Working with biogas

[Mark S]

It can be a smelly pastime but get past that and it is really quite an exciting prospect.I have been invlovled in the gas industry for 30 years and got into biogas through working on waste sites. The sites we look after at the moment use boilers which run on biogas to heat the digestors to make the bacteria break down the waste quicker which in turn makes more gas so it is completly self sufficent. The only problem being if the boilers or plant break down and the digestor goes cold and kills all the bacteria you have to introduce new bacteria which i understand is quite expensive.The gas produced is rather wet and as such can require more maintanence.The prospect of more farms introducing bio digestors is also a good step in the right direction but as usuall we are miles behind Europe.

[Hairyloon]

I was thinking about this. Why haven't we got these digesters everywhere dealing with sewage?

I don't believe it is difficult. I understand that there is a minimum size before it becomes practical.

The lions share of your water bill is for dealing with your sewage, so surely there is a market for community bio-gas plants?

[goslow]

I'm not quite up on waterworks but doesn't this already happen at many sewage plants? At least, they manage to make some energy from digesting sewage sludge to run the plant, if not export.

[mikepepler]

It does happen at some sewage plants, they burn the gas to generate electricity to tun the site and export.

I'm pretty sure that you can start a biogas plant with cow dung - it has the right bacteria already in it. We've awarded loads of biogas projects overseas at work, and none of them ever used any special bacteria to start them. It's easier in a warm country though I guess.

Anyway, here's some links to videos and case studies on the overseas biogas projects we've given awards to.
Ashden Awards biogas projects

[Mark S]

There was a good piece on country file a few weeks ago re bio digestors on farms.good item with loads of info.if all farms which have the possibilty to use a plant did, then it would save our poor farmers!!!! a few bob.

[wolfemoves]

I am about to renovate an old house in Portugal. Biogas seems like a better option that dry compost toilet (faster digestion, less smell potential, produces a useful cooking fuel/gas, etc).

I contacted the Senior biogas consultant to the Ashden Awards, Dr Fulford, of Kingdom bioenergy, and he said there are no domestic systems available, on the market in Europe. A situation he is trying to rectify, by designing moulds that can be sold to suppliers at the local country level.

But he said that a domestic sized system that uses both kitchen waste and human manure are very viable. Indeed are applied in various Asian countries (many of the Ashen Awards videos show just kitchen waste fed systems).

He said that he is not very "practical", but recommended a Nepalese fellow that is, but getting him over here to build it costs thousands and seems daft.

So my questions are thus:
- should we just give it a go ourselves / our plumber, based on designs that are available on the net?
- are there domestic systems available to buy in Europe - that take toilet and kitchen waste?
- to deal with the cold factor discussed in this thread, is it realistic to keep the system heated, from the main house heating system (solar thermal, etc.)?

Thanks

[RenewableCandy]

A bit far-out, but is there anyone else locally you could team up with so your man from Nepal could do a job lot of loos and you all share the cost of his plane/Orient-express ticket?

[wolfemoves]

Yes I have thought of that - suggested it on a local permaculture ring that exists here, but the feeback so far was that people should work for free, and there is little appetite for paying a consultant...
So, thus far I have not found others who want to contribute.