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AEE CO����ITIES <br /> value for the utility. ( head effluent pump that should last I flow-through area can necessitate <br /> Each material should be evalu- more than 20 years.Effluent filters can more frequent site visits for cleaning <br /> "x eted relative to longevity,cost,and ran e from less than 0.05 m' 0.5 it) clogged <br /> g ( gged filters.Tanks can range from <br /> k reliability.For example,STEP pumps of flow-through area of 6.4-mm(0.25-I structurally unsound tanks that crack <br /> can range from a$150 cast-iron efflu- in.)mesh up to filters with more than or collapse during installation and <br /> ent pump that will provide 5 years 11.9 mC(20 it`)of flow-through area leak immediately to watertight tanks <br /> of service to a$500 multistage,high- of 3.18-min(0.1254n.)mesh.Smaller I with watertight connections that can <br /> provide up to 50 years Of anticipated <br /> e I life with proper installation.When <br /> m m ® substandard materials are used,either <br /> e s a <br /> in new construction of all components <br /> (including building sewers)or for re- <br /> placement parts,an increase in O&M <br /> _ I costs is a certainty. <br /> a <br /> Reactive and Preventive <br /> Maintenance <br /> O&M of onsite STEP systems typical- <br /> `I ( ly is divided into two activities:reactive <br /> ° o <br /> maintenance(RM)and preventive main- <br /> ' ° ° ° - •.- •- • • '� �. -, tenance(PM).The.protocol for onsite <br /> - - system maintenance varies greatly,even <br /> when comparingA m Iar systems. <br /> Most systems have been oper- <br /> ated with varying degrees of emphasis <br /> T i se•� laced on PM activities,the frequency <br /> lran gwrinvI1111111 of which is dictated by the most sensi- <br /> ' f Awr1��' live components.Extremely aggres- <br /> - <br /> v' I sive PM programs have been able to <br /> + reduce RM service calls to a point that <br /> they become relatively insignificant in <br /> the overall O&M costs.Unfortunately, <br /> an overly aggressive PM program <br /> I also can result in higher overall O&M <br /> ' I costs when PM activities unneces- <br /> sarily target components that have a <br /> ' significant level of reliability with less <br /> r I PM.A proper balance is the key to an <br /> h <br /> optimal maintenance program. <br /> � � � A less well-known RM protocol <br /> is a run-to-fail approach,whereby <br /> { •iv maintenance Is only performed when <br /> equipment fails.Essentially,the op- <br /> t e era""waits for an alarm.While this <br /> ( - approach is fairly uncommon, <br /> RE�t�B� it has <br /> �e�"zen Delta Blower some important implications.While <br /> - daily O&M costs(at least in the early <br /> [ w One step ahead <br /> `= AerzentlSi4.eorte years)maybe extremely low,increas- <br /> *' ?Click or call to see the new C5 Delta Mower. ng frequency of major repairs and <br /> AEAZEN USA Corporation 108 independence Way,Coatesville,PA 19320 lac <br /> activities will escalate <br /> Phone(610)380-0244 A Fax(610)380-0278 6 E-mail:Inquinesr?aer7enasa.com I as the system suffers from neglect. <br /> ' `t Additionally,public perception of a <br /> 9. run-to-fail approach is generally poor, <br /> P �' WF.&r WWW.WF.F.ORG/MAGAZINE <br />