Anaerobic pre-treatment technology delivers water and energy gains for brewer

A water recovery plant designed to target world’s best-practice water reuse standards in the food and beverage industry has exceeded its designers’ expectations in its first year of service at a brewery in Australia.

The waste water treatment and green energy plant at the $120 million Pacific Beverages’ Bluetongue Brewery in NSW also provides renewable energy for the brewery, reducing its dependence on fossil fuels and ultimately cutting overall energy needs by 15 per cent.

Performance targets

The plant – engineered by Australia’s CST Wastewater Solutions in partnership with Global Water Engineering – has achieved all the environmental performance targets set by Pacific Beverages, a SABMiller/ Coca Cola Amatil joint venture, according to CST Wastewater Solutions Managing Director Mike Bambridge.

The plant was also a finalist in two categories of this year’s Engineering Excellence Awards, Sydney 2011, conducted by Engineers Australia, which attracted a record field of more than 90 entrants. Bluetongue was a finalist in the Environmental and Heritage category and the Products, Manufacturing, Facilities and Processes category.

Pacific Beverages designed the plant to ultimately have an annual capacity of 150 million litres, while targeting a reduction in water usage to 2.2 litres per litre of beer produced. This figure is amongst the best in the world and certainly well above the global average of four to five litres of water to every one litre of beer, says the CEO of Pacific Beverages, Peter McLoughlin.

Green energy

The GWE anaerobic technology plant employed at the plant produces sufficient green energy (methane) from its closed anaerobic reactor to power a designated steam boiler and cut the brewery’s overall energy consumption by about 15 per cent. This equates to about 300,000 Mj.

Bambridge says the plant indirectly reduces the brewery’s carbon footprint by reducing the brewery’s demands on fossil fuels and the electricity needs for wastewater treatment by using energy-friendly anaerobic pre-treatment technology in which GWE is considered a world leader.

Fresh water

"And the plant produces treated effluent to be safely reused as process and cleaning water within the brewery, reducing by approximately 50 per cent the need for fresh water, thereby greatly contributing to reducing the amount of water typically used to produce a litre of beer," says Bambridge.

The design philosophy has been to treat the waste water as a resource from which water and energy can be recovered in addition to reducing the site’s carbon foot print.

"This is a landmark achievement of water conservation and green energy production, achieved by combining the latest versions of advanced and reliable technologies available globally," says Bambridge.

It demonstrates the technology’s practicality for extensive use not only throughout the Australian food and beverage sector – which involves more than 20,000 companies – but also globally, notes Bambridge.

Industrial effluent

His company employed the latest technologies from a range proven globally by Global Water Engineering (GWE), headed by CEO Jean Pierre Ombregt.

GWE has built more than 250 plants producing biogas as part of the industrial effluent clean-up system, of which more than 75 were supplied with subsequent biogas utilisation systems for clients worldwide.

Global players

Users of GWE technologies extend from the Bluetongue Brewery to global players such as Budweiser, Chang, Carlsberg, Coca Cola, Corn Products, Danone, Fosters, Heineken, Interbrew, Kraft, National Starch & Chemicals, Nestlé, Pepsi Cola, SAB-Miller, San Miguel, Singha, Sunkist and Tsingtao.

Many of the latest installations use advanced technologies – including anaerobic pre-treatment of water and aerobic polishing – to enhance water discharge purities while converting waste to methane to be burned to power boiler and hot water systems, for example, or to power generators and permanently replace fossil fuels.

On average, the removal efficiency of GWE’s anaerobic wastewater treatment installations is 90 to 95 per cent, bringing the organic load down to regulatory discharge standards for most types of wastewater, says Ombregt.

Environmental advantage

Besides the economic advantages of anaerobic wastewater treatment, there is also a clear environmental advantage in significantly reducing a factory’s carbon footprint.

This is done not only by supplying renewable energy from the closed anaerobic reactor, thus reducing or even eliminating reliance on fossil fuels, but also by replacing traditional, open, methane-producing lagoons, and by replacing power-consuming, sludge-producing aerobic WWTPs.

"The concept of using wastewater to create green energy is much more widely applicable than often realised. Any factory with a biological waste stream or wastewater with high COD (chemical oxygen demand) can easily use this model to generate energy," says Ombregt.

Anaerobic basics

In the absence of oxygen, many different groups of anaerobic bacteria "work" together to degrade complex organic pollutants in methane and carbon dioxide. The microbiology is more complex and delicate than in case of aerobic processes, were most bacteria are able to "work" individually.

As a result anaerobic systems require more control and monitoring systems to operate successfully. Each system has its advantages and disadvantages, but for treatment of industrial wastewaters, the advantages of anaerobic systems are most often predominant.