sewer backflow prevention

slipstream

i want to get some backflow protection/non-return valve to protect our rainwater soakpit which has a 4" overflow to the sewer.

ideally i'd like to do this with the plastic ajs we have in place without adding a new manhole.

do these flap like backflow devices work well?

what do you guys think the best options are?

thanks,

slip

K.Flyer

There are non return valves available and from what I have seen they work quite well.
A lot of business' places in Dublin central have had them fitted after being flooded too many times during high tide and heavy rains.
You will need to dig a small section of pipe up in order to fit it though.
Contact Davies (drainage section) in Dublin or Heiton Buckley, they should have more information on types that are available.

antoinolachtnai

I fitted a backflow valve a while back, for the main sewer. This guy is worth talking to about your specific requirement. They know more about it than anybody else I talked to in Ireland.

http://www.floodgateireland.com

Whether the type of valve you linked (which is a bit like http://www.floodgateireland.com/Brochures%20Ireland/Flap%20Valves.pdf) will fit into an AJ, I don't really know. My feeling is that it will not fit. I looked at this for another project which I approached differently in the end. But if you ring floodgate, they will be able to tell you.

Incidentally, that type of valve, whilst probably suitable for your application, would not suit many situations. You shouldn't expect that valve to be completely watertight, for instance, and you shouldn't be too surprised if it gets fouled up by solids. But this shouldn't be a big problem for you. (For most foul sewer situations, where these are issues, the 'mainline' valve is the way to go.)

I don't think you're going to be able to do this without a new manhole. But there may be a solution.

slipstream

antoin,

which valve have you fitted and how successful have they been?

slip

antoinolachtnai

I got the 'mainline' valve from floodgate. It is a canadian design, as simple and elegant as the videos suggest. It seems good to me, and I think it has done its job on a few occasions.

It does benefit from being cleaned out every year or two, to make sure it will raise correctly when needed.

One thing to remember with all these valves is that you do need some extra fall on the pipe, something that is generally in short supply in these situations.

This was for a combined sewer (waste and rainwater) in central Dublin.