Environment, Coasts, Oceans, & Infrastructure

Hello everyone,

I want to design a sump pump for a sewage system. For designing this sump volume an influent (incoming) discharge is required. I just need to know is we take peak discharge or average discharge for designing the volume of sump?

Thanks!

------------------------------
Syed Alvi M.ASCE
junior engineer
Techno Consult International
Karachi
923242637117
------------------------------

​My experience is that you would design for average daily flow (ADF) multiplied by a peaking factor that is set by local regulations. I expect peaking factor values vary.  What values have others in your location used?

------------------------------
Michael Meadows Ph.D., P.E., F.ASCE
Assoc Professor
Univ Of South Carolina
Columbia SC
(803) 777-3614
------------------------------

Once you have determined the peak flow rate into the sump the minimum design volume necessary would be:

V(min) = Q(out)*T(min)/4

Q(out) = the pumping rate which is assumed to be half of the peak inflow rate.

T(min) = Minimum cycle time between pump starts.

If the pump rate is NOT half of the peak inflow rate then you would need to write the formula in terms of T(min) and solve by an iterative process:

T(min) = [V(min)/Q(in)] + [V(min)/Q(out)-Q(in))]





------------------------------
Daniel Rosenberg P.E., M.ASCE
AECOM
Cleveland OH
(216)416-2000
------------------------------

Original Message:
Sent: 12-25-2018 08:20
From: Michael Meadows
Subject: Sump Pump Design

​My experience is that you would design for average daily flow (ADF) multiplied by a peaking factor that is set by local regulations. I expect peaking factor values vary.  What values have others in your location used?

------------------------------
Michael Meadows Ph.D., P.E., F.ASCE
Assoc Professor
Univ Of South Carolina
Columbia SC
(803) 777-3614
------------------------------

Thanks for your response. In standard (which I am following) we have a statement "The effective volume of the wet well shall be based on the design average flow."

Mean for designing the volume we have to use design average flow. If we think logically, we have peak flow once on an hour remaining we have average flow condition. If we design the volume on peak so we have requirement of high volume in comparison to volume calculated for average flow. Also we know that the high volume for low flow cause sedimentation in sump which is not allowed. High volume causes high cost of construction.

Please share your views.

Also, please share reference standard in support of using peak flow flow calculating sump volume. (if any)

Thanks!

------------------------------
Syed Alvi M.ASCE
junior engineer
Techno Consult International
Karachi
923242637117
------------------------------

Original Message:
Sent: 12-26-2018 05:02
From: Daniel Rosenberg
Subject: Sump Pump Design

Once you have determined the peak flow rate into the sump the minimum design volume necessary would be:

V(min) = Q(out)*T(min)/4

Q(out) = the pumping rate which is assumed to be half of the peak inflow rate.

T(min) = Minimum cycle time between pump starts.

If the pump rate is NOT half of the peak inflow rate then you would need to write the formula in terms of T(min) and solve by an iterative process:

T(min) = [V(min)/Q(in)] + [V(min)/Q(out)-Q(in))]





------------------------------
Daniel Rosenberg P.E., M.ASCE
AECOM
Cleveland OH
(216)416-2000
------------------------------


Original Message:
Sent: 12-25-2018 08:20
From: Michael Meadows
Subject: Sump Pump Design

​My experience is that you would design for average daily flow (ADF) multiplied by a peaking factor that is set by local regulations. I expect peaking factor values vary.  What values have others in your location used?

------------------------------
Michael Meadows Ph.D., P.E., F.ASCE
Assoc Professor
Univ Of South Carolina
Columbia SC
(803) 777-3614

------Original Message------

Thanks for your response. In standard (which I am following) we have a statement "The effective volume of the wet well shall be based on the design average flow."

Mean for designing the volume we have to use design average flow. If we think logically, we have peak flow once on an hour remaining we have average flow condition. If we design the volume on peak so we have requirement of high volume in comparison to volume calculated for average flow. Also we know that the high volume for low flow cause sedimentation in sump which is not allowed. High volume causes high cost of construction.

Please share your views.

Also, please share reference standard in support of using peak flow flow calculating sump volume. (if any)

Thanks!

------------------------------
Syed Alvi M.ASCE
junior engineer
Techno Consult International
Karachi
923242637117
------------------------------

Original Message:
Sent: 12-26-2018 05:02
From: Daniel Rosenberg
Subject: Sump Pump Design

Once you have determined the peak flow rate into the sump the minimum design volume necessary would be:

V(min) = Q(out)*T(min)/4

Q(out) = the pumping rate which is assumed to be half of the peak inflow rate.

T(min) = Minimum cycle time between pump starts.

If the pump rate is NOT half of the peak inflow rate then you would need to write the formula in terms of T(min) and solve by an iterative process:

T(min) = [V(min)/Q(in)] + [V(min)/Q(out)-Q(in))]





------------------------------
Daniel Rosenberg P.E., M.ASCE
AECOM
Cleveland OH
(216)416-2000
------------------------------


Original Message:
Sent: 12-25-2018 08:20
From: Michael Meadows
Subject: Sump Pump Design

​My experience is that you would design for average daily flow (ADF) multiplied by a peaking factor that is set by local regulations. I expect peaking factor values vary.  What values have others in your location used?

------------------------------
Michael Meadows Ph.D., P.E., F.ASCE
Assoc Professor
Univ Of South Carolina
Columbia SC
(803) 777-3614


Original Message:
Sent: 12-24-2018 04:21
From: Syed Alvi
Subject: Sump Pump Design

Hello everyone,

I want to design a sump pump for a sewage system. For designing this sump volume an influent (incoming) discharge is required. I just need to know is we take peak discharge or average discharge for designing the volume of sump?

Thanks!

------------------------------
Syed Alvi M.ASCE
junior engineer
Techno Consult International
Karachi
923242637117
------------------------------

We are in arid zone we have separate collection system (i-e storm water drain separate and sanitary sewer separate).
In Ten State Standards it is mentioned that wet well (sump) to be designed on average flow condition.
See attached. 

------------------------------
Syed Alvi M.ASCE
junior engineer
Techno Consult International
Karachi
923242637117
------------------------------

Original Message:
Sent: 12-26-2018 05:02
From: Daniel Rosenberg
Subject: Sump Pump Design

Once you have determined the peak flow rate into the sump the minimum design volume necessary would be:

V(min) = Q(out)*T(min)/4

Q(out) = the pumping rate which is assumed to be half of the peak inflow rate.

T(min) = Minimum cycle time between pump starts.

If the pump rate is NOT half of the peak inflow rate then you would need to write the formula in terms of T(min) and solve by an iterative process:

T(min) = [V(min)/Q(in)] + [V(min)/Q(out)-Q(in))]





------------------------------
Daniel Rosenberg P.E., M.ASCE
AECOM
Cleveland OH
(216)416-2000
------------------------------


Original Message:
Sent: 12-25-2018 08:20
From: Michael Meadows
Subject: Sump Pump Design

​My experience is that you would design for average daily flow (ADF) multiplied by a peaking factor that is set by local regulations. I expect peaking factor values vary.  What values have others in your location used?

------------------------------
Michael Meadows Ph.D., P.E., F.ASCE
Assoc Professor
Univ Of South Carolina
Columbia SC
(803) 777-3614

Syed,

By "sump pump" I assume that you are referring to a sewage pump station, where the sump is what we usually refer to as the "wet well." The best-practice design considerations are as follows. The flow rate to be handled by the pump station depends on the peak flow to be handled when the pump station is first brought on line, and the ultimate peak flow to be handled by the pump station. Particular attention should be paid to dry-weather flows and rainfall-dependent inflows to the sewer system served by the pump station. Design flow rates for pump stations are typically based on the average dry-weather flow and the peak wet-weather flow. Since flow rates typically vary over the lifetime of a pump, it is usually convenient to select a pump that can handle future increased flows by changing the impeller size from smaller to larger within the same pump casing.


------------------------------
David Chin Ph.D., P.E., D.WRE, F.ASCE
Professor
University of Miami
Coral Gables FL
(305) 284-3391
------------------------------

Some sewage systems are subject to infiltration during rain events.  Make sure your inflow data takes due account of this.

------------------------------
James Anderson, MASCE
Principal
Anderson Consulting
North Richland Hills, TX
817-946-9943
James
------------------------------