How do you handle design of a pump station that has gravity flow plus pumped discharge from upstream pump stations?
We have (2) pump stations that pump into the gravity sewer system (an 8" pvc sewer @ 0.33% slope). The (2) existing upstream pump stations are 100 gpm each. A conservative approach would be to calculate the average daily flow into the pump station multiply by peaking factor and then add 200 gpm from the pump discharges. I believe this would oversize the pumps but would be appropriate for discharge directly into the wetwell.
Since the upstream pumps discharge into the gravity system then flow through 3000 lf of 8" sewer, I'm thinking that a more realistic approach is to calculate the gravity flow (gpm) from the full sewer pipe into the wetwell and then add that to the average daily flow into the pump station multiplied by peaking factor.
We'd have 2.5xADF (peaking factor x average daily flow)+ maximum flow from an 8" pipe.
We have (2) pump stations that pump into the gravity sewer system (an 8" pvc sewer @ 0.33% slope). The (2) existing upstream pump stations are 100 gpm each. A conservative approach would be to calculate the average daily flow into the pump station multiply by peaking factor and then add 200 gpm from the pump discharges. I believe this would oversize the pumps but would be appropriate for discharge directly into the wetwell.
Since the upstream pumps discharge into the gravity system then flow through 3000 lf of 8" sewer, I'm thinking that a more realistic approach is to calculate the gravity flow (gpm) from the full sewer pipe into the wetwell and then add that to the average daily flow into the pump station multiplied by peaking factor.
We'd have 2.5xADF (peaking factor x average daily flow)+ maximum flow from an 8" pipe.