Smith Engineering / Water Treatment / Deionization

Exchange Deionization (DI) Systems

Exchange DI tanks use cation and anion resins to remove ionic impurities from water. These systems can be designed to use one or more of the following technologies:

  • Carbon Filtration
  • U.V. disinfection and TOC reduction
  • Ultrafiltration
  • Microfiltration
  • Reverse Osmosis
  • Ozonation
  • Sanitary plumbing designs
  • Semi-Automatic system treatment

The exchange DI service allows you to have deionized water without the use of concentrated acids or bases.

  • Exchange tanks
  • Dedicated tanks
  • Two-bed deionizers
  • Mixed-bed deionizers
  • Weakbase deionizers
  • Reverse Osmosis pre-treatment
  • Standby tanks
  • Automatic switchover systems
  • Automated Exchange Notification
  • Piping; PVC, CPVC, Sani-Tech, Polypropylene, Teflon, Halar, PVDF and stainless steel

Our exchange DI systems are custom designed to meet the following water requirements (partial list):

  • Resistivity-other ionic standards (ohms-cm)
  • TOC (Total Organic Carbon) (ppb)
  • Ultrafiltration
  • Silica (ppb)
  • Particulates (Particles per liter)
  • Bacteria (CFU/ml)
  • Endotoxins (EU/ml)
  • Trace metals
DI Exchange Tank Service

In-House Deionization (DI) Systems

In-house deionization systems allow our customers to regenerate their own tanks. These systems can be designed to meet the same water quality requirements as standard exchange deionization systems. Chemicals such as HCI and NaOH are used to regenerate the cation and anion resins.

The in-house systems offer operating cost savings over exchange DI systems. In-house systems are custom designed to meet individual safety requirements and also offer the following options:

  • Manual semi-automatic and automatic systems
  • Single, duplexed and multiple unit systems
  • Softening, deionizing, dealkalization and metal removal
  • Reverse Osmosis pre-treatment
  • Waste stream treatment and neutralization
  • Custom skids
  • Custom system controls (such as PLCs and display panels)

Closed Loop Systems

Closed loop systems can use exchange and in-house deionization to deionize your water. Closed loop systems can be designed to meet the same water quality requirements as standard exchange deionization systems. These systems purify your water for use, return the process water for purification and reuse the water. Closed loop systems become cost effective if the used or returned water quality is purer than the incoming city water quality. These systems can also become effective for some specific waste treatment considerations. Operating costs are based on your ongoing process conditions.

Basic system options:
  • Flow rates up to 500 GPM
  • On-site cation, anion and chelate resins regeneration
  • In-line heaters and heat exchangers
  • Hot systems
  • Open frame skids and custom skids (upon request)
  • Reverse osmosis systems
  • Enclosed plastic and metal cabinets
  • Smith AquaSystem recirculating deionizer for printed circuit board assembly
  • Custom controls (such as PLCs and display panels

Closed loop equipment applications:

Printed circuit board wash – High temp or Automated


Smith-Link™ is a replacement system for remote monitoring and alarm signaling directly to Smith Engineering DI exchange schedulers. We can monitor incoming alarms and values for tank exchanges when the set points for that system have been exceeded. Smith-Link™ allows us to dispatch the exchange trucks more efficiently so the customer spends less time monitoring the system. This is a win, win situation for both Smith Engineering and the customer.

Smith Link