A Night and Day Change to an EQ Tank

Abrasive Blasting

Flour, fat, salt, baking powder, sugar, and water—all ingredients used in baking. That is also what is found in the wastewater from an industrial bakery.


EQ tanks provide constant discharge flow

Bakeries use massive amounts of water, half of which is discharged as wastewater. Pretreatment of the wastewater is necessary before discharging it to a municipal sewer system. Equalization (EQ) tanks provide storage at the industrial bakery to keep the wastewater discharge at a more constant ebb and flow, so it does not overload the sewer system.


Small holes become larger

This open topped EQ tank, made with riveted steel paneling, developed holes in the panels and leaks at the panel seams due to failure of the interior coating liner. The small holes can become larger holes because of steel corrosion and the water pressure near the bottom of the tank. The tank is fifty feet in diameter and twenty feet in height.

Blackwell’s, Inc. was contracted by the bakery to make repairs to the EQ tank and install a new liner.

These are the steps we took:

  1. Residual liquids and solids were removed from the tank using two vacuum trucks.
  2. Tank interior was thoroughly cleaned using hot water pressure washing.
  3. Abrasive blasting (vapor blasting) to NACE 2/SSPC-SP10 specifications removed the failed liner coating and prepared the steel for maximum adhesion of a new liner.
  4. After abrasive blasting, the tank was inspected for holes and weakened steel. 263 steel patches were welded in place where needed. Smaller holes were repaired with a steel seam epoxy surfacing compound.
  5. Ceramic epoxy was applied as a new liner using a high pressure pneumatic airless sprayer. Joints and seams were “striped” to ensure a full seal.

Once Blackwell’s, Inc. made the repairs to the EQ tank and installed the new liner, the difference in appearance and serviceability was like night and day.


Safety first

Safety always comes first at Blackwell’s, Inc. Prior to the job start date for this work, our project manager met with the wastewater coordinator at the bakery to discuss any safety concerns and/or LOTO procedures. Blackwell’s, Inc. supplied all protective equipment for this job.

We stay committed to ensuring every project is planned, communicated, and executed to guarantee safe, first-time quality, a tightly managed timetable, and attention to cost benefit.

Abrasive blasting the tank interior removed the failed tank liner.
263 steel patches welded in place over larger holes in tank. The larger patch was 12 x 14 in.
Abrasive blasting profiled the tank interior in preparation for this ceramic epoxy liner .

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