Coca-Cola opts for oxygen-based WWT
The soft drinks manufacturer Coca-Cola needed to review the wastewater treatment (WWT) system at its development and quality control laboratory in Anderlecht, Belgium. An increase in wastewater produced at the site meant that the existing plant was struggling to meet demand. European water business manager at Air Products, Peter Barratt, explains how an innovative oxygen system was developed to meet the plant's requirements.
The site is involved in a wide-range of activities including research and development and quality control in products and packaging. The company's focus on new product development was one reason for the shortage of effluent treatment capacity.
Sebastien Berlanger, Coca-Cola Services' facilities manager in Anderlecht, said, "Our treated effluent risked exceeding the limits set for biological oxygen demand (BOD) and suspended matter and we needed to increase the capacity of our wastewater treatment system significantly. We also test around 6000 trade samples every month and this has significantly increased the laboratory's chemical oxygen demand (COD) output."
With limited space available, the site itself posed a particular challenge. The existing WWT system was situated underneath a car park and therefore just accessing the system in order to carry out the necessary upgrade would be difficult.
In addition, a significant increase in capacity was required. The existing system comprised a sequencing batch reactor (SBR), with a basin volume of 80m3 and a capacity for treating about 50kg/d of COD. To allow room for future growth, Coca-Cola had calculated that it needed to increase capacity to around 120kg/d.
After considering the demands of the site, Air Products proposed an oxygen-aerated WWT solution. Traditional aerated WWT systems work by reducing the oxygen demand of the wastewater by dissolving as much of the oxygen found in the air as possible, so encouraging the growth of natural micro-organisms that cleanse the water and remove organic and other contaminants.
Air Products' oxygen-based system, known as the Oxy-Dep VSA system, works in the same way but uses high-purity oxygen in place of air to aerate the wastewater, providing in-creased capacity due to a faster rate of oxygen dissolution. The Oxy-Dep VSA system is a compact, modular solution that requires little on-site space and which can be easily installed as an upgrade to an existing system.
Coca-Cola had been offered a number of specialist solutions which had failed to meet their specification, primarily because they were either expensive or could cause disruption to the existing WWT process during installation. The Oxy-Dep VSA system was an ideal solution as it is particularly compact and easy to install. Fitted with a single submersible 2.2kW mixer-oxygenator, it was also capable of reducing oxygen demand by as much as 250kg/d.
Facilities and environmental managers can now assess the efficiency of their existing wastewater treatment system using a unique process risk assessment tool, which is available online at www.airproducts.co.uk/environmental.
For many businesses, investment in a brand new WWT system is not a cost-effective or practical option. The location or size of the site can present constraints. A system overhaul would also require a break in production, which would incur further cost and might be disruptive for customers.
In view of this, manufacturers are increasingly looking for alternative ways to extend the capacity of their existing systems, creating a more sustainable solution, without replacing it altogether.
Far-reaching legislation, such as the Water Framework Directive, which aims to achieve 'good status' for all surface and ground waters across EU member states by 2015, has raised awareness of the importance of protecting the water environment. Fortunately, advances in wastewater treatment technology mean there are now more options available, designed to optimise efficiency while minimising plant disruption.