Rov inspection in potable water applications

[colin65]

Hi,looking for some info on cleaning /disinfecting Rov before Water tank inspection, any guidelines on amounts/dilutions of Chlorine solution
Thanks for your help

[rovsteve]

Prior to placing the ROV in a potable water tank, the standards of the American Water Works Assn. (AWWA), the guiding light of the potable water industry, require a bath or spray of a 20% chlorine/water (5 parts water to one part bleach). Make sure you use plain bleach, not the newer scented types. First I would make sure the ROV is washed in soap and water to remove any grease or grime from previous work. Then just prior to inserting into the tank do the bleach dunk. Make sure you also do the tether. I prefer using a plastic tub that holds a few gallons of solution for dunking the ROV. I also use a small spray bottle sometimes but don't feel it does a really good job. Also make sure you retreat the ROV when moving from one tank to another to prevent cross contamination.

Something I have noted on some tank inspection is the potable water in the tank is so bad that I dunk the ROV at the end of the job to protect myself. It makes you wonder how someone can drink the water.

The biggest problem or issue with this process is getting the bleach solution on your clothes, I have seveal pairs of jeans and lots of shirts with bleach spots from splashing.

That's about all you need to do to be compliant.

Steve

[Chief]

Colin,

Make sure the bleach you use (chlorine...) is NSF 60 Approved. Basically any chemical that is put into contact with a potable water system should meet this requirement. Unfortunately, the operators of most water systems don't know what is or isn't approved, they rely on the diver/ROV pilot to be the expert which is rarely the case (as it relates to AWWA and NSF Standards). Everyone thinks all chlorine is the same, but it isn't. Different manufactures put different items in their chemicals, and some never intended their chemicals to come in contact with drinking water...

Here is a link where you can see if chlorine your using is certified and approved by AWWA & NSF Standards:
http://www.nsf.com/Certified/PwsChemicals/

Chief

[prowe]

Colin,
As part of the waterworks work I have done I have been using the protocol adopted and approved by the water works (The client). I offer to allow them to do the decontamination of the system, that seems to make them happy and gives them a chance to look over the equipment. Remember the gloves and safety glasses (Full face shield recommended) when working with any chemicals. An apron is also nice to protect you and your cloths. Like the latex gloves you can get the food service plastic aprons by the box at a reasonable price.

I clean the ROV and tether before leaving the office using chlorine (NSF60) @ 5 to 1 as Chief and ROVSteve have recommended and put both the ROV and tether into a double plastic bags for transport to the site. At one job they didn't have a hard protocol but ended up using a bit heaver concentration (4 to 1) for 5 minutes in a 5 gallon bucket followed by spraying the tether (still in the double plastic bag).
As part of your report I would also document the procedure and materials used for decontamination just in case there is any questions or issues later.

Hope this helps and I know there are many methods and suggestions out there, Talk with your customers and if you can get a copy of their decontamination procedure before the job it will be helpful in planning for doing it. One client wanted the chlorine soak plus 5 min under UV light! The float block looks way cool under black light!

Good luck and clean waters!
Patrick

NSF60 Ref: http://www.nsf.org/business/water_distribution/pdf/NSF_Fact_Sheet.pdf
A good thing to have on hand for reference.

[colin65]

Steve.chief,Patrick

Thanks for taking time to reply to my posting. I am pritty new to service reservoirs need all the advice i can get

once again thanks for your help

Regards

Colin

[colin65]

Hi again chaps. need abit more advice

The job in question in a concrete Reservoir of 15m dia with a Wall height/water level of 5.5m. the roof is domed shape takeing it up to hight of 7.5 meters at centre.
The client is has some concerns about Rov getting good footage of roof dome. i have a Pro 3 trying to hire Pro 4. can any one tell me the distance the top camera on Pro 4 will see in this environment. or any other tips to overcome clients concerns

thanks

Colin

[colin65]

P S can external camera attach faceing the verticle/strait up ? on top of Pro 4

[prowe]

Colin,
Just a thought, but after you finish the inspecting below the water line of the tank, re-weight the ROV a bit positive and AFT to cause the front to float higher in the water. (Move the main weight aft should do it). Then see how much of the front dome you can get out of the water. This should allow you to get a reasonable view of the inside of the cover using the PRO III ROV lights and camera. You might want to try it in a pool before to get the weighting correct before you get on site.
2m isn't that far to look up, I have inspected under docks before just by looking up with my PRO III. The detail isn't that great but it was good enough to see what the client wanted to see.

Good luck and let us know how it goes??

Patrick

[rovsteve]

Colin,

As detailed in the other posting, bring the Pro 3 to the surface and tilt the camera up, you will be able to see adequate detail for the client. This is a regular part of my tank inspections and is not a difficult task. You need to relax and just do the job, you will find it's a lot easier than you are thinking. The Pro 3 is a great machine for this type of work and your client will not be disappointed. This is a small tank and should not take more than 30 minutes to conduct your video survey. However, since this is something new to you spend some time practicing in the tank. Do a complete inspection for the client then do it again for yourself and keep the video separate for training and evaluation.

I would first do a 360 view of the interior from the VideoRay floating on the surface so you can see what everything looks like, thendo some runs along the walls and the a full 360 of the wall floor interface. Then do the bottom and try to determine how much sediment is on the floor (percent of coverage and depth) these are just rough estimates and don't need to be to the mm. Next do any ladders, structures, pipes, openings, cathodic protection anodes, then the roof wall interface and the dome underside of the tank roof. While flying along the walls and such look for any bumps or blisters in the coating surface, get real close and use your close focus to see them in detail.

Enjoy the job and gain confidence to be able to give advice to the next guys who needs it.

Let me know how it goes.

Steve

[colin65]

Hi chaps.

Thanks for your comments, this contract is for 3 years with major UK utility company . they have twenty resavours to start with.I have give them reassurance that Pro 3 is good enough to do the job.
but they still have concerns concerning dome. they are not in any rush to start they just want everything right. this has been going on for a couple of mounth,s

I have put forward the Pro 4.can you give me any info on Pro 4 top Camera; ie can it be fitted vertically,how far can camera see,

thanks

Colin