Techno Press
Techno Press

Advances in Environmental Research   Volume 3, Number 3, September 2014, pages 199-206
DOI: http://dx.doi.org/10.12989/aer.2014.3.3.199
 
Influence of sludge solids content on sludge dewaterability using bioleaching
Jonathan W.C. Wong, Jun Zhou, Lixiang Zhou, Mayur B. Kurade and Ammaiyappan Selvam

 
Abstract     [Full Text]
    Dewatering is an extremely important step in wastewater treatment process to reduce the final sludge volume in order to minimize the cost of sludge transportation and disposal. In the present study, the effect of different sludge solids content (1, 2 and 3.8%) on the dewaterability of anaerobically digested sludge using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was studied. The pH reduction rate was higher during initial process in the sludge having low solids content, but after 48 h of bioleaching, similar pH of below 3 was observed with all the different solids content. Bio-oxidation rate of Fe2+ was initially higher in sludge with low solids content, but 100% Fe2+ was oxidized within 60 h in all the three treatment levels. Compared to the control, specific resistance to filtration was reduced by 75, 78 and 80% in the sludge with a solids content of 1, 2 and 3.8% respectively, showing improvement in dewaterability with an increase in sludge solids content. Sludge effluent quality and sludge settling rate were also improved in treatments with higher solids content after the bioleaching process.
 
Key Words
    acidithiobacillus ferrooxidans; acidithiobacillus thiooxidans; sludge dewaterability; bioleaching
 
Address
(1) Jonathan W.C. Wong, Mayur B. Kurade, Ammaiyappan Selvam:
Sino Forest Applied Research Center for Pearl River Delta Environment & Department of Biology, Hong Kong Baptist University, Hong Kong SAR;
(2) Jun Zhou, Lixiang Zhou:
College of Resources and Environment, Nanjing Agricultural University, Nanjing, PR China.
 

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