Fats, oils and grease – do the Irish have the answer?

Fats oils and grease (aka FOG) is a big problem for the water sector.  Too much is being washed down drains (“out of sight, out of mind”) and blocking the nation’s sewers.  And blockages inevitably lead to flooding of properties with sewage, pollution of watercourses and risks to public health.

FOG causes around 75% of the 200,000 or so sewer blockages each year.  It’s estimated these blockages result in flooding to more than 3000 properties.  It’s a problem that’s got to be tackled.

The water and sewerage companies are doing their bit – with £1.15 billion set to be spent over the next 5 years reducing the risk and incidence of sewer flooding.

But the fats oils and grease problem really needs to be addressed at source – by the cafes, fast food outlets, restaurants, hotels, pubs and all commercial kitchens and food outlets.  It’s much easier to collect it at source than dig hardened FOG out of a sewer pipe.  Water and sewerage companies estimate that costs them more than £15 million a year in direct costs, that have to be met by all customers.

The time was right therefore for the major conference on FOG hosted by Cranfield this week.  Experts from UK, Ireland and the USA were on hand to outline the problems and identify solutions.

To cut a long story short – the Irish seem to have the answer.  Well at least Dublin does.  Fed up with flooding, losing Blue Flag status for the local beach and digging FOG out of the sewers they’ve tackled this head on.

Under their legislation (which isn’t so different from that in England & Wales) they’ve now included FOG as a trade effluent.  This means that food outlets now require a license from Dublin City Council (the owner and operator of the sewers) to discharge fats, oils or grease to the public sewer.  Dublin City council adopted a staged approach that included education, awareness and training.  But food outlets now have to do their bit.  To get a license they need to install properly designed grease traps and maintain them.  And they have to meet tight limits of FOG in the effluent from their premises – 100 mg per litre.  But three years on this has achieved considerable benefits.  Around 80% of premises now have trade effluent licenses with grease traps fitted and maintained.  Importantly for DCC and the citizens and visitors to Dublin around 2100 tonnes of FOG has been kept out of Dublin’s sewers and the number of sewer flooding and pollution incidents reduced considerably

There has to be a lesson here for the UK.   The polluter should pay, not the water customer.  Let’s keep sewers for what they were intended.  It’s not sustainable to keep digging FOG out of sewers.  We need their full capacity to meet the challenge of changing weather patterns, more intense rainfall and greater run off.