Boreholes can help manufacturers safeguard their production processes from potential water shortages, explains Gary Sewell.
04 February 2019 | Gary Sewell
A growing gap between supply and demand is raising water scarcity concerns. Against limited supply, mega-trends such as population growth, urbanisation and development are driving up demand. The local authority water supply upon which manufacturing facilities rely must also serve local public and domestic needs.
In just two decades' time, the minimum amount of water required to serve those needs could reach 4,000 megalitres a day (ML/d) requiring an additional 2,000 Olympic-size swimming pools'worth of water each day.
Sustainability is a growing concern and manufacturers are under scrutiny from end customers and supply chain partners to adhere to ethical production standards.
A 2017 study by Unilever found that a third of consumers bought from brands based on their social and environmental impact and that an estimated 966 billion opportunity exists for brands that make their sustainability credentials clear.
1. Manage your demand
Boreholes provide a means for manufacturers to build an ethical reputation, as they are cost-efficient, sustainable and independent from local water authorities.
Once a borehole source has been identified, a water treatment provider will be required to carry out an analysis of the water quality. A full mineral analysis will reveal any contaminants in the water such as pesticides, iron content, calcium carbonate, suspended solids, organics and microbial activity.
The results of the analysis will indicate the treatment methods required to make the borehole water usable. This could require filtration through mechanical removal of solids.
Depending on the mineral content, the water treatment provider will make recommendations for further treatment, which could include microfiltration through ultrafiltration or reverse osmosis.
Once the water is of a quality that is free of suspended solids, microbial activity can be treated. Chlorine dioxide is commonly used to treat the water and ensures that it is free from bacteria and clean enough to use in the manufacturing process.
2. Analyse monthly
Following the installation of this turnkey system by the water treatment provider, a regular programme of monitoring and servicing of the filtration and pre-treatment equipment must begin.
This should include monthly analysis of chlorine dioxide units with chlorine dioxide readings taken at different points around the site with microbial testing also taking place on a regular basis.
3. Save money
Borehole-sourced water is by no means 'free' when we consider the cost of implementing the water treatment process required to bring the water to a usable quality. Yet once the required water treatment and recovery processes are in place, manufacturers typically see a full return on investment within two years, with running costs at just a third of the cost of sourcing water from the local water authority.
4. Overcome water limits
A facility could be sourcing its limit of 600 cubic metres of water a day from its local water authority. If the manufacturing process is likely to demand more than that daily limit, not only can you reduce the amount you are sourcing by switching to a borehole supply, you could also recycle that borehole water if it is being used as a process.
5. Optimise the cooling tower
Roughly one-third of treated borehole water that feeds a site's cooling towers will evaporate in the cooling tower and another third will be sent to the effluent plant as waste water. Optimising the cooling tower with a bleed recovery system that re-treats the water through reverse osmosis can significantly reduce the amount of water sent to the drain by reusing the recycled water to feed the cooling towers water make up.
6. Recover water
By feeding cooling towers and even steam boilers with borehole water and implementing a bleed recovery system to recycle the effluent water generated by either piece of equipment, manufacturers can significantly reduce their reliance on a scarce water resource while generating substantial cost savings.
You wouldn't think the dark depths of an antiquated, unused borehole could have the potential to unlock significant cost savings and more sustainable means of energy consumption for your manufacturing facility. The reality is that this is entirely plausible with the right water treatment and water-saving technologies.
Gary Sewell is general manager at Clearwater