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November 2013 MM # 1351 SANITARY SEWER FEASIBILITY STUDY & REPORT NORTH SEBASTIAN AREA OPERATION & MAINTENANCE CONSIDERATIONS Indian River County Utilities has experience in operation and maintenance of the three (3) sewer system alternatives (except the STEP system) evaluated in this study and report. The operating and maintenance expense of the alternatives will be absorbed into the normal operating and maintenance expense of the utility. In general, the operation and maintenance expense of the conventional gravity system represents the alternative with the lowest operating and maintenance expense to the Indian River County Utilities Department. The low pressure and vacuum collection system alternatives will have a higher maintenance and operating expense due to higher electrical costs and the need for oversight personnel to monitor the system. The majority of the operating and maintenance expense related to the low pressure grinder pump and STEP systems is shifted from the Utility Department to the individual user to maintain and operate the pump stations. In the case of the low pressure alternative, the user must pay the expense of electrical service, periodic repairs to the pump station, and replacement of worn out mechanical and electrical pump station components to maintain their pump station in operating condition. In the case of the conventional gravity system and vacuum sewer system alternatives, the individual user has no operation and maintenance expense for the sewer lateral except for occasional removal of blockages which may occur infrequently in that portion of the system. The fact that the user is responsible for operation and maintenance of their own pump station is one of the main objections that are commonly made when discussing the low pressure system. The conventional gravity system operates without any need for mechanical or electrical equipment. Wastewater flows by gravity to a sub regional pumping station. There are operation and maintenance expenses connected with the sub regional pumping station but a good gravity sewer design will minimize the number of these stations. The operation and maintenance expense incurred by the Utility Department related to the low pressure system are minimal in the small diameter force main system. Occasional force main breaks may occur, but they are infrequent. As stated earlier, the major operation and maintenance expense connected with the low pressure system involves the operation and maintenance of each individual pump station and that financial burden falls on the shoulders of the individual user. The operating and maintenance expense of the vacuum system is related to the central pumping station which involves the electrical expense and maintenance cost of vacuum pumps, sewage pumps, standby generator, and electrical switch gear. There also appears to be periodic replacement of pneumatic control elements in the valve pits. The vacuum system manufacturer 20