Water Supply Vol 2 No 5-6 pp 119–125 © IWA Publishing 2002
A comparison of conventional and non-conventional treatment technologies on arsenic removal from water
H.H. Ngo*, S. Vigneswaran**, J.Y. Hu***, O. Thirunavukkarasu**** and T. Viraraghavan*****
*Faculty of Engineering, University of Technology, Sydney, Australia (E-mail: H.Ngo@uts.edu.au)
**Faculty of Engineering, University of Technology, Sydney, Australia
***Faculty of Engineering, University of Technology, Sydney, Australia
****Faculty of Engineeering, University of Regina, Regina, Saskatchewan, Canada S4S OA2
*****Faculty of Engineeering, University of Regina, Regina, Saskatchewan, Canada S4S OA2
ABSTRACT
In this study, four treatment methods were used to remove arsenic from water, namely: (i) chemical precipitation, (ii) arsenic adsorption onto iron-oxide-coated sand, (iii) high-rate saturated floating-medium flocculator/filter and (iv) membrane hybrid system (adsorption-microfiltration). The results indicated that more than 90% of total arsenic was removed by using FeCl3 (40 mg/L) as coagulant. The removal efficiency was 10% lower when polysilicato-iron (PSI, 2.5 mg/L) was used as a flocculant. The results of both the batch and column adsorption studies showed that iron-oxide-coated sand can effectively be used to achieve very high levels of arsenic removal (less than 5  m/L as As in drinking water). Arsenic was removed up to 78% from the packed polystyrene beads filter with in-line FeCl3 addition at a high loading rate of 30 m3/m2.h. When powder activated carbon (PAC) was used in the membrane hybrid system, 87% removal of arsenic was achieved. A mixing time of 2.7 min with the mixing intensity of 87.8 s-1 were used. A very high filtration (permeate flux of 760 L/m2.h) was observed with a membrane of pore size of 0.2 m.
Full article (PDF Format)
PAY-PER-VIEW: Buy this article for £20.00 (IWA MEMBER PRICE: £15.00)
|
