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Aquionics technology replaces low pressure, multi-lamp system

A wastewater treatment plant (WWTP) in Richmond, BC, Canada, has opted to replace its existing low pressure UV disinfection system with a medium pressure UV system from Aquionics Inc. The WWTP serves the Riverport Sports and Entertainment Complex and surrounding residential areas in the City of Richmond, south of Vancouver.

The facility decided to switch to medium pressure UV because cleaning the low pressure system was proving to be very difficult. Each of the two disinfection chambers in the old system contained 24 low pressure lamps – automatic wiping is not an option with that number of lamps, so cleaning had to be done either manually or with chemicals. Both of these methods is extremely time consuming and requires the entire system to be shut down.

The operators therefore decided to look at other options, and medium pressure UV seemed an obvious alternative. While having a similar footprint, medium pressure systems utilise UV lamps with a much higher UV output than low pressure lamps. In fact, only two lamps per disinfection chamber are required for the same level of disinfection. Each of the medium pressure lamps is fitted with a mechanical wiper, which automatically moves up and down the lamp’s protective quartz sleeve, keeping it clean. This is simply not possible with multi-lamp, low pressure systems. Periodic chemical cleaning of the medium pressure lamps, if required, is simple and can be done by injecting the chemical into the treatment chamber where it cleans the lamps ‘in-line’, without the necessity of removing the lamps or shutting down the system.

How UV works

UV is the part of the electromagnetic spectrum between visible light and X-rays. The specific portion of the UV spectrum between 185-400nm has a strong ‘germicidal’ effect, disrupting the DNA of microorganisms, rendering them unable to reproduce. It is generally accepted that microbial DNA absorbs UV most effectively at 265nm, a wavelength that MP lamps produce in abundance. In addition to emitting UV at this optimum ‘peak’ wavelength,  medium pressure lamps also emit UV over a much broader range of wavelengths (between about 185 – 400nm) than low pressure lamps. This broad output, has been shown in independent tests to cause permanent inactivation of both pathogenic and non-pathogenic microorganisms such as E.coli  (references 1, 2, 3).

Low pressure UV lamps, on the other hand, produce just a single peak of UV output at 254nm. While also having a strong germicidal effect, the independent tests mentioned above showed that some microorganisms were able to repair or ‘reactivate’ themselves after exposure to UV from low pressure lamps, especially if they are subsequently exposed to sunlight (known as photoreactivation) – as is often the case in wastewater treatment facilities.

It is thought that the permanent damage caused by medium pressure UV may be a result of the UV at other wavelengths, such as 240nm and 280nm, having an effect on other intracellular molecules such as RNA and enzymes, which are unable to repair themselves.

The implications of the research into photoreactivation are far-reaching. For any industry where UV is used to disinfect water or wastewater, the operator needs to be sure that the treatment is permanent. This is especially the case when the treated liquid will subsequently be exposed to light and make its way back into the environment. Zimmer at al (reference 1) suggest that medium pressure UV could therefore provide better protection against photoreactivation if UV treatment occurs prior to any process units in which water is exposed to light for even a short time. According to their study, “Using low pressure UV in this type of situation should be avoided, since repair occurs rapidly following exposure to light.” A much larger research effort into the area of photoreactivation is still required, however, especially research involving real water and wastewater treatment plants.

The two Aquionics medium pressure units installed at the Riverport facility are situated after a Sequencing Batch Reactor and treat a combined flow of up to 2271 litres per minute (600 gallons per minute) of wastewater from the adjacent sports complex and residential areas. The disinfected wastewater is discharged into the Fraser River and meets all necessary quality standards for emission into watercourses.

Each of the two UV chambers is fitted with a UV monitor which measures actual UV intensity and dose from the two lamps. This provides real-time disinfection information which can be downloaded for record keeping. Operating the UV system is simple and, when lamps need replacing, it can easily be carried out by on-site staff.

The Riverport Sports and Entertainment Complex is a major development covering 14.5 hectares (36 acres) in southern Richmond, BC. It contains shops and restaurants, cinemas, bowling alleys, ice rinks swimming pools and spas. The WWTP is a private facility serving the complex and some surrounding residential areas. The complex is situated along a stretch of the Fraser River known as the Fraser River Port, which begins at the mouth of the river and extends 270 kilometres (168 miles) inland. 38.8 million tonnes of cargo are shipped through the port annually, making it the second largest in Canada.

References:

1. Zimmer, J. L., Slawson, R. M. & Huck, P.M. Potential repair of Escherichia coli DNA following exposure to UV radiation from both medium- and low-pressure UV sources used in drinking water treatment. Applied & Environmental Microbiology, Vol. 68 (2002), No. 7, 3293-3299.
2. Oguma, K., Katayama, H. & Ohgaki, S. Photoreactivation of Escherichia coli after Low- and Medium-Pressure UV Disinfection Determined by an Endonuclease Sensitivity Site Assay. Applied & Environmental Microbiology, Vol. 68 (2002), No. 12, 6029-6035.
3. Hu J. Y.,  Chu, S. N.,  Quek, P. H., Feng, Y. Y.,  and Tan, X. L. (2005). Repair and regrowth of Escherichia coli after low- and medium-pressure ultraviolet disinfection. Water Science and Technology: Water Supply, Vol. 5, No. 5, 101-108.

UV disinfection specialist Aquionics will be showing its industrial UV disinfection systems at the 50th Annual InterBev Convention and Trade Show in Las Vegas, NV in September (booth 673 ).

Among the new products on show will be the AF3 industrial UV system. Capable of handling flows between 400 and 13,300 gallons per hour (1.5 and 51.0 m3 per hour) with lamp outputs ranging from 51 to 270 watts, the AF3 series uses low pressure amalgam UV lamps. The units have a small footprint and can easily be installed within existing pipework, vertically or horizontally, even in very restricted spaces. They can be fitted either with automatic wipers or quick release Tri-Clamps, both of which keep the quartz sleeves surrounding the UV lamps clean and clear of deposits, ensuring optimum UV output at all times.

A selection of Aquionics’ other UV systems will also be on display, including a transparent model showing the internal workings of a typical UV system. Experts will be on hand at all times to provide technical expertise and answer questions on the applications and advantages of UV in beverage manufacturing.

UV disinfection specialist Aquionics will be showing its validated, medium pressure InLine+ UV system at this year’s WEFTEC Technical Exhibition & Conference in Chicago, Illinois. The InLine+, which is specially optimized to treat high volume water and wastewater flows, is validated under the German DVGW* standard for drinking water and is currently undergoing US EPA drinking water validation.

A selection of Aquionics’ other UV systems will also be on display, including a transparent model showing the internal workings of a UV system, such as the lamp wiper mechanism. Experts will be on hand at all times to provide technical expertise and answer questions.

WEFTEC Technical Exhibition & Conference
October 18-22, 2008
McCormick Place
Chicago, IL
Aquionics Booth No: 32109

* German Technical and Scientific Association for Gas and Water

UV disinfection specialist Aquionics has appointed Bill Decker as its new President. Bill has extensive experience in the wastewater treatment industry, having spent 14 years with Ashbrook-Hartley Operations L.P., a company specializing in wastewater treatment technology. He held various positions with Ashbrook-Hartley, most recently Vice President of Biosolids. He also spent two years as an Operations Director at the company’s United Kingdom manufacturing facility.

Commenting on his appointment, Bill says, “Aquionics is a well respected company with proven, market leading technology. We were the first company to introduce the ‘InLine’ concept to UV wastewater treatment applications in the USA. My aim is to consolidate and build on our position as an industry leader by providing high quality UV systems and excellent customer support across the entire spectrum of water and wastewater treatment applications – both municipal and industrial, including high purity water.”

Bill has a BSc in Civil Engineering from the US Air Force Academy and is a member of both the Water Environment Federation (WEF) and the Water and Wastewater Equipment Manufacturers Association (WWEMA).

UV disinfection specialist Aquionics exhibited its validated medium pressure InLine UV system at the ACE08 Annual Conference & Exposition in Atlanta, Georgia in June.

A selection of Aquionics’ other UV systems were also on display, including a transparent model showing the internal workings of a UV system, such as the lamp wiper mechanism. Experts were on hand at all times and answered many questions from visitors interested in UV technology for municipal water treatment applications.

It is now almost five years since UV disinfection technology from Aquionics was selected to provide Cryptosporidium-free drinking water for the City of Henderson in Nevada. Henderson, the second largest city in Nevada, decided to upgrade and modernize its water treatment system in 2001 to enhance water quality and meet increasing demand. It was the first surface water plant in the USA to be specifically designed for Cryptosporidium inactivation with approval from the State and the USEPA.

“We were very proud to be the first plant in the USA to utilize this technology for Cryptosporidium inactivation,” says Mike Morine, Manager of Technical Services. “We take our commitment to the health and safety of our residents very seriously and we implemented this project to provide the best possible disinfection for our community. We saw UV as a cost-effective way of achieving this and since its installation almost seven years ago the Aquionics plant has helped us to exceed the USEPA’s water quality regulations. It has certainly exceeded our expectations.”

Treating 15 million gallons per day (mgd), the UV disinfection plant consists of four medium pressure UV chambers, each with an independently validated capacity of 5 mgd. Three chambers are in constant use, with the fourth on standby. The plant is completely automated with UV dose control, fail-safe features and reliable automatic cleaning for ease of maintenance. The water, which originates from Lake Mead, is coagulated with ferric chloride then flocculated and filtered before passing through the UV chambers prior to distribution. The Aquionics system provides at least 99 percent inactivation of Cryptosporidium oocysts, the infective stage of the organism which is resistant to chlorine.

Cryptosporidium is a single-celled parasite that invades the human digestive and respiratory systems, causing cryptosporidiosis. While the disease is often asymptomatic, intestinal cryptosporidiosis can cause severe diarrhea lasting two to four days in adults or up to four weeks in children.

UV disinfection is among only a few proven methods for rendering Cryptosporidium harmless, and it does so without the use of chemicals. UV light has been used successfully for disinfection of industrial process water and municipal effluent worldwide and for drinking water treatment for many years. Recent research documenting the effectiveness of UV disinfection against Cryptosporidium oocysts and Giardia cysts has made the technique a powerful and cost-effective alternative to ozone disinfection and other methods for water treatment.

UV disinfection specialist Aquionics has appointed Kevin Shannon as its new Vice President of Sales and Marketing.

Kevin has considerable experience managing the sale of electrical equipment, lighting ballasts and specialty electronics. He joins Aquionics from Schneider Electric–Square D, where he was Senior Product Marketing Manager with responsibility for a portfolio of electrical equipment products. Prior to that he was Product Marketing Manager for Busway and Wire Management Products. Kevin has a B.S. in Industrial Engineering from Clarkson College of Technology, Potsdam, NY.

Aquionics is a market leader in the manufacture, application and development of UV technology for progressive, non-chemical disinfection and microbiological control. The company’s systems are used in a wide variety of applications including municipal water and wastewater treatment, high purity water treatment in the pharmaceutical, electronics and power generation industries, food and beverage processing, brewing, and aquaculture.

The Salish Kootenai Tribal Reservation in north-west Montana has recently opted for a mobile UV disinfection unit from Aquionics to treat wastewater at two remote wastewater treatment plants (WWTPs).

 
The two WWTPs, which are approximately 15 miles apart, are both small aerated secondary lagoon facilities that only discharge their effluent for one or two months a year. The Tribe had originally considered commissioning open channel UV disinfection systems at each location, but was concerned about the expense involved with this approach.

Aquionics’ local representative, Doug Mitch of Able Wright, worked closely with the Tribe’s in-house engineering staff to develop a different approach. The solution was a turn-key mobile disinfection unit capable of serving both wastewater facilities. Consisting of an 8′ x 16′ enclosed trailer, it contains a pair of Aquionics closed vessel UV chambers installed in series and their associated controls, an end-suction centrifugal pump and piping system, along with lights, ventilation and cam lock hose connections located on the exterior.

The only site work required at the two facilities was the installation of single phase 230V buried power supplies and outlet pedestals at the discharge locations. The total cost of the mobile disinfection unit, along with the site work at both facilities was approximately 40% of the cost of two open channel UV systems.

“We are very proud of the project as it addressed the technical disinfection needs of the community, with proper attention paid to their cost and value concerns. It also provides the Tribe with a highly versatile disinfection system,” commented Mitch.

It is now nearly three years since Poughkeepsies’ Water Treatment Facility in New York state installed six Aquionics UV disinfection systems for drinking water treatment. In that time the closed chamber, medium pressure systems have been performing beyond expectations.

“We get approximately 5,000 hours of lamp life per UV system, but a few lamps have run for as long as 11,000 hours, which is excellent” commented Paul Lill, the facility’s plant manager. “This means we only have to change the lamps about once a year while also reducing our running costs – always an important consideration.”

Poughkeepsies’ Water Treatment Facility serves a community of nearly 80,000, drawing water from the Hudson River to meet an average daily demand of 10.5MGD.  Prior to installing the Aquionics equipment in March of 2005, chlorination was used in open settling basins, followed by filtration. This process required substantial chemical usage and produced significant disinfection byproducts.

With the addition of the Aquionics UV treatment equipment the amount of chlorine required for primary disinfection was significantly reduced, with a corresponding lowering of disinfection byproducts by up to 20%. Secondary, residual disinfection is provided by chloramines. The resulting disinfection levels complied with the new guidelines of the Surface Water Treatment Rule issued by the EPA.

The six Aquionics UV systems are situated downstream of the filters and operate in parallel.  The medium pressure, closed channel design disinfects with far fewer lamps and with a much smaller footprint than comparable low pressure systems. Each chamber is fitted with UV monitors to measure actual UV fluence and dose for record keeping. With the addition of an optional online transmittance monitor, real time transmittance values are used to automatically adjust the dose pacing of the UV system.

“We originally considered alternative disinfection technologies to meet our goals,” explained Lill. “The units’ lower relative cost, their compact size which fits into our existing facility and the technical merit were all deciding factors in choosing Aquionics equipment.”

To keep maintenance low, the systems are equipped with automatic cleaning mechanisms which keep the UV lamp sleeves free of organic deposits. When the lamps need replacing, it is a simple operation that is carried out by on-site staff.

Loch Fyne Oysters in Scotland, United Kingdom, has chosen two medium pressure UV disinfection systems from Aquionics’ British sister company for its oyster farm in Loch Fyne, Cairndow. The UV systems destroy harmful E.Coli bacteria from the oyster and mussel depuration tanks. Each UV chamber can treat up to 40,000 gallons of water per hour (150 cubic meters per hour).

According to a spokesperson from Loch Fyne Oysters, “The UV units were recommended to us by the installers Barr and Wray because of their 99.99% log reduction of E.Coli, their robust, stainless steel construction, their ease of installation and easy maintenance – including easy UV lamp replacement and daily cleaning with a manual wiper – and low running costs. We also find the digital run-time read-out very useful, and the price was very competitive.”

Aquionics UV systems can be used in farms and hatcheries to treat both incoming and recirculation water, allowing flexibility in the choice of site and a rapid payback for farmers. UV is ideally suited for this application as it uses no chemicals and does not create by-products which would harm the stock, or other aquatic life, on discharge. Unlike other treatment methods, UV also avoids the expense of complex monitoring systems involved in adding and removing chemicals before the water reaches the stock. In addition, it does not alter the pH of the water. Indeed, UV is the most economical disinfection technique that can be used in aquaculture.

Maintenance of the systems is restricted to the replacement of the UV lamps every 12 months, a simple operation that can be carried out by on-site staff. An automatic or manual wiper can be fitted over the quartz sleeve which surrounds the UV lamp to prevent the build-up of any deposits, ensuring maximum levels of irradiation at all times.

A significant feature of Aquionics’ UV systems is the Photon control panel which displays a range of useful functions such as flow rate, UV dose and intensity. It is capable of logging up to one year’s performance data, which can be downloaded to a PC through an RS232 port. Linked into a central computer, the control panel can also be operated remotely, and allows the system to operate around the clock.

To date Aquionics has installed over 300 aquaculture systems in 14 countries around the world. Applications include water treatment in hatcheries, fish farms, shellfish depuration tanks and fry rearing tanks, as well as treating re-circulation water in marine parks and aquaria.