Week 2 - Anaerobic Digestion From lecture info/vid Flashcards
How does the standard free energy determine a reaction
The more negative the more likely and faster it is to occur
Le Chetliers Principle
If a stress is brought to a ayatem in equilibrium it will move to the other side to alleviate the stress
In the AD reactions why does species 2 react
Based on the 4.1 reaction as it adds a stress to the systems then as per le chetliers principle
Why could you feed an AD in a pulse?
More gas is produced and the hydrogenotrophic route as the other route doesn’t like stress
Wastewater treatment plant for sludge production
Aerobic or anaerobic. Anaerobic makes 10x less sludge. Look at formulas from slides
Why is it important to have pH correction in the AD
as the VFAs form to pH of , to continue the process needs a pH of 7 so you can form your CH4 etc
Dry Batch Reactor configuration
Draw. Is batch process
Big tank. Biogas out top, substrate in side. Percolation liquid stogae tank below. line joins from that back to outlet of biogas
How does a dry batch reactor work
Feedstock, sprinkle water over the feedstock to make a percolation liquor full of COD
Dry continuous configuration process description.
Low footprint 6/7s recycled 1/7th moves on. One in brecht in belgium.
REPower EU target for biomethane production
35billion cubic metres by 2030. 10x from 2020.
What is Irelands climate action plan by 2030 for biomethan production
5.7TWh of biomethane by 2030. Equivalent to 220 3MW facilities
Parkland Grass cuttings in Brazil case study
20MW of hydroelectric scheme. They flooded the land equivalent of Munster to get the DAM. Irena don’t consider it renewable due to the land flooded as trees flooded.
400 hectres of grassland, put the grass into a digester and they run 60 cars on biomethane.
WHat percentage of methane is emitted from open slurry tanks
17.5%
Explain the circular economy of an AD/biogas plant.
Biogas used for fuel, het transport.
Animal waste, human waste and process waste to the plant.
Digestate as biofertiliser for crop farming.
Crops to plants and animal feed.
What s the importance of acclimatising the feedstock in AD
Archae need time to adjust to the feedstock before it effectively produces biogas. Therefore batch tests have to be done properly to allow for this
