Corrective action for identified nonconformity

Members are requested to suggest feasible corrective action for following identified nonconformity:

Frogs were seen under the cover of the main underground tank for potable water storage.

One simple corrective action as recommended by auditor is to clean the tank on regular basis and maintain its cleaning records. He also suggest to do microbiological analysis to verify the pathogen load on inhouse water treatment plant.

Problem is that first of all tank is very large in dimension and it seems very difficult to control over frogs. We can place a gauze or net at the main water supply inlet but it may chock due to any incoming contamination or may cause other problems like regular stressful cleaning. Whether there exist any solution or treatment to control frog arrival, growth and survival in potable water tanks?

Regards:

Dear Zeeshan,

You don't mention whether you receive bought water pumped directly into the tank or if you hv a system of filters for treating an underground raw water supply.

My first reaction is to simply avoid the problem and change to overhead water storage tanks. I suspect frogs are not that good at levitating.

Rgds / Charles.C

Dear Charles!

Sorry for late response.

Raw water is collected in underground tank. Then it is pumped up to the overhead tank. Then we have system of multiple filters with UV arrangements for treating that raw water before supplying it to the processing area.

Regards:
Zeeshan

Dear Zeeshan,

For me I would go the auditor way where you clean the tanks and have a cleaning record e.g once a month.
You can buy cleaning suit where cleaning staff can get into the tank with long scrubbing brushes and detergents.After rinsing,disinfect the tanks preferably with chlorine.Also you can put scrrens which are locked to keep away other animals and birds.

Regards,
Jeremy

Dear Zeeshan,

I suppose the first priority is to determine how the frog contamination is occurring ?? This will surely depend on the tank design, protection and environment. I hope they are not simply coming in with the water !

Similarly the option of inlet filters will depend on the method of bringing the water into the tank, if direct pumping, people often add an in-line water flow meter set with a protecting filter which can be readily removed periodically.

The effort required in cleaning large underground tanks is usually sufficient motivation to only need to do it annually IMEX.

In contrast, many factories typically do monthly monitoring of basic micro. quality of water to check, for example, conformance to EC standards plus a detailed chemical / micro. analysis - verification done annually.

Rgds / Charles.C