The biological treatment stage is inspired by nature itself – microorganisms and bacteria are a natural part of wastewater and help to purify it. On its own, though, this process would take a very long time, so we speed it up by cultivating naturally occurring microbes in what is called “activated sludge”, and stimulating their activity by aeration. This process is made still more effective by stirring the contents of the tanks, so the bacteria don’t settle at the bottom, but work throughout the wastewater. These bacteria use organic pollutants as an energy source and their activity decomposes the organic matter in wastewater.
The process part of the plant involves a large amount of machinery, equipment, instruments and sensors, along with tens of kilometres of pipelines and hundreds of kilometres of electrical wires. A great example is what we call the “temple of pumps” – a long corridor running almost the length of the site, where 48 huge sludge pumps are installed.
... due to aeration, water is mixed with air in a 1:1 ratio during biological cleaning process, and so the tank is half water and half air?
Workers moving around the tanks must therefore be cautious. Even very good swimmers are at risk of drowning as it is impossible to swim in aerated water.
If you want to know more, continue to other parts of the treatment plant ...