Zeta Rod Blog

US Army Corps of Engineers' Engineer Research & Development Center Reports 20% Water Savings in Cooling Towers with Zeta Rod

From July 2007 to September 2008 the US Army Corps of Engineers' Engineer Research and Development Center (ERDC)conducted an independent and thorough comparative study between the Zeta Rod and a conventional chemical water treatment program for cooling towers. Two sites were chosen for the study, Davis Monthan AFB in Tucson, and Fort Huachuca in Sierra Vista, AZ.

The study looked at corrosion, scale and biofouling control as the parameters to be used as the metric to evaluate both programs, however, the ERDC had a special interest in water saving capabilities in order to meet requirements set by Executive Order 13423 regarding water conservation. 

This study was also the launching platform for the Zeta Water Management System, which allows remote control, data logging and monitoring of a cooling tower.

The Abstract of the report reads:

 The United States Department of Defense (DoD) has a specific legislative mandate to increase its conservation of water and energy. It also is interested in improving the effectiveness of open-loop, cooling water treatment processes at its installations worldwide, for purposes of extending the useful life of evaporative cooling equipment and reducing energy use/costs. A Cooperative Research and Development Agreement (CRADA) was approved to demonstrate that, without using chemical additives, a capacitor-based water treatment system is capable of (1)providing equivalent protection to a chemical treatment program in preventing scale, corrosion, and bio-fouling; (2) allowing cooling systems to be operated in an enhanced water conservation mode; (3) delivering measurable reductions in water usage over conventional methods; and (4)providing control, monitoring, and wireless data transfer via the Internet.

Results documented in the subsequent demonstration and evaluation project showed the technology was able to meet every objective and also was able to deliver a 20% reduction in cooling water use over standard chemical treatment methods.

Application of this technology would allow the DoD to (1) reduce chemical usage, exposure, and disposal expenses; (2) conserve water and energy; (3) facilitate water re-use; and (4) meet new goals for conservation of resources.

The complete report can be read and downloaded by going to the following link.

 

Zeta Rod and Tankless Water Heaters

One of the most frequently asked questions we receive from potential residential Zeta Rod customers is whether the Zeta Rod will help protect their Tankless Water Heater from scaling. The answer is: "Yes, the Zeta Rod will prevent scale deposits from forming on the tankless water heater pipes".

The following is a brief description on how tankless water heaters work and why are they susceptible to scale deposits forming on their pipes.

Tankless water heaters are gaining popularity over the older tank water heater model. Some of the advantages that tankless water heaters offer over the older tank design include: reduced floor space, lower energy consumption and endless hot water available on demand .

Tankless water heaters work by rapidly heating the water in a heat exchanger to the desired temperature as the water flows through the heater. The burner of the unit only turns on when there is demand for hot water, this is how it is able to use less energy while providing endless hot water. Older model hot water heaters store water in a tank and heat it up with a burner (or electric heating elements) when the water drops below a certain temperature. This has the inconvenience that the burner may turn on even when there is no demand for hot water.  The following diagram shows a simplified version of a tankless water heater.

Because of the design of the tankless heaters, the water is heated at a very fast rate, forcing the water to come in contact with very hot surfaces on the pipes as it goes through the heat exchanger. This provides conditions that favor minerals in the water to precipitate and form scale deposits on the tube  walls. In places with hard water the problem is exacerbated and precautions must be taken to prevent scaling of the heat exchanger tubes.

Mineral scale is primarily composed of calcium carbonate (hardness in the water) which precipitates from the water under certain conditions (such as high temperature, high pH or high concentrations). Scale has a very low heat transfer coefficient, or thermal conductivity. The thermal conductivity of copper is 384 W/(m*K) and the thermal conductivity of scale is 2.6 W/(m*K). This means that scale is about 140 times less efficient in transferring heat than the copper which is used in the tankless heater pipes. The following graph shows the amount of energy increase that would be required to overcome a layer of scale.

The lower thermal conductivity  of scale has a direct negative effect on the performance of the tankless water heater. Since the amount of heat transfered to the water is reduced, the unit would have to operate at a higher rate in order to try to get the water to the design temperature, which in turn would result in higher energy consumption. If the scale is thick enough, the unit may not be able to heat the water to the desired temperature at all. And if scaling is very aggressive, water flow can be restricted through the unit and it eventually could lead to tube failure.

The Zeta Rod is an ideal low cost and environmentally friendly option to prevent scale formation in tankless water heaters. A Zeta Rod installed in the main water line entering a home will protect the tankless water heater as well as all the fixtures in the house. The following pictures are courtesy of R&G Sales and show a Zeta Rod displayed with a Noritz Tankless Water Heater at Central Arizona Supply. At this show room's display the Zeta Rod protects the tankless heater and the shower fixtures. This picture shows the small floor space that both the tankless heater and the Zeta Rod take.

Reverse Osmosis: "Will the Zeta Rod Replace my RO?"

This is a question that we get quite often, especially from home owners who are considering the use of a Zeta Rod to treat the water in their home.

The short answer is: "depends".

Before we go into more detail to the answer, we should look at how an RO system is and how it works.

First the definition of osmosis: movement of a solvent through a semi-permeable membrane into a solution of higher solute concentration that tends to equalize the concentration of solute on both sides of the membrane.

Basically what this means is that nature will find a way to move systems that are out of equilibrium, into equilibrium. Osmosis is one of such ways. In nature the wall of a cell can act as a semi-permeable membrane (a semi permeable membrane is one that will allow the passage of water only). When the concentration of salts (the solute) is higher inside the cell than in the environment surrounding the cell, the difference in concentration (osmotic pressure) will cause solvent (water) to pass through the cell's wall and in this way balance the amount of salts within the cell to its environment.

Osmosis is a little counterintuitive. Another example would be this: consider that you have two columns of water separated by a semipermeable membrane (fig 1). Column A has water with a low salt concentration and column B has water in it with a high salt concentration. At the initial time both columns have the same amount of water. 

 

After a period of time, water from column A will permeate through the membrane to column B in order to try to balance the concentration of solute in the water. Once the solutions have reached equilibrium, the difference in height will determine the osmotic pressure.

If at this time you're thinking: "hold on a minute, this seems to be backwards fro what my RO unit does!". You are correct, this is osmosis, what your RO unit does is reverse osmosis.

If we go back to the initial drawing, but this time we apply pressure, through a piston for example, to column B. We would have to apply a pressure equal or larger to the osmotic pressure of the solution to force water from Column B to Column A. And what we would have in Column A is known as the permeate, which is very high purity water. The left over in Column B is referred to as  concentrate.

So a reverse osmosis system forces the water that has a high concentration of salts across a semi-permeable membrane by applying enough force to overcome the osmotic pressure of the water. Every RO unit will have a permeate, in your home application this will be the drinking water, and a concentrate, in your home this will be the water that goes to the drain.

RO units produce very high quality water, it removes practically all salts and any pollutant that may be in the water.

The primary problem with RO units is membrane fouling. The membranes are prone to mineral scaling and biofouling (bacteria). As the membrane fouls the efficiency of the RO diminishes until it gets to the point where replacing the membrane, or cleaning it is necessary.

The Zeta Rod is an excellent pretreatment option for RO units, for it will prevent the membranes from fouling, thus extending the life of your RO membranes, and reducing the cost of maintaining and operating the RO unit.

SO, going back to the original question of the post, It depends on what function is the RO unit performing.

If you have an RO unit because you have a private well and there may be some contaminants in the water, then the RO should stay and the Zeta Rod will be of great help to the unit by keeping the membranes from fouling.

However, if you have an RO unit just to prevent scaling in your dishes, sink, faucets, etc. Then the Zeta Rod can be a suitable replacement for the system.

Zeta Corporation has treated RO units ranging in size from small under the sink units to large municipal plants. This Case Study shows the benefits that the Zeta Rod provided to a Pepsi Cola bottling plant's RO unit. 

So if you have an RO unit at home, installing a Zeta Rod system will greatly benefit your RO operation and help you with scaling issues in the rest of your home.

For any questions or comments, please contact Zeta Corporation at 888-785-9660, or by email to info@zetacorp.com. 

Zeta Rod as an Alternative to a Water Softener, Part II

As discussed in our previous post removing hardness from water is done primarily to avoid some of the nuisances that hard water cause on the home owner. Salt based water softeners are facing more and more regulations, bans and opposition because of the discharge of the brine into municipal sewer systems and and an increased awareness from people on the need for green technologies that benefit the environment.

The Zeta Rod is an electronic deposit control system. It has been around for nearly 15 years in a wide range of industrial applications. The principle of operation of the Zeta Rod is explained in colloidal chemistry books and relates to the dispersion of colloidal particles in a solution. The Zeta Rod has a direct impact on the Zeta Potential of the particles in the water.

In quite simplified terms, the Zeta Rod creates a stable dispersion amongst particles in the water and prevents them from agglomerating and forming larger crystals, or from forming deposits on wet surfaces. So, the Zeta Rod does not change the chemistry of the water, we don't take the hardness out of the water, that is why it is not a "water softener". However, the Zeta Rod will prevent the mineral buildup on appliances, shower nozzles, faucet aerators, water heaters, etc that are associated with water hardness, and that is why it is a suitable alternative for a water softener.

The Zeta Rod also lowers the surface tension of the water. This reduction in surface tension is comparable to the effect that a water softener has when it comes to using soaps and detergents. So while the hardness in the water remains, Zeta treated water will have similar benefits as that of soft water.

Other benefits that the Zeta Rod offers include:

* Low maintenance: no replacing parts, regenerating of media, or disposal of brine down the sewer

* No environmental concerns with the use of the Zeta Rod.

* Water is safe for drinking and irrigation.

The Zeta Rod will work both with cold and hot water systems. It will work with water with hardness levels ranging from "soft" to "very hard". It will help prevent scale buildup in pools. Prevent scale formation on evaporative coolers (swamp coolers).

So when the question is asked on whether a Zeta Rod actually is a water softener, the answer is "No", but can it replace a water softener and still offer the same benefits, the answer is "most definitely yes".

Please contact us if you have any questions or would like some additional information on the Zeta Rod. You can also visit our Web Site for more information and to find a local distributor in your area.

Zeta Rod as an Alternative to a Water Softener, Part I

One of the most frequently asked questions we receive by home owners whether the Zeta Rod can replace a water softener? . The answer to this question is: "YES". However, many people assume that by that we mean that the Zeta Rod is a water softener. This is a common misconception, while the Zeta Rod is a viable alternative for a water softener, it is not a water softener.

There seem to be many people out there on the internet that are fast in criticizing the Zeta Rod, more from a lack of understanding of the technology than anything else. Through this blog we want to help people get a better understanding of the technology and the benefits it can offer.

This will be a two part post. In this first part we will discuss what is Water Hardness, why do people want to get rid of it, and how do salt based water softeners work. In the second part we will explain how the Zeta Rod works and how it differs from a water softener.

In order to understand what a water softener is, and how a Zeta Rod differentiates from one, we need to understand what Hard Water is. Water as supplied by municipal water systems, or wells, is not pure water, it has many dissolved minerals in it (pure water is not good for drinking). Calcium and Magnesium tend to be amongst the most common minerals found dissolved in water, and amongst the ones in higher concentrations. The amount of these minerals dissolved in the water are referred to as the Hardness of the water and it can be measured in parts per million (ppm), milligrams per liter (mg/l) or in grains per gallon (gpg). One ppm is equivalent to one mg/l, and one gpg equals 17.1 mg/l or ppm.

Water Hardness varies from zone to zone as it can be seen in the next picture that was borrowed from the USGS website.

The US Department of Interior and Water Quality Association classify water hardness as follows:

Classification	mg/l or ppm	grains/gal
Soft	0 - 17.1	0 - 1
Slightly hard	17.1 - 60	1 - 3.5
Moderately hard	60 - 120	3.5 - 7.0
Hard	120 - 180	7.0 - 10.5
Very Hard	180 & over	10.5 & over

Hard water in itself does not pose a health hazard, quite contrary, some agencies such as the National Research Council (National Academy of Sciences) state that hard drinking water generally contributes a small amount toward total calcium and magnesium human dietary needs.

So why do people want to get rid of hardness?? The Wilkes University Center For Environmental Quality Environmental Engineering and Earth Sciences department explain it perfectly. On their website they write:

"Hard water interferes with almost every cleaning task from laundering and dish washing to bathing and personal grooming. Clothes laundered in hard water may look dingy and feel harsh and scratchy. Dishes and glasses may be spotted when dry. Hard water may cause a film on glass shower doors, shower walls, bathtubs, sinks, faucets, etc. Hair washed in hard water may feel sticky and look dull. Water flow may be reduced by deposits in pipes.

Hard water also contributes to inefficient and costly operation of water-using appliances. Heated hard water forms a scale of calcium and magnesium minerals that can contribute to the inefficient operation or failure of water-using appliances. Pipes can become clogged with scale that reduces water flow and ultimately requires pipe replacement. "

One way to address these issues caused by the hardness in the water is to install a water softener in your house.

Water softeners have been around for quite a while and their principle of operation is quite simple. It consists of replacing the hardness ions in the water (Calcium -Ca- and Magnesium-Mg-) with a different ion, Sodium (Na). The way this is done is by passing the hard water that comes into the house through a bed of small plastic beads or through a chemical called zeolite. This resin bed is saturated with sodium ions that attach to the beads. Calcium and Magnesium have a stronger attraction to the zeolite, so as the hard water passes through it, they take the place of the sodium, and hence the hardness of the water is removed.

As the zeolite becomes saturated with calcium and magnesium, the water softener starts losing its efficiency and the hardness of the water that makes it into the house gets higher (this is why some places even with water softeners see the effects of hard water over time). At this point it is time to regenerate the resin. This is done by flushing it with brine, which is a solution of water with salt. As this concentrated brine goes through the media, it displaces the Ca & Mg and replenishes the media with Na.

Water softeners not only are far from being perfect, they have many inconveniences such as:

* They require frequent maintenance and regenerating of the media

* They are not environmentally friendly: More and more locations are setting strict regulations on the use of water softeners because of the brine discharge. California is banning the use of water softeners in some areas all together.

* Soft water is not good for irrigation, it will damage plants.

* People with high blood pressure problems should not drink soft water.

The Zeta Rod is a green technology  that offers an alternative to water softeners without the inconveniences associated with them. In the next post we will explore how the Zeta Rod works, what benefits will it offer to the home owner (or commercial/industrial customer) and how it differs from a water softener.

NSF Certification & IAPMO Listings

In Zeta Corporation we take the quality of our products very seriously. That is why we have done extensive testing to our products to ensure that they meet the highest standards for industrial and residential applications both domestically and internationally.

The International Association of Plumbing and Mechanical Officials (IAPMO)  has been protecting the public’s health and safety for more than eighty years by working in concert with government and industry to implement comprehensive plumbing and mechanical systems around the world. The Zeta Rod is an IAPMO listed product and meets NSF Part 61 Standards.

NSF part 61 refers to drinking water standards- health effects and assures that there are no contaminating factors present in the product that would be a threat to drinking water safety. All Zeta Rod systems are certified to NSF part 61.

Scale Control in Potable Hot Water Heaters at Houston Airport.

We have received from many potential customers the question:

-"Will the Zeta Rod work for my hot water heater?".

Apparently many have heard from some "Internet self proclaimed water experts" that the Zeta Rod does not work in hot water applications.

The short answer to the question is: YES.

As an example, we have the Houston Intercontinental Airport. Back in 2000 it was going through a major expansion project involving all terminals.

One of the problems that the engineering firm in charge of the project was facing was a severe calcium precipitate fouling problem with the domestic hot water generators. The heat exchangers (HX) had historically been plagued by persistent fouling on the domestic water (shell) side due to the high temperature of the heat source on the tube side. HX tube bundles would become clogged with fouling annually before we installed the Zeta Rod.

The Airport did not want to consider a water softener as an option because of the inconveniences and costs associated with the operation and maintenance of these systems.

The Zeta Rod was then considered and a trial was set for one of the older units in one of the airport terminals. The HX bundle used in the test was already partially fouled when the pilot program was began but replacement of the bundle was postponed.  About 6 months after the Zeta Rod was installed, the HX bundle was pulled for scheduled replacement but the fouling was found to be reversing from the prior inspection!!  The client was so impressed with the results that Zeta rods were installed on all domestic hot water generator applications. Picture on the right shows two Zeta Rod electrodes installed in the return line to one of the potable hot water heaters in one of the terminals.

Following the success of the hot water systems, the Zeta Rod was then implemented in the Central Cooling Plant to help with fouling problems in the Condensers.

The same principle that allowed the Zeta Rod to protect these large hot water heaters is the principle that applies to your home unit.

Will it work for my pool?

One question that we seem to get quite often from prospective pool users is whether the Zeta Rod will help them with their pool. Primary concern seems to be with the "bath tub ring" that forms around the water level and the use of chlorine.

Mike Pitts, President of Zeta Corporation explains:

"The continuous evaporation of water (typically in Arizona 1" / day) quickly raises the concentration of mineral matter to the saturation point and precipitation of all mineral salts is very active. Pool filters handle much of the precipitate load, pool vacuuming and pool cleaning services get the rest. Evaporation of the wet splash zone establishes the "bathtub ring". A year long demo in Phoenix proved complete "ring " prevention and slow removal or softening of the old hard deposit.

Public pool chlorine is a legal mandate for active CL residual, home pools don't fall under this mandate, so they are generally fed chlorine by appearance and by demand as needed for algae control.

Liquid chlorine commonly used in large facilities yields acid condition requiring neutralization with soda ash. Smaller pools and some large use calcium hypochlorite with obvious addition of both high alkali and calcium. Sodium hypo' is generally considered too expensive for pool use.

Numerous home ZR residential pool owners report improved pool conditions even with just the continuous refill of evaporation by Zeta treated city water. some residential use is coming on of the ZR and more is expected and justified quickly because of the high cost of the service when cleaning is contracted to a pool service. 3k - 4k + per year

Bacteria is not a prime concern ion home pools because of over us of chlorine public pools have continuous testing program to assure hygiene

The deal with ZR in pools is the expensive ring cleaning payout with much more clear water in the pool . Water features of home pools -rock, water falls etc quickly lime up with unsightly white deposits-- ZR minimizes this."

                                                                                         M. Michael Pitts