Entry for October 16, 2008

The European division of the International Ozone association will holds its annual conference in Berlin on March 30 through April 2, 2009 in cooperation with teh International Water Association.  The conference is also being held in conjunction with Wasser Berlin, one of the largest water shows in Europe.  The focus of the conference will be advanced oxidation processes (AOP).  it is our understanding that a large number of abstracts have been submitted for the conference indicating a significant interest in the topic.

AOP are oxidation processes that combine various technologies, such as UV and ozone to produce hydroxyl radicals.  Hydroxyl radicals are the one fo the strongest oxidizers known.  They ahve a wide variety of applications int water treatment and the conference will cover both applications and the equipment and technologies needed for advanced oxidation.  Spartan Environmental Technologies offers AOP technologies for water treatment.

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Entry for October 8, 2008

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An important aspect of drinking water treatment is the balance between disinfection and disinfection byproducts (DBP) control.  DBP such as trihalomethanes (THM), haloacetic acids (HAA) and bromate ion are potential carcinogens.   The formation of these compounds with the use of drinking water disinfectants such as chlorine and ozone must be controlled.  On the other hand, dangerous pathogens in drinking water can rapidly sicken or kill thousands of people if not controlled as well.  So, finding the proper balance is indeed critical.

The US EPA has set limits for the levels of these compounds in drinking water as well as the as levels of certain pathogens typically found in water.  Operators as a result try to use the minimum amount of disinfectant necessary to kill the pathogens while staying below the DBP limits.

Recently, there has been increased attention regarding the formation of bromate during ozone water treatment.  The limit for bromate in drinking water is 10 ppb.  Bromate formation during ozonation is affecting by the amount of ozone applied, pH, dissolved organic matter, temperature, bromide ion content of the water, and alkalinity.  Out of these factors, pH and ozone dose are within the control of the operator.  The other factors are function of water quality and not easily changed.  The most easily applied rule is to minimize ozone dose while still achieving the disinfection objective.

It is fairly obvious that the more difficult to kill a pathogen is the more ozone would be required.  One of the most difficult to kill pathogens is cryptosporidium.  It goes to reason that if this compound can be killed in water containing bromide ion while staying below the 10 ppb limit for bromate, that it should be possible to use ozone to kill less difficult organisms at low bromate levels.

A study of 14 large drinking water plants using ozone with bromide ion in the water in 2001, showed that the majority could meet the disinfection objective for cryptosporidium while staying below the 10 ppb limit for bromate without any additional treatment steps in the process other than control of ozone dose and pH.

In cases where bromate formation will occur during ozonation, it is possible to control the levels below the 10 ppb target by the addition of chlorine or ammonia to the water.  The presence of these compounds, often used in drinking water treatment prevents bromate formation in the presence of ozone.  As a result, very few municipal WTP or bottled water producers should have issues with bromate formation during ozonation with proper control techniques.

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Entry for October 1, 2008

We are frequently approached by customers looking to treat complex water problems.  Ozone water treatment systems can solve many water quality problems simultaneously, so it is often considered for these situations.  In many cases, however, some additional water treatment technology needs to be added to the ozone system in order to provide a complete solution.

Spartan works with a number of partner companies to provide complete water treatment packages which include ozone as an integral component.  The two technologies that are often added are some form of filtration and UV. 

While ozone acts as a micro flocculent, essentially a filtration aid, particulates formed need to be filtered out of the water.  This means that after ozonation there will need to be some form of filtration.  Normally, ozone is added to enhance filtration in these situations while simultaneously providing disinfection. 

Another application where filtration needs to be combined with ozonation is where the primary application for ozone is disinfection and the water contains significant amounts suspended solids.  Suspended solid can provide places for micro organisms to grow and shield them from the ozone.  It is important to reduce the turbidity of the water to minimize this problem. 

The exact method of filtration will depend on the nature of the water treatment application and can range from simple bag filters to reverse osmosis.  Spartan works with filtration experts that not only match the proper filtration method to the application, but also ensures that the ozone will not damage the filter elements.

The other technology employed with ozone is UV.  UV in combination with ozone creates an advanced oxidation process (AOP).  AOP is one where there is the formation of hydroxyl radicals, a chemical compound that is a very powerful oxidant.  Thus AOP form an oxidant that is more powerful than ozone alone.  While hydroxyl radicals can be formed by a variety of advanced oxidation processes, e.g. ozone with hydrogen peroxide, UV ozone is attractive since it can be formed without the need to purchase or store any chemical compounds.  The UV light and ozone can be created on site from electricity and air.  This makes for a simple and safe process.

AOP, such as UV ozone, can be used for a variety of applications such as the removal of difficult to treat organic compounds from water.  As a result this process finds application in ground water remediation and industrial wastewater treatment.

Spartan Environmental Technologies provides complete ozone water treatment solutions that can integrate filtration and UV.

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