Retirement Village

Retirement Village

Customer: Engineering Consultancy

Problem

The Retirement Village project is a 200 plus room capacity complex with a large commercial kitchen located in the basement of the complex. The kitchen basement is 3.5m below ground level and there is some risk of liquefaction. The kitchen wastewater load comprises 3 x 90L wash sinks and a large dishwasher.

The client’s priority is is to ensure there is no odour or risk of spillage in the kitchen area from the grease management system.

Design Considerations
  • The greasy water will need to be collected in a location seperated from the kitchen.
  • The drainage collection point from kitchen is below ground requiring either the greasy water or wastewater to be lifted.
  • Pumping greasy water with a centrifugal pump will emulsify the grease, significantly reducing the ability of the greasy water to separate.
  • Grease water lift pump will need to be positive displacement with a containment chamber.
  • Distance from FOG sources to grease trap may require heat trace and inspection rodding points not located in the kitchen area.
  • 270L sink capacity @ 75% = 202.5L. One minute drain time = 3.375L/sec. Sizing = NS4.
  • Oversized grease trap may be needed to compensate for pump emulsification.
Options

Locate the grease trap below basement level outside the main building footing and wall at sufficient depth to allow gravity flow from the kitchen. Use a lift pump to raise the wastewater to sewer.

Considerations: Grease trap will need to be located approximately 5M deep to allow flow. Liquefaction risk means that the grease trap will probably require a surrounding concrete chamber. 

Use a greasy water lift pump to lift the greasy water to an inground grease trap located at the surface and outside the main building footing and wall.

Considerations:  A lift pump specifically designed to avoid grease emulsification will be required. The pump will need to be a positive displacement screw type.

Use a greasy water lift pump to lift the greasy water to a free-standing sealed grease trap located in an adjacent basement storeroom. Use an internal lift pump to raise the wastewater to sewer.

Considerations: The basement will have limited access for pump out so the grease trap will require an auto mix and pump function or a vacuum line to an outside connection point.

Restrict the sink flow rate and install an under bench automatic grease removal units for each sink.

Considerations: Potential for spillage or odour if under bench units are not properly maintained.

Solution: Greasy Water Lift Pump

Install KESSEL Greasy Lift Pump solution in a basement location and lift the greasy water 3.5m to an external grease trap.

Install MACTRAP 1500L Passive Grease Trap outside the main building footing and wall. Gravity drain to utility.

Advantages

The greasy water lift pump has a sealed containment chamber for the greasy water effectively eliminating the possibility of spills or odours during normal operation. The pumps can be serviced from the basement without the requirement to enter deep chambers, and are isolated from the containment chamber to enable replacement or service without interruption to the operation.

The external grease trap is easily accessed for emptying and servicing with standard vacuum trucks. No additional pumping is required for the wastewater as outflow is gravity fed.