The processing benefits that are at the heart of wastewater treatment systems manufactured by Lancy Technology, part of NHE, can be applied to a long list of manufacturing applications. The recovery of rinse water by ion exchange, to limit the size of zero discharge evaporation systems, is a typical example. As with many Lancy Technology installations, facilities which achieve targeted results in this context are centred on the use of selected modular components. Operating together, they provide clear-cut performance and environmental advantages.
“In such an installation, we would see re-circulated rinses from process tanks flowing to a rinse water collection facility via a series of pumping stations,” explains Keith Allen, Business Development Manager at Lancy Technology. “In many cases, we would utilise a pre-filter to remove suspended solids ahead of an organic absorber unit which would contain specialist, non-regenerable resin. Because this needs to be changed very infrequently, there is a clear advantage from a maintenance perspective.”
Typically, two sets of pressure vessels would comprise the rinse water re-circulation DI plant with one containing cation and the other anion exchange media, using a high performance macro-reticular resin. As the rinse water passes through the cation vessel, positively-charged ions exchange with hydrogen on the resin before it is transferred to the anion vessel where the negatively-charged ions then exchange with resin’s hydroxyl ions. “As a result,” continues Keith Allen, “the water leaves the anion exchanger free from cations and anions as de-ionised water.”
Installations such as this need to accommodate the fact that both cation and anion resins have a limited exchange capacity in terms of their ability to remove the charged ions. “Regeneration to restore this capability is therefore a central part of a typical Lancy Technology design of this type and is achieved through the use of hydrochloric acid for the cation and caustic soda for the anion elements,” continues Keith Allen. “This is then followed by a rinse of the vessels with DI water with any waste from the regeneration itself treated in the effluent treatment plant.”
He points out that DI water produced is directed back to the process lines with a small bleed flow to a DI holding tank to complete the treatment and regeneration cycle. The regeneration effluent, and other waste, can be collected through a pH control tank where it is optimised for the final stage of treatment in the vacuum evaporator. This efficiently reduces and concentrates the volume of liquid required for off-site disposal.
“The key factor that this typical installation illustrates is our ability to tailor each project to precise operational requirements,” adds Keith Allen. “Each of the modular elements described performs a specific function relating to a given installation and variable elements, such as volume and material solution involved, would dictate the precise specification of each system component.
“By working closely with every customer, we deliver tailor-made solutions each time to ensure that installations of this type – both in the UK and, indeed, worldwide – deliver both operational performance benefits and help our customers optimise their environmental credentials.”