Temporary Water Pipeline

[enve2014]

I’ve been tasked with designing a temporary water pipeline to transport 10,500,000 gallons of water from a river to a tank approximately 1.7mi away. The elevation difference between the river and the tank is approximately 180ft. The height of the tank is 66ft. I’ve calculated a head loss due to friction of approx 153ft. Therefore a TDH of approximately 400ft (I believe this is correct).

Pump selection is not my strong suit, but we would like to run 1 main pump with 2-3 booster pumps along the line at low pressures. I’m wondering if this would be necessary, and how I would go about determining this.

Also, has anyone used a sediment removal system at this high of a flow rate with any success? We’ll be using 8 inch Victaulic coupled line.

Any thoughts or insight would be very helpful.

 

[cvg]

there are contractors that can do this for you, for instance rain for rent could do it all and will do the design for you. stick with 1 pump if possible, fewer headaches. HDPE fused pipe might be a better option.

http://www.rainforrent.com/

 

[oldestguy]

Any chance you can buy a bunch of fire hose for the job? Then sell it at discount to fire departments. If you are not rushed for time, the daily pumpage might not have to be so great that large diameter "pipes' are not needed, in spite of head losses. On the other hand used fire hoses are readily available on the surplus market, but what to do with them after that?

 

[enve2014]

Thanks for the input cvg. Unfortunately I don't think i'll be able to subcontract out this job to them as they're not in an area where we're performing the work. It seems like they would have the best idea of which pumps and pipe to use though. I was thinking about HDPE piping too and we could run a higher pressure system with it....safety issues with that though.

 

[enve2014]

quite a bit of fire hose.. but it's definitely an option. Again, we're not really in a great area for it.

 

[bimr]

One would need to know how much sediment is in the water and how much is desired in the product. What is the use for the water?

A gravity plate settler or a ballasted flocculation clarifier can be used to remove the sediment.

One pump would be the preferred approach.

 

[enve2014]

Thanks bimr. We're hoping to withdraw the water (from a river) after spring runoff so I'm hoping sediment will be minimal. The water is going to be used for hydrostatic testing of a tank.

 

[bimr]

Since the application is temporary, you may rent a cartridge filter with an approximate 100 micron filter rating.

 

[rconner]

[While I guess this probably goes without saying and if the end product of the tank happens to be intended for potable water and you go with the rented/used pipe or hose route, you might want to check with the provider as to what exactly the pipe/hose has been previously "used" for etc. before you start pumping.]

 

[LittleInch]

From a pipeline perspective there is some missing data here, namely - elevation profile. end point elevation is needed , but you also need to know the profile and post it so we know as well.

You don't actually give the flow rate or time you want to fill the tank in.

You might want to consider using something like 180mm PE pipe (or two pipes) which as a standard comes on a reel of up to 150m length or bigger if you ask them nicely. For that sort of distance one pump should be enough, but depends on your profile. Running booster pumps is not easy and for a temporary system you would probably need break tanks at each location to avoid control issues.

Sediment removal you could try hydro cyclones especially if you can dump the discharge back into the river you got it from.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[enve2014]

Thanks LittleInch. I've uploaded my elevation profile. Start point is approx 612m and the end point is about 660m (about 57m elevation difference). As you can see, we have a fairly large elevation change at around 1300m in distance. I would like the flow rate to be around 4.5m3/min which would fill the tank in around 6 days. I too would rather not use booster pumps but that elevation change may require one.

I was thinking either hydro cyclones or bag filters but I think the hydro cyclone system would have less pressure drop than the bag filters.

 

[LittleInch]

That profile is nearly ideal and doesn't present any issues. Only if you're being limited by your temporary pipe to some pressure less than 6-7 bar should you need booster pumps.

A thing to watch with cyclones is that they like to operate with relatively low discharge pressure. Hence you might need a small lift pump with cyclone followed by a more meaty main pump otherwise they need to make the outlet nozzle so small that it either wears away or gets blocked every hour by a small pebble... Of course the vendor doesn't tell you this until after you've installed the bloody thing. However they generally have a fixed DP and don't normally block, but you need a big pebble catcher to prevent the outlet becoming blocked. Normally about 10 to 15% of the flow is returned as the discharge.

Although it might be a bit steep, think about these sorts of suppliers

http://www.flexsteelpipe.com/rental-equipment

FOr a temporary pipe, anything you can unreel then reel back again should be better than jointing 12 or lower metre lengths of pipe.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[cvg]

I believe your headloss is going to be significantly more than the 153 feet that you calculated if you use 8 inch jointed pipe. you need to use the actual ID and a good estimate of the roughness.

 

[enve2014]

good point cvg. I was just using a generic roughness coefficient, but it will probably be quite a bit more than 153ft.

 

[enve2014]

Thanks LittleInch. That's interesting about the cyclone. It will be a low pressure system, so we'll have to run some booster pumps along the way.