Cargill greens waste water to cut carbon footprint

The meat processing giant said its A$13m (US$11m) investment would include a purification system that would “significantly improve”​ the quality of the plant’s waste water allowing it to be re-used.

The initiative is being carried out in partnership with the New South Wales Department of Environment, Climate Change and Water (DECCW) which contributed A$ 2.9m to the project.

Anaerobic ponds​

Cargill said it is to replace existing waste water lagoons at its Wagga Wagga plant with covered anaerobic ponds – each with a volume of 28,000 cubic metres. As part of the covering phase, which is already underway, a collection system will be fitted to reclaim methane-rich biogas given off by the waste. Last year, biogas contributed to 7,467 tons of carbon dioxide emissions from the plant.

A Cargill Australia spokesman told FoodProductionDaily.com: “We will then burn this biogas off through an enclosed flare. The flares will combust the captured methane rich biogas, thus reducing our green house gas emissions.”​

It is anticipated the scheme will be completed in six months and commissioned in mid-2011 and Cargill said it was the first stage in helping it meet the company’s eco-targets of a five per cent reduction in greenhouse gas emissions, five per cent reduction in fresh water use and five per cent improvement in energy efficiency by 2015.

The project also allows for the future installation of a cogeneration facility with the capacity to generate around one megawatt of electricity – which would cut the Wagga facility’s total electricity demand from the local power grid by around 20 per cent. However, Cargill said it had not made a decision on when this investment would be made.

Water purification​

As part of the initiative, Cargill has also pledged to build a Biological Nutrient Removal (BNR) system which would treat its waste water for nutrients such as nitrogen and phosphorus that are not fully removed by the current method.

“The new BNR system will better treat the waste water to make it cleaner and allow us to reuse the water in our plant”,​ said a company spokesman.

The waste water upgrade is aimed at meeting new state limits for discharge into the municipal sewer system. The newly treated water will be suitable for on-site irrigation and increased reuse applications within the facility, added the spokesman.

The company said a second Australian processing plant at Tamworth is planning a similar waste water upgrade scheme and the technology is already in use in a number of its North American facilities.

Cargill said it is also working with other companies in both the US and Asia to apply this green expertise to a variety of industries.