Linde Corporate Responsibility Report 2005

The industrial gases provided by Linde serve a number of applications in the realm of water and sewage treatment. In the area of additive environmental protection measures, the effective neutralization of alkaline effluent using CO₂ and sewage treatment by means of industrial oxygen are of particular importance.

Carbon dioxide is being used by industry in increasing quantities for the legally prescribed neutralization of alkaline effluent. Linde supplies the requisite carbon dioxide tank systems – precisely tailored to specific customer requirements. The major advantage of carbon dioxide in sewage treatment lies in its relative safety of use compared to the aggressive mineral acids that are conventionally deployed. Additionally, carbon dioxide does not produce corrosion; nor does it increase the salt content of the effluent and lead to excess acidification.

Haikou, China
Clean water isn’t simply a given. Sometimes it’s the product of innovative technology. Water purification is environmental protection in action. For decades, Linde has been perfecting innovative processes to sustain the water quality for generations to come. One such method is the anaerobic sludge treatment of wastewater containing heavy metals at our plant in Haikou, China. This technology dispenses with the use of ecologically unsound chemicals and thus makes an important contribution to cleaning industrial wastewater.

Using pure oxygen from decentralized on-site plants supplied by Linde Gas, sewage treatment facilities – which are also built by our subsidiary Linde-KCA-Dresden GmbH (LKCA) – can be operated in a more environment-friendly and cost-effective way, and largely without any odor pollution. In this process, the selective addition of oxygen to the clearing basins produces a reduction in the hydrogen sulfide generated by the treatment and decay processes. On the other hand, the addition of oxygen also prevents acute oxygen depletion in the basin.

Linde Gas has now installed gas applications for wastewater treatment at more than 400 sewage treatment plants around the globe, among them the world’s largest plant in Los Angeles, California.

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