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HomeMy WebLinkAboutPPP P1-100 Contingency Increase Iwo 46 = r�'��•/•r•�~/III+I►�• r� SLUDGE DIGESTER REHABILITATION AT PLANT NO. 1 PROJECT P1-100 00. r � • • • JAS • • 1 • Ah - R I ME low am M �I M� 1 Plant No . 1 Digesters Before P1 -100 & P1 -101 Projects PRIMARY CLARIFIER DIGESTER BELT FILTER PRESSES CAKE CAKE STORAGE LOADOUT DISSOLVED AIR SECONDARY FLOTATION CLARIFIER THICKENERS i After P1 -100 & P1 -101 Projects PRIMARY THICKENING CLARIFIER CENTRIFUGE DIGESTER DEWATERNG CAKE CAKE CENTRIFUGE STORAGE LOADOUT 71-F17 - i ---00-N, SECONDARY CLARIFIER Plant No . 1 Digesters Digester Year Built Most Recent Cleaning Prior to P 1 -100 5 1959 N/A - Holding - - 6 1962 N/A - Holding 7 1964 N/A — Empty 8 1970 N/A — Empty , 9 1978 2003 e 10 1978 2003 ram; 11 1993 2007 12 1993 2003 13 1993 2009 14 1993 2004 15 1993 2008 16 1993 2002 : Project Challenges • Unknown and unanticipated conditions — Higher volume and concentration of sludge — Extensive PVC T-lock repairs at all digesters — Additional mechanical repairs and replacements — Concrete repairs inside digesters • Extra work resulted in delays with cost impacts — Delay mitigation or recovery was minimal due to sequenced schedule. iK 12/ 11 /2014 10 ' 11 s Digesters Cleaning ( Before After) MORON =20 r r Concrete Dome Repairs 1,7 MUM WN Concrete Dome Repairs for- _ Exposed rebar showing ' * possible severe corrosion A pocket of concrete where the rebar is exposed and corrosion is evident (moderate to severe). ' Exposed Rebar at Digesters _ I . i r, .t, �" a PVC TmIock Repairs Inside Digesters =v-` o Unanticipated condition - encountered at all digesters. PVC Tmlock Repairs Inside Digesters 9309^! �1VJ ll9 ExistingPiping Conditions 77 Cone leak, Digester 16 Hole in mix pump suction Line Digester 9 • � • • • • • .� b .A-� t �,�� �y ..... ,!�, ..� ,� ,�v L,,yd��s��`lti�,• Possible Future Unknown Conditions • Replacement valves in lieu of rehabilitation • Leak repair at existing pipes inside digesters • PVC T-lock repairs & scaffolding • Concrete crack and corrosion repairs • Manway corrosion repairs • Cleaning interior of existing piping Lessons Learned • Rehabilitate in smaller groups (i .e. limit risk exposure) • Additional condition assessment during design • Consider end of life replacement vs rehabilitation • Clean on separate contracts if possible. If not possible, specify sludge removal carefully. • Replace equipment completely vs. rehabilitate or partial replacement. 4 , . Recommended Action • Approve a budget increase of $500,000 for Sludge Digester Rehabilitation at Plant No. 1, Project No. P1-100, for a total budget amount of $67,150,000; and • Approve a contingency increase of $837,500 (2.5%) to the construction contract with JR Filanc Construction Company for Sludge Digester Rehabilitation at Plant No. 1, Project No. P1-100, for a total contingency of $9,212,500 (27.5%).