Biofuels And Food Production Flashcards
What are the two types of biogas generators?
Batch generator and continuous generator.
Why can’t biogas be stored as a liquid?
Because biogas needs to high a pressure so it has to be used straight away.
What conditions do you need for a biogas generator?
Warm and anaerobic (no oxygen) conditions.
What would happen to a biogas generator if the conditions were not anaerobic?
The certain bacteria would not be able to grow so it wouldn’t produce biogas.
Meaning anaerobic fermentation can not take place.
What are the main gases found in biogas?
Methane (70%) Carbon dioxide (30%)
Why is methane the more important gas produced from biogas?
As it can be burnt so we can use it for cooking, heating, electricity production.
What type of reaction happens in a biogas generator?
Exothermic reaction, gives off heat
Why does it take some time before a biogas generator produces methane?
Because there will still be some oxygen in it at the start so the aerobic reaction takes place first producing carbon dioxide but when the oxygen gets used up methane levels will start raising.
What economic and environmental effects do biogas generators have?
It is a carbon neutral process, the carbon released was taken in by the plants which lived recently.
Burning methane as a biogas means it’s not released into the atmosphere.
Biogas generators act as a waste disposal system, so the waste is not left to cause disease or pollute water supplies.
The raw material is cheap and readily available.
The digested material is a good fertiliser so people can grow more crops.
What goes into a biogas generator?
Plant, animal and food waste
What can improve the efficiency of food production? (In general)
Reducing the number of stages in the food chain
Restricting the energy lost by farm animals
Developing new food sources (such as mycoprotein)
How is energy lost by farm animals?
Energy is lost through: Movement Heat (regulating body temp) Excretion Growth
What happens as the number of stages in a food chain increase?
Every time you move up a stage in a food chain there’s less energy and less biomass.
What are the advantages of food made from microorganisms?
In some developing countries it is hard to find enough protein.
Growing mycoprotein in a fermenter is an efficient way of producing protein for people.
Microorganisms grow very quickly and don’t need much space.
Microorganisms can feed on waste that feeding animals would not.
What fishing regulations are there to maintain fish stocks in the ocean?
Net size (not to big) Quotas (limits on the number of fish that can be caught) Avoid fishing during mating season Avoid breeding grounds Mesh size (reduce the number of unwanted/younger fish being caught)
What is mycoprotein?
It is a source if food that comes from a fungus which is very high in protein and low in fat so it can be used as a meat substitute.
How is mycoprotein produced?
The fungus, fusarium is grown on glucose syrup in aerobic conditions in a fermenter. The biomass is then harvested and purified.
How does the fermenter producing mycoprotein prevent other microorganisms growing?
The fermenter is initially sterilised using steam.
The incoming nutrients are then heat sterilised.
The air supply is filtered.
What are the advantages of factory farming?
Faster growth (by controlling energy loss) Cheaper (less land is needed) More food is produced (animals are raised and slaughtered quicker)
What are the disadvantages of factory farming?
Disease spread (lots of animals are in confined spaces) Animal cruelty (bad conditions) Lots of power is used to keep animals warm (using more fossil fuels)
What the advantages of organic farming?
Less cruelty
Grown in natural conditions (animals grow more healthily)
Less power is need to raise them (less carbon dioxide emissions)
What are the disadvantages of organic farming?
More food to feed the animals (they're alive longer) More expensive (more land needed) Longer to grow
What are the advantages of sourcing local food?
Less travel needed so less carbon dioxide emissions.
Less effect on global warming.
What are the disadvantages of sourcing local food?
Weather isn’t constant all year round (less availability in winter)
Greenhouse may need to be used (light/heat produces carbon dioxide)
