Ferndale WTP Upgrade Project
This project upgrades the water treatment plant to 100% reverse osmosis (RO) by adding one more 500-GPM RO unit (four total) and by eliminating greensand treatment. Currently, about 20% of water is treated only with the greensand filters and then blended with the RO treated water (aka “permeate”). Eliminating the greensand filters is necessary because they do not remove any of the excess salt and hardness from the new “deep” well. The production rate for the upgraded treatment system will be 2,000 GPM (2.88 MGD). The future production rate will be 3,000 GPM (4.32 MGD) with six RO units.
RO permeate contains very low concentrations of minerals and is very soft water, which makes remineralization with calcium carbonate a necessity. A new building and remineralization tanks will be constructed to achieve optimal hardness and alkalinity levels of between 50 mg/L and 70 mg/L (as CaCO3).
A new 52-ft by 38-ft, 24-ft tall building will be constructed to house the remineralization system including two 20-ft by 10-ft calcite contactor tanks, carbon dioxide injection system, and pH adjustment system.
Carbon dioxide (CO2) will be used to dissolve the calcite into the permeate. A 6-ton capacity CO2 tank (16-ft tall) will be installed outside the new building. A CO2 dosing system, using 15-GPM water and the CO2 supply, will inject dissolved CO2 into the permeate discharge piping. A backup CO2 supply will consist of twelve CO2 gas cylinders.
Final pH will be adjusted by injecting a soda ash solution into the remineralized water. This system includes two new 3,000-gallon tanks, a mixing pump, and the existing repurposed dosing pumps.
A bridge crane will be installed in the new building for loading calcite and soda ash into the tanks.
EXISTING WATER TREATMENT PLANT IMPROVEMENTS
Improvements include one new RO unit and modifications to the three existing RO units to improve water production and decrease the rate of membrane scaling. The Greensand filter tanks and chlorine contact tank will be demolished to make room for new equipment.
A new Permeate Flush system will be installed. This system is used daily to flush the RO filter membranes with permeate, which is necessary to extend the useful life of the membranes. This system will include a 4,000-gallon water tank and a 380-GPM pump. The existing CIP/Permeate Flush system will be used only for CIP (clean-in-place), which is a semi-annual chemical cleaning of the membranes.
The existing RO antiscalant dosing system will be rebuilt adding two more dosing pumps (total of six). Antiscalant is used to maximize water production and protect the membranes from scaling.
The existing greensand filter backwash pump will be reused and repurposed for the remineralization tanks.
Three chlorine injection points will include (1) the permeate discharge pipe and (2) before and (3) after the clear well.
A new distribution system flow meter will be installed to replace the old meter for the discharge to the distribution system.
A new bridge crane will be installed in the existing building for serving the Distribution System Pumps and the new RO Unit(s).
News and Information
- Invitation to Bid
- Pre-Bid Meeting: September 13th, 2023 – 1:00PM
- Pre-bid meeting will be held at City Hall, 2095 Main Street, Ferndale, WA
- Site visit to the Ferndale WTP following the meeting
- Bid Opening: September 20th, 2023 – 11:00AM
- Bid opening will be held at City Hall, 2095 Main Street, Ferndale, WA
- Record of Bid Opening
- Planholders’s List
- Bid Tabulation
Project Specifications and Plans
- Project Specifications
- Project Plans 11″ x 17″ sheet size
- Addendums to bid documents will be available online on the Wilson Engineering website here: http://www.wilsonengineering.com/bidding-documents.aspx/