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40 <br />C> <br />0 <br />Contractor shall provide the water source, chlorine feed system, chlorine test <br />€ equipment, and bacteriological testing lab, subject to the Engineer's approval <br />prior to disinfection. <br />B. The Contractor shall provide and install a minimum 314" threaded tap for <br />chlorine introduction and a stand pipe will, 112" hose bib sampling tali above <br />grade at the upstream end of the piping section being disinfected, and a 2" <br />valved blow off will, a 1f2" hose bib sampling tap at the downstream end of the <br />section. At least one additio€cal above -grade sampling tap shtnll he installed in <br />r each branch of a looped system at locations specified by the Engineer. Fire <br />hydrants shall not be used as sampling points for bacscriological samples. <br />C. The Contractor shall connect one end of the pipe system to a suitable potable <br />water source and chlorine feed system and slowly fill the pipe with water while <br />l feeding chlorine at a continuous rate until the pipe system is full and a free <br />residual chlorine of at least 200 mgll is obtained at cacti end and at <br />intermediate sampling points as directed by the Engineer. Daring filling, cacti <br />service and hydrant shall be cracked open and allowed to flow until chlorine is <br />detected in the discharge. <br />L <br />D. When the systen, is full and the required initial chlorine concentration is <br />s obtained, all outlet valves shit[] be closed and the chlorinated water retained for <br />t <br />ill least 24 hours, at which time the free residual chlorine shall be checked at tt,e <br />designated sampling paints. If the free residual chlorine is less than Sp iligll at <br />any point, the pipe system shall be reflushed and rechlorinated until the <br />required 24 -hours residual chlorine is obtained, at which tittle the system shall be <br />purged with potable water until residual chlorine is reduced to that of the water <br />I source. <br />E. Si".€able bacteriological samples shall then he taken at designated sampling <br />points on 2 consecutive days and tested for total colilorn, by it laboratory <br />I certified by D.H.R.S, for microbiological analysis. Satisfactory results for <br />i <br />coliform analysis shall be 'indicated by it total coliforo, count of less than I per <br />100 ml. (MF) or less than 2.2 per 1{10 nil. (MPhil, 5 tube, to oll.) for each <br />sample. If any sample result is unsatisfactory, tie disinfection and sampling <br />s procedure shall lie repeated oil part or all of the installed system, tis directed by <br />lite Engineer, until all samples from 2 consecutive days show satisfactory <br />results. <br />F. Once lite installed pipe system has been disinfected and bacteriological <br />sampling boron, the system shall he kept continuously fill] w'i!h potable Water <br />under sufficient positive pressure to preclude cont.uniii-tion from outside <br />sources, and shall he maintained in such condition until intcrconi,cctian with the <br />permanent water supply source is approved and completed. If, in the opinion <br />of the Engineer, any part or the insianat on is subject to rceimt.sniill, on <br />due to water loss from all or part of the installatiun, the cause shall be <br />itnined'tately corrected and the installation shall be rctlisinl ct01 ..incl <br />retested to the extent directed by the Engineer. <br />Al 4 <br />