Window cleaning van fleets have the option to use either onboard purification systems, or utilise a central filling hub to refill their vans that only contain tanks. There are two options when running an operation which uses a central filling hub. Either a large scale water treatment system, which pure water can be stored into to refill vans, or treating raw water as it is pulled from a mains supply point.
When pulling water directly from source to fill storage tanks, a deionisation resin stage that is targeted towards hard water areas is utilised to withstand high TDS levels. This is due to the lack of filtration before the treatment process.
Typically, some pre filtration is used before the resin filled pressure vessel to remove particles and organics from the feed water. The effect of this is a prolonged service life for the resin, as it does not have to deal with as high a concentration of contaminants.