THE HYDROMAX ULTRA-PURE WATER SYSTEM PROCESS

Every aspect of a water system used for production of ultra-pure water is critical in order for the system to be capable of consistently producing pure water that meets the desired water quality standard. Proper system design, component and materials of construction selection and fabrication, installation and preventative maintenance practices all contribute significantly to the long-term reliability and cost effectiveness of the ultra-pure water system.

It is important to consult with a HydroMax design engineer when first considering a new ultra-pure water system. As part of your design-build team, a HydroMax engineer will investigate your facility’s ultra-pure water requirements, feed water chemistry and available utilities. HydroMax will then provide a recommended system design and answer questions concerning water quality, recommended water production and distribution flow rates, proper distribution piping system sizing and configuration and expected future maintenance requirements. Only after the HydroMax design satisfies all of your requirements, system fabrication will begin.

The following is a very basic HydroMax ultra-pure water system process description that meets many of the typical applications that we encounter. Of course if you have special requirements, HydroMax can easily customize the system for superior performance in any application.

1. Water supplied by the local water utility or private water pumping equipment enters your building and travels though a pipe to the water equipment room.
2. The raw water is filtered and conditioned by HydroMax equipment in preparation for the first stage of purification. This stage removes objectionable constituents in the water such as sediment, chlorine, and detrimental minerals and reduces the chance of bacterial contamination of the system. Selection of proper filtration, conditioning and treatment technologies is critical for reducing system maintenance and permitting the ultra-pure water system to consistently produce acceptable water quality.
3. Once the raw water is properly prepared, it enters the HydroMax reverse osmosis unit. The reverse osmosis system removes the ionic and organic contaminants from the raw water to very low levels. The reverse osmosis membrane also acts as a mechanical filter, effectively removing essentially all particulate matter. The reverse osmosis system’s purified water production rate is limited by the number and size of membrane modules provided on the unit and by its pressure pump’s capability. The reverse osmosis system is a critical component in the overall Ultra-Pure water system design. The unit should be complete with automatic controls for normal operation, periodic flush cycles, sanitization and permeate divert functions. Status indicating lights, alarm outputs and water flow, pressure and quality instrumentation devices should be included for ease of system operation and to meet validation requirements.
4. It is usually most economical, and minimizes sanitization and membrane cleaning requirements, when the system is designed to run 24 hours per day and just meet the maximum daily water volume requirement. It is actually better to attempt to size the system to run all the time for ultra-pure water than to sit idle. Often this is difficult to do. In reality, production runs may not occur every day. The HydroMax system is equipped with functions that prevent water from stagnating in the unit. We also provide an exclusive, automatic periodic sanitization cycle for the HydroMax reverse osmosis system that will help to prevent bio-growth from progressing inside of the unit.
5. The water produced by the reverse osmosis system flows into the pure water storage tank. The storage tank acts as a buffer between the reverse osmosis unit’s production rate (relatively slow) and the demand from the points of use. The storage tank should be sized so that the largest batch of water that is required at a point of use, in a relatively short period of time, can be completely satisfied without running out of water. The tank should be designed for complete drainage and should be equipped with vent filtration or nitrogen blanketing appropriate for the application.
6. Pumps draw water from the water storage tank and propel it under pressure to the points of use. It is always best to install a circulation "loop" piping system. This type of piping arrangement allows water that is not used at the points of use, or all of the pumped flow during periods of non-use, to flow back to the water storage tank. This constantly moving flow of water helps to prevent water stagnation, bacteria growth and water quality deterioration. A properly designed circulation system will provide constant pressure or constant water flow throughout the piping system. The circulation pumps also provide the motive flow to move the pure water through the final stages of purification.
7. In order to ensure that the water meets the selected ultra-pure water standards, most systems require the use of ion exchange deionization modules or an Electronic Deionization System. This component removes the remaining low level of ionic impurities following the reverse osmosis process. Proper selection of the final purification processes, such as ultraviolet sterilization and TOC reduction, sub-micron filtration and deionization, reduces total organic carbon levels, eliminates bacteria and prevents particulate material larger than 0.2 microns from entering the production water.
8. The piping system should be fabricated from a high quality, smooth surfaced, low leaching material such as PVDF. The joining technique should use either a sanitary flange or "crevice-free" weld technology. Extreme care must be taken to prevent welding contamination into the pipe joint or improperly forming crevices in the pipe joints that might be capable of harboring bacteria. The pipe needs to be sized to enhance turbulent boundary layer flow in order to prevent bio-films from developing on the pipe walls. The piping system should be designed with no static water zones. Valved outlets should be designed so that there is no stagnant water between the main flow and the outlet. Although these seem like small details, even with a perfectly designed water purification system, the reliability of the pure water system can be compromised with a substandard distribution piping installation. So that the entire system’s quality control can be assured, HydroMax frequently provides complete piping system installation with our state of the art thermoplastic pipe fabrication techniques.
9. An ultra-pure water system requires various instrumentation in order to verify and log water quality produced by the system. Today’s technologies allow for continuous, on-line monitoring of vital pure water standard water chemistry parameters. Resistivity, pH, some ions and TOC can be measured directly in line to constantly verify compliance. Alarms and automatic action to out of range conditions can prevent wasting valuable product due to batch rejection or recalled product lots. System performance monitoring, bacteria and endotoxin analysis and daily water quality documentation are generally required to be a part of any validated standard operating procedure.
10. The selection of materials of construction and finishing techniques for every component that comes in contact with the purified water is of great importance. Improperly selected materials, or improper installation techniques, can cause mechanical problems and may add contaminants to the water that prevents water quality standards from being attained.

Regardless of how or where the ultra-pure water is applied, it is wise to thoroughly investigate the demands that will be placed upon the water system, the quality and quantity of ultra-pure water required by the application, the types of monitoring desired and the future maintenance requirements of the water generating equipment when investing in possibly your most critical utility — Ultra-Pure Water!