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Aerobic Digestion and Anaerobic Digestion
Aerobic and anaerobic digestion process of waste. What is the aerobic digestion process of waste. Aerobic Digestion is a biological waste water treatment process. Aerobic digestion Is a process in sewage treatment designed to reduce the volume of sewage sludge and make it suitable for subsequent use. Biological processes use natural microbial colonies and molecular oxygen to decompose organic substances in the waste water (picture 1.1 and 1.2).
picture 1.1 Microbe picture 1.2 Microbes in waste water
The first biological process in biomass digestion is biomass destruction. In this process food supply is depleted (picture 1.3).
picture 1.3. biomass destruction
To feed on their own protoplasm for cell metabolism. Through oxidation process. To produce carbon dioxide plus water plus ammonia which increases. In this process produces a lot of ammonia which is very toxic to microbes (picture 1.4.)
picture 1.4. ammonia molecule
And this brings us to the next process. This process is accomplished by the nitrifying bacteria (picture 1.5.).
picture 1.5. Formula for Nitrifying bacteria
The nitrifying bacteria oxidizes ammonia with two additional moles of oxygen. Reducing it to water two moles of acid H+ and nitrate. After both process and the byproducts of the processes are five moles of carbon dioxide three moles of water and nitric acid. Nitric acid is a toxic acid and can kill the biomass because microorganisms are very sensitive to PH conditions.
picture 1.6. PH Conditions
In other to reduce nitric acid comes their final process biological process.
Denitrification is accomplished in the absence of oxygen by the denitrifying bacteria. This forces the biomass to oxidize for moles of nitrate reducing them to a bicarbonate and 2 moles of nitrogen gas.
Anaerobic digestion is a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen. Anaerobe access oxygen from sources other than the surrounding the oxygen source for these microorganisms can be the organic material itself we may be supplied by inorganic oxides from within the input material. In the process waste has collected and treated.
picture 1.7. Truck for collecting a waste picture 1.8. Anaerobic Digestion Tank
Its then fed into the digestion tank. This is where anaerobic digestion takes place. And this process produces two main product. Firstly they is methane which is collected and stored for electricity and fuel (picture 1.9).
picture 1.9. Methane is collected and stored for electricity and fuel
What takes place in anaerobic digester?
Inside an anaerobic digester naturally occurring microorganisms grow in the tanks oxygen free environment and break down (picture 1.10).
picture 1.10. Microorganism grow in anaerobic digestor
As the organic matter decomposes, the bio gases created. Once established, into digested microorganisms will continue to break down organic materials and released bio gases. In the right conditions the microorganisms need a steady supply of feed stock and a comfortable environment and warm temperatures, neutral acidity and no oxygen. Bio gas is made up of mainly methane CH4 and carbon dioxide CO2 with small amounts of water vapor particulate and other gases such as hydrogen sulfide H2S.. Such as the generation of heat power and fuel.
✔ PLAYLIST (Environmental Engineering)
Create: Hrvoje Čočić
Mustaf King II
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