Omnifit® Bottle Caps Cut The Cost Of Laboratory Safety

Bio-Chem Fluidics manufactures a range of Omnifit® bottle caps and accessories which prevent harmful chemicals and solvent vapours from escaping, ensuring a safe and dependable solvent delivery system in the laboratory.

T-Series bottle caps

Following an extensive re-engineering programme, the company has now reduced the cost of its T-Series bottle caps. Featuring a PTFE* inner portion, which offers a high level of chemical compatibility, T-Series caps have an anti-twist design which allows the inner body of the cap to spin freely. This prevents tubes being twisted when the cap is fitted or removed and eliminates the need to disconnect fluid lines before unscrewing the cap.

The caps are very easy to use and require no fittings – standard 1/8” laboratory tubing is simply pushed through Luer ports on the top of the cap. These ports allow connection of other tubing sizes and types with a range of Luer adaptors which are available separately. Optional integrated check-valves and filters are also available, enabling pressure to be equalized within the bottle as liquid is drawn out and preventing particulate contamination.

*PTFE – poly(tetrafluoroethene) or poly(tetrafluoroethylene) is an inert, synthetic fluoropolymer. Because of its non-reactive properties it is ideal for use in containers and tubing for reactive and corrosive chemicals.

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Volk H-R Wide Field Lens for Laser and Diagnostic Work

High resolution lens allows visualization of details approaching the ora serrata

Volk Optical, a world leader in aspheric optics, has released the H-R Wide Field Laser Lens, a new pan-retinal lens for diagnosis and laser treatment. Its high resolution imaging, coupled with an extremely wide field capability, provides detailed views for diagnostic and laser work.

HR Wide

(Photo Caption: The Volk H-R Wide Field Laser Lens delivers superior imaging for diagnostic needs and PRP laser treatment)

The H-R Wide Field’s deep field of view reveals details as far out as the ora serrata and most importantly, is distortion free across the entire viewing area. The combination of Volk’s patented double aspheric glass design with low dispersion glass ensures the highest resolution imaging across the entire viewing field.

This superior viewing power is contained in a low-profile, reduced-size housing to simplify manipulation of the lens within the orbit. The H-R Wide Field has been compared favourably to the popular discontinued Rodenstock Pan Fundus Laser lens, with an even wider field of view and better image quality.

The lens provides a 0.50x magnification, and a 2.0x laser spot magnification and is the best choice for widest field diagnosis and PRP laser treatment. While the H-R Wide Field is a contact lens, requiring the added step of a coupling solution to the examination, it ensures clear visualisation of retinal tears or lesions across the entire retinal surface.  No non-contact lens exam method is able to achieve this level of image clarity and detail.

For more information about Volk products, please visit www.volk.com, e-mail John Strobel at johns@volk.com or phone him on +1 440-942-6161. The company is currently looking for distributors in India and any interested parties are invited to contact John Strobel for more information.

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New – Complete Range of Soil Testing Kits from Palintest

On-Site Analysis for Growing, Farming and Soil Management

Palintest, leaders in the supply of specialist water and environmental analysis equipment, have launched a complete new range of soil testing kits. The kits are designed for use ‘in the field’, and cover all levels of user requirement.

Soil Test Kit

The kits are tailored to cater for the needs of everyone from the keen gardener to the professional soil specialist: from a simple ‘colour match’ pH & lime requirement testing kit (the SK 100), to the comprehensive Complete Soil Kit (SK 500) which provides both macro and micro nutrient analysis.

Soil testing is integral to effective agricultural and horticultural management, as well as a vital aspect of disaster relief and recovery efforts. The safety and suitability of soil for use can be measured quantitatively by testing for the presence and concentration of various chemical elements. This can be carried out by taking samples and sending them away to a laboratory for analysis and awaiting the results – or, with the right equipment and components, tested for instantly on the spot.

The kits are supplied with portable carrying cases for both the chemicals and instruments, and include easy-to-follow instructions for correct usage. The Palintest Soil Test Kits use reagents compressed into a stable tablet form for easy, safe and precise transportation and application. This negates the need for the careful measurement and handling of liquid components in the field. The more advanced kits also include a portable Palintest photometer, which makes the measurement even quicker, easier, and more accurate. Please visit the www.palintest.com for further information on the specific details of each of the test kits in the range.

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Fireray Protects Indian Cinemas

28 of British company Fire Fighting Enterprises’ Fireray reflective beam detectors have been installed across eight Adlabs Films cinema complexes in India, by regional distributor Code Red Electronics & Security Systems. A further seven Adlabs cinema projects are expected to follow suit, requiring another 30 detectors.

Indian cinemas

Adlabs Films Ltd. is India’s fastest growing film entertainment company, and runs the largest Indian cinema chain – BIG Cinemas, with nearly 400 screens across the subcontinent, Malaysia and the U.S. In the year to come, more than 30 million people are expected to watch a film in one of the company’s theatres, and it is naturally of vital importance to safely protect them in the event of a fire. To that end, eight F100R and 20 F50R Fireray units are now protecting the Lakshmi, Alankar, Ganesh, KS, Nagalaskhmi, Keerthana Ramana, Prakash Kailiash and Majesty Theatres, all in the south-eastern region of Tamilnadu.

FFE’s reflective beam products were selected for these installations due to their proven reliability, easy maintenance and installation, and exceptional coverage range in large indoor areas – the wide, high ceilings of the cinema screens would take many, many point detectors to protect effectively. One Fireray F100R can safely detect smoke over an area of 1500m2 – 100m x 15m, 7.5m laterally either side of the beam; it would take at least 14 point detectors to cover that same space.

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Halma p.l.c. Appoints Director Of New India Hub

Multinational Extends its Presence into India

Halma has appointed Kuniyur Srinivasan as Managing Director of its new India Hub in Mumbai. Kuniyur has extensive experience of starting up and growing businesses in India and also of selling high quality foreign products into the Indian market. He will play a pivotal role in establishing Halma and its subsidiary companies in India.

Srini

Kuniyur, 43, joins Halma from Satisloh AG, an optical machinery manufacturing company, where he served for six years as Country Head, with responsibility for all business aspects in India and the Middle East. He previously held a number of senior sales positions in the industrial products business of a large Indian industrial group, most recently serving as Head of International Business. As well as having a degree in Mechanical Engineering, Kuniyur has a  postgraduate degree in Foreign Trade from the  Directorate General of Foreign Trade.

The new India hub is part of an expansion by Halma into the fast growing economies of Asia. The company recently opened hubs in Beijing and Shanghai, and the Mumbai hub is a continuation of this process. It will initially provide administrative, accounting, legal and business development services to Halma’s subsidiaries, eventually expanding to offer other services such as sales and marketing. Another important role is the provision of R&D and software development assistance to subsidiary companies, taking advantage of India’s highly educated workforce.

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UV Disinfection Of Drinking Water – Innovation, Development and Opportunities

Introduction

Conventional drinking water treatment technologies include the use of chlorine or other oxidants for final disinfection. In the case of surface waters, pre-treatment such as coagulation, sedimentation and filtration is generally used to prepare the water before final disinfection. The disinfection of drinking water using chemicals has successfully protected public health against waterborne disease for many years.

UV lamp

There are a number of drawbacks to chemical disinfection, however, such as potentially toxic by-products and problems with taste and odour. The emergence of water-borne pathogens such as Cryptosporidium, which are resistant to chemical disinfection, has led to a reappraisal of traditional disinfection practices. Water companies and regulators need to consider how they can respond to such concerns without compromising safety and public health and whilst maintaining scientific credibility.

The development of UV disinfection technology over the last decade has been a perfect example of an industry investing to meet this demand need for an effective, low cost, non hazardous and environmentally friendly water disinfection technology. The acceptance of UV disinfection at water plants treating in excess of three billion litres daily worldwide is proof that UV is no longer an ’emerging’ technology, but rather an accepted technology to be used routinely by engineers to safeguard human health. The UV industry continues to change, grow and invent new products and applications.

Growing Maturity of the UV Industry

Virtually all of the leading UV companies have now been acquired by multi-product, financially mature industrial groups such as ITT, GE, Halma, Siemens and Suez. This has induced market stability and, whilst this will ensure highly professional product offerings, it also means that many of these newly acquired companies must either become or remain profitable to justify the investment made in them. The regulatory acceptance of UV for treating drinking water and regulatory standards for validating new UV reactor designs all signal a major shift in the acceptance of the technology into the mainstream. The UV industry has experienced double digit sales growth over the last 20 years, and combined annual sales of UV products worldwide will soon be in excess of US$600 million.

Massive Potential for Growth

Probably the greatest potential market for UV disinfection is drinking water. UV is now accepted as a suitable technology to deactivate Cryptosporidium and Giardia in surface water and other vulnerable sources. From 1997 to the present growth in this market has been generally slow due to several factors, including the uncertainty of sensitivity of Cryptosporidium and Giardia to UV, the lack of a regulatory framework for UV disinfection, the widespread lack of guidance manuals, the lack of case histories and engineering knowledge in the application of UV in drinking water plants, the general conservatism of the water industry and, finally, the uncertainty of the outcome of several court cases considering a royalty on the use of UV for Cryptosporidium and Giardia destruction.  All of these issues have now either been resolved or resolutions are imminent, paving the way for rapid growth in this market.

UV Disinfection – the basics

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.

There are two main types of UV technology, based on the type of UV lamps used: low pressure and medium pressure. Low pressure lamps have a monochromatic UV output (limited to a single wavelength at 254nm), whereas medium pressure lamps have a polychromatic UV output (between 185-400nm).

DNA has its maximum absorption at both 200nm and 265nm (Von Sonntag, 1986). Maximum absorption does not occur at 254nm, the wavelength produced by low pressure lamps and often wrongly assumed to be optimum wavelength for killing microorganisms. At 200nm most absorption occurs in the ‘backbone’ DNA molecules of deoxyribose and phosphate. At 265nm, UV absorption mainly occurs in the nucleotide bases: adenine, guanine, cytosine and thymine (and uracil in the case of RNA). The most common products resulting from damage by UV radiation are thymine dimers, which are formed when two adjacent thymine molecules become fused. The formation of these dimers and other photoproducts prevents the DNA from being able to replicate, effectively killing the cell.

In some cases UV is effective above 265nm. It has been shown, for example, that the optimum wavelength for destroying Cryptosporidium parvum oocysts is 271nm (15% more effective than 254nm) (Linden, 2001), while the optimum wavelength for Bacillus subtillis is 270nm (40% more effective than 254nm) (Waites, 1988).

In addition to DNA and RNA, UV also causes photochemical reactions in proteins, enzymes and other molecules within the cell. Absorption in proteins peaks around 280nm, and there is some absorption in the peptide bond (-CONH-) within proteins at wavelengths below 240nm. Other biological molecules with unsaturated bonds may also be susceptible to destruction by UV – examples include coenzymes, hormones and electron carriers. The ability of UV to affect molecules other than DNA and RNA is particularly interesting in the case of larger microorganisms such as fungi, protozoa and algae. In these microorganisms, although UV may be unable to penetrate as far as the DNA, it could still have a lethal effect by damaging other molecules.

Recovery from UV Damage

The need to recover from or repair UV damage is common to virtually all microorganisms that are regularly exposed to UV light in nature. Known as reactivation, the process can take place in both light and dark conditions and is called, respectively, photoreactivation and dark repair. The ability to reactivate varies significantly depending on the type of UV damage inflicted and by the level of biological organization of the microorganism. The repair mechanism is not universal and there are no clearly defined characteristics determining which species can repair themselves and those which cannot.

The part of cells most vulnerable to UV damage is the DNA and RNA. This is due partly to its unique function as the repository of the cell’s genetic code, and also because of its highly complex structure and large size. It is hardly surprising therefore that all known molecular repair mechanisms have evolved to act upon the macromolecular nucleic acids, particularly DNA. In photoreactivation, repair is carried out by an enzyme called photolyase which reverses the UV-induced damage, while in the case of dark repair it is carried out by a complex combination of more than a dozen enzymes. To begin reactivation (both light and dark), these enzymes must first be activated by an energy source – in photoreactivation this energy is supplied by visible light (300-500nm), and in dark repair it is provided by nutrients within the cell. In both cases, reactivation is achieved by the enzymes repairing the damaged DNA, allowing replication to take place again.

Common strains of E. coli contain about 20 photolyase enzymes, each of which can repair up to five thymine dimers per minute – this means that, in a single cell, up to 100 such dimers can be repaired per minute. 1mJ/cm2 of UV produces approximately 3000-4000 dimers (Oguma, 2002) so, theoretically, damage induced by 1mJ/cm2 of UV can be repaired in just 30 minutes.

Repair After Exposure to Low and Medium Pressure UV

Low pressure UV lamps have traditionally been used in water treatment plants because their UV output at 254nm closely matches the absorption peak of DNA bases at 265nm. A number of studies, however, have shown that microbial DNA is capable of photoreactivation after exposure to low pressure UV (e.g. Sommer et al, 2000).

Because of these findings, and because of the increased use of medium pressure UV lamps in water and effluent treatment, recent research has begun to look at whether medium pressure UV can permanently inactivate the DNA of microorganisms. It has been suggested that, because the broader wavelengths emitted by medium pressure lamps not only damage DNA but also cause damage to other molecules, it is therefore much more difficult for cells to repair their DNA.

The recent research compared the effects of low pressure and medium pressure UV on the ability of microorganisms to repair their DNA. In their tests they compared the ability of E. coli to recover in photoreactivating light after being exposed to different amounts of low and medium pressure UV. E.coli was used in the study as it is a useful ‘biological indicator’ of disinfection efficiency in water systems. The results of these studies showed a significant difference in photoreactivation following low and medium pressure radiation. While high levels of photorepair were observed after low pressure irradiation, with maximum repair occurring after 2–3 hours, there was virtually no photorepair after medium pressure treatment. This was particularly the case at higher log reductions (log 3 and above) (Oguma et al (2002), Zimmer et al (2002) and Hu et al (2005).

Zimmer et al proposed a number of reasons why medium pressure UV causes irreparable damage, while low pressure UV does not. One hypothesis is that there is a synergistic effect between the various wavelengths emitted by medium pressure lamps that causes irreparable damage to the DNA. Another possible explanation is that the repair enzymes themselves are damaged. According to Zimmer et al, while absorption of UV by proteins is considered of little importance to cells, any damage to repair enzymes would be critical due to that fact that there are so few of them present in the cell.

All these studies concluded that polychromatic medium pressure UV radiation was more effective than monochromatic low pressure UV at causing permanent, irreparable damage to the DNA of E. coli.

Implications of the Findings

The implications of these findings are far-reaching. For any installation where UV is used to disinfect drinking water, the operator needs to be sure that the treatment is permanent. Zimmer at al suggest that medium pressure UV could therefore provide better protection against reactivation. A much larger research effort into the area of photoreactivation is still required, especially research involving real water treatment plants, and this will most likely be forthcoming over the next 5 years.

Developing UV Technology

The use of computational fluid dynamics modelling has vastly improved UV system manufacturers’ ability to predict with confidence the level of treatment required using their proprietary equipment. System sizing is no longer a black art, as the selected manufacturer can work with the design engineer to accurately predict treatment levels under varying conditions of water quality and flow. All UV equipment manufacturers will soon use this tool to optimize the dose delivery of their reactors and minimize energy costs. As manufacturers develop and improve optimized reactors, they will then validate the designs using USEPA* validation protocols.

Conventional UV lamp technology will also improve, with medium pressure lamps continuing to see gains in energy efficiency, lamp life and power density. This approach will remain favoured for compact, small footprint installations, particularly retrofit, or where automated wiping is required. Low pressure, high output lamps will also have increasing power, perhaps approaching 1kW, which will decrease the footprint and maintenance requirements for systems using this technology. Lamp disposal will emerge as a significant issue for low pressure UV installations which use many thousands of low pressure  lamps.

UV monitor technology has also greatly improved over the last decade, with stable, reliable and germicidally accurate sensors now available and a well regulated calibration protocol now in place. In addition, manufacturers have improved the proprietary control systems for taking information from the sensors, flow meters and other monitoring devices and using this information to optimize the performance of their equipment. They can also interface with the operator at a plant’s control centre.

The D10 values** of more and more microorganisms is now known, with the list growing all the time. Most notably, research has confirmed the very low doses required to disinfect Cryptosporidium and Giardia, while also finding several viruses that have an unusually high D10. As new applications for UV are found, new microbes will be added to existing D10 tables.

Case Study – Paris, France

A large scale UV disinfection system from Dutch UV specialist Berson is treating drinking water for around 650,000 people in Paris, France. Located to the north of the city in the suburb of Méry-sur-Oise, the system is one of the largest European installations of Berson’s InLine range of UV equipment. Five InLine 1500 units are installed in parallel to provide disinfected drinking water at the rate of 7500 m3/h.

Owned by SEDIF (the Syndicat des Eaux d’Île-de-France) and operated by the Compagnie Générale des Eaux, the plant uses water from the nearby River Oise. Following pre-treatment and nanofiltration, the water is pumped through the UV units which kill any remaining microorganisms. The treated drinking water is supplied to 37 districts in the northern suburbs of Paris, with daily production totalling 340,000 m3.

The InLine units feature Berson’s innovative MultiWave medium pressure UV lamps, which are orientated perpendicular to the water flow to achieve optimum UV exposure. An integral sensor monitors UV light intensity in each treatment chamber, while a custom-built control panel provides communication between the UV units and the plant control room.  Also incorporated in each UV unit is an automatic wiping mechanism which cleans the quartz sleeves surrounding the lamps and keeps them free of water-borne deposits.

Conclusion

The UV industry has matured considerably over the last decade and is now highly regulated and dominated by major water companies. Conventional UV technologies have been field tested and now have considerable track records in a wide range of applications.  Uncertainties surrounding regulations, royalties, technology and engineering have decreased and acceptance of UV is expected to grow rapidly over the next 20 years.

The advantages of medium pressure UV is becoming more apparent as a way of permanently destroying microorganisms. More research in this area is required, especially in real water treatment plants.

Conventional UV designs have been greatly aided by CFD***, which will be used as a routine sizing tool for future designs. Incremental improvements in conventional lamps, monitors and controls will also continue over the next decade. The stage is now set for dramatic growth in the drinking water market, especially if new technologies can bring increased efficiencies and lower costs.

Notes

* U.S. Environmental Protection Agency
** The D10 value for a microorganism is the UV dose necessary to cause a 99% reduction in colony forming units. The relationship between UV dose and kill rate is logarithmic. For example, if a 99.99% kill rate of a particular microorganism is desired, the necessary dose is determined by multiplying the D10 value by four.
*** Computational Fluid Dynamics

References

Harm, W. (1980). Biological effects of ultraviolet radiation, pp. 23-39. Cambridge University Press, New York, NY.

Hu, J.Y., Chu, S.N., Ouek, P.H., Feng, Y.Y. & 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, IWA Publishing.

Linden, K. G. (2001). Comparative effects of UV wavelengths for the inactivation of Cryptosporidium parvum oocysts in water. Water, Science & Technology, Vol. 34, No. 12, 171-174, IWA Publishing.

Oguma, K., Katayama, H. & Ohgaki, S. (2002). Effects of wavelengths of inactivating UV light on photoreactivation of Escherichia coli. Department of Urban Engineering, University of Tokyo.

Oguma, K., Katayama, H. & Ohgaki, S. (2002). Photoreactivation of Escherichia coli after low- or medium-pressure UV disinfection determined by an endonuclease sensitive site assay. Applied & Environmental Microbiology, Vol. 68, No. 12, 6029-6035.

Sommer, R., Lhotsky, T., Haider, T. & Cabaj, A. (2000). UV inactivation, liquid-holding recovery, and photoreactivation of Escherichia coli O157 and other pathogenic Escherichia coli strains in water. Journal of Food Protection, 63, 1015-1020.

Zimmer, J. L. & Slawson, R. M.  (2002). 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, No. 7, 3293-3299.

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The Advantages Of Closed Pipe Medium Pressure UV Disinfection For Wastewater

Introduction

While a relatievly new technology in India, the use of closed pipe, medium pressure UV disinfection systems for wastewater treatment has seen tremendous growth in Europe, the USA and Australia over the last 10 years. More and more operators of wastewater treatment facilities in these regions are now opting for closed pipe UV disinfection systems instead of older, open channel low pressure UV systems. This change is being driven by the very real advantages of closed pipe systems.

In-Line cutaway

The disadvantages of open channel disinfection include the large footprint required for the disinfection channels; the large number of low pressure lamps required; the difficulty in cleaning the lamps, which sometimes have to be cleaned manually –  a laborious procedure – or physically lifted and moved to an acid bath; significant pressure drop; the danger of personnel being exposed to UV light; and the growth of algae in the open channels. Also, the hydraulic movement of liquids through open channels is not particularly turbulent, so some sections of the wastewater may not pass close enough to the UV lamps to receive the minimum required UV dose.

Closed pipe medium pressure UV systems, on the other hand, have a much smaller footprint, as the UV chambers are inserted into existing pipework; the number of lamps is much less as medium pressure lamps have a significantly higher UV output than low pressure lamps; the lamps are fitted with a mechanical wiper on their protective quartz sleeve which keeps them clean – something that is not possible with low pressure systems. Periodic chemical cleaning, if required, is simple and can be done ‘in-line’ without removing the lamps. Pressure drop is much less as the wastewater passes directly through the treatment chambers. In addition, as the chambers are completely enclosed there is no danger to staff; this also eliminates the problem of algal growth. In addition, lamp change-over is easy and can be done in minutes. The hydraulic design of closed-pipe systems also means the movement of wastewater through the treatment chamber is more turbulent than in open-channels, ensuring all the wastewater receives the minimum required UV dose by passing close to the lamps. This has been confirmed by CFD modelling.

Medium pressure lamp technology

Medium pressure UV lamps emit UV over a broad wavelength and have 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 a single peak of UV output. It has been shown that many microorganisms are able to repair themselves after exposure to UV from these low pressure lamps, especially if they are subsequently exposed to sunlight – as is often the case in wastewater treatment facilities (see references above).

In addition, only a few medium pressure lamps do the same job as many low pressure lamps – this makes medium pressure systems much easier to operate, monitor and maintain. Because of these factors, low pressure UV lamp technology should be avoided in wastewater applications.

Cleaning of quartz sleeves

A major factor to consider with UV wastewater treatment plant is fouling of the protective quartz sleeves surrounding the UV lamps. Suspended solids and minerals in the wastewater attach themselves to the sleeves and must be removed at regular intervals to ensure maximum UV output. This is something that happens to both low and medium pressure UV lamps, and in both open-channel and closed-pipe systems.

There are two main ways to control fouling: mechanical cleaning of the sleeves (with O-rings or brushes) or chemical cleaning with acids. Even when mechanical cleaning is used, the sleeves will still need to be chemically cleaned from time to time. As explained above, with open-channel UV systems the UV lamps must be physically lifted from the channel and transferred to an external chemical bath.

With closed-pipe UV systems, cleaning agents are simply added to the UV chamber and cleaning takes place internally. When the UV system is on, automatic wipers move up and down the quartz sleeves, removing any deposits. At the same time, a small volume of low concentration acid is applied directly to the sleeves.  This ‘direct dosing’ means significantly less chemicals are required to keep the sleeves clean than with conventional chemical dosing. The chemicals used are not harmful in any way either to the environment or to the wastewater plant’s pipeline infrastructure.

Case Studies

Georgia, USA
Berson’s closed vessel UV disinfection equipment is helping the award-winning Flat Creek Water Reclamation Facility (WRF) in Georgia, USA, exceed permit limits for faecal output by a significant margin.

“We installed three Berson medium pressure InLine UV systems over six years ago, adding three more in 2004, and they have performed exactly as expected, with all our faecal samples well below the permit limit,” commented Flat Creek’s Plant Manager Michael West.

The Flat Creek WRF recently gained a second place National Clean Water Act Recognition Award for operations and maintenance from the US Environment Protection Agency (USEPA). According to the USEPA, the Flat Creek Water Reclamation Facility is one of the two treatment plants in Georgia recognized for “their innovative approaches and achievements,” which “improve water quality and protect public health and the environment in the communities they serve.”

The Berson units are arranged in three trains of two chambers each, providing a ‘series’ approach to ensure adequate disinfection to the 23 faecal colonies per 100ml sample required by the National Pollution Discharge Elimination System (NPDES) permit. The systems are designed to treat a combined total of over 45 million litres per day of wastewater (up to 80% industrial and 20% low level commercial and residential) for discharge into nearby Lake Lanier. “With the impact of the severe drought in our area causing the level of the lake to fall to historically low levels, every drop of reclaimed water that can possibly be returned to the lake is essential,” added West.

This closed vessel design was an important feature for the City of Gainesville, which Flat Creek serves. When first selecting UV equipment for the Flat Creek WRF, representatives from the City’s Public Utilities Department visited several neighbouring metro Atlanta facilities and examined a range of open and closed pipe systems from various manufacturers. “The excessive man-hours required to keep an open channel unit clean was a large factor in choosing the Berson closed channel system initially,” said West.

Ease of handling was another positive feature, according to West, as rather than handling an entire bank of UV lamps at a time, the InLine’s single lamps may be changed quickly and easily by plant personnel. To further reduce maintenance, the chambers are equipped with an automatic cleaning mechanism to keep lamp sleeves free of organic deposits.

Arizona, USA
Two golf courses in Anthem, Arizona, are using UV-treated wastewater for irrigation. Founded less than 10 years ago Anthem, a town just north of Phoenix, now has a population of over 40,000. As part of its rapid expansion the town recently installed three closed chamber, medium pressure Berson UV systems to disinfect its wastewater. This allows the town to not only meet increased demands in its water and wastewater treatment capacity, but also to exceed the output quality standards.

“The wastewater is treated by three Berson InLine systems handling a combined flow of three million gallons per day,” explained Anthem’s wastewater Foreman Jeff Marlow. “They work in conjunction with microfiltration and nitrification/denitrification. We chose the Berson UV systems because they are optimized to meet the upcoming Arizona Pollutant Discharge Elimination System (AZPDES) Permit Program,” he added.

The two local golf courses currently use a combination of UV treated wastewater and fresh river water for irrigation, but with increase in population, it is expected that the courses will soon be using wastewater exclusively.

An automatic cleaning mechanism keeps the lamp sleeves free of organic deposits for consistent UV dosing. Each chamber is also fitted with UV monitors to measure actual UV 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.

Conclusions

Closed-pipe UV wastewater treatment systems are increasing in popularity with operators of wastewater treatment plant. There are many reasons why these systems are now taking over from older, open-channel systems. Firstly, closed-pipe systems are safer. Secondly, cleaning the UV lamps’ protective quartz sleeves is straightforward – either mechanically or chemically – without having to remove the lamps. Thirdly, the hydraulic design of closed-pipe systems ensures most of the wastewater receives the minimum required UV dose. Finally, closed-pipe systems, in conjunction with medium pressure UV lamps, ensure that microorganisms are permanently deactivated and cannot repair themselves.

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 Sensitivite 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.

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Alcoa Aluminium Chooses Fortress Interlocks To Keep Chinese Workers Safe

The Alcoa (Shanghai) Aluminium Products Co. Ltd. has chosen safety interlocks from Fortress Interlocks to keep workers safe at its factory in Shanghai. 42 Fortress amGard interlocks are installed at the factory to prevent workers from accessing dangerous machinery unless it is safe to do so.

Alcoa

The factory produces premium aluminum foil and the manufacturing process involves hazardous machinery and processes, including casting lines, rolling mills and heavy gauge slitters. Access to this machinery is closed off by heavy duty gates, to which the amGard interlocks are attached. The amGard units are connected to the machinery power supply and only by pressing a button is the power supply switched off. When the machinery has completely shut down the amGard allows the gate to be opened and the machinery can be accessed. The power supply can only be switched on again when the worker has vacated the area, shut the safety gate, and pressed the start button.

Commenting on the Fortress interlocks, Li Hongbing, Alcoa’s Secure Engineer, said, “The Fortress interlocks were recommended to us by one of Alcoa’s Australian factories. We ran a trial and were happy with the result. Since installation they have been working very well – they are easy to use and can withstand constant, heavy use in a harsh industrial environment. I would certainly recommend them to other companies.”

Tested over 1,000,000 operations, Fortress’ amGard products are very robust and designed for the harshest, high risk, industrial applications. amGard consists of a range of control interlocks that are split into gate switches and solenoid interlocks, and also include As-i enabled varieties that require minimal wiring. Its locking mechanism is completely tamperproof and has dual channel safety circuitry, offering a highly secure working environment. The products allow quick and easy access to machinery with minimum production down-time. Users regard the product’s virtually zero maintenance as a major benefit in its daily operation.

In addition to the robust amGard range, Fortress Interlocks also supplies products from its mGard and eGard range for multiple applications. The mGard range is a completely modular set of trapped key interlocks offering mechanical technology to safeguard dangerous machines and hazardous processes. eGard is a fully modular system that controls access to dangerous machinery by combining mechanical trapped key interlocks with electrical safety gate switches and electrical operator controls all in one unit. The modules simply clip together and its lightweight, modular design allows flexibility with over 4,000 billion possible combinations to cater for every application.

Fortress Interlocks is a UK-based company that designs and manufactures mechanical and electromechanical interlocking systems. These provide many benefits to a wide variety of industrial sectors, including metal processing, power generation and distribution, automotive, pulp and paper, textiles and material processing.

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