Miami-Dade County Wastewater Facilities Master Plan
Rapid population growth and redevelopment in Miami-Dade County required significant expansion of the wastewater system. At the same time, regulatory pressure required the upgrade/rehabilitation of the existing collection and transmission system and the implementation of reuse to obtain consumptive use permit increases. To continue to provide high-quality service to its customers, the County selected Hazen and Sawyer to update its Wastewater Master Plan.
In the Spring of 2006, Hazen and Sawyer was selected by the Department to provide Master Planning Services, which was a condition of the consent decree they entered into with the U.S. EPA. This update addressed many existing regulatory requirements, such as peak flow management and Infiltration / Inflow (I/I) reduction, as well as permitting requirements such as reuse treatment to replenish drinking water aquifers and endangered wetland areas.
The specific services provided by Hazen and Sawyer include:
- Development of average daily and 2-year storm event hydrographs to allocate and evaluate the existing system flows.
- Determination of per capita flow projections and population growth, using state-of-the-art GIS software.
- Development of system specific operating characteristics, such as, peak flow factors and dampening coefficients based on actual data collected during storm events.
- Evaluation of innovative programs to reduce I/I and optimize pump station operation during storm events.
- Dynamic collection and transmission system modeling to determine the time-variable operation of over 1,000 pump stations and 150,000 sections of pipe, that include the gravity portion of the system.
- Development of a transmission and collection system capital improvement plan including Remedial Action Plans for all deficient pump stations and force mains.
- Evaluation of the existing wastewater treatment system with respect to current regulations.
- Determination of future regulatory requirements and treatment needs including incorporation of a recently issued Reuse Feasibility Study and compliance with anticipated nutrient removal limits.
- Development of a wastewater treatment and reuse implementation capital improvement plan.
Project Outcomes and Benefits
- Enabled Miami-Dade Water and Sewer Department (MDWASD) to meet the consent order dates required by the EPA for a peak flow management study
- By using a dynamic model MDWASD was able to imitate variable conditions in their system during a peak wet weather event, enabling development of a cost effective capital plan than took advantage of the existing system capacity.