Tetra Tech, Inc

Alexander Orr Water Treatment Plant
Task Authorization No. 11 – Process
Optimization Study
Miami, Florida
• Performance of phased bench scale testing and evaluations (lime softening, enhanced lime softening and
stabilization) to determine chemical feed rates to produce optimum hardness, color and DBP precursor
removals; raw water characterization and analysis.
• Establishment of water quality goals, review of operational protocols; theoretical estimation of chemicals
required to achieve various levels of hardness control; analysis of the effect of optimizing the lime softening
and stabilization processes upon chlorine usage for disinfection and the formation of disinfection byproducts;
and review of power and chemical usage/costs.
• Determine if increasing the level of automation of the treatment process can improve plant performance and
consistency of treatment, optimize the feeding of chemicals, and provide operators a greater degree of control of
the treatment process.
• Identification of cost savings that can be potentially realized by the optimization of the existing lime softening
and stabilization processes. The disinfection/DBP control evaluations consist of chlorine demand/decay and
trihalomethane/halo acetic acid formation potential investigations for chlorine demand and decay, as well as
trihalomethane and halo acetic acid formation potential.
Five alternative recommendations for optimizing the lime softening and stabilization processes are provided in order
to improve treatment performance and reduce operation and maintenance costs.
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