TDH calculation tips for Temporary onsite treatment trains

[jcth]

Sizing my centrifugal pumps for treatment train systems I tend to overestimate TDH, and need some tips please.

We utilize various components in series such as sand filters, bag/cartridge filters, adsorptive mix media filters (Granular Activated Carbon), static mixers, etc… I typically calculate friction loss in piping and fittings, add vertical rise, and tend to add up all my component operating pressures, convert to feet of head for TDH to size a pump.

For example I add 44 ft head (for 1500 ft 4” sched 40 pvc, 20 elbows), 45psi for sand filter, 10 psi for bag/cartridge filter (10 psid at media change out), 3.5psi for GAC Vessels (liquid phase is top down flow, and top ports are 8ft tall X 1psi/2.31 ft = 3.5 psi each), x 2 for lead vessel and lag vessel, and 5 psi for static mixer; = ~200 ft head?

Thank you for any tips

 

[ashtree]

Unless you have a particular design that says otherwise i think 45 psi is way too high for your sand filters. I think 10psi would be more appropriate as a maximum value.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[LittleInch]

Designing for max filter DP's will lead you to overestimate. You need to do a worst case and best case calculation then choose something in the middle to get the overall average flow, unless you really have minimum flow you need at all times. Then you need to add flow control into your system to cope with the 90% of the time when it's not worst case.

I didn't understand the X2 for lead and lag vessels, but then I can't see your system design.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

Why are you bothering to make estimates when you state that these systems are in operation?

Update your estimates using the real world information from your operating systems.