ULTRA PURE WATER
Nalco Pretreatment Solutions (PTS) is a leading manufacturer and supplier of water treatment for producing ultrapure water in the semiconductor, chemical, pharmaceutical, nanotechnology, electronics, laboratory and medical device markets.
Every water source is different and the required water quality depends upon the product being manufactured and the industry being served. Our modular approach uses a simple water treatment design and minimal equipment to achieve the required water quality for any process or industry.
For more information, please refer to our Nalco PTS Modular Ultrapure Water system bulletin.
Click the blue arrows below to learn more about our Nalco PTS ultra pure water systems.
Our high purity systems incorporate regenerable deionization
(DI) exchange tanks for flows of 2-5 GPM and 6-12 GPM using 1.2 cubic foot and 3.6 cubic foot DI exchange tanks respectively. Higher flow systems are also available using multiple 3.6 cubic foot tanks, 23 cubic foot or 30 cubic foot skid mounted DI exchange tanks. Additional customization can be implemented by using different pumps, DI tank sizes, line sizes and UV lamps. We also provide DI exchange service in most of the United States.
Using all of the treatment modules will achieve the highest water quality. For less critical water quality requirements, fewer modules will be necessary to achieve the water quality for your process.
All systems require a filter to treat all of the water entering the water treatment system. A prefilter will remove any large suspended particles and solids that can damage downstream equipment. A cartridge prefilter is generally the lowest installed capital cost, but the operating cost can be very high if there is poor quality inlet water. A multi-media filter has a slightly higher capital cost, but virtually no operating costs as the system simply backwashes on an as-needed basis.
A water softener
should be installed when the inlet water hardness is greater than 50 ppm or 3 grains/gallon. The industrial water softener is particularly important in systems with a Reverse Osmosis
, RO system. A water softener will reduce downtime required for membrane cleaning, increase membrane life and virtually eliminate unplanned system shutdowns. When continuous flow is required, a dual tank softener will be required. If a plant operates 1-2 shifts per day, a properly sized, single tank softener is fine.
If a system has an RO and is on city water, an activated carbon filter
is required to remove the chlorine or chloramine used to protect the population from harmful bacteria. Otherwise, the life of the RO will be severely shortened. The simplest option is to use a carbon exchange service, which requires a smaller capital investment, but a higher operating expense. Another option is to install a simple backwashable activated carbon filter to increase the life of the carbon by removing suspended material from the top of the bed where it may accumulate. This system has a nominally higher capital cost and requires a drain line connection and carbon replacement every 2-4 years.
The RO System
removes 95-98% of the feedwater ions as well as particles and bacteria. While an RO is a great tool to consistently produce high quality water, it is particularly susceptible to foulants and oxidants. To reduce the potential for the damage, we have the pretreatment modules of filtration, softener and/or carbon filtration described above. To keep the RO system at or near continuous operation, the number of elements should be tailored to the typical water demand downstream of the RO system.
As the water quality requirements increase, a deionization
process should be added to the RO permeate line before the water enters the RO/Recirculation loop storage tank. Doing this increases the "makeup" water resistivity and quality. A service DI tank provider will deliver regenerated mixed bed resin in pressure vessels or tanks, connect the tanks into the water treatment system and remove the used or exhausted tanks of resin. After the tanks are brought back to the service company, the resins are recycled at a regeneration facility.
Almost without exception, a properly designed recirculation loop and storage tank will substantially improve the operation and reduce the capital cost of the entire treatment system. A storage tank and recirculation loop pump easily handles rapid and large surges in water demand. As stated above, an RO is designed for relatively constant flow rate. Without a tank, the only option is to size the RO, and all equipment ahead of it, for the instantaneous demand. The capital expenditure will be dramatically higher when you have to up-size the equipment versus adding the cost of a tank.
The final module of the water treatment system is the repressurization and final treatment before the water enters the recirculation loop. This module includes a recirculation loop pump, two service DI mixed beds tanks in series, an ultraviolet unit and a final filter. A resistivity monitor and sample ports insure the correct water quality is going to your manufacturing process.
Posted on April 7, 2015 by Brian Krummel