As big users of water, dairy companies are affected more than most by the UK's escalating water costs. With business water rates due to increase by up to 50% over the next five years, now is an ideal time to focus on water recycling.
Water use and effluent disposal often go hand in hand and the 1996 European Commission Directive on Integrated Pollution Prevention and Control (IPPC) is a further incentive to look at reducing both. According to Neil Johnston, md of Alpheus Environmental, companies applying for IPPC permits are now obliged to undertake waste minimisation and water audits. These have to be carried out by August 31, or one year after the permit has been granted.
In certain respects the dairy industry leads the field in water and waste minimisation. Many of the new-build super dairies have incorporated the latest water-saving technologies right from the planning stage.
The huge Westbury dairy, currently run as a joint venture between dairy co-operatives Dairy Farmers of Britain, First Milk and Milk Link, is a case in point. The largest single site dairy in the UK, it can process over 2m litres of milk a day into butter, cream and skimmed milk powder. Located just outside the town of Westbury in Wiltshire, the plant was commissioned in 2002 and was designed to use zero net water from the mains, making an estimated saving of just over £1m a year.
It achieves this by the recovery, treatment and reuse of condensate formed during the milk evaporation process. The water is collected while still hot and, being low in suspended solids, still relatively clean. This enables the company to purify and then reuse it. For example, the hot water is used for clean-in-place (CIP) operations and boiler feed make up. And because the water is already at 44°C, the dairy saves on its heating costs too.
Water and waste efficiencies were also a major consideration for ice cream producer Loseley. The company was forced to move to a new production site when its factory was hit by floods in 2002. It found the perfect location in an former electronics factory on a 13.5 acre freehold site in Cwmbran, Wales, and decided to combine the production of all three of its brands -- Loseley, Thayers and Yorkshire Dales -- under one roof.
A special feature of the new factory, which came on stream in March, is its environmental approach. No waste from the factory is sent to the mains drainage. Instead, the waste water is pumped to reed beds. The beds contain microbes which feed on the mostly organic, waste material breaking it down to leave behind pure water. The process can take up to two weeks after which time the clean water is fed to the company's two lakes where it is used to cool the refrigeration compressors.
The company ensures that the cooling lakes are kept topped up to their full level by harvesting rainwater into large underground tanks. This rainwater is also used to flush the toilets on site, saving an enormous amount of water.
Few small companies working with existing factories have the opportunity or the land to recycle water on such a scale. However substantial savings can still be made simply by ensuring water efficiency is taken into account when specifying new equipment.
CIP equipment, for example, can use less water than manual cleaning. Boilers, homogenisers and cooling systems can also be improved. For example, the installation of a new Tetra Pak homogeniser at Nijjar Dairies' Acton plant has helped the company save water, energy and effluent disposal costs amounting to £11,000 a year.
The dairy, which supplies fresh milk to London catering and retailing establishments, replaced its old homogeniser, which had a flow rate of 20,000 litres an hour, with a new Tetra Alex 2 homogeniser with a flow rate of just 5,500 litres an hour.
Invensys APV, meanwhile, was able to help a dairy in Silkenborg, Denmark, owned by The Them Co-operative, cut its water bill by 15% through reusing the water from its cheese cooling operation.
For most companies, however, the first step to making savings is a basic audit of how much water is being used in the factory. After all, says Johnston, "if you haven't got the data on how much you are using you can't make decisions about where to save it"
Installation of temporary -- or better still permanent -- metering devices will help to give a true picture of overall water consumption.
Alpheus recently implemented a programme of meter installation and logging to achieve over 90% metering at a dairy where previously only 40% of all softened water was metered. Data collected revealed that significant unaccounted water use was occurring at a cooling tower. Further investigation confirmed a ball valve had failed and its repair saved the company approximately £12,000 a year.
At the same site, minor modifications costing around £3,000 to a trolley washer produced savings of £19,500 a year with a payback time of less than eight weeks.
There are other very simple actions that can be taken to ensure water minimisation. For example, most people take water for granted, so staff need to be made aware of the costs involved in its use. Appointing a water monitor to take periodic walks around the factory to identify minimisation opportunities and to fit minimising controls such as push taps, flow regulators, spray nozzles on hoses, wherever possible, cost little but can bring savings.
The next step is to look at the quality of water required for each operation to see if any water can be reused. Even consider the use of alternative water sources such as rainwater.
To encourage smaller companies to save on water bills, a new initiative -- The Big Splash -- is being launched this summer by Envirowise. Funded by the Department of Trade and Industry and Department for the Environment, Food and Rural Affairs, it will provide support that ranges from specific water use guidance and regional workshops to on-site water and waste reviews.
Envirowise says sites that have not previously had their water consumption examined can usually achieve instant savings of around 30% on water and effluent bills by implementing simple water management measures.
For companies with fewer than 250 employees, it also offers free on-site waste reviews. These are conducted by independent experts who provide practical help to evaluate each company's business activities and the current costs of wastes produced, and then identify avoidable waste and potential savings.
The Big Splash will run until March 2005 after which all the results will be compiled and the best performing companies will receive an award for their efforts! FM
Key steps to water and waste minimisation
- The introduction of clean-in-place technology can use less water and chemicals than manual cleaning.
- The recovery of the final rinse for re-use as the initial rinse in the subsequent cycle, (where hygiene standards will not be compromised) saves water.
- Recovery of chemicals for subsequent reuse (made up to strength) helps to reduce effluent strength and chemical use.
- Steam condensate can be recovered, reducing steam requirements and associated energy input.
- Pigging lines can be used for product recovery prior to cleaning, reducing effluent strength and increasing product yield.
- Trigger nozzles attached to hose pipes can prevent water use when they are left unattended.
- Double-seat mix-proof valves can be used where possible. These reduce the length of pipe requiring cleaning and consequently reduce the volume of water required for cleaning.
Loseley First with Hygienic panels
Maintaining a clean plant is crucial in the dairy sector, as products such as milk and ice cream need to be kept as sterile as possible. The very wet environment of dairy plants, however, favours the proliferation of mould and yeast spores on floors and walls. This means regular washdowns and the use of chemicals to remove or control their growth.
In the building of its advanced facility for the production of ice cream in Cwmbran, south Wales, Loseley chose to incorporate innovative materials for minimising bacterial growth as an additional protection to the normal rigorous cleaning routines. Among these is a new antibacterial coated steel called Assure, developed jointly by Corus and Microban International for wall and ceiling applications.
Corus and Microban have developed a way to incorporate the antibacterial protection within the steel panel's paint or film coating. This means it keeps on working in between cleans, even if the coating surface is abraded.
Corus says it works by neutralising the capacity of bacteria such as Salmonella, E.coli and Listeria monocytogenes to function, grow and reproduce.
Loseley md Tim Wilson says: "The versatility of the product was very appealing as it meant we could use it as a casing for the blast tunnels operating at -40°C and also on the walls in the main production hall."
There is a growing trend for the inclusion of antimicrobials in wall and equipment surfaces in food factories. But the trend has raised concerns from some industry bodies that it could lead to complacency over traditional cleaning regimes.
The European Hygienic Engineering Design Group (EHEDG), for example, warns that the use of surfaces impregnated with antimicrobial biocide could give a false sense of security and undermine traditional surface cleaning and disinfection practices.
It also calls for standardised testing to assess the efficacy of such materials, as this currently does not exist. Such investigations are necessary, it says, because typically no one biocide is active against all bacteria, yeasts and moulds.