Case Study - New Civic Centre

Customer: Engineering Consultancy

The requirement was for one single unit to service an entire establishment.  The installation which was to be underground and external to the buildings required a grease trap which was light and easy to install. The distance required was < 5m underground with liquefaction risk. 

Design issues:

  • Needs a high capacity grease separator - capable of treating NS35 (35L/s)
  • Needs to be located deep underground
  • Extreme length riser system that also permits manual cleanout
  • Remote means of measuring FOG for correct cleanout timing
  • Located in liquefaction area 

Options considered

1. Provide two basic MACTRAP 4000L passive traps in parallel but

  • One unit has higher treating efficiency than two.
  • Inflow drainage tends to favour one tank due to any unevenness in installation levels.
  • The tanks have limit to load-bearing integrity guarantee at required depth
  1. Provide a single tank system designed specifically to adapt to the depth required
  • Performs FOG recovery to <100mg/litre at inflow rate of <35L/sec coupled with KESSEL leading sonic controller.

Use the KESSEL advanced grease separator system based on NS treating capacity.

  • KESSEL NS35 basic underground tank with risers and CAT D lids to suit extremes depth.* The KESSEL NS35 was lightweight and easy to install and has a 20year guarantee.
  • Provide a remote compatible sonic control. This constantly measures the ratio of grease to sludge to maintain the required efficiency of the grease trap to recover the FOG to meet consent limits. It also ensures correct clean out times .

Note* To overcome liquefaction the unit was encased in a concrete bracing system including a load eliminating bridge as referred to example above