Waste is not an easy thing to be handled with. Tons of waste are being dumped into the landfill and incinerator every day causing the world to get more heated up. When the whole world is busy generating waste every day, some do find ways to turn the waste into something useful for the human being and to combat the climate change. And one of the most effective method anaerobic digestion process. What is anaerobic digestion?

Anaerobic digestion is a treatment that compost waste in the absence of oxygen. The process will produce biogas that can be used to supply electricity and heat. Although main component of biogas is methane and carbon dioxide, the biogas is not harmful to the environment since the carbon dioxide are not released directly to the surrounding. Furthermore, biogas is a source of renewable energy means that it will not going to deplete as time goes by. Well, we are not going to stop producing waste too, are we?

Figure 1 Stages of anaerobic digestion (Photo from Google)

During the three phases of anaerobic digestion, there is a bunch of acid produced called volatile fatty acid (VFA). While these acids are needed for methane production, it also can be a poison to the process. Too much of acid can kill all the bacteria since bacteria don’t like acidic condition. Therefore, it is important to monitor the volatile fatty acid production in anaerobic digestion. In lab scale, the analysis is done by doing distillation and titration but there are lots of other way to determine the amount of volatile fatty acid content in the reactor such as using gas chromatography (GC).

Other factor that also crucial to anaerobic digestion is the total solid content (TSS) and volatile suspended solid (VSS). In reactors where the feed and effluent are being constantly added and thrown away, there is possibility of washout of biological solid to happen. This is an unfavourable condition since washout of biological solid means washout of the bacteria that helps us to generate biogas! Anaerobic digester is operated in two condition which is high solid or low solid content. In high solid content, we can save more space as it takes up lesser volume than low solid content. Low solid content is associated with high liquid composition in the digester.
To sum up, anaerobic digestion has getting more attention now since it has a lot to offer from the easy execution to economically affordable. Farmers and even factories are building their own biodigesters as an alternative for the electricity. Thanks to anaerobic digestion, waste is not a waste anymore 😊

Let’s watch below video, to learn one example of anaerobic digestion application for treating Palm Oil Mill Effluent / POME waste. (Kontributor: Nurul Afiqah Binti Mohd Ma’asom)