Special Edition: Plant Efficiency
Consultant reveals the secrets behind water efficiency
That is the claim of Stuart Ballinger, a water specialist at AEA Technology, which runs the Rippleffect water efficiency programme on behalf of WRAP in the UK.
In an interview for the second part of a special edition on plant efficiency, Ballinger explained how food and drink processors can achieve big savings on a budget.
The first stage is to map water usage to establish how much is coming in, how much is going out and where it is being used.
Using a water balance technique, companies can establish whether what is coming in from the mains supply or other sources matches the amount coming out through product, effluent and evaporation.
Ballinger said there is no need to go overboard at this stage and that accounting for 90 per cent of water use is a pretty good start.
Once the measurements have been taken, the next step is to do the accounting to check that outputs match inputs. If there is a major discrepancy that could suggest that there are leaks that need to be dealt with.
The data from the measurement stage will also give companies insight into areas of highest usage so they can draw up an action plan for water reduction.
At a food and drink plant, Ballinger said that, generally speaking, processing and equipment cleaning accounts for more than half of water usage with other significant elements being cooling towers and the boiler house. Comparatively speaking, office areas only account for a tiny amount of water.
Relative usage varies significantly depending on the manufacturer so for example, a meat processor uses large amounts of water for cleaning while a soft drinks manufacturer sees a lot of water going into products.
Giving an insight into typical water saving opportunities in food and drink, Ballinger said there is a lot of quick wins to be had through good maintenance. By ensuring flow rates are correct, for example, unnecessary water use can be avoided.
Other simple steps include brushing first when cleaning up work areas. This can significantly reduce the amount of hosing down that is needed.
When it comes to identifying water saving steps, Ballinger underlined the importance of dialogue with those who work on the processing lines and who therefore know them best.
This can be a great source of line specific water reduction ideas. For example, on a vegetable processing line it may be discovered that installing a simple Passive InfraRed sensor (PRI) could cut water use significantly by stopping sprays when vegetables are no longer passing down the conveyor belt.
Ballinger said when introducing a water efficiency programme, project leaders should start with easy win opportunities like these. They can report back to senior management to demonstrate savings and pave the way for presenting a convincing case for capital investment.
The water consultant said it is crucial that at the reporting stage, the cost of water is properly accounted for. Management should be aware that saving one cubic meter of water does not just add up to the initial cost of the water. The variable costs of treating that water, such as softening, have to be included along with the energy cost of pumping the water around the plant.
If programme champions have got the support of management for capital investment then there are opportunities for some really big savings. With some investment in more water efficient technologies like clean-in-place systems that sit within machines to clean equipment, Ballinger said a 50 per cent reduction in water bills can be achieved.
This can be increased to as much as 60 to 90 per cent with investment in membrane treatment equipment that allows water to be reused. Ballinger claimed that as the cost of the technology has come down and the cost of water and effluent has gone up, investment in membrane technology can now deliver a return on investment within 3 years.
For companies with water availability issues or high costs related to disposal of effluent, a membrane filtration system that allows for 80 – 90 per cent of water to be reused can be an attractive solution. This was the case for G’s Beetroot in East Anglia, the UK, which installed a membrane treatment system to combat a water availability issue and high effluent costs related to the color and composition of its effluent.
With some observers suggesting water could be for the 21st century what oil was for the 20th, it is important for companies to take a much closer look at their water use.