IPPC boosts membrane clean-up technology

The market for membrane water treatment technology is set to receive a boost as the new integrated pollution prevention and control (IPPC) regime is phased in. The technology makes it possible to reduce effluent bills and reuse water, and is particularly well suited to the water-hungry food and drink sector.

Under IPPC, pollutant releases must be prevented, or otherwise minimised, by means of the "best available techniques" (BAT). Operators must demonstrate that they are using BAT in their applications to the Environment Agency.

Membrane technology is a filtration technique that can be used to treat liquid effluent or integrated into the production process. It is becoming increasingly common in sewage treatment where water companies face stringent regulatory standards. In the dairy industry, membranes are already used in the production process to separate water from a solution, such as in making cheese whey.

IPPC is set to drive new applications of membrane filtration and expand the market for the technology. The food and drink sector begins to fall under the regime in 2004.

The most important driver is the requirement for companies to minimise water consumption, in part by recycling wastewater. Membrane technology is specified in Agency guidance as a technique which they should consider because it can clean up effluent to very high standards. The water can then be reused either by the operator or sold to a neighbouring business with a need, for instance, for de-ionised water.

Another driver is the potential to reduce costs. Most food and drink companies discharge to sewer and have to pay for increasingly costly treatment at sewage works. Effluent from food processors often has a high biochemical oxygen demand - between 10-100 times stronger than sewage.

Some food firms produce as much as 10m3 of effluent per tonne of production. By reusing water, costs can also be reduced for companies which take supplies from the mains. In addition, membrane plant is very space-efficient, unlike conventional effluent treatment plant.

Two companies which engineer membrane bioreactor (MBR) treatment plant are confident that IPPC will be a boon for their business.

Steve Goodwin, director of Aquabio, said that "IPPC will definitely be a driver for industry...MBRs mean that potable quality water can be produced in a small space both cheaply and reliably."

Tony Robinson, from Wehrle Environmental, agreed. He said that another important driver is the Agency's presumption under IPPC that waste is best treated on site. Companies will have to demonstrate that a sewage works provides an equivalent level of treatment to that which could be achieved on site using BAT.

One company due to come under IPPC and which is installing an Aquabio MBR system is Golden West Foods in Corby, which supplies McDonald's fast-food eateries.

Another example is rendering firm William Forrest of Motherwell, which is installing a Wehrle MBR. Chris Bond, Forrest's environmental compliance manager, said that the reactor will "undoubtedly make a significant improvement to the plant's environmental performance and help it meet the requirements of IPPC."

Aquabio has also installed an MBR system for food company Kanes, which produces vegetables for Sainsbury's and Asda. Although Kanes' site is not regulated by IPPC, the system illustrates the advantages of the membrane technology.

The MBR system treats the wastewater in a bioreactor with ultra-filtration cross-flow membranes. Reverse osmosis and ultraviolet disinfection processes follow and the water is mixed with mains water.

Kanes' MBR takes 1,200m3 of effluent per day with an average chemical oxygen demand (COD) of 1,000mg/l and suspended solids of 310mg/l. After treatment, some 650m3 of recycled water can be returned to the process. The final water has a COD of 16mg/l and suspended solids of 4mg/l. The water is reused to wash vegetables and water crops.

John Randall, Kanes' owner, said that the company's need to expand was the main motivation. No additional discharge consent was available from the sewerage undertaker. The firm is also saving money on mains water. Dr Randall estimated that the MBR cost close to £1 million, but the investment would be paid back in six years.

Water reuse remains a thorny issue. It is possible that some food and drink businesses may dismiss it out of hand for spurious hygiene or product quality reasons. The Agency guidance says that there are likely to be opportunities for water reuse where lower water quality is required, for instance as boiler feed water or for washing.

Another potential barrier may stem from weak implementation of IPPC by the Agency.

The Environmental Industries Commission, which represents pollution control equipment suppliers, recently wrote to the Agency to express concern about the delays in permitting companies falling under the regime and low inspection rates (ENDS Report 335, pp 4-5 ).

An additional danger is that, in an attempt to deal with the permitting backlog, the Agency may be forced to rush the process and fail to push companies to justify BAT.

The EIC said: "IPPC should be a key driver for the environmental technology and services sector as mainstream industry invests to meet the requirement to employ BAT. Long delays in the implementation of IPPC, however, will lead to long delays in investment by mainstream industry in BAT."

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