Mechanical Technology March 2016

⎪ Pump systems, pipes, valves and seals ⎪

Oxy-Dep: increasing the efficiency of

Air Products’ oxygen-based technologies provide effective solutions to increase treatment capacity of existing water treatment plants. This according to Sachin Kulkarni (right), national sales manager, bulk at Air Products South Africa.

C ompanies around the world are facing increasing pressure to reduce their environmental impact and re-examine their long-term sustainability. To this end, many companies are seeking solutions to effective wastewater treatment. This is in line with the worldwide trend towards zero liquid discharge (ZLD), which encourages industries to adopt wastewater technologies to assist in the drive towards water recycling and reduc- ing water wastage. In a country such as South Africa, where water is a precious resource that needs to be carefully managed, effective wastewater technologies have become an imperative, which cannot be ignored, says Air Products’ Sachin Kulkarni. “The drive towards effective water usage is not only an environmental con- cern, 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 that 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 dis- tributor 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 spe- cific industrial problems. The company has introduced a number of technologies to address wastewater 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 to optimise wastewater treatment facilities through improved oxygen-based technologies, which bring direct benefits to the user.” Air Products works with original equipment manufacturers (OEMs), envi- ronmental organisations as well as end- users to tailor-make solutions to specific problems with regards to the treatment of wastewater, such as high biological oxygen demand (BOD) or high chemi- cal oxygen demand (COD). In this field, the company has worked closely with companies in the global food processing, paper and pulp, tanneries and distilleries industries. “The key to the efficient use of oxygen includes the design of the wastewater 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 opti- mise wastewater processing and address BOD is oxy-Dep ® , a biological wastewater treatment process that uses pure oxygen instead of air. “While air plays an important role in industrial wastewater treatment, it can- not always do the job alone. Treatment methods that use oxygen-based technol- ogy to purify and neutralise wastewater are gaining popularity in the industry,” says Kulkarni. The use of high purity (HP) oxygen has particular application in wastewater treatment facilities in cases where the

Wastewater aeration using oxygen versus air significantly lowers VOC emissions by reducing gas stripping. Air Products’ Oxy-Dep range of technologies provide efficient oxygenation (usually >90% oxygen transfer efficiency), where high loads exist. Oxy-Dep also provides a reduction in odours, surface foaming, aerosols and VOCs, as well as improved sludge settling and dewatering, either when retrofitted or in a purpose-built activated sludge plant. Inset: Traditional aeration (using air) associated with significantly more surface foaming.

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Mechanical Technology — March 2016