high pressure + high tds = corossion ?

[TominTunis]

I've cross-posted this in pump engineer forum.

Hi folks,
Given:
Pumping water
TDH - 286 m
flow - 300 lps
water quality (concentration of dissolved solids - high)
ph - ?
concentration of CO2 - ?
temp - 18 - 28C
pipe material - concrete lined DI

Wanted:rate at which my pipes are going to lose cross sectional area

Have any of you done such a calculation, or can you indicate a reference. I checked AWWA and a 2010 pump handbook and have come here next. By the way, it's a site in East Africa. Thx.

 

[bimr]

You have not posted enough details on your problem.

Take a look at this website, it may be able to assist you:

http://www.awwa.org/Resources/RTWCorrosivityCalc.cfm?navItemNumber=1576&showLogin=N

 

[TominTunis]

I think i was misleading and should have said "high pressure + high TDS = calcification".

if my first year chemistry comes back to life, i recall that under increasing pressure dissolved calcium products precipitate out of solution. i have a groundwater with high concentration of calcium products and want to see at what concentration and duration the calcification of the pipe becomes too costly.

 

[bimr]

There will be negligable calcium precipitation because of elevated pressures. Calcium precipitation does not occur at the normal operating pressures experienced by water distribution systems.

The importance of these parameters is demonstrated by the langelier index shown on the AWWA link. As you can see, there is no pressure listed.

Calcium precipitation is more closely associated with pH, carbon dioxide, and alkalinity.

If the water is corrosive, the langelier index will be negative. If the water is scaling, the langelier index will be positive. The goal is to have a slightly positive langelier index.