Entry for March 27, 2008

In our previous posting we discussed the presence of pharmaceuticals and other personal care products in both drinking water and drinking water source waters in the US. According to a scientific survey conducted nationwide for the Water Quality Association, a large majority of Americans are becoming increasingly concerned about the presence of these compounds in their drinking water.

“Americans are increasingly aware of potential problems in the water they drink,” said Pete Censky, executive director of WQA.

The survey found that 45 percent of respondents feel very concerned and 23 percent somewhat concerned about pharmaceuticals in their water. More than 80 percent were aware of news reports on the issue.

Full poll results are below. A fact sheet on pharmaceuticals in water and the association’s Water Information Library are also online at WQA’s Web site. WQA is a non-profit association that provides public information about water treatment issues and also trains and certifies professionals to better serve consumers.

Below are results of two telephone opinion poll surveys conducted for the Water Quality Association. Results given in percentages.

Overall, how concerned are you about the quality of your household water supply, 1 being not concerned at all, 5 being extremely concerned? (January/March): 5) 32/40 4) 23/27 3) 21/15 2) 12/10 1) 13/8

Have you heard of news stories of pharmaceuticals found in water? (March only). Yes/No: 81/19

How concerned are you about the presence of pharmaceuticals in drinking water? (1 being not concerned at all, 5 being extremely concerned. March only) 5) 45 4) 23 3) 15 2) 9 1) 8

(If 4 or 5 in Q3): Are you already planning or do you plan to purchase a home filtration device in the near future? (March only.) Yes/No: 57/43.

Would you say that your drinking water is (January/March): as safe as it should be (48/39), not as safe as it should be (41/50), don’t know/refused (11/11).

The responsibility of ensuring safe drinking water lies primarily (January/March): inside the home with water treatment products (20/24), outside your home at a bottle water plant (8/8), outside your home with the municipality (72/68).

Should home filtration be expected to play a role, along with municipalities, in providing the safest drinking water possible? (March only.) 70/30.

Methodology: Surveys conducted by Applied Research-West, Inc. Respondents are representative of all US adults over 18 years old.

The survey also indicated that people are willing to increasingly take action in their homes to reduce the presence of these materials in their water by purchasing filtration devices. The actual effectiveness of these devices to treat part per trillion levels of these chemicals is not clear. It does show that public concern is elevated and may motivate municipalities and their regulatory agencies to consider treatment proven treatment technologies for removing these compounds from the water at much lower costs per gallon versus home based solutions.

These water treatment plant based solutions also have the additional benefit of improving other aspects of the treatment process. The use of ozone for example can not only improve reduction of pharmaceutical compounds, but also improve disinfection of the water as well as improve taste, odor and appearance.

Spartan Environmental Technologies supplies ozone generators and other ozone water treatment systems for drinking water applications.

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Entry for March 16, 2008

In this posting we review recent news about pharmaceuticals found in drinking water.  Drinking water serving greater than 41 million Americans have been found to contain pharmaceutical compounds according to an Associated Press investigation. The Associated Press’ investigation also indicates that watersheds and other surface water sources also are contaminated.

The concentrations of these pharmaceuticals are extremely low, measured in quantities of parts per billion or trillion. Researchers do not yet understand the exact risks from decades of persistent exposure to random combinations of low levels of pharmaceuticals. Pharmaceuticals in waterways have been found to  damage wildlife across the US.  Notably, male fish are being feminized, creating egg yolk proteins, a process usually restricted to females. Benjamin H. Grumbles, assistant administrator for water at the U.S. Environmental Protection Agency states, “We recognize it is a growing concern, and we’re taking it very seriously.”

These compounds enter the water through the sewage system.  People take medication and their bodies absorb some of the medication, but the rest of it passes through and is flushed down the toilet. Despite treatment at both wastewater and rinking water plants, treatment processes do not remove all drug residue.

Even users of bottled water and home filtration systems don’t necessarily avoid exposure. Bottlers, some of which simply repackage tap water, do not typically treat or test for pharmaceuticals, according to the industry’s main trade group. The same goes for the makers of home filtration systems.

Research is being done to determine how to treat water to remove these compounds.  Oxidation by means of ozone is proven to be a very promising treatment solution for the removal of pharmaceuticals, EDCs and pathogens in effluents of municipal waste water treatment plants.

Even in waste water matrices ozone reacts fast and specifically with many of the investigated compounds. Therefore it is possible to achieve reduction rates > 90% even with relatively low ozone dosage of 5 to 10 mg/L. It is possible to reduce the concentrations of specific contaminants, the pathogens and to eliminate estrogenicity. The operational cost of ozone treatment is in the range of 0.06 to 0.12 $ per 1000 gallons of treated water.

Ozone does not completely destroy pharmaceutical compounds, but instead breaks them down into smaller biodegradable compounds that can be further degraded by natural biological organisms in the environment safely.

Spartan Environmental Technologies provides ozone generators and other advanced oxidation processes for water treatment such as the treatment of drinking water and wastewater.

 

 

 

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Entry for March 9, 2008

In this posting we are going to discuss the ozonation of sump water.  Sump water often is a good environment for the growth of micro organisms.  In some cases the biological growth is significant and can create odors and potential blockage of the sump pump.  To prevent this problem, many facilities will add a biocide to prevent the growth of the microorganisms.  Ozone is a good choice for this application.

One of our customers, a manufacturer of small tractors, had a problem with odor from their sump.  We supplied one of our AE series air cooled ozone generators and an Onyx oxygen concentrator.  The ozone was introduced by a fine bubble diffuser on the bottom of the tank. 

It is important to note that when ozone is used as the biocide that the tank needs to be closed and have a vent to outside the building.  In the case of the specific customer referenced here.   The tank in the case referenced here was eight feet deep.  Typically this would not be deep enough for good ozone transfer efficiency, but since the requirement for ozone was rather low, high transfer efficiency was not critical.

The AE series ozone generators have a large turn down ratio.  The client set the ozone generators so as to kill the unpleasant sump odor, but not to smell ozone in the work space.  A light ozone smell would be acceptable since people can smell ozone at 0.01 to 0.04 ppm and people can work in an ozone environment with a concentration of up to 0.10 ppm.  An ambient ozone monitor should be used to make sure that the ozone level in the work space does not exceed 0.1 ppm.  In addition, the tank should be vented to further protect the work space from high ozone levels.

Our client reported that they were easily able to find the level of ozone to keep the odor down on the sump.  This same approach could be used in other applications.  For example, truck washing set-ups often recycle the wash water after filtration.  This water is also subject to biological growth.  The tank holding the recycled water could be handled using the same approach as above.

If you have a sump or recycled water tank that is creating odor problems, contact Spartan Environmental Technologies.

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Entry for March 2, 2008

In this posting we will discuss an application where a farmer employed a Spartan Environmental Technologies ozone generator, a model AE13M, for use in an irrigation system to control biological growth.  The farmer had been using hypochlorite solution for this application.   Our client was not satisfied with the hypochlorite solution due to rising costs and the handling issues with the chemical.  He felt that a system that employed ozone would be easier to use.

The irrigation system took surface water and pumped it through a pipe network to spray nozzles.  The clogging of these nozzles with biological growth was the primary purpose for the ozone water treatment system.  The irrigation system had a maximum pressure of 70 psi and a flow of 35 to 40 gpm. 

As noted in a previous posting an ozone water treatment system is composed of three major subsystems: gas preparation, ozone generation and ozone water mixing.  In this case the client opted to use an oxygen cylinder as a source of gas feed for the AE13M ozone generator.  This provided a clean and dry source of oxygen for the application.  Since the irrigation system only worked for a few hour a day, it was an economical choice for the application.

In terms of ozone water mixing, the design called for a side stream injection system.  About half of the main flow was taken from the pipeline and fed, using a booster pump, through a venturi injector.  This system was sized to pull about 15 SCFH of gas, containing the ozone, into the side stream.  Since the pipe line had a pressure of 70 psi, the booster pump was required to provide a pressure to the venturi injector of 120 psi to support a pressure drop of about 50 psi at a flow rate of around 20 gpm.

The side stream sent a mixture of fine bubbles and water into the main pipeline.  To mix the side stream with the main flow to injection nozzles were placed opposite of each other each taking half of the side stream flow.  This created a mixing zone inside the main pipeline to insure that the full flow was evenly mixed with the ozone.

Since the ozone concentration was around 5%, 95% of the case was oxygen.  This gas needed to be released from the main pipeline where it could gas binding in the rest of the irrigation network.   To accomplish this a tee was added to the pipeline downstream of the injection point, but before the point where the water branched off into the irrigation network.   A four foot standpipe was added to the tee with a flanged top.  A gas relief valve was tied into the standpipe.  Oxygen gas that accumulated in the standpipe was thus vented to atmosphere while maintaining the pressure in the line.

The system has operated as expected without incident.  If you have an irrigation system, and would like to explore the use of ozone for maintaining the biological control of your pipe network, contact Spartan for additional information.

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