Beyond the plug hole

Drainage doesn’t just carry human waste that ends up in toilets – it also receives what goes down the kitchen sink, shower, bath and basin plug holes.

Yes what goes down these modern facilities all ends up in the sewers – it all falls under the banner of ‘foul waste’.

People tend to not give much thought beyond their kitchen plugs I find – everything gets scraped from the plates into the sink and the objective is just to get it all to fit through the small hole in the bottom using water, washing up brush, fingers and anything else to hand.

Those households empowered with a mascerator can fit half eaten meals down there along with stale bread, dead goldfish and other household waste so you can get the washing up done in record time and back to the TV.

Essentially the stainless steel or ceramic confines of the kitchen sink represent the end of anybody’s thought process regarding ‘my problem’ and once the stuff disappears through the magic hole it’s then ‘not my problem’.

However because 80% of London’s waste system is still propped up by the sewer system put in by the Victorians over 150 years ago, it’s not really designed for all the rice, grease, spaghetti, oils and God knows what else that gets introduced via the modern waste stream.

Stir fry’s and takeaway’s just weren’t in existence back then and food was just too much of a luxury to wash down a plug hole – it was all stale bread and whelks from what I’ve read and nothing was wasted.

In addition there wasn’t the hot water availability back then either – if you wanted hot water you had to heat up a kettle over a fire so the on-tap 60 degree water supply that we just take for granted now simply wasn’t around till the 1950’s & 60’s when gas and electricity based central heating systems became mainstream.

This makes a difference as hot water emulsifies oils & greases – i.e. effectively dissolves them – so the water then carries them invisibly within its body.

This emulsification helps oils & greases get into the sewers through the plug hole in the first place as they can pass through the plug hole as simply water.

Compare this to pushing a lump of lard through the plug hole (which would have been the Victorian option) and you can see how the advent of hot water and modern detergents made it very easy for lumps of lard to all disappear into the sewers.

This combined with the huge rise in takeaways, pub grub and different cooking practices post war meant that the amount of emulsified grease that entered our sewers rocketed.

Problem is as hot water cools and as detergents become diluted they loose their grip on the emulsified fats and they congeal out into their original form.

Local water authorities call this phenomenon ‘FOG’ – Fats Oils & Greases – and it manifests as globules of white or creamy thick lard-like stuff all along certain sections of pipe line.

This FOG slowly builds up inside the pipes reducing their internal diameter just like cholesterol in arteries – ‘fat bergs’ as you read about in the news are just example of extreme FOG.

A compounding factor is that the Victorians were obsessive about ‘traps’ when they diligently built their sewer system and would introduce them at regular intervals in various forms – Buchan traps, Winser traps etc.

Traps are essentially U-bends that form a water seal and stop sewer smells passing up the pipework – this was very important to the Victorians as they deemed sewer smells to be deeply unhealthy so it was important to them that houses connected to sewers should be protected from them.

Nowadays we have small plastic U-bends (or ‘traps’) to seal the waste system from the attached facility so the big clay-engineered Victorian units aren’t necessary.

But what these traps do in modern times is regularly block due to the higher solid content and general demand of modern waste and when they block water flow rates drop considerably.

Slow moving water is the best place for FOG to occur and so you tend to find the approaching pipework to traps thick with it.

All very interesting you say but what’s the relevance to rats?

Well rats love FOG – it represents a high calorie nutritious snack that boosts their overall energy levels and fat reserves in the same way a Full English with black pudding can jump start the day.

In addition FOG will encapsulate any other dissolved human waste that goes down the plug hole – protein shakes, vitamins, caffeine, food particles, alcohol, medicines – so you end up with essentially a lard ‘omelette’ with often some quite exotic ingredients and flavours.

Without the FOG element of the waste stream, this content would otherwise remain in the water and would struggle to get inside a rat – the FOG entraps it all and grows it all on the pipe internal surfaces where it remains ever ready to nourish those rats in need.

I’ve no idea what protein shakes, vitamins & caffeine do to rats but the imagination boggles and I don’t think the outcome is a good thing.

Combine this with the inevitable Viagra content and rat life in the sewers these days must be like a wild night out in Soho – no wonder rat populations within the sewers of developed countries are increasing year on year at an exponential rate.

On another note, virtually everybody these days take vitamins the size of horse pills which of course passes through us as urine but what you didn’t know is that vitamin K is the anti-dote for most of the rodenticides out there.  Therefore no wonder there’s resistance – we’re feeding them the antidope!

Local water authorities regularly advertise the problems caused by washing fats and greases down the plugs and each year they incur huge costs removing the Victorian traps across London and jetting the stuff out – all in a constant battle against FOG.

I feel most people don’t care due to the ‘not my problem’ culture that exists beyond the plug hole but if people saw what FOG was doing to resident sewer rat populations they may well change that.

Make no mistake, if we want to breed a physically fit, mentally alert and horny breed of rat that exists in huge numbers then we are going the right way about it so think twice before pouring that Pot Noodle down the sink – Mr Rat is waiting and grateful for it.