Plumbing Africa February 2018 | Page 33

HEALTH AND SANITATION << Continued from page 29 • • a proposed UV installation. Power protection, power conditioning equipment or an uninterruptible power supply may be necessary in some cases. Alarm and reactor shutdown conditions should be clearly identified. A lamp breakage response plan should be developed that defines emergency response actions that will be taken if a lamp breaks. Low velocity traps or other piping configurations to collect broken lamp components should be considered. The potential for hydraulic transients should be evaluated because they may cause the quartz sleeves that house UV lamps to fail. MAINTENANCE NEEDS UV reactors, like other legionella treatment options, require routine maintenance to ensure that the UV dose remains adequate for inactivation of pathogens. Some of the basic maintenance items include cleaning the quartz sleeves housing the lamps and periodically replacing the lamps, as their output decreases with time. Most UV lamps installed in smaller reactors will typically be rated for 8 000– 12 000 hours of operation (one year of continuous operation equals 8 736 hours). To better understand the lamp output over time, premise plumbing operators may want to consult with the UV equipment manufacturer (USEPA, 2006c). In addition, some reactor components can be affected by disinfectants, including chlorine, added prior to the reactor, requiring additional maintenance. For a detailed list of recommended maintenance activities for a UV reactor, please see EPA’s Ultraviolet Disinfection Guidance Manual for the Final Long Term 2 Enhanced Surface Water Treatment Rule. PA Water treated using only UV disinfection may, in some cases, be susceptible to contamination at downstream points. 31