washing m/c waste

[stgiles]

Hi,
I have a friend who has asked me for some help and i now need some advice too. They have a washing machine sitting in a garage. Next to the washing machine is a saniflow. The waste comprises of blue mdpe pipe rising from the ground in which the saniflow is connected, but also the washing machine waste has been connected via a tee. They are saying that the w/m waste is backfilling to the saniflow which is quite obvious.
I'm just glad the saniflow wasnt in working order.
Anyway their question is how to plumb the w/m waste in seperately although the rainwater drain is the other side of the back door in the garden so unable to connect into the existing waste pipework, all short of digging up garden to install another drain

[Bernie2]

Its not at all clear what you mean.

Is blue MDPE potable water pipe being used as a waste from a saniflo?

Is a waste water appliance fitted to a waste that may be connected to a surface water drain?

I assume its a combined drainage system?

Where exactly does the waste off the saniflo finish?

You can actually get None Return valves for waste pipes. They are of the swinging door type. I don't know if you can get one small enough for a saniflo though, but admit I have never tried. If you can get one, just put it in the saniflo line. I think the NRV's are made by McAlpine waste products. The 1 1/2" ones are McAlpine Multi fit T28M-NRV straight couplers. But how you would work it in is up to you.

[stgiles]

Hi bernie,
Sorry, tried to be as clear as poss. Yes they are using the mdpe pipe as waste from the saniflow. The waste comes out the top of the saniflow in what looks like 1.5" waste pipe and then connects to the mdpe. The mdpe pipe then goes down to a tee where the washing m/c waste is connected and then the mdpe pipe goes through the wall, into the garden and underground. I guess like you say it must be a combined system. I will research the nrv to try and cure their backflow problem. Just one thing though, when the saniflow is back in service, is there not a risk of the waste rising up the washing m/c waste pipe.