Cleaning a water tank.

[Kiwi Phil]

I have 2 large tanks, maybe 7-8,000 gal each.
Because i pump dirty water in to 1, settle it, treat it etc, i find there is a lot of stinking sediment building up on the bottom, and the tap hole is maybe 4" up the outside wall, so I can never get the last 'lot' out without have to lower myself in and spend hours stuffing about.
Anyone any ideas or suggestions?
Cheers
Phillip

 

[Xcusme]

Re: Cleaning a water tank.

Two options I guess. Cut a new drain in the bottom of the tank and weld on an adapter to fit a drain pipe with shut off. Or, cut a hole in the outside wall to encompass the existing drain tap with the new hole tangent with the bottom of the tank. Weld the new drain pipe to this opening etc.

 

[SS MAYFLOAT]

Re: Cleaning a water tank.

If your tanks are steel, I can see your concern as the sediment can eat through the tank eventually.

Is one end of your tank higher than the opposite end? This would help get the sediment to at least one end of your tank vs the whole length.

One of the local dairy farms has a system that flushes the stalls of the cattle. He uses a couple of large tanks. After the flush, the water goes into a retention pond along with its debris that it washes out of the barn. Once the majority of the debris has settled in the pond, he pumps the top water back into his tanks. He too was getting sediment in his tank that he could not remove without physically getting into the tank.

To correct his problem, he raised one end of the tank to increase the flow to the drain. He then had concrete pumped into the tank to raise the bottom of the tank to be higher than the drain. In the middle of the concrete, he made a channel so that all the debris would move to the center and then it could flow down to the drain and out during cleaning.

 

[Kiwi Phil]

Re: Cleaning a water tank.

Thank you for those 2 suggestions.

X-
It is a plastic tank so putting a hole in the bottom and buying off-the-shelf fittings is easy.
Leaning the tank over is not so easy....it is heavy.

I have done this to my 2,500 gal tank.....hole in the bottom, with a 1.5" plastic drain pipe out to a pump....have it all on a concrete pad, dish shaped, with a ditch dug for 1.5" pipe to sit in.
It was actually quite a big job, and very difficult lowering the tank down, (it was on its side) as it always wanted to twist or roll sideways just a little, so the horrizontal pipe wouldn't line up with the ditch.

I will think this one thru. Maybe I need a crane to lift it straight up, hold it there, while we work on it and the ditch.

SS
I never thought of that one!!
I have had to read your post a couple of times to get a clear understanding.
I have always made my tanks level....that's what the instructions always say!!
The concrete idea is great....especially as I don't need to cover the complete floor if one side is raised.

That is what is great about this site.....so many different ways of looking at problems.

Thank you both for your replies.
I will chew them over for a while and do one of them.

Cheers
Phillip

 

[SS MAYFLOAT]

Re: Cleaning a water tank.

If you go the concrete way, you wouldn't need to tilt your tank. Use the concrete to build up a tapered bottom to your drain.

After seeing TD's post about a toilet bowl cleaner, maybe a few PO'd cats would get it cleaned out for you ...........SS

 

[Xcusme]

Re: Cleaning a water tank.

Yea, the concrete idea is great. I find myself over thinking it though...it would seem an easy thing to lift the drain end a bit and then toss in the 'crete until it's level with the drain hole. After it sets, lower the tank back down, the concrete would then be sloped to the drain.....
Like I said, I think I may have given this way too much thought!

 

[Kiwi Phil]

Re: Cleaning a water tank.

Right....this is what I have done...had to move quickly as i need to treat a tank of water every 6 days.....so I am using quite a bit in this heat.

Pumped it down, put John in....and cleaned it out manually.

Where the big tap is on the outside bottom, we found we could thread a plastic joiner (40mm threat one end and 40mm bayonet other) on the inside of it too.(inside the tank that is).

We then got a length of that swimming pool flexible pipe they use on Kreepy Krawlys. Attached to the bayonet (inside the tank) and clamped it tight.

I thought, when I filled the tank, this hose would sit on the bottom of the tank, and move about when the pump sucked, taking out water with silt to the sand filter.

Wrong.....the !@##$% hose floats, and when the tank is full, it sticks vertically above the water.

Next move.....grab the Kreep Krawly out of the swimming pool and put it on the end of the pipe....what a brilliant solution...for all of 10 minutes....the Kreepy Krawly caused the pipe to get knots in itself.

Next move.....grabbed the swimming pool vacum head (the one you attached the hose to, and the long alloy handle, and manually vacum the bottom of the pool).

Guess what, it is not designed to be used at 180 degrees.....the suction is strong enough to bow the vacum head and the hose just sticks to the bottom, and the pump makes a funny noise and you don't get any water.

So now I am making up a long plastic handle (like a broom, but in 40mm hard plastic irrigation pipe), weight it at bottom, and going to duct tape the flexible pipe to it, about 6" up the handle.

I have some worn heavy duty irrigation "T's" I may attach to the bottom also.....fill with a little cement for weight, then screw a plastic broom head to, so I can sweep the bottom slowly, and everything will be drawn out the pipe to the sand filter.

Now we have this hose clamped inside the tank, we have no option but to go this way......no one is volunterring to duck-dive down and undo the hose clamp, plus I'm not having one person take their socks off a 2nd time!!!

I like the idea of the concrete in the bottom of the tank...... have to wait till it cools down and water usage drops.

Will keep you posted.

Cheers
Phillip