Sunday, December 16, 2012

Cooking fat: don't flush it, put it to good use.

There is a Christmassy message from London's sewermen here

London's sewermen looked out
on their fat-blocked sewers
fat had fallen round about
fat from turkey dinners
fat is flushed both day and night
by those sewer sinners
fat should not be flushed but binned
'cos it blocks the sew-ers

They plead that fat from Christmas dinners be not flushed down the sink, as it congeals and forms "fat bergs" in the sewers.

It seems that 500 tonnes of fat will be flushed into the sewers over Christmas.

500 tonnes of fat can be converted into about 500 tonnes of diesel fuel.

500 tonnes of diesel equates to about 500,000 litres of diesel.

Which could power a small diesel car doing 50mpg for 10,000 miles. About a year's worth.

Let's assume Londoners eat three times as much on Christmas Day as they do on the average day.

About 100 cars that could be powered by the domestic fat thrown away down London's sewers.

London has about 7 million people - about 12% of the UK population.

Therefore if we collected all the fat thrown down domestic sinks each year, we could power 800 cars each year.

This is of course a tiny proportion of the cars on Britain's roads. There are about 30 million cars in the UK. If we assume that only one third are used each day, that is still 10,000,000 cars.

So the 800 fat-powered cars are only 0.008% of the total.

Nevertheless, 800 is 800. It is probably a large chunk of the fleets run by water companies.

More to the point, it represents a huge improvement in the efficiency of our sewers, since they save on a huge amount of time and effort spent clearing out the fat.

What we need is to pour superfluous cooking fat into, for example, empty plastic milk bottles, and put them out with the recycling.

This also provides useful jobs for the people who collect and process the fat. Smelly messy work, but no more smelly and messy than the vital services supplied by Thames Water's excellent sewerpersons.

Who have also done a Gangnam stylepublic message on sewer abuse.

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