Dewatering of saline sewage sludge using iron-oxidizing bacteria: Effect of substrate concentration.
This study investigated the improvement in dewaterability of activated sludge (ACS) and anaerobically digested sludge (ADS) through bioacidification approach using iron-oxidizing bacterium, Acidithiobacillus ferrooxidans. ACS and ADS were treated with A. ferrooxidans culture with addition of different concentrations of energy substrate, in terms of Fe(2+):sludge solids ratio (0:1, 0.01:1, 0.05:1 and 0.1:1), and the dewaterability was assessed by determining the capillary suction time (CST), time to filter (TTF) and specific resistance to filtration (SRF) of the sludge. The results revealed that the levels of Fe(2+) significantly influenced the sludge acidification (pH⩽3). The CST, TTF and SRF values rapidly decreased in treated sludge, indicating that dewaterability of the sludge was significantly (p<0.05) improved than untreated sludge. This investigation clearly demonstrates that A. ferrooxidans culture, as biogenic flocculant, can be potentially used for improving the sludge flocculation, stabilization and dewaterability.
Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong; Department of Biology, Hong Kong Baptist University, Hong Kong.
Jonathan W C
JWC
Wong
Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong; Department of Environmental Science, Periyar University, Salem, India. Electronic address: kmurugesan@gmail.com.
Kumarasamy
K
Murugesan
Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong.
Ammaiyappan
A
Selvam
Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong.
Balasubramanian
B
Ravindran
Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong.
Mayur B
MB
Kurade
Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong.
Shuk-Man
SM
Yu
D042763:Acidithiobacillus / Q000378:metabolism*; D005374:Filtration; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism*; D010084:Oxidation-Reduction; D054712:Salinity; D012722:Sewage; D018505:Waste Management / Q000379:methods*
D012722:Sewage; D007501:Iron
Acidithiobacillus ferrooxidans; Activated sludge; Anaerobically digested sludge; Biogenic flocculant; Sludge dewaterability