Wastewater Chlorine Contact Basin – Miami-Dade Water & Sewer – Concrete Rehabilitation & Protective Coating

MDWS_Previous Coating_2003

Maintenance crews at Miami-Dade Water & Sewer shut down a section of their chlorine contact disinfection system at South District Wastewater Treatment Plant for inspection. These tanks are typically coated with a coal tar epoxy coating and from the pictures, it was evident that the previous coating reached the end of its life cycle. The concrete surfaces have to be repaired and recoated to protect against the erosive activity of these troughs and from the corrosive nature of chlorination.

After high-pressure water blasting, Epoxytec CPP was chosen to repair and fill any voids in the concrete before coating.

Epoxytec CPP is an epoxy paste used to fill, repair, patch, and sometimes rebuild and line concrete. It is an ideal selection for this application because many of the voids are just shallow surface spalls and CPP can be applied ultra-thin without any need for build-up, unlike mortar.

Note: if needed CPP can be built up to 1/2 inch per pass.


CPP structurally reinforces any damaged concrete with 16,000 psi compressive strength, has excellent bond strength, and has incredible tolerance and forgiveness to questionable surfaces (perfect for wastewater applications, as many unknowns often arise). Not to mention, CPP is chemical resistant and seals. It is easy to apply and has no harmful fumes – great for in-house, DIY municipal crews.

After patching the corroded area of concrete with Epoxytec CPP, crews began to apply a roller-applied bitumen coal tar epoxy to stay consistent with prior and past material type selections. Because of the County’s long history and success with Epoxytec, the material chosen is Epoxytec UroShield Bitumastic – a two-component, modified coal tar epoxy.

One area of the basin (the back wall) was completely resurfaced with Epoxytec CPP.

Finishing up the rolling application of Epoxytec UroShield Bitumastic (2 x 15 mils for total DFT 30 mils).