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Wastewater Treatment:
The Oxygen and Water Challenge

Air Liquide - Future Water - The Oxygen and Water Challenge

Ensuring proper treatment of wastewater is one of the top priorities for the future of humanity. According to UNESCO, only 64 per cent of people globally have access to clean drinking water and 80 per cent of all wastewater flows back into the planet’s ecosystem untreated. As such, many countries have recognised the importance of reducing damage to the environment, and are legislating and spending accordingly.

In Australia, water scarcity, extensive mining and agricultural activities – along with growing urban population density – make water treatment to limit the human impact on the environment and preserve the unique Australian biodiversity one of the key challenges of this century.

The Wastewater Treatment Process in Sewage Plants

Both at industrial treatment plants and municipal sewage works, wastewater treatment generally involves three stages. In primary treatment, used water and sewage are held in a clarifier tank so that solids can settle on the bottom and be removed, while lighter materials float and are skimmed off the top. The water then goes into secondary treatment, where water-borne microorganisms are used to break down biological matter. Finally, the water undergoes tertiary treatment before it is released into the ecosystem.

How Air Liquide is Improving Water Treatment

Oxygen is required during secondary treatment so that microorganisms can breathe and metabolise biological matter. Currently, most facilities inject air into their biological basins, which is only 21 per cent oxygen. Replacing air with pure oxygen increases the effectiveness of the basins and their treatment capacity can be boosted by up to 50 per cent. There’s no need to expand basins or build new ones, thus limiting capital expenditure. Moreover, foam on the surface of the water in treatment basins, generated by chemicals and airflow, is reduced and unpleasant odors caused by insufficient oxygen are eliminated. In addition to significant investments in research and development, Air Liquide has a unique know-how of more than 20 years experience, with over 1500 references worldwide at both industrial water treatment sites and municipal sewage works. Air Liquide is ideally positioned to improve the efficiency, capacity and performance of existing facilities and to help equip state-of-the-art new builds.

Future Developments

Air Liquide customers continuously generate data points related to temperature, pH, oxygen concentration in biological treatment basins or volumes entering and leaving the plant. Analysing this data allows Air Liquide to optimise site performance and raise alerts if the computed statistics indicate the presence of a malfunction. This MRV (Monitoring, Recording and Verifying) approach prefigures ongoing developments so Air Liquide can use big data and the Internet of Things to offer even greater performance and efficiency. The planet’s population is set to grow from 7.5 billion to 9 billion by 2050, while the amount of freshwater available remains the same. Thanks to its know-how and technological innovations, Air Liquide is helping industries and municipalities rise to the challenge.

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This article can be found in the 2019 edition of Future Water Magazine

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