Energy

1. conditions required for production of biogas
3. animal waste produced from intensive farming techniques
4. large pits lined with clay where rubbish is deposited.
6. a by product of fermentation
8. container dug into the ground to collect animal and domestic waste and produce biogas
11. a gas produced from the decay of remains of animals and plants
12. ethanol and petrol mixture
13. organic material produced by green plants that can be used as an energy source

1. Starchy crops may have to be pretreated with these before fermentation can proceed
2. a natural substrate for the production of ethanol as fuel
5. Zymomonas mobilis can tolerate high levels of ethanol and is this type of micro-organism
7. process by which sugar is converted to alcohol
9. type of processing with all raw materials needed inside an enclosed container at start
10. type of processing where raw materials are constantly added and product constantly being removed
14. substrate for production of biogas in sewage works