Sewage Pumping over hill

Hi

I am modeling a sewer project and there is only one path for the Sewage Force-main. there is a high point in the middle of the path for direct pumping from Wet Well W-7 to Manhole Su-MH-1354 and there was a negative pressure at the high point , so I suggested to put pressure breaker tank Wet Well "W-20" , to overcome the negative pressures My Questions as follows:-

1- is there any other solution than using W-20 wet well ??

2- How to control the outlet flow from Wet well W-20 (2,915.5 m3/d) to be the same as pumped flow to the wet well W-20 (891.7 m3/d), I know that the outlet flow from wet well is based on static head and downstream forcemain size , but is there any way to control, because actually the flow which will enter to W-20 is 891.7 m3/d not 2,915.5 m3/d

Hydraulic model attached in below link

https://we.tl/t-uISz3GDFVr

Regards

Sayed Ali

Parents Reply
  • I did not get what you mean by there is no negative pressure in GVF solver, can you explain this point more?

    What I understand that when pump will start flow will reach the high point and then  water column separation will happen and vacuum will happen at these high point and this the reason why we adding double acting air valve so when pipe line is filling accumulated air will be released and  a water column separation will happen air will enter the pipeline to overcome vacuum condition 

Children
  • If you have an air valve at the high point you will not have column separation.  You will get air into the pipe which is different from column separation where the water vaporizes. Air and water vapor are very different.

    The GVF solver for pressure pipes assumes the pipe will flow full. When you report negative pressure and you have an air valve, the interpretation is that the flow down the pipe is less that what it would take to fill the pipe.

    Answer Verified By: Sayed Elhagr