Tuesday, April 02, 2013
Anaerobic Digestion - Is the Time NOW?
Anaerobic digestion seems to have had a recent surge in development around the world.
While small communal facilities are relatively common in rural areas of many less developed countries, including China, where in general they provide a decent contribution to energy and heat, often for hot water, it seems the first world has "discovered"the idea as well.
A recent article has shown an enormous increase in the UK, essentially a doubling of facilities since 2010. While scale is not mentioned, it seems thay are referring to medium, industrial scale developments, not the sort that featured on Kevin Mcleod's "Cabin in the Woods" tv show, for a single small weekend cabin.
It is a sensible idea - generate the methane upfront, with the organic residuals then suitable composted, or sometimes even gasified and used for energy. I prefer the compost route, but not all areas are able to handle the volumes of compost generated.
Nutrients are a critical part of the remainder organics - too much of these are simply transported from farm to city and then lost down the sewer, or as food waste. That connot continue, as the supply of most nutrients is finite.
The article is here - http://www.waste-management-world.com/articles/2013/03/rapid-expansion--uk-waste-to-biogas-anaerobic-digestion-industry.html
and clearly shows the rapid development in the UK.
Not so sure about Australia, but the trend is likely to develop. There have seen some smaller systems developed including in WA, but none in the tropical north that I am aware of, yet that is where the bulk of organic residuals from crops - think sugar cane - are generated, along with food waste from cities and towns of modest size that could easily allow for development of suitable digestion and biogas systems.