Long pressure pipes fpr sewage water needs to be flushed with pompressed air at time. At the end of the pressure pipe sewage water and air flow out of the pipe simultaneously.
The ratio between sewage water and air is 1:10.
The separation between sewage water and air hapen is a Separation buildung.
Afterwards the sawage water flows out by gravity.
Hence the unrefined gas will run into a biological filter where the odour will be eliminated.