CCP 07-14-1997 - Laserfiche WebLink

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. .' I Mr. Dwayne Stafford .. July 9, 1997 Page 3 I Old Hiahwav 10 This area includes approximately 1,400 feet of 10 inch diameter VCP sewer and seven manholes. I The pipe structure in this area is fair with numerous cracks, extensive root intrusions, some leaking joints, and joints with mineral deposits. Again, the groundwater table appears to be relatively high so the III which was observed is probably continuous throughout the year. I In this area, surface access is more readily available and a joint test and seal program would be appropriate to reduce the III observed from the pipe joints. The sections of cracked or broken pipe I cannot be effectively sealed with grout compound but they may be corrected with a link pipe product if necessary. The "link pipe" repair process may cost $1,500 per site repaired but the process is generally "cost effective" in paved areas because it does not require any excavation so there are no restoration costs. The joints with heavy root intrusion can be cleaned, tested and I sealed with a root inhibiting grout to reduce future problems. Testing and sealing the joints in this section may cost approximately $30,000 depending on the I quantity of grout used. Using the video records it is estimated that this segment may contribute about 0.65 million gallons Ie of III per year to the collection system. Preliminarv Cost Analvsis I Using rough estimates of the potential III removal and construction cost estimates, the cost per unit of III removed can be calculated as follows: I Compost Site $48 per 1,000 gallons per year Valentine Park Area $142 per 1,000 gallons per year I Old Highway 10 Area $46 per 1,000 gallons per year Wastewater, and clear water III, from the City of Arden Hills is treated at a Metropolitan Council I Treatment Facility and the City is charged annually based on actual flow rates. In 1996 the charge was $1.37452 per 1,000 gallons. I Using this value and the cost per unit previously calculated, the "cost recovery period," considering III savings alone, would be as follows: . Compost Site 35 years Valentine Park Area 103 years Old Highway 10 Area 34 years I The proposed rehabilitation will address the III but the sliplining of the lines will also provide an operation and maintenance benefit that should be considered but is difficult to define financially. .. In addition, differences in the III quantities andlor the construction costs will have a direct affect on the calculated "cost recovery period." Howard R. Green Company I CONSULTING ENGINEERS