Tetra Tech, Inc

Alexander Orr Water Treatment Plant
Task Authorization No. 11 – Process
Optimization Study
Miami, Florida
Project Highlights:
• Provides renewal,
improvement, and
optimization for the
majority of the
MDWASD system
• Includes upgrading
one of the largest
and oldest lime
softening treatment
plants in the
southeast United
States
• Develops a
prioritization
schedule of the
identified facility
needs for the Orr
WTP
Project Value:
$200,000
Project Duration:
On-going
Tetra Tech, as a subconsultant, is assisting the Miami-Dade Water and Sewer
Department (MDWASD) with the renewal, improvement, and process optimization of
the South Dade water system, including its largest water treatment plant. The Alexander
Orr, Jr. Water Treatment Plant (Orr WTP) is one of the largest water treatment plants in
the southeastern United States. The Orr WTP treats Biscayne Aquifer water with lime
softening, filtration, and disinfection.
The Alexander Orr, Jr. Water Treatment Plant (Orr WTP) uses the conventional lime
softening process to soften the hard water withdrawn from the Biscayne Aquifer to
produce drinking water for MDWASD customers. To soften the water, the raw water pH
is increased by adding calcium oxide to precipitate calcium carbonate and reduce the
hardness of the water sent to the consumer. Unfortunately, the pH of the water of the
softened water is too high, so it must be reduced to a level that prevents further calcium
carbonate precipitation and is acceptable to the consumer.
This study will evaluate alternatives to improve the efficiency of the lime softening and
stabilization processes with the intent of reducing operational costs for the facility.
Process optimization alternatives that can be implemented at the plant to reduce
operating costs will be identified.
Specific recommendations for modifications and additions to the existing treatment
processes will be developed to improve treatment plant performance, reduce operating
costs and provide a consistent finished water quality meeting the treatment goals. The
scope of the study includes the following:
Project Staff:
Ken Caban, PE
Project Manager
James Christopher, PE
Project Engineer
Stephen Glatthorn, PE
Project Engineer
Reference:
Miami-Dade Water and
Sewer Department
3071 SW 38 Avenue
Suite 515
Miami, Fl 33146
Mr. Rafael A. Terrero,
PE, BCEE
786.552.8112
Terrero@miamidade.gov
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