Friday, October 28, 2011

Water Sampling a Critical Step in Residential Water Equipment Selection

For our wholesale equipment customers who treat well water, we offer a very basic water analysis. Ultimately, the success of the water treatment starts with proper sampling methods. We aren't talking rocket surgery here. Most residential water treatment systems can be prescribed by testing for 3-5 parameters, including hardness, pH, iron and Total Dissolved solids (TDS). However, what I find are samples collected in old pickle jars with little documentation. Most treatment companies will provide you with a clean sample bottle and a questionnaire, not pickle jar the home owner gave you.  If your customer wants an independent analysis, your customer can also find a certified laboratory in your State.

Critical questions for a questionnaire:
  • Is there an existing treatment system?
  • How powerful is the water pump?
  • How many bathrooms?
  • Any mega showers and Jacuzzi tubs? Irrigation?
  • Taste, odor, color?
Make as many observations as possible, listen to the homeowner. Part of your sample tool kit are your eyes, ears and nose. One of the best water observation tools are is a simple white Styrofoam cup. Fill it with water and see if there is any color or sediment. Always carry a washing machine hose and 5 gallon bucket. They make great sampling tools, especially if you are sampling from the well tank. Run off at least one five gallon bucket to clear the line.

LaMotte Color Q DW model 2059
 Of course you can forgo future brow beating and lectures from me if you purchase your own test kit and test the water yourself. You'll still need to ask the same questions above. Test kits range from mild to wild. We use the LaMotte Color Q DW model 2059. Now don't get excited. We don't sell test kits we sell the equipment after the test. If you get it right, every one's happy.

For additional information:
Certified water testing laboratories in your State
LaMotte Drinking Water Testing Products

Condensate Polishing System Shipped to University in Massachusetts

A triple all stainless steel condensate polisher was shipped to a university in Cambridge, Massachusetts.  The system is designed to treat 445 gpm of condensate and is replacing an existing unit which had reached the end of its life.  This is part of a major upgrade of the steam plant including the condensate polishers, a triple dealkalizer system, which Res-Kem will provide in November, and a deaerator.
A triple stainless steel condensate polishing system that Res-Kem offers
Res-Kem Triple Stainless Steel Condensate Polishing System
Here are the key features of the condensate polisher:
  • For long equipment life, the system has three, 54" ASME-code tanks manufactured in 304 L stainless steel. 
  • To simplify field installation, the system includes inlet, outlet, drain, backwash supply, brine and sub-surface wash headers.
  • The condensate polisher incorporates Bray 31 series butterfly valves with 92 series air open/air close actuators.
  • We supplied a custom designed FRP NEMA 12 panel with an Allen Bradley PLC with three solenoid boxes..
  • 304L stainless steel face piping.
  • Regeneration initiated via totalized flow or differential pressure.
  • The flow sensors to measure the treated condensate from each of the vessels were supplied by others.
  • The differential pressure switches are Orange Research 1203 DP transmitters with 4-20 mA output.
  • A subsurface wash is included to increase the time between regenerations increasing total energy efficiency.
  • A brine distributor for reduced salt usage
  • A separate source backwash is included to increase condensate heat recovery.
  • To prevent downstream damage, stainless steel resin traps are included in the treated water line.
A condensate polishing system that is in the middle of being off-loaded for a customer
Condensate Polishing System Being Off-Loaded at Customer's Site
Given the small space where the system is located, the standard design of the condensate polisher had to be re-engineered.  For example:
  • The three pressure vessels could not be evenly placed because a vertical support beam would be in the way making each header piece unique.
  • A height restriction required numerous engineering design iterations to get the system in the space allotted.
  • All headers needed to be nested in a very small envelop on the front of the system.
Additional information:

Condensate Polisher Checklist Webpage Version
Condensate Polisher Checklist - PDF Version
Condensate Polisher System Brochure
Need Applications Engineer

Tuesday, October 04, 2011

Ultra Filtration - The Membrane Problem Solver

There are very few innovations in the water treatment market these days. Sure the electronic controls have gotten more intuitive and compact, that is about it. Ion exchange hasn’t really made quantum leaps into the 22nd century either. So before I depress my fellow colleagues and influence young people to seek another career path, there is one exciting application of an innovation that really works. Ultra Filtration (UF). UF isn’t something new, but the membrane technology that makes it work has been refined and tamed over the years. For this Blog, I want to discuss its residential and light commercial applications as they relate to problem well water.
Ultrafiltration membrane fibers that have been magnified
Magnified Ultrafiltration Membrane Fibers

What is an UF filter?
For the uninitiated, a UF filter at first glance looks similar to a Reverse Osmosis membrane, only because it shares the same membrane housing. But that is where it stops. Same on the outside, vastly different on the inside. A UF filter is a bundle of tubes tightly bound together. A UF membrane system doesn’t require pumps and storage tanks like an RO. Depending on conditions your typical 4”x40” UF membrane can yield 7 gpm service water and require a backwash every 100-400 gallons of processed water. A UF will effectively filter down to .025 micron. .025 micron is where virus and cysts live! GONE!

What is a good UF application?
Basically UF’s are applied to water with color or sediments that are not being removed by conventional 1 micron or larger filtration, or sediment that takes days to settle out. In the past a professional would feed Alum into 120 gallon tank(s) to coagulate, precipitate, then filter. Quite messy and labor intensive. Now you can send the same water right through the UF membrane. The result is sparkling clear water. Let me rephrase that, AMAZINGLY clear water. Only use treated water to backwash a UF filter. Failure to use treated backwash water will cause the membrane to foul. Since the backwash cycle is only 30 seconds and uses only 3 gallons of water, most people add a large pressure tank (40 gallons with 15 gallon draw down) after the UF to act as the clean water storage. Short comings? What won't this membrane miracle handle? AVOID anything that "grows". Iron, manganese and sulfur bacteria for example could clog the membrane. Oil and grease is also a poor choice. Consider a UF on your next "murky" water job. Be AMAZED.

Composite Fiberglass Softeners Versus Lined Carbon Steel Softeners

Epoxy Coated Dual Tank Water Softener along with an Optional Stainless Steel Piping
Epoxy Coated Dual Tank Water Softener with Optional Stainless Steel Piping
Here are a few pro's and con's for a lined carbon steel softener option and a composite fiberglass softener system

Advantages of carbon steel lined softener system:
  • Lined carbon steel system has top man ways and side wall handholes. Having these access points to get to the resin bed and underdrain hub and lateral can be extremely helpful when changing the resin. Changing the resin can take place every 3-8 years and is contingent on chlorine levels in raw water. 
  • If the underdrain fails the lined carbon steel tank would stay in place with face piping left in-tact. The repairs could be accomplished from the side wall handholes. 
  • Lined carbon steel tank can resist being damaged with a passing forklift or other moving equipment 
  • If power fails and water pressure is still available, the unit can be generated manually. This is done by manually turning the pilot stager to each service cycle for the specified time in the step. 
  • If a temporary vacuum was ever introduced on a lined carbon steel tank it would likely not have any damages to the liner or tank. 
  • Higher flow rates can be achieved with lower pressure drops on 2" inlet/outlet 30" diameter carbon steel softener system versus a fiberglass system same tank diameter using a Fleck 2" 2900 valve
Disadvantages of a carbon steel lined system: 
  • Lined carbon steel pressure vessel softeners are more costly and more expensive to assemble
  • Longer lead times associated with these systems (4-8 weeks) 
  • Lined carbon steel tanks make for a lot of condensation and unlike fiberglass tanks aren't as resistant to corrosion even with a primed and painted exterior
  • Longer Lead Time to procure system components and to build the softener system
Example of a Manual Fiberglass Water softener
Manual Fiberglass Water Softener 
Advantages of a composite fiberglass tank softener system:
  • Lower cost materials to build the softener system 
  • A spare identical multi-port valve and control can be kept as a complete spare and be changed out in kind.
  • Shorter lead time. valves and composite fiberglass tanks are readily available. (1 - 3 weeks)
  • Pressure vessel is resistant to corrosion from tank condensation
Disadvantages of a composite fiberglass tank softener system: 
  • Can't withstand a vacuum being drawn on the tank. A lined composite fiberglass vessel under a vacuum would likely have a polyethylene liner failure. For this reason a vacuum breaker should be installed in a tee on the inlet water piping.
  • The piping needs to be supported by framework and the connections to the tank need to be flexible. 
  • On a fiberglass tank softener system if the hub and lateral needs to be changed the tank would have to be lowered down to the ground in order to reach in and replace the hub and lateral 
  • In order to change resin, the unions on the multi-port valve inlet, outlet and drain would need to be broken and the multi-port valve must be to unthreaded from the top of the tank. If this is done multiple times over a short period of time, the tank threads are prone to leaking
  • If seismic specifications are needed on the pressure vessels, fiberglass tanks shouldn't be selected 
  • If there is an electrical power failure the multi-port valve is not operable and the unit can't be regenerated
  • The commerically available controllers that are available with multi-port valve softeners are local only and integration with a PLC is not possible in most cases

Condensate Polisher Shipped to Arkansas

We shipped another condensate polishing system last month. This dual tank unit was shipped to a government facility in Arkansas.

a dual tank water condensate polishing system shipped to arkansas
Here are the key features of the polisher:
  • The system has two, 36" stainless steel, ASME-code tanks mounted on a skid to treat steam condensate.
  • The condensate polisher incorporates Bray 31 series butterfly valves with 93 series air open/spring return actuators.
  • We use a custom designed FRP NEMA 4X panel with an Allen Bradley PLC.
  • 304L stainless steel face piping.
  • Regeneration initiated via totalized flow or differential pressure.
  • Seametrics model IP101S flow sensors measure the treated condensate from each of the vessels.
  • The differential pressure switches are Orange Research 1201 series.
  • A subsurface wash is included to increase the time between regenerations increasing total energy efficiency.
  • A separate source backwash is included to increase condensate heat recovery.
Additional information:
Condensate Polisher system brochure
Condensate Polisher Checklist
Need Applications Engineer