Sewage Tanks, Storm Water Sumps, Sewage and Sump Pumps

The vast majority of both sumps and sewage pumps are of the centrifugal kind.


Sump and Sewage Pumps (Ejectors)        

There are generally two types of basement water pumps: pedestal and submersible. The pedestal pump's motor is mounted above the pit, where it is more easily serviced but also more conspicuous. The submersible pump is entirely mounted inside the pit, and is specially sealed to prevent electrical short circuits. Although the submersible models are known for quieter operation, they are considerably more expensive. Although there is no considerable difference in performance, and both styles are considered fine for basement water drainage purposes.



Submersible Pump


Pedestal Pump


Grinder Pump


All solids are ground into fine particles, allowing them to pass easily through the pump, check valve and small diameter pipelines. Even objects that are not normally found in sewage, such as plastic, rubber, fiber, wood, etc., are ground into fine particles.


The grinder is designed not to jam and for minimum wear to the grinding mechanism. The AMGP comes complete with a self-contained level control system, eliminating troublesome float switches. The grinder pump is automatically activated. It runs infrequently for very short periods. The annual energy consumption is typically that of a 40-watt light bulb.


The 1 1/4" slide face discharge connection is adaptable to any existing discharge piping.


The internal check valve assembly, located on the grinder pump, is custom designed for non-clog, trouble-free operation.


Units are available with a number of discharge hose lengths to accommodate a wide range of existing tank depths.


Effluent Pump


Effluent pumps are designed to pump liquid human waste only, and for that reason they cannot replace standard sewage or grinder pumps. They are usually installed in a septic tank, pumping the liquid from the tank out to the leaching bed, or in any other location where liquid human waste must be pumped to another site.



Pump Controls


Pump Mounted Float Switch


Diaphragm Pump Switch


Tank Mounted Float Switch


Sumps or Tanks



Storm Water Basin


Sewage Tank


Sewage tanks, unlike storm tanks, must be completely water and air tight


Duplex Tank


7.4.8.3.

  1. Only piping that is too low drain into a building sewer by gravity shall be drained to a sump or receiving tank.
  2. Where the sump or tank receives sanitary sewage it shall be water and air-tight and shall be vented.
  3. Equipment such as a pump or ejector that can lift the contents of the sump or tank and discharge it into the sanitary building drain or sanitary building sewer shall be installed.
  4. Where the equipment does not operate automatically the capacity of the sump shall be sufficient to hold at least a 24 hours accumulation of liquid.
  5. Where there is a building trap the discharge pipe from the equipment shall be connected to the sanitary building drain downstream of the trap.



  1. The discharge pipe from every sanitary sewage sump shall be equipped with a union, a check valve and a shut-off valve installed in that sequence in the direction of discharge.




  1. The discharge piping from a pump or ejector shall be sized for optimum flow velocities at pump design conditions.

Note: The diameter of the discharge pipe from a sewage or storm pump is determined by the manufacturer.


The discharge piping from a sewage pipe is referred to as a "force main" and is defined this way:

"Force main means a sanitary drainage pipe through which sanitary sewage is conveyed by mechanical or pneumatic propulsion".


Force main from a sewage pump in a rural and a residential installation



Force main from a sewage pump in an urban installation


Venting Sewage Tanks

7.5.4.1.(1)

Every tank that receives sanitary sewage shall be provided with a vent pipe that is connected to the top of the tank and that is sized in accordance with Article 7.5.6.5..


7.5.6.5.

  1. Where the diameter of an inlet pipe to a sanitary sewage tank is
  1. 5" or larger, the diameter of the vent pipe from the tank shall be at least 4", and
  2. less than 5", the diameter of the vent pipe from the tank shall be the grater

i) 1 /1/4" and

ii) one trade size smaller than the inlet pipe.


Fixture Connection

Fixtures discharging to a sewage tank and pump must be trapped and vented just like any other fixture installed in the sanitary drainage system. Circuit Vented branch must not connect to a sewage tank installation (7.5.5.2.(1)).




Determining the Diameter of a building Drain

The total GPM load of the sewage pump at the point of connection to the sanitary building drain should be added to the GPM load of the sanitary building drain. This is the only occasion when doing pipe sizing that gallons per minute flows are added together in order to determine the diameter of a drainage pipe.


7.4.10.4(1)

For the purpose of determining the size of sanitary drainage pipe in accordance with Table 7.4.10.3.C. pumped discharge and other continuous and semi-continuous flows shall be calculated in gallons per minute flow and added to the drainage rate in gallons per minute flow from Table 7.4.10.3.B.


Example

The sanitary building drain carries 170 f. u. or 67 GPM.

The diameter of the sanitary building drain is 4".

The rating of the sewage pump is 30 GPM.

Therefore, at the point of connection, the total combined load on the building drain is 97 GPM.

Table 7.4.10.3.C says that 4" pipe with a slope 1:50 can carry up to 91 GPM.

That is why at the point of the connection the drain must be increase to 5" to accommodate the 97 GPM.