The bottom line is important for any company. Efficient use of resources is essential in any sector, but the increasing costs of water and wastewater management mean that an inadequate water strategy can lead to businesses effectively pouring money down the drain. Kalpesh Shah, industrial sales manager at Veolia Water Technologies explains how companies looking to increase profit while generating positive publicity can start by analysing the total cost and environmental impact of their water use, and implement solutions to reduce consumption.
Where water is concerned, there is a perception that sewer discharge costs nothing and there is little you can do with wastewater once it has been treated and cleaned in line with industry regulations. Unfortunately, nothing could be further from the truth, and businesses need to change how they see water. Delivery of mains water costs £1 per cubic metre, and it typically costs twice as much to discharge the equivalent volume, meaning that reusing and recycling wastewater can save up to £3 per cubic metre, not to mention the potential for converting waste to energy to be used elsewhere in a facility.
Responsibilities and regulations
There are considerable costs associated with water processing – whether it’s before or after use – and making the best use of this paid-for resource can make a significant difference to profit margins. All industries have a responsibility to make sure that their trade effluent meets regulatory requirements, but companies should be encouraged to look beyond statutory requirements to see how, once they’ve paid for it and treated it, water can be used and re-used to best effect before disposal. This can not only reduce overall consumption and waste costs, it can also potentially provide valuable by-products for use in other areas of the business.
Under the Water Industry Act 1991, trade effluent is defined as any water discharged as a result of cleaning, cooling or production and other trade activities. The specific regulations for any business will be outlined in a trade effluent consent obtained from the sewerage undertaker responsible for your water, such as Anglian Water or Thames Water.
The trade effluent consent will vary with each local water authority, but will typically set out the following conditions:
- maximum quantity and rate of discharge;
- temperature limits and permitted pH range;
- limits on fat, oil and grease, chemical oxygen demand, suspended solids, sulphate levels and other chemical compounds;
- the point of sewer system entry;
- sampling and monitoring specifications.
Restrictions
There are currently no restrictions for most customers on the amount of water that can be drawn from the network or returned to the drain: you simply pay for the amount you use or discharge. However, we are now beginning to see the emergence of limits for industrial water use to try to manage demand. Although penalties for excess use are currently only financial, if demand continues to exceed supply, the situation may arise in the future whereby water supplies are cut off once water limits are reached. This would have a far more significant impact, leading to temporary shutdown of manufacturing processes and significantly harming profitability.
If you’re in an industry that cannot operate without water, now is the time to consider how you can improve water re-use and recycling to reduce consumption and disposal costs before they start to have an impact on your bottom line.
Reduce
Reducing water consumption is the most direct way to save money, and an internal audit of processes can often reveal examples of inefficient or wasteful water use, such as leaving taps or hoses running unnecessarily during washing processes. Regular water monitoring can help highlight leaks or unexplained water use in your facility. If your trade activities primarily occur during the daytime, for example, you should expect to see your water consumption drop almost to zero overnight.
Real-time monitoring and automated control offer a more robust approach, and companies can work with a water technology supplier to implement data-driven water saving solutions. Immediate access to up-to-date figures drives efficient operating conditions, maximising equipment lifecycles, reducing maintenance and demonstrating regulatory compliance. Real-time monitoring is particularly well suited to systems using water for heat exchange processes – which are subject to corrosion, deposits, fouling and microbiological growth – and can support adaptive chemical dosing, responding to fluctuations in the water’s make-up to achieve peak efficiency and performance, and optimal water use.
Re-use and recycle
Re-using and recycling wastewater can offer even more significant savings, due to the high cost of discharging wastewater. There is reluctance within some industries to re-use and recycle water, for example because of nervousness about using treated wastewater to clean a tank involved in food production. But greater understanding of how efficient and effective wastewater treatment can be should alleviate any concerns and overcome such objections. It is easy to forget that every drop of mains water has at some stage been re-used and recycled. Sometimes all it takes is a fresh perspective to ask the right questions.
In many cases, specific wastewater treatment technology is needed before wastewater can be re-used in an industrial process. Water recovery systems involving filtration, reverse osmosis (RO) and clarification prevent hundreds of thousands of litres of wastewater entering the sewerage system, reducing initial water consumption and offering significant financial savings. Recycling is vital in water-intensive processes, such as renal dialysis, which typically uses around 22,000 litres of ultra-pure water annually for each patient.
Reject water from the RO system can be recovered in a separate process, with the permeate quality often significantly better than mains water. In the pharmaceutical industry, recalcitrant wastewater can be concentrated by evaporation, and the recovered distillate used in a variety of processes such as boilers or cooling towers. Alternatively, recovered water from an RO unit can be recycled back to a plant inlet to begin the purification cycle once again as raw water.
Recover resources
Part of the problem lies in language. It is difficult not to think of “wastewater” as unusable and worthless. However, wastewater can be a very valuable resource, particularly in the food and beverage industry. For example, wastewater from dairies and distilleries could be passed through an anaerobic bioreactor to produce biogas, which could be returned to the grid or back to the plant to supply energy – up to 80% of the electrical needs of some distilleries. A second by-product, biomass, could be reused as fuel, or as land fertiliser on farms.
Return on investment
This type of innovative water use can have a significant positive impact on a balance sheet, but it requires a new way of thinking and investment in new technologies and equipment to gain the benefits. For many sectors, the perceived “slow” return on investment (ROI) can be a stumbling block, because many boards of directors and shareholders demand an ROI within the same financial cycle. However, by looking at water treatment and recycling as a slightly longer term investment – generally achieving a return over two years – companies can help to safeguard their future water supplies against any imposed limits and reduce their environmental impact for many years to come.
Putting theory into practice
The following case studies demonstrate how the principles described here work to best advantage when applied to particular industry sectors.
Reusing water in energy plants
A boiler producing steam to drive a 43 MWe gas turbine required 100,000 litres of high purity water per day. The rainwater and surface run-off at the energy plant was combined with other wastewater, treated and then discharged, which was proving to be expensive. The energy supplier approached Veolia Water Technologies to help treat and recover their wastewater for boiler use. The company supplied a membrane based water purification system to recover water, using RO to remove around 97% of dissolved salts, followed by continuous electro-deionisation).
Results
• Recovery of 5,000 litres per hour of high purity water.
Quick return on wastewater investment in the pharmaceutical sector
A pharmaceutical client’s research and development facility was sending approximately 25% of its supplied raw water to the drain from an RO process. Veolia Water Technologies installed a recovery RO system adjacent to the two production RO units to recycle and re-use over 50% of the RO concentrate and subsequently reduce operating costs.
Results
• Operating water recovery increased from 75 to 87.5%;
• 20,000,000 litres of water recovered annually;
• £32,000 in financial savings annually.
Cutting waste in the food and beverage industry
Dairy operations – involving the processing and packaging up to one billion litres of milk a year – are energy and water intensive procedures, producing hundreds of thousands of litres of high strength wastewater every day. A dairy client approached Veolia Water Technologies to find solutions to energy and water reductions for its new facility. The company designed and supplied a waste-to-energy facility that generated biogas and biomass through an anaerobic membrane bioreactor.
Results
• 800,000 litres of wastewater processed daily;
• Chemical oxygen demand in wastewater reduced by 99%;
• 600 to 700 litres of biogas generated per kilogram of COD, and converted to energy for dairy use or returned to the National Grid;
• Nutrient-rich biomass harvested and used as a fertiliser substitute by local famers as part of a circular economy.
Summary: Rethinking the approach to water management
It is hard to deny the strong business and environmental arguments for changing industry’s approach to water management. Ignoring water consumption is no longer a viable option, and industries can benefit from implementing technology to achieve water and energy savings, as well as reaping financial benefits.
The time has come to rethink water.