Submitted on: 12 October 1999.
Revised on: 07 November 1999.
Accepted on: 09 December 1999.
___________________Engenharia Sanitaria e Ambiental
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Submitted on: 31 August 2010.
Revised on: 13 November 2010.
Accepted on: 24 November 2010.
___________________Engenharia Sanitaria e Ambiental
Submitted on: 07 November 2007.
Revised on: 07 February 2008.
Accepted on: 19 March 2008.
___________________Engenharia Sanitaria e Ambiental
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