I've Got a Dirty Secret in the Cellar

It's been bothering me for a while if I’m honest, I know it’s really unpleasant and most people don’t have this issue. I’ve not handled it in the right way and until now I’ve not really been sure of what to do about it.

In a stone vault beneath my house, under a pile of cardboard is a barrel of thick dark sludge. The offensive liquid is waste engine oil. Litres of the stuff, stored for no other reason than I’m not sure about the most ethical way to dispose of it. As a child I remember it being mixed with sand and old fuel and being burnt to avoid it killing the grass… I’m not sure which is worse to be honest.

The issue of excess used motor oil is one that goes unseen by most of us, but when you pay for a service on your car, you have unwittingly contributed a few litres of waste oil back into the environment. Most of which is disposed of responsibly but unfortunately the environmental impact is often unavoidable due to the scale of oil being collected.

As I reconditioned a set of drum brake cams on my kitchen table, I was able to ignore the disapproving looks from my wife long enough to have an idea of how to resolve the problem.

As with all work I carry out on any machine, the first ‘tool’ to leave the locker is a container of grease. Grease is a semi solid lubricant that engineers apply to bolts, pivots, and other moving parts. It's like an oil but its much thicker and stays in place much longer. To get technical, it actually made of oil mixed with soap and exhibits similar lubricating characteristic as its base oil when exposed to shear force. A good example of its application would be in a nut and bolt where oil might be driven out by rain over the years. Grease will stay in the thread, patiently waiting for the day it can be gently removed without undue effort by an engineer. Without grease the bolt would seize in place and could snap when the next person comes to remove it.

For me, the use of grease has always been a message you send to other engineers to show them how good you are at your job. The chances are the bolt you grease won’t be touched again for years, maybe even decades. But when the next person comes to undo that bolt, they will appreciate the effort you went to in applying the grease.

Surely if oil is accumulating and engineers are using grease every day in their work, there could be a prospect of recycling this waste product into useable grease.

After a little research its clear this is very much a concept being explored by Indian chemists where oil pollution is a major source of environmental damage. There’s a bit of a process involved by running the used oil over magnets to remove tiny grains of swarf and contamination before filtering the oil and heating it to burn off any moisture. Ultimately, it can then be added to a soap and converted into grease. By mixing the motor oil with 15% C18H35NaO2 (sodium soap to you and me), a thick usable grease can be manufactured that would lock this pollutant in place rather than it contributing to the damage of an environment on its knees.

My only concern from this process is that grease may accidently end up in the environment itself which of course undermines the point of recycling the product in many ways.

For anyone who has read my previous piece on electric vehicles you’ll know that an EV (Electric Vehicle) is a far simpler machine in many ways than its ICE (Internal Combustion Engine) equivalent. That said there’s something most readers won’t realise about the manufacturing of large EV batteries.

To waterproof a modern EV battery, the cells are packed in litres of grease before being enclosed in their casings. Far more grease is used in the manufacturing of an electric vehicle than its petrol-powered cousin because of this. I’m just thinking out loud but could the production of modern EV batteries be supported by the recycling of waste motor oil?

For now I’ll put my grand ideas on the shelf and use this grease on my own machines knowing I’ve tried my best to recycle where I can.