Water leak test of concrete reservoir

[hakQ]

We have 50m x 20m x 5m(h) concrete reservoir which is designed to contain the acidic water. Its original anti acid protection coating had got degraded and concrete structure had got damaged for years. Thus, we removed all the old coating, restored the damaged concrete partially for the required area and have done the new coating for entire surface.

However, during the water filling test, water seepage and dripping is seen at the outside bottom of the structure. We think that it is the captured acidic water between the floor concrete and HDPE liner which was leaked and captured during the years’ operation, and it is now enforced to travel towards outside by the heavy pressure of the filled water.

I need your idea to prove the observed water outside the structure is not coming from inside the reservoir.

 

[ukengineer58]

Test the PH of the liquid. use a dye in the tank (guess that may not be reasonable due to size).
wait until the acid would have theoretically be expunged.
not sure why it would leak through the wall/floor - what is the joint detail?

 

[hakQ]

The original coating was urethane type, but the acid contains a certain level of iodine and iodine is told as harmful to urethane, so we changed with epoxy type of coating which was tested as good. We have been daily checking pH of outside water, but it very fluctuates between 1.14 to 2.54 and we are not sure if the filled water gets acidity while it passes through the structure. I was thinking of dye but size is too big even though it would be most clear way.

 

[LittleInch]

Are there any penetrations in the concrete shell?

That's where the liner is suspect.

You need to measure flow. If the volume starts to drop off then you might be right.

I strongly suspect your new liner has a leak though

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[le99]

Dye the water so you can easily identify the source of the suspicious water.

 

[LittleInch]

Whenever this happens everyone finds lots of good reasons why the fluid coming out or the tank level is falling isn't coming from inside.

However once it starts and then doesn't stop you kind of run out of excuses. How long that time is varies, but it can take 2-3 weeks of constant leaking / level falling before the excuses become invalid.

What is level control like here?

Constant flows in and out or does it get a volume for a week and just sit there?



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[le99]

If the fluid is highly acidic, I would consider a liner rather than a coating. You should also investigate the reason for the deterioration and leaking of the former protective material if it wasn't by aging as expected. Without solving the root problem, it will reoccur/

 

[GeoEnvGuy]

If you can obtain enough of the seepage you can run chemical tests to determine how contaminated it is compared to the clean water you put in.

You an also track the water level over a week and have a corresponding evaporation pan for baseline.

 

[Canuck65]

A gallon or two of pond dye should provide enough colouration for 5,000 cu.m of water. Not sure how it will react with the acidic water. Pond dyes are typically used for protecting stocked fish from predators (mainly birds) and reducing algae.

 

[bimr]

Based on your problem description, it would appear unlikely that the tank is leaking.

A quick and inexpensive test will be to compare the conductivity of the testing water to the conductivity of the water seepage.

 

[hakQ]

We are going to do the tracer test soon. Thanks for the comments, and will update.