Milky water
Milky water
(OP)
Our small muni water system uses a ~10,000 gal hydro-pneumatic tank in combination with booster pumps to deliver water to our customers. A suitable elevated tank is not feasible. The system works OK, but air infuses into the flow in the tank causing a very objectionable temporary cloudiness at the tap.
The tank is about 40 feet long by 6 ft dia. It has a small port at one end. Water flows from the boosters through the tank to the system.
What are some of the possible solutions ? I have some ideas, but could use some help.
Thanks,
Ron
The tank is about 40 feet long by 6 ft dia. It has a small port at one end. Water flows from the boosters through the tank to the system.
What are some of the possible solutions ? I have some ideas, but could use some help.
Thanks,
Ron





RE: Milky water
Clearly the gas is dissolving into the water at pressure so you need to separate the two. If you allow the tank to fill completely and use bladder type accumulators attached to the tank or within the tank you should avoid this problem once you've cleared the current water out.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Milky water
Our system flows about 100 gpm to 2000 gpm and the boosters are on/off 25 to 75 hp pumps. So, the railroad car sized air-over-water tank/accumulator seems necessary.
I should probably ask this vast pool of knowledge here if bladders are readily available and could a tank of this size be retrofit?
BTW, I even thought about the feasibility of floating a plastic membrane, maybe polypropylene or LDPE in the tank to separate the air and water.
Or maybe, re-plumbing it to a single connection tee'd into the system would reduce the dissolved air being pushed into the system? I am sure this issue is common and nearly everything has been tried. So, I am hoping that an affordable solution is possible. Thanks.
Ron
RE: Milky water
RE: Milky water
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Milky water
Opjoe: If air was being pulled in by the pumps, the sight gauge would show falling water level as additional air entered,I would think. In this case, however, an air compressor is necessary to replenish the air which dissolves in the water. This is expected behavior for any air/water pressure tank without air/water isolation.
Ron
RE: Milky water
RE: Milky water
RE: Milky water
RE: Milky water
Thanks, should have said. This prob has been there for several years.
Short history: The tank date is 1999. There hadn't been much talent around or motivation to get things right. Recent newspaper articles pointed out deficiencies including this problem. That produced a jolt of motivation and your truly is standing by with, I hope, the talent.
Ron
RE: Milky water
It would appear that you only need a relatively small volume to be maintianed at pressure before you pumps kick in.
Sizing bladders and pressure tanks is a balance between the variation in flow and how often your pumps start and stop. Make it too big and you've wasted a bit of money. Make it too small and you burn your motors out due to constant start / stop. Only you can really judge what the right volume is based on the flow rate and amount of times the motors can start and stop.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Milky water
A bladder of several hundred cubic feet for that tank would certainly do the job. Now where to start looking for that? Some tank people maybe. To get the badder in the tank, it would have to modified to increase access and re-certified anyway.
There was an interesting hint in a prev post by Operatorjoe. His tank is teed off to the side with no flow-through. It apparently functions without producing temporary turbidity. Promising. Need more info.
Ron
RE: Milky water
they are NSF-PW ASME
http://www.charlattetanks.com/
Hydrae
RE: Milky water