The biggest part of the composting process relies on bacteria.
Aerobic bacteria require;
- Food and minerals
Not dissimilar to what humans need to survive and grow!
Warmth is not that widely understood. The speed of composting is directly related to how warm the bacteria are.
At Zero C – they are frozen and little happens. They work faster all the way to 75C. We normally describe composting as either ‘HOT’ ( 40-60C) or ‘COLD’ (>20C).
In most outdoor UK compost heaps, over the year the average temperature achieved will be 10C – i.e. the same as the ambient UK average temperature. There are many things that have to be right for composting to occur, but when it comes to how long it takes, there is one overriding factor that affects the speed (rate) at which waste decays and this is temperature.
In very simple terms for every 10C increase in temperature, the speed doubles. So if the average UK temperature over the year is 10C and we call this speed 1; at 60C (HOT), composting is 32 times faster.
To compare this on average you will find a UK open/outdoor heap typically takes 12-24 months to compost. If the same material was composted at 60C, it would take 12-24 days.
That is the real difference between COLD composting and HOT composting!