Wastewater Lift Station #685 – Miami-Dade Water & Sewer – concrete rehabilitation & protective coating

Miami-Dade Water & Sewer – Miami-Dade County, Florida, USA
Sewer Collections Division

Pump Station #685
February 2003
Pump station maintenance crews at Miami-Dade Water and Sewer decide to rehab and apply epoxy protective coatings to wastewater master lift station #685 in-house (DIY).
Inspection (pictures of concrete pump station surfaces, troughs and containment exposed to raw sewage, erosion, and hydrogen sulfide).
H2S corrosion taking a toll on the concrete walls, deteriorating the profile down to the rebar and potentially jeopardizing the integrity of the structure. Miami-Dade Water & Sewer crews got to the station in time to self-apply materials designed to structurally enhance the concrete, protect and seal it for its return to service and to further extend its next service life cycle.

Considering the surface showed major signs of contamination and rebar was exposed and oxidized/rusted. It was best decided to abrasively blast the concrete in lieu of high pressure water so that the steel rebar could be descaled while blasting.

Note: some lift stations can be simply high pressure water blasted, choosing between abrasive or water is simply a case-by-case judgement.
Initial blast passes reveals exposed aggregate, highly deteriorated surfaces with rebar exposure.
Miami-Dade Water & Sewer begins applying materials. They select Epoxytec products for the rehabilitation of the concrete and its protection with epoxy coatings. Epoxytec has been successfully training and supporting crews like Miami-Dade’s in order to offer in-house, “Do-It-Yourself” municipal personnel the means to apply their own rehab and lining systems. Epoxytec is typically selected for DIY projects because their product line is environmentally friendly, “green” with no solvents nor V.O.C.s (volatile organic compounds). The materials are also very simple to apply, requiring everyday tools and minimal mobilization. Also, Epoxytec materials are proven to be very forgiving and tolerant to the surface, high levels of humidity, moisture, and other uncontrollable sewer contaminants that arise during application.

The incredible amount of concrete deterioration created the need to restore the concrete about 2 -3 inches (depending on different areas). For the resurfacing stage of the project, Miami-Dade crews selected an ultra-dense 10,000psi, quick curing mortar – Epoxytec MortarTec Silicate.

After applying the mortar, Miami-Dade then applied a very proven, durable epoxy as an intermediate coating – Epoxytec CPP. Epoxytec’s CPP, has unbelievable bond strength, is chemical resistant and impermeable and therefore seals against infiltration (eliminating inflow), and refortifies the concrete with structural 16,000psi strength.
Epoxytec CPP works well for a simple in-house solution. The material requires minimal mobilization and tools, typically needing just a mixing drill and trowel. Also, the product is safe, 100% solid, no solvents (no VOCs). One other great feature, especially for trenchless, collection sewer systems is that it is extremely forgiving and tolerant to moisture and imperfect surfaces.

 

Lift station maintenance crews top coated the underlayment, consisting of Epoxytec Mortartec Silicate (rebuilding mortar) and Epoxytec CPP (epoxy liner) with a urethane-modified-epoxy (UME). Epoxytec Uroflex is a UME and proven with over 2,000,000 square feet coated at Miami-Dade Water & Sewer since 1989.

Considering the corrosion was so bad in this pumping station, the option to top coat with Uroflex will extend the life cycle with added H2S protection and grease build up prevention (the finish has great self-leveling properties and high gloss). Again, like the other materials, Epoxytec Uroflex is ideal for self-appliers being it is rollable, brushable, or spray optional. In this case, simple brushing and rolling was selected; therefore, requiring no need for complicated equipment.

Note: During this project, Uroflex came in seafoam green (used here as the first coat), and in red (used as the second coat).

Epoxytec Uroflex, 2nd coat in red.

The total system applied:

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