Wastewater Outfall Pipe Capacity

[Jeamon]

Hi,

I am reviewing an existing WWTP outfall pipe capacity. The outfall has a diffuser assembly on it, which is made up of four riser pipes with 90deg. elbows and nozzles. I've done a lot of pressurized tile bed calculations and was thinking of using the same technique to analyze the capacity of this diffuser (essentially I was going to create a system head curve for this outfall). However, the difference with this system is the riser pipe and nozzles (much difference than the standard orifice). Can anyone provide assistance or point me to a good source of information on this?

Thanks

Jeamon

 

[BarryEng]

The long answer is - use EPANET for the layout. EPANET is a free program that is downloadable from the net (EPA, USA web site). You can model the whole pipe system from start to finish in one go.

The short answer is you can model each single pipe system (outlet) & use each result as a head loss on the header pipe.

It depends on the size of the outfall. I recently designed a DN 1000 outfall for a desal installation subject to a tidal range of nearly 10 m. In this case you have to be very careful of your results. If the outfall is only a small dia, you can take short cuts.

What is your dia, flow rate, size of upstands, etc?