UV treatments: flexible, safe and low-maintenance

Paul Boughton

Modern UV technologies bring chemical-free, low-maintenance treatment options for all of the process industries. Sean Ottewell investigates.

Hanovia's new PureLine UV range provides chemical-free treatment and water disinfection for the food, beverage and brewing sector (Fig. 1). Joining the PharmaLine and SwimLine ranges, the PureLine is the latest industry-specific UV system from Hanovia designed to make product selection as easy as possible. All that's needed to choose the correct model is the application and the required flow - the appropriate model is then simply selected from the appropriate datasheet. Hanovia will have already specified the necessary dose, chamber geometry, lamp type, surface finish, seal materials and connections that are typically required by that application. Special designs can also be supplied for users who have unusual requirements.[Page Break]

Disinfection of water

Standard PureLine models are available for the disinfection of water, syrups, brines and for the de-ozonation of process water (designated D, S, B and DO respectively), with the range being supplemented by the PureLine PQ.

Ensuring biosecurity of water systems, the performance qualified PureLine PQ is tested and approved by independent experts to the requirements of the USEPA UV disinfection guidance Manual (UVDGM). Benefiting from full flow bioassays conducted by independent engineers across a wide range of operating and water quality conditions, the PureLine PQ guarantees 99.999 per cent disinfection at its maximum bioassayed dose.[Page Break]

Calibrated absolute intensity

Providing proven, constantly displayed and verified disinfection, PureLine PQ is equipped with a calibrated absolute intensity UV monitor and controller, which automatically corrects the dose calculation as UV transmittance varies, without requiring an external UV transmittance monitor. This provides the user with an accurate and instant measurement of the PQ's disinfecting activity.

In addition, because the monitor remains outside the water flow, it can be removed and inspected without interrupting the process, allowing on-site verification using a portable reference UV sensor traceable back to a NIST standard. In addition, material certificates for all the FDA compliant wetted parts and an ability to cope with clean in place/sterilisation in place (CIP/SIP) provides compatibility with food and beverage requirements and above all ensures UV biosecurity of the highest level.

Operating at a lower energy level, PureLine D is intended for general purpose disinfection of water or CIP solutions as part of a multi-barrier system, while the PureLine S and B systems are designed specifically for the disinfection of sugar syrups, liquid sugars, de-aerated liquor (in breweries) and for disinfection of brine in the meat packaging industry.[Page Break]

Unlimited stop-start capability

The PureLine range utilise either high output amalgam or medium pressure UV lamps, whichever is most effective for the application in question. Lamp changing is a simple procedure that can usually be done by on-site personnel with no specialist training. With lamp life up to 12,000 hours and with electronic ballasts and unlimited start-stop and variable output capability on some models, life-time costs and energy consumption are optimised across the range.

The entire range is rated to IP54 as a minimum, with options to IP65, and has a state-of-the-art controller with an on-board message display panel, as well as many other safety and alarm features.

UV treatments supplied by Atg UV Technology are used in a number of key areas to vastly reduce the risk of product rejection and increase shelf life. Additionally full traceability is provided by Atg UV's state-of-the-art Spectra controllers.

One example is bottled water: even high-quality borehole and spring waters can contain natural flora and fauna. The only appropriate method of disinfection is by UV treatment. This will not affect the natural taste or mineral balance of these distinctive brands, and will vastly enhance shelf life.

Another is brewing, where cutting of high-gravity brews poses risk of contamination by deaerated liquor. UV is an effective and convenient technology, as units function automatically. Also, CIP rinse systems usually rely on UV for non-chemical disinfection.

Yeasts and moulds are a major contaminant in concentrated liquid sugar solutions and can contaminate the final product. Atg UV has designed a specific range of liquid sugar UV disinfection systems to deal with the high viscosities encountered in sugar solutions up to 67 brix. The SS (sugar solution) range utilises the latest in thin-film quartz and UVC lamp technology, with specially designed UV chambers. According to the company, the leading SS System range has been adopted by leading food and beverage brands and manufactures worldwide.[Page Break]

Slicing and wrapping

In baking, the company's UV technology is used extensively in both slicing and wrapping units and bread cooling rooms, where bread left cooling in ventilated areas offers the ideal breeding conditions for moulds, and bacteria.

When it comes to make-up water, UV systems can effectively be applied as a final treatment at point of use. Installation can be on a recirculation loop or at strategic points feeding mixing vessels. UV systems can be fully automatic, which is particularly relevant when the water use is batch or intermittent. Process equipment such as sprayers and heat exchangers also benefits from pure water supplies.

The company is also seeing a growth in less traditional applications, for example the disinfection of cranberry juice, orange juice, meat brines and marinades. Most recently it has been used to disinfect ballast water on ocean going vessels in order to prevent to transit of invasive species such as Zebra mussels that get introduced when vessels discharge ballast water at the destination port..[Page Break]

Joint R&D in China

Air Products, a leading global industrial gases and performance materials supplier, has signed a joint research and development (R&D) agreement with South China University of Technology (SCUT) on water purification technology to accelerate the development of sustainable and efficient water treatment solutions, helping local customers meet increasing energy efficiency and environmental improvement targets.

The collaboration between Air Products and the water research group of the School of Environmental Science and Engineering of SCUT will focus on the development of a flexible and effective bioreactor resulting from the integration of ozone reaction and biological aerated filter (BAF) technologies.[Page Break]

Wastewater treatment and reuse

The technologies and solutions developed will be applied to various water and wastewater treatment areas including industrial wastewater treatment and reuse.

In addition, Air Products also has established a scholarship program at SCUT for outstanding students at the School of Environmental Science and Engineering.

"SCUT is outstanding in environmental science with a focus on water treatment. Our strategic collaboration will enable us to advance water purification technology and commercialise sustainable and innovative solutions to meet China's local market needs, as well as cultivate talent. We hope to continue to explore further ways of working together," said Steve Jones, China president, and senior vice president and general manager of tonnage gases, energy and equipment, at Air Products.

SCUT is one of China's key universities operating under the direct leadership of the Ministry of Education of China. SCUT's School of Environmental Science and Engineering owns a number of patents in water treatment technologies and is one of the top research institutes focusing on pollution control and environmental protection.

Air Products has been supplying the water and wastewater industries for over 30 years. Its innovative, value-added technology solutions help improve water treatment processes and have set the industry standard, such as its ozone vent gas reuse application and the recently launched Halia mixer aeration system.[Page Break]

Onsite ozone generation

Halia onsite ozone generation provides safe, reliable, 'over the fence' ozone gas supply to your process with predictable long-term pricing while eliminating your exposure to ozone generation operations and maintenance costs. The offering consists of dedicated ozone production capacity consisting of liquid oxygen supply necessary for making ozone as well as the ozone generator, necessary controls and monitoring equipment.

Meanwhile the Halia oxygen recycle system can recover and recycle greater than 70 per cent of the unconverted feed oxygen within the ozone generation system. For the customer, this can be a means of significantly lowering oxygen costs. Air Products was the first global industrial gas company to establish an internal R&D capability in China when it set up its Asia Technology Centre in 2005.[Page Break]

Slicing and wrapping

Aquionics has launched what it says is the world's first UV LED disinfection system. Known as UV-Pearl, it offers highly efficient disinfection for the pharmaceutical and health care industry using a mercury free design for flows lower than five gallons/minute. The new system is easily integrated into OEM devices, ultrapure water generation, process water loops, laboratory research equipment and washing/rinsing machines.

The UV-LED disinfection technology activates instantly to begin treatment and can easily operate in no flow conditions if needed. On/off cycles have no effect on system operation. "The UV-Pearl's novel compact design allows for an unlimited number of configurations," says the company.

Meanwhile Purion now offers its range of Airpurion units and UV sets with a safety film that prevents splintering. The quartz glass is coated with a special UVC-transparent film, ensuring that no glass splinters can be released if the quartz tube is damaged. It is particularly aimed at food and feed production processes.[Page Break]

Reliability and flexibility

Meanwhile, in other process equipment developments, reliability, flexibility, ease of use and safety are the watchwords for modern mixing systems.

For example, Uni tec is a newly developed, individually designed general-purpose mixer provided by MTI Mischtechnik for manually or fully automatically controlled preparation of bulk materials in the process industries.

Depending on its configuration, uses of the new mixer unit range from homogenising bulk stock of diverse material characteristics to performing complex processing cycles aimed at providing specific product properties.

The design criteria of the mixing vessel, mixing tool and optional chopper systems are variable over a very broad range.

As a result, the unit can be optimally adapted to specific application needs - from gentle homogenisation of the most sensitive starting materials to the pre-dispersion of, for example, cohesive pigments.

Further options - including spraying systems for fluids, a double jacket for temperature-controlled process management, and a vacuum-proof or pressure shock resistant design of the mixing vessel - are available to handle coating and granulating tasks with high accuracy and repeatability. Thanks to the operator-friendly design of the new Uni tec universal mixer, it ensures convenient filling, evacuating and cleaning in every situation.

"The new Uni tec system combines high ease of use, maximum process reliability and safety, as well as application-focused configurability in one single unit. This standard-setting combination enables users to obtain high-quality mixing results with remarkably superior efficiencies compared to most conventional mixers. Needless to say, MTI's products conform to all applicable codes and regulations including ATEX requirements according to the raw material property specifications," said MTI ceo Christian Honemeyer.

Apart from the new Uni tec universal mixer, MTI's product range comprises an easy-to-clean horizontal mixer, the application-focused MTI Flex-line and MTI Eco-line heating-/cooling mixer combinations, and highly efficient dehumidification and aspiration systems.

In late 2010, the company launched its Cool tec mixer, pioneering direct cooling by means of a refrigerant rather than with cooling water. According to MTI, the technology has been widely acclaimed for its much enhanced cooling performance and concurrently reduced energy demand.[Page Break]

Advantages of UV disifection

Siemens Water Technologies offers a complete range of ultraviolet (UV) disinfection solutions for municipal drinking water, industrial, commercial, aquatic and high-purity applications.

UV irradiation can be used for multiple purposes in water treatment, but is primarily employed as a disinfection process that inactivates waterborne pathogens without chemicals. For other applications, UV is used for the removal of organic and inorganic chemicals, including chlorine, chloramines, ozone and total organic carbon (TOC). When combined with oxidants such as ozone or hydrogen peroxide, or semiconductors such as titanium dioxide, UV can be used for the oxidation of refractory chemicals such as chlorinated solvents, taste and odour compounds, and other emerging contaminants.

Siemens cites a number of technology advantages associated with UV, notably the effective control of all types of microorganisms, including those which are chlorine-resistant, without chemicals. It also improves disinfection efficacy, reduces environmental, health and safety risks, eliminates formation of disinfection by-products, has no effect on the aesthetic qualities of the water, and raises no over-dosing concerns.

For its part, Lenntech also has a long track record in successfully solving individual water quality problems. The company offers offer medium pressure, low pressure and low pressure amalgam disinfection systems, together with special ultraviolet systems. The company's customers therefore have individually tailored service to solve the most complex of disinfection problems. Among the sectors to benefit are: pharmaceuticals, catering, offshore industries, drinking water industry, food and beverage production and wastewater treatment.