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Management of Fats, Oils and Grease (FOG)

Estimates reveal that FOG reaching the nations drains causes up to 75% of sewer blockages and related floods. The management of this waste stream is being taken increasingly seriously by the authorities, including Environmental Health Officers, The Environment Agency and the Water Companies.

There are a number of simple guidelines that can be followed to ensure that best kitchen practice is followed. The key rule, which is obvious enough, is not to pour fat down the drain!

The basic rules are:

  • All debris on plates should be scraped into a bin before washing.
  • All waste cooking oil should be collected in designated drums, and this should be collected regularly. (see below for more on waste oil collection).
  • Food macerating/disposal units should be disconnected from the drain network.
  • All sinks should be fitted with effective food strainers to prevent food waste from entering the drain. These should not be removable.
  • All grease management systems should be effectively maintained, if necessary by an outside service provider.

Water UK has published this guide to advise catering establishments on best practice for disposal of food waste and the need to keep fat, oil and grease out of drains and sewers. The guide also outlines your legal requirements. Please see Downloads at the bottom of the page. 

Grease Management Systems

However diligent your kitchen practices may be there will be unavoidable amount of FOG that will reach the drains. In these circumstances there a range of grease management systems available that can help reduce the likelihood of any on-going drainage problems.

  • Biological Grease Management: these systems rely on dosing a regulated quantity of either bacteria or enzymes into the affected drain. The bacteria then colonise the drainline and breakdown the fat in the drains as part of their normal metabolism.
  • Grease Traps: these are specially designed units which will act to collect the fat in the waste water. However the unit must be correctly sized and not positioned too closely to the sink or the fat can flow straight through the system. They often come with a food strainer that must be emptied on a daily basis.
  • Physical Grease Removal: These are mechanical units that operate to physically remove fat from a waste stream either with a boom or rotating wheel. If correctly placed and sized these can be very effective but they do require daily attendance by the kitchen staff to ensure they are operating correctly.

All these systems require regular servicing and maintenance checks to ensure their effectiveness.