forming was also confirmed using a novel assessment of lens-free shadow imaging technique (LSIT), which was firstly applied for the rapid and quantitative assessment of microalgal flocculation. | ||
| Key Words | ||
| microalgae; extracellular polymeric substances (EPS); bioflocculant; activated sludge; lens-free shadow imaging technique (LSIT) | ||
| Address | ||
| Dandan Dong, Jae Woo Lee: Program in Environmental Technology and Policy, Korea University, Sejong, 30019, Republic of Korea Dongmin Seo, Sungkyu Seo: Department of Electronics and Information Engineering, Korea University, Sejong, 30019, Republic of Korea | ||
