drainage trench slope inside a building
drainage trench slope inside a building
(OP)
I have a project (Flue gas desulfurization) where we'll have slurry pumps and lines as part of the process. We're planning to have a trench system draining to a sump to collect line flushes, drain flows, etc.
The slurries will be a 30 wt% limestone, 20 wt% (mostly) gypsum, and we'll have some other lines that will range from water to 5 wt% solids.
Containing the flow is not an issue - a reasonably sized and sloped trench will contain 5x what we think our maximum flow will be. The dilemma I have is how much to slope the trench to keep the slurries moving and eliminating buildup / solidification in the trenches.
Our first shot has been engineering by doing what the last job did - always trouble. A prior project used 1/2" /ft for the heavier slurries - 1/8"/ft for water and the very light slurries - but they were pretty conservative and that particular project had much shorter trenches. I'd be looking at a 4-5' deep trench at the end if I were to follow that criterion.
I was wondering if there are any studies / references or opinions out there as to what a good minimum trench slope would be.
Thanks in advance
Greg
The slurries will be a 30 wt% limestone, 20 wt% (mostly) gypsum, and we'll have some other lines that will range from water to 5 wt% solids.
Containing the flow is not an issue - a reasonably sized and sloped trench will contain 5x what we think our maximum flow will be. The dilemma I have is how much to slope the trench to keep the slurries moving and eliminating buildup / solidification in the trenches.
Our first shot has been engineering by doing what the last job did - always trouble. A prior project used 1/2" /ft for the heavier slurries - 1/8"/ft for water and the very light slurries - but they were pretty conservative and that particular project had much shorter trenches. I'd be looking at a 4-5' deep trench at the end if I were to follow that criterion.
I was wondering if there are any studies / references or opinions out there as to what a good minimum trench slope would be.
Thanks in advance
Greg





RE: drainage trench slope inside a building
Pardal
RE: drainage trench slope inside a building
RE: drainage trench slope inside a building
I understand the rationale, but I'll have to see if the rounded bottom idea flies with the structural engineers - there might be some resistance there due to the added construction cost. I'm also concerned that if I did get a little buildup in the bottom of a rounded trench, it would make a dam and mess up my slope, creating more deposits.
I am planning on having flush water at critical locations - though I can't overdo it. Any water I use will end up back in the process. I'm trying to sell the project team on an actuated flush valve, timed to go off before and after I flush a line & send slurry to the trench.
Just wondering where your 2.5-3 ft/sec criterion came from - a rule of thumb???
RE: drainage trench slope inside a building