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A breath of ‘pure oxygen’ for the water treatment industry

South African News

A breath of ‘pure oxygen’ for the water treatment industry

Air Products’ oxygen-based technologies provide effective solutions to increase treatment capacity of existing water treatment plants

Companies around the world are facing increasing pressure to reduce their environmental impact and re-examine at their long-term sustainability. To this end, many companies are seeking solutions to effective waste water treatment. This is in line with the world-wide trend towards zero liquid discharge (ZLD) which encourages industries to adopt waste water technologies to assist in the drive towards water recycling and reducing water wastage.

In a country such as South Africa, where water is a precious resource which needs to be carefully managed, effective waste water technologies have become an imperative which cannot be ignored, says Sachin Kulkarni, National Sales Manager – Bulk at Air Products South Africa.

“The drive towards effective water usage is not only an environmental concern, but has become a strong business imperative as well,” he says.  “While legislation is in place regarding waste water management, it is the business community which is driving demand for new technology. The market is actively seeking water treatment solutions in order to become sustainable in the long term.”

Air Products, a manufacturer and distributor of a wide range of industrial gases and chemicals, has a proud track record of being at the forefront of continuous improvement in technological innovation, and providing effective solutions to specific industrial problems. The company has introduced a number of technologies to address waste water treatment issues to global industry, notably oxygen and ozone technologies.

“Waste water technologies must have economic benefits to the company, in other words they must be cost-effective in addition to being environmentally-friendly,” Kulkarni notes. “Air Products is continually looking for ways in which to optimise waste water treatment facilities through improved oxygen-based technologies which bring direct benefits to the user.”

Air Products works with original equipment manufacturers (OEMs), environmental organisations as well as end-users to tailor-make solutions to specific problems with regards to the treatment of waste water, such as high biological oxygen demand (BOD) or high chemical oxygen demand (COD).  In this field, the company has worked closely with companies in the food processing, paper and pulp, tanneries and distilleries industries globally.

“The key to the efficient use of oxygen includes the design of the waste water plant, the equipment used to transfer gaseous oxygen into the liquid effluent, and an intimate understanding of the biological process,” says Kulkarni.

One of the technologies that Air Products has introduced in order to optimise waste water processing and address BOD is oxy-Dep®, a biological waste water treatment process which uses pure oxygen, instead of air.

“While air plays an important role in industrial waste water treatment, it cannot always do the job alone. Treatment methods that use oxygen-based technology to purify and neutralise waste water are gaining popularity in the industry,” says Kulkarni.

The use of high purity (HP) oxygen has particular application in waste water treatment facilities in cases where the aeration basin reaches its limit in terms of load.
“All waste water plants have a limited capacity – and if, due to seasonal demands, for instance, the plant exceeds its capacity for waste water, the introduction of HP oxygen technology can serve to augment the capacity of the basin in the short term.  This is a highly cost-effective alternative to expanding an existing plant’s infrastructure,” notes Kulkarni.

“Moreover,” he adds, “the use of oxygen-based technology eliminates wasted energy in terms of separating oxygen from nitrogen in normal aeration processes. Using high pressure (HP) oxygen also achieves faster oxygen mass transfer rates into water, than air. Greater oxygen solubility enhances and assists the development of micro-organisms in effluent or sludge.”

Oxy-Dep® offers treatment plants a highly efficient oxygen dissolution system which incorporates a side-stream injector to deliver oxygen in the form of very fine bubbles to an activated sludge process, with minimal power consumption.

“This technology is ideal when space is too limited for the installation of a new or additional plant, as it effectively increases the treatment capacity of the existing plant. This has important implications in minimising the need for large capital expenditure,” Kulkarni emphasises.

Other specialist solutions offered by Air Products to address specific waste water-related problems include ozone technology, which the company provides not only for water treatment but also for cyanide destruction in the mining industry; and carbon dioxide, which the company supplies to water-treatment companies for pH balancing.

Looking beyond waste water treatment and purification, Kulkarni notes that aquaculture, as a one of the fastest growing food-producing sectors, represents further opportunities for the introduction of oxygen technology.

Air Products develops and designs its oxygen-based technologies in line with changing markets and industry demand for optimising efficiencies and minimising environmental impact.

“While oxygen processes for the biological treatment of waste water are not new technology, there is scope for increased application of these technologies in the current environment.  The watchwords in industry are ‘reuse’ and ‘recycle’ – especially in the context of water scarcity in South Africa.

“Although oxy-Dep® provides recognised benefits when compared to conventional aeration methods, it is not the final word in waste water treatment. Air Products is making ongoing advances in the field through its research and development efforts, to gain a deeper understanding of the role of oxygen in the biological and water treatment process.

This will enable us to further assist our customers in industries with specific needs and to also address ever-present environmental demands going forward,” Kulkarni concludes.