22. January 2021

Almost all wastewater treatment plants treat wastewater in three stages. Bacteria decomposes the organic fertilizers in the wastewater with the participation of oxygen, thus purifying the wastewater. Among them, oxygen is added into the wastewater treatment equipment in the form of compressed air.

In the past, the amount of compressed air injected was mostly estimated and difficult to control precisely. In the environment of energy saving and environmental protection, Praxair GmbH has established a new Oxygen Supply Control System using the S418 flow sensor (See the figure). This system can measure the bacteria concentration online 7*24 and accurately supply the optimal amount of oxygen according to the bacteria count, which improves the efficiency of compressed air usage.

China is undertaking a five-year project to build municipal wastewater treatment plants and to rebuild and modernize old wastewater treatment plants, with a total investment of 190 billion RMB. In both projects, the use of flow meters is indispensable for energy saving and efficiency improvement, and the demand for flow meters is very promising.