Longwave UV (formerly Salcor)

Longwave (formerly Salcor) manufactures a UV disinfection unit for wastewater treatment applications. UV disinfection is the preferred method to protect the health and environment from pathogens in wastewater because:

• • It extremely effective at ‘killing’ viruses and bacteria
• • It is energy-efficient, using under 30 watts
• • There are no harmful residuals or by-products

Longwave’s 3G unit is NEMA-6P certified, meaning it is flood-proof, and has been tested extensively by several Third Party testing sites, including 19 separate times by NSF. It’s been used in residential, commercial and municipal projects and can be clustered to treat up to 100,000 GPD. Because it lamp has a Teflon™ cover, it resists fouling and reduces maintenance – which is limited to simply wiping it down every six months and replacing the lamp every two years. The unit can be installed in-ground or in a pump tank, so the footprint is minimal and includes an alarm circuit (N.O/N.C.) for reliable, continuous performance monitoring.

How it Works

3G disinfection chamber couples directly to the aerobic plant discharge pipe and is permanently installed below grade. The ultraviolet light source for disinfection is mounted in a sub-assembly which can be inserted or removed through the top of the riser pipe for periodic servicing. The light source is mounted in the center of an anodized aluminum frame which divides the disinfection chamber in half. The frame seals against the inner surface of the disinfection chamber to prevent flow bypass. When fully inserted, the disinfection sub-assembly is properly located by two pins mounted near the top of the disinfection chamber. The disinfection sub-assembly causes the wastewater entering one side of the unit to flow vertically downward, make a 180 degree turn, and then flow vertically upward and out the other side of the unit. This well-defined flow path is designed to give the fluid proper exposure time and no short circuiting.

The ultraviolet light source is surrounded by a clear fused quartz tube to control the lamp surface temperature. A clear Teflon film covers the quartz tube to minimize surface fouling. This design feature incorporates the beneficial attributes of both quartz and Teflon.

When the disinfection chamber is filled with water, the ultraviolet light source can operate continuously, whether or not water is flowing. Continuous operation with a lamp surface temperature range of between 105 and 120 degrees Fahrenheit provides optimum ultraviolet light output and long lamp life.

The electrical sub-assembly is mounted in a junction box located on top of the 4-inch riser pipe. The box contains fuses, alarm circuitry, UV lamp ballast, power cable connections, voltage surge protection, and electronic noise filters. The Longwave Model 3G alarm relay circuit triggers an external alarm to warn the user when the UV lamp is not operating properly. The alarm relay circuit has been designed to be compatible with a wide variety of alarm systems used on upstream aerobic treatment plants. The relay contacts are rated for alarm power sources that operate at up to 250 Volts AC or DC, and up to 12 Amps. When the UV lamp is producing ultraviolet germicidal light at a safe level, a green LED indicator light, located on the top of the electrical junction box, glows indicating proper UV lamp operation. The light stops glowing when the light output from the UV lamp falls below a safe level or is not operating.