A drain on resources

Posted on 18 Aug 2008 by The Manufacturer

Water may be an overlooked resource, but we can no longer afford to let so much money go down the drain. Debbie Giggle looks at some innovative ways of recovering and recycling waste water, and how some companies even harness it to generate power

At a time when oil prices are soaring and electricity bills are making painful reading, it may seem rather daft to be talking about the cost of water. But in many industries, particularly the food and drink sector, the cost of buying water and disposing of effluent within Environment Agency limits is far more than just a drop in the ocean.

Manufacturers on average spend 4.43 per cent of turnover on water-related costs, and for food and drink manufacturers the figure can be almost eight per cent. Any reduction could be crucial at a time when other utilities costs remain obstinately beyond our control.

And cost, of course, is just one issue. Water management is a key element of sustainability, figuring prominently in CSR strategy.

In January 2008 the Federation House Commitment, jointly developed by the Food and Drink Federation and Envirowise was signed by an initial tranche of 21 leading UK food and drink manufacturers. Signatories have pledged to reduce their water use (outside of that embedded in products) by 20 per cent by the year 2020. Once the initiative is rolled out the companies could collectively save around 140 million litres of water a day – equivalent to 56 Olympic-size swimming pools – and save around £60 million between them on water bills.

Greg Blais, principal wastewater consultant, URS Corporation, commented: “Water has been long overlooked as a resource, but the sustainability movement and the increasing pressure of low cost economies has brought water management to the forefront.

“Manufacturers of ten feel they lack waste water handling knowledge, and perceive improvements as technically complex and expensive. They also frequently underestimate the magnitude of the efficiencies and cost savings that can be made.

“In reality, manufacturers can work at a number of different levels to optimise their water usage – often without capital expenditure. The first step is to understand water usage by identifying individual water processes. Once this is established, employee awareness of water conservation alone has the potential to deliver a saving of one and two per cent of total manufacturing costs – even without any additional initiative to recycle, re-use or recover energy.”

For Uniq Prepared Foods (one of the Federation House Commitment signatories), changes in culture have had an immediate impact. Mark Carter, environment manager, explained: “Water conservation is something we’ve been on top of for years. The amount we can recycle has limitations because so much of our process water has to be portable. But we recover and reuse water in our steam boilers, and recycle and retreat waste water for cooling processes – for example, after pasteurisation.

“The biggest reductions we’ve made, however, have been in the last two years, when we began involving the whole workforce. To create a structure for this we identified an environmental correspondent at each of our sites and they took part in training for environmental impact auditing.

“The environmental correspondents then canvassed for volunteer ‘green teams’ at their respective sites, and passed on the training. In this way each department on each site was able to carry out its own environmental impact audit, within which water consumption and effluent levels were key factors. “I’ve been a water technologist for 20 years and some might say that, with experience already available, you should dictate ways of improving. But that’s not what we wanted. Our aim was to involve everyone so that people would have the chance to realise the impacts for themselves and generate changes that would really make a difference.

“I’ve been thrilled with the results actually. Some great ideas have come out of this initiative. For example, in one department a hot water hose was previously used to melt the ice in which fish is packed. Instead of running the hot water hose almost all day as had been the case before, the team came up with a way of containing the ice in one area where it is melted by a hot water coil using recirculated water.

“With this and many other changes in ways of working, and a greater awareness across the company, water consumption was reduced last year by about 17 per cent compared to the year before.”

From the point of view of the Federation House pledge, the timing wasn’t ideal for Uniq. Last year was the base year against which reductions will be measured. So having already reduced usage by 17 per cent, Uniq is now embarking on a project to find a further 20 per cent reduction by 2020.

“I was thinking that, after such an excellent year, the 20 per cent target would prove very tough,” commented Carter. “But in the latest figures I’ve received for 2008, one of our sites has reduced their water usage by 15 per cent in the first quarter. So I’m now more confident of delivering these further reductions by 2020.”

Walkers, the potato processing company, has also worked to change the attitude and behaviour of factory staff regarding water conservation. This is part of a two-pronged strategy. First the company developed a range of engineering solutions, including a starch recovery programme for use in potato fluming and washing. This has enabled 400 million litres of water to be saved each year.

Alongside this, the company decided to measure water use and report the data by shift to show variations in performance. Leak busters and water champions were assigned to each site and the best performing teams are rewarded and recognised by the company for their contribution towards sustainability.

Overall, the strategy led to water consumption falling from 17.67 to 9.24 litres per kilogram of potatoes processed at Walkers’ Bursom site and from 13.65 to 6.38 litres per kilogram at its Leycroft site.

In addition to the harnessing of employee involvement, there are a range of technology ‘fixes’ for manufacturers. Blais explained: “At the simplest this could include measures such as checking all flow meters and pressure reducers to check that you’re using the correct amount of flow. Water controls, such as efficient spray nozzles with automatic shutoff, water meters and pressure reducers can also be installed. “The next step would be to look for ways of reusing water – using effluent water from one process as a source for another process. “Another cost reduction opportunity is to treat wastewater prior to discharge, to lower the cost for disposal.

After treatment there might be additional opportunities to recycle this cleaner water within your processes. “For companies where there is a high degree of carbon-based matter in the effluent stream, there may be opportunities to recover energy using anaerobic digestion. Potentially, this is feasible for facilities that create more than 10,000 pounds per day COD (chemical oxygen demand).”

This technology is proving highly beneficial for McCain Foods. At its Whittlesey factory the company has built a 77,000 square metre anaerobic lagoon. Starchy water, in which potatoes are transported around the factory, is piped into the lagoon where starch rises to the surface. The methane gas released is contained under a giant cover and drawn off to power the site’s boilers and an electrical generator.

The anaerobic lagoon is expected to generate around 10 per cent of the Whittlesey plant’s electricity. A further 60 per cent is generated by three on-site wind turbines.

Bill Bartlett, corporate affairs director, said: “Prior to the installation of the anaerobic digester we used a bulk fermenter to process waste water to meet Environment Agency discharge requirements. The plant was 25 years old, however, and needed replacement. We have on-site generation experience within our own engineering team, and in other parts of the McCain Group we had experience of anaerobic digestion technology. To carry out the project, these inter-company experts joined our in-house team, and we worked with an external civil engineering firm and a design consultancy. It was a big project, taking about six months in all – four months to dig out, and another two months to line. To give you some idea of the size of the lagoon, it is about the size of two football pitches and took 42 days to fill.

“The rapidly increasing costs of energy make a project like this even more viable than it would have been a few years ago, and reduce our levels of risk. Most importantly, we are acutely aware of our corporate and social responsibilities. The lagoon, like the wind turbines, is a key part of our CSR strategy. As well as enabling us to generate renewable energy, anaerobic digestion treats the waste water more thoroughly so that water leaves the process cleaner and requiring less treatment after disposal.”

So what are the main challenges relating to water management projects?

“There are almost too many ways of tackling the problem,” Carter commented. “The challenge is deciding which solutions to implement first. Our employees are already very conversant with lean principles, so we used techniques such as the wastes hierarchy to drive the project.”

“The most difficult decisions revolved around how big the lagoon needed to be to cater for existing and future production requirements,” Barlett concluded. “Even though this involved a £4.5 million capital expenditure, the cost-justification was not the challenge.”

Water has, for so many years, been the overlooked resource, but in today’s economic climate, stopping it going down the drain really can pay.