Sawgrass 3 MGD Reverse Osmosis Water Treatment Plant and Nano-Filtration Re-Rate

City of Sunrise, 
Florida

Sawgrass 3 MGD Reverse Osmosis Water Treatment Plant and Nano-Filtration Re-Rate

Service Type: 
Project Highlights: 
  • The RO treatment facilities were designed and bid on a fast tracked schedule to allow the City options in meeting its alternative water supply requirements.
  • Modular RO treatment units were designed for commonality among two of the City’s water treatment plants.
  • Carollo evaluated the existing nano-filtration (NF) process and provided the necessary technical support to re-rate the NF facility from 18 to 24 mgd.
  • 3D design was utilized to minimize design conflicts and simplify stakeholder understanding of the complex water treatment processes.
Sawgrass NF WTP was expanded from 18 to 24 mgd.
The existing 18 mgd Sawgrass NF WTP was expanded from 18 to 24 mgd.

Carollo performed study and design services for a 3 million gallon per day (mgd) reverse osmosis (RO) water treatment plant to be constructed at the existing 18 mgd Sawgrass Water Treatment Plant (WTP). Provisions were included in the design that will allow the facility to expand it to 6 mgd in the future. The RO treatment facilities included design of an RO system that is expandable in 1.5 mgd treatment units to an initial capacity of 3 mgd of permeate. The treatment processes included chemical storage and feed systems, connection to a raw water pipeline, sand strainers, cartridge filters, RO membrane treatment system with associated clean-in-place system, degasification, and two-stage air quality control units. The RO treatment system was designed to blend RO permeate with existing nano-filtration (NF) permeate upstream of the existing clearwell to produce a composite finished water.

In addition to the RO treatment facilities, Carollo evaluated the existing 18 mgd NF treatment system and provided the necessary technical support to re-rate the NF facility from 18 to 24 mgd.

Carollo also performed bench-scale testing of ion exchange technologies for organics control alternatives. Fixed bed vessel type ion exchange was recommended for full scale implementation. This system, when implemented, will allow surficial aquifer water to be treated for organics control and color reduction and blended with NF permeate to be subsequently disinfected. By not treating a portion of the water with the NF treatment system, but rather with IX, the blended finished water would increase the facility’s water supply by approximately 1 mgd without the addition of any surficial wells or consumptive use allocation. (The IX treatment system has very little water loss while the NF system operates at 15% recovery, which results in a “loss” of 15% of the raw water pumped to the facility in the form of membrane concentrate.) Another benefit of the IX treatment system is that it would increase finished water hardness and alkalinity that results in a more balanced product. The IX treatment system also costs less than operating the NF treatment system.