A bridge over troubled water
02 January 2018
Frank Burn, field based technical manager of Christeyns, discusses the impact of water quality on wash outcomes in the commercial laundry arena
In the UK the water quality is generally good but none the less when looking at a new project our team would always test for impurities and hardness as a matter of course. Hard water, typically higher than 3 °Clarke or 43ppm, reduces the effectiveness of the detergent system, causing poor soil, stain removal and reducing whiteness. Iron levels greater than 0.01ppm reduce the effectiveness of the bleaching system, resulting in poor stain removal and increased textile chemical damage.
Both of these can be overcome with the introduction of additional chemicals. However, this approach often increases effluent COD and may result in consent limit breaches. Collectively, they significantly increase ongoing processing costs and do not address the root causes.
In commercial laundries, whilst efficiency is paramount, the challenge is keeping the quality of the cleaning performance at a very high standard as well as protecting our environment.
Christeyns has invested significantly over a long period into how to best achieve the most energy efficient laundry system whilst maintaining excellent standards. A process which is on-going.
Through laundry chemical developments and research into energy systems, Christeyns has been able to assist many commercial laundries achieve outstanding wash results, whilst meeting their water and energy reduction targets and reducing running costs.
Monitoring is key
Left unchecked, hard water and high iron levels can significantly increase the process gap. With production costs typically accounting for 40% - 50% of turnover, depending on type and size of the laundry, effective management of the process gap is critical. Water, energy, chemicals, labour and engineering costs all increase. Management of water hardness and iron is therefore extremely important, as both have potential to erode profit margin.
Christeyns account managers will always check water hardness and iron levels during a visit, but spot checks every few weeks are not enough. Checks are simple, taking only a few minutes, so checking the levels daily is something the laundry can do to keep on top of things. Christeyns can help establish methodology and provide training to support its customers in these checks.
Water softness is usually achieved with base exchange softeners. They need to have sufficient capacity to meet demand and be set up according to local water hardness conditions.
Sources of iron
Iron is typically introduced into process water from three sources: 1) Water supply 2) Corroded pipework 3) Steam (corroded pipework).
Town mains water usually has low iron levels, whereas bore hole water can have high levels along with other impurities which can negatively impact chemistry performance and wash quality. Christeyns can test bore hole water for these wide range of impurities and if found, then these should be treated to avoid short term soil and stain removal problems and long-term deterioration of whiteness.
Corroded pipework and storage tanks introduce iron into the water supply. Normally aged, the tank and pipes have usually come to the end of their useful working life. There are no simple solutions to overcome this, the obvious option being the replacement of any affected pipework or components, lining of tanks is also sometimes possible.
If untreated, steam that condenses back into water can also cause corrosion of steel pipework. Following an overnight or weekend shut down, condensed steam carries iron into the wash process and it can take several hours in a tunnel washer before it reduces to safer levels. Because washer extractors introduce steam infrequently, condensing is common throughout shut down and production periods, high iron levels are therefore more likely.
Adding traps helps to carry condensed steam to drain to help reduce or avoid corrosion. Neutralising Amines can also be added to the steam boiler to protect steam and condensate pipes against corrosion.
Although these corrective actions are costly, when compared with premature replacement of textiles, additional production costs and lost business, these options put the launderer in a stronger, long term position to maintain consistent wash quality and processing costs and should not, therefore, be dismissed lightly.