Water treatment equipment

Buying guide

The water quality a method demands is the figure that settles the purchase, and everything else follows from it. A buffer for cell culture, a mobile phase for HPLC, a rinse for glassware and a feed for a steam generator are four different specifications, usually written as resistivity in megohm-centimetres, total organic carbon in parts per billion, and bacterial or endotoxin limits. Match the output grade to the most demanding method on the bench, not to an average, because a system sized for Type III water cannot be upgraded to Type I by changing a cartridge. Feed water matters as much as the target: a unit fed from a hard municipal supply works harder than one fed from already-softened water, and the running cost of consumables tracks that difference.

What to verify on a used unit

Condition on a second-hand purifier is mostly about what the previous owner ran through it. UV lamps and quartz sleeves have a rated service life and dim long before they fail outright, so a used ultraviolet system is worth more with lamp hours documented than without. Reverse osmosis membranes foul and ion exchange resins exhaust, and neither failure is visible from the outside, so ask what the last output reading was and when the consumables were changed. The pressure vessels, pumps and plumbing are the parts that carry real value on a used system; the replaceable media is expected to be replaced. Any used weighing or metering electronics benefit from a recalibration check before the unit is relied on for a validated method.

Where the price band sits depends entirely on scale. A point-of-use cartridge and a plant feeding an entire floor both appear under this heading, which is why the range is as wide as it is. Prices run from EUR 1 to EUR 139.943 across the catalogue. Benchtop polishing units and filtration housings occupy the lower and middle of that band; multi-stage reverse osmosis and ion exchange plant sit at the top. Millipore, Yamato, Acros Organics, CLiR, Thermo Scientific are the names that recur most often in the listings, and their presence affects what a buyer can budget for, since a widely sold model is easier to compare on price and easier to find replacement media for. Used and refurbished systems are listed below the cost of equivalent new equipment, and for buyers whose output grade is met by an older generation that difference can be substantial. What fits a given budget is less about the headline price than about the consumables the unit will consume over its working life, so read the running cost into any system offered for sale before comparing two on sticker alone.

Types of Water treatment equipment

Ultraviolet systems

Among the listings that specify a type, ultraviolet systems are the most numerous. They pass water through a chamber lit by a UV lamp at 254 nanometres, which inactivates bacteria and breaks down organic molecules without adding anything to the water. In a laboratory polishing loop a 185-nanometre lamp is often used instead, to reduce total organic carbon for sensitive work. These units are chosen where bacterial and endotoxin control matters, so they are standard in cell culture and in microbiology, and they also support molecular biology benches that need low-organic water for sensitive assays. The lamp and quartz sleeve are the wearing parts, and output falls off as the lamp ages well before it stops lighting.

Water filtration equipment

Filtration equipment removes particulates, colloids and in some configurations dissolved organics by passing water through a membrane or a packed medium. The category covers cartridge housings, depth filters and activated-carbon beds, each separating a different size fraction. Depth and particulate filters protect downstream membranes and columns from fouling, which is why they usually sit upstream of a reverse osmosis or ion exchange stage rather than acting alone. Activated carbon removes chlorine and organics that would otherwise damage an RO membrane. In life sciences work these filters feed the clean-water stages that supply protein purification and electrophoresis buffers, where particulate carryover would compromise a result. The housings carry the value; the cartridges are consumable and sized by micron rating and flow.

Ion exchange equipment

Ion exchange equipment removes dissolved ionic contaminants by passing water over resin beds that swap unwanted ions for hydrogen and hydroxyl. A mixed-bed polisher brings deionised water close to the theoretical maximum resistivity, which is why ion exchange is the final stage in most Type I systems. Cation and anion beds can also run separately where a specific ion has to be targeted. The resin exhausts in service and is either regenerated with acid and base or replaced as a cartridge, and an exhausted bed lets ions through silently, so output resistivity is the reading that tells a buyer where the resin stands. Deionised water from these systems feeds gravimetric analysis and trace work in genomics and proteomics, where a dissolved ion would register as background.

Reverse osmosis equipment

Reverse osmosis equipment forces feed water through a semi-permeable membrane under pressure, rejecting the large majority of dissolved salts, organics and microorganisms in a single stage. It is the workhorse pre-treatment that sits ahead of ion exchange and UV polishing, producing Type II or Type III water directly and the bulk feed for a Type I loop. An RO system needs a pump, a pressure vessel and good pre-filtration, and it rejects a share of its feed as concentrate, so recovery rate and feed pressure are specifications a buyer reads carefully. Reverse osmosis supplies the volume of purified water that biomanufacturing and bioprocessing consume, and it feeds the clean-water demand of a busy cell culture suite. The membrane fouls over time and is the part most likely to need replacement on a used unit.