What's a simple way to add waste to under sink?

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I'm building a living wall where the water will drip down to a tray more or less at floor level. What's the best/simplest way of getting that run-off water to the waste under the sink?

The living wall is at the end of the run of kitchen units and so it's a straight line to the sink about 2.5m away, but I can't get behind the units to run a waste pipe - only underneath.

I've drawn a little sketch - see below.

I was thinking of a little pump in the bottom of the drip tray which pumps the run-off water into something like a washing machine standpipe just next to the living wall. I'd then route that under the units with a 40mm waste pipe and then connect it with a bit of washing machine waste pipe into the under sink trap. Intuitively it feels a little convoluted and I don't know enough about siphons to be confident in this set up.

A more direct alternative might be to pump direct from the tray to the under-sink trap, but the route would have to go up and down and up again, so I'm concerned I might get an airlock that would prevent the pump from pumping out the water from the drip tray .

I'd welcome any thoughts.

20210317_225322.jpg
 
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You would have to pump direct to the sink waste otherwise the pump wont pump anything other than into the standpipe and will eventually just overflow.
 
the pump wont pump anything other than into the standpipe and will eventually just overflow.
Bother. I thought gravity might take care of it as long as the standpipe was higher than the point where it connected to the trap under the sink. :(


pump direct to the sink waste
Not sure I'm going to be able to avoid creating an air lock because the pipe is going to have to go up and over the side of the drip tray, then down to go under the kitchen units before going up again to the sink trap.

What`s a living wall
Plants on a wall.
 
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Sanishower pump
Yikes! they're big and expensive.

I was more down at the £10 mark for a mini pump. Maybe one of these little 12V inline pumps might do it . It says that it's self priming, so I hope that means I could put the pump outside of the drip tray. Then I could make sure the pump is at the very lowest level in the whole run*. As long as the opening of the input pipe is also a bit higher than the pump, at least the water won't get siphoned all the way back into the tray when the pump goes off.

What do you reckon?

And that particular one has the added benefit of "Super hydrostatic bring extreme atomization enjoyment." according to the description. Not sure what that is, but it's got to be worth 7quid alone

Edit: * and then I'd pump all the way to the trap under the sink.
 
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Best thing for the drip tray is something like the drain you get on the back of the fridge, this will mean the pump won't burn out from trying to suck the water up.
 
There's a drip irrigation system like you might put in the garden. That goes at the top of the living wall and the water trickles down some felt, And any excess drips into the tray. So should be small amounts, but will build up over a few days I guess
 
A removable drip tray is the simplest answer. Or a wet vac to empty the drip tray in situ.
 
The standpipe would fill up and if higher than the sink waste would flow out but the whole of that leg would be full of standing water.
How would you switch the pump on when necessary? A float switch?
What about just recirculating the water?
 
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Channel drain, and then get the lowest point outside if possible?
 
Great suggestions all.

I'm aiming for a completely automatic system - one which I don't have to remember to check the water level in the reservoir and one that won't run out of water if we ever get to go on holiday again.

Yes, thinking of a simple float switch like this in the drip tray to turn the pump on when the water level gets high and then switch off when it drops by about an inch. Anyone had any experience with these float switches? How reliable are they?

Can't see a way of getting the water outside and don't want to attack the fabric of the house.
 
Why don't you just pump any water that gets into the drip tray back onto the living wall? You could set the float switch to cut of the drip irrigation whenever the water level lifts the float and turns on the recirc pump.

No drain required then.
 

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