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HomeMy WebLinkAboutBrief BackgroundBRIEF BACKGROUND INFORMATION REGARDING THE CITY OF SEBASTIAN WATER AND WASTEWATER UTILITY SYSTEM The City of Sebastian is the second most populated municipality in Indian River County, Florida, and is located in the northeast comer of the County on the west bank of the Indian River. The most significant land use feature of the City is the large number of vacant platted residential lots. There are approximately 14,170 platted residential lots of which 5,512 are improved and the remaining 8,658 are unimproved. The large number of platted residential lots are the reason the City is expected to become the most populous municipality in the County during the next 10 years. The land area of the City of Sebastian is approximately 8,643 acres or 13.5 square miles. A large portion of the City of Sebastian is the Sebastian Highlands planned community. This General Development Corporation (GDC) planned community was platted in the 1960's and includes over 13,000 single family residential lots. However, as indicated previously, only a small percentage of the platted lots have been developed at this time. Between 1986 and December 12, 1990, the City of Sebastian and Indian River County entered into a series of agreements which changed the provisions of water and wastewater service within the incorporated limits of the City. Beginning in 1986, Indian River County and the City of Sebastian held discussions and hearings regarding the County's desire to provide water and wastewater service with the City of Sebastian. At that time, the County was beginning the development of the North County subregional wastewater system and viewed the City of Sebastian as a potential source of customers for this system. At those hearings, the City adopted a series of documents which have changed the nature of the provisions, and to some extent, the regulation of water and wastewater service within the City of Sebastian. These initial documents involved Ordinance No. 0-87-01, Resolution Nos. R-87-6 and R-87-7, and an Intergovernmental Agreement between Indian River County and the City of Sebastian. Since 1987, there have been no less than five (5) City Resolutions which have further supplemented the Indian River County Agreements. These included Resolution Nos. R-87-85, R-89-12, R-89-60, R-90-30 and R-90-31. On December 12, 1990, the City entered into a series of agreements relating to the water and wastewater franchises granted to GDU. These agreements transferred to the County all of the City's rights, titles and interests in the water and wastewater franchises granted to GDU, with the exception of the City's right to receive franchise revenues and to regulate rates and charges pursuant to said franchise. 7�i7 On March 5, 1991, the City received an offer from Indian River County to "...relinquish its franchise rights within the City of Sebastian if that was what the City Council wished ... ". On April 5, 1991, Special Counsel for the City responded to the Board of County Commissioners by accepting the County's offer subject to completion of the necessary documents containing terms and conditions applicable to the City and the County so that the agreements, ordinance and resolutions could be rescinded in such a manner as to not impact innocent third parties. Meetings were then held with various County and City officials, including a meeting on April 17, 1991, in which the City and the County agreed to work together in order to "unbuckle" the Indian River County agreements to the extent necessary and as ultimately determined by the Sebastian City Council and the Board of County Commissioners of Indian River County. On April 11, 1992, the City and County signed an Agreement whereby the County relinquished its rights to provide retail water and wastewater service in the City and only provide wholesale wastewater service. The effective date of this Agreement was April 22, 1993. The City's primary water treatment facilities are the Sebastian Highlands water treatment plant (WTP) and the Park Place WTP. The Sebastian Highlands WTP treats raw water from the surficial aquifer by utilizing aeration, lime softening, filtration, and disinfection processes. The Sebastian Highlands WTP has a current rated capacity of 0.671 million gallons per day (MGD). The Park Place WTP utilizes aeration and disinfection to treat a rated capacity of 0.1 MGD. The City's primary wastewater treatment facility is the Sebastian Highlands wastewater treatment plant (WWTP). The Sebastian Highlands WWTP, located at 810 Bailey Drive, is an extended aeration activated sludge WWTP design for secondary treatment of municipal sewage, with a total design capacity of 0.3 MGD. The effluent treated at the Sebastian Highlands WWTP is disposed of in a series of percolation ponds, that have a total disposal capacity of 0.142 MGD. The current raw water quality continues to only require the softening process for water treatment. Chlorides are increasing concern in this area of Florida following excessive demands on the fresh water source. These excessive demands on the aquifer have caused a gradual increase in the elevation of the salt water interface with the fresh water source. This interface has increased in elevation to the point where several cities along the east coast have been required to construct desalination facilities. Fortunately, the City of Sebastian is not currently required to construct such facilities. 1.1 The present treatment problems noted at the Sebastian Highlands WTP appear to be caused by the availability of treatment capacity. The Sebastian Highlands WTP is currently operated between the hours of 0700 and 1500, seven (7) days per week. In order to produce the current average daily demand, the plant must be operated at approximately 750 gpm for just over 8 hours per day. The existing treatment facilities at the Sebastian Highlands WTP were designed for a flow rate of 466 gpm. Operating the existing facilities at 750 gpm would understandably cause low treatment efficiency or higher effluent hardness and excessive filter backwashing requirements. There are two (2) alternative methods of correcting these problems. The first method would consist of designing and constructing additional treatment units. Based on the design conditions of the existing units, this would require a second precipitator, one (1) additional filter and associated pumps and yard piping. The second method would consist of operating the facility for longer periods during the day and lowering the flow rate through the plant. The current average daily flow for 1993 was approximately 370,000 gpd. AT the design flow rate of 466 gpm, the operation time for 1994/95 would be increased to approximately 14 hours per day. Modifications of these times can be varied to match scheduling of actual 8 -hour shifts. Based on the current operation of the system, the schedules would have to be matched to ensure the ground storage tank volume did not reach critically low levels. The method recommended would be based partially on the availability of capital funds versus operational funds. The limited fresh water supply experienced in coastal areas of Florida has resulted in the identification and utilization of alternative water resources a source of raw water supply for municipal potable water systems. Potable water withdrawals from the surficial aquifer have resulted in increased chloride concentrations which are an indicator of salt water intrusion into an aquifer. The obvious alternative water supplies that are available as a source of raw water for coastal potable water systems are brackish surface waters, seawater, or high TDS Floridan aquifer water. Reverse osmosis consists of separating a solvent, such as water, from a saline solution by the use of a semi -permeable membrane and hydrostatic pressure. The flow through the semi -permeable membrane is in the direction of a drop in solvent concentration. This transfer of solvent water through a semi -permeable membrane is referred to as osmosis. Eventually the system will reach equilibrium, where the hydrostatic pressure is referred to as the 'osmotic pressure". If a force is applied to a piston to produce a pressure greater than the osmotic pressure, there will be a transfer of the solvent in the reverse direction. This mass transfer of a solvent using a semi -permeable membrane and a hydrostatic pressure is referred to as reverse osmosis. 1.2 An application of osmotic pressure principles in environmental engineering is in the demineralization of salt -laden (brackish) water by the reverse osmosis process. As the name implies, this process is the reverse of osmosis, and water is caused to flow in a reverse manner through a semi -permeable membrane from brackish water in excess of the osmotic pressure. The semi -permeable membrane acts like a filter to retain the ions and particles in solution on the brackish water side, while permitting water alone to pass through the membrane. Theoretically the process will work if a pressure just in excess of the osmotic pressure is used. In practice, however, a considerably higher pressure is necessary to obtain an appreciable flow of water through the membrane. Also, as fresh water passes through the membrane, the concentration of salts in the brackish water remaining increases, creating a greater osmotic pressure differential. The improvements to the potable water system for the 1995 to 1999 planning period include improvements and expansion of the supply, treatment, storage, high service pumping, transmission and distribution facilities. It has been recommended that the City investigate the feasibility of constructing a third well in the area of the Sebastian Highlands WP to increase the reliable water supply capacity. This modification to the operation will provide the same daily treated water volume for the system, but will operate the plant facilities at a much lower rate. This lower rate should reduce or eliminate the current operational problems at the facility. The improvements to the wastewater system for the 1995 to 1999 planning period include improvements and expansion of the collection, transmission, treatment and effluent disposal facilities. The wastewater collection system requires a continual maintenance program to identify and correct infiltration and inflow (UI) contributions. The 1995 to 1999 planning period may also consist of expansion for the existing collection and transmission system to provide service to new customers. The recommended transmission system improvements consist of minor lift station and transmission main improvements to optimize the pumping operation of the entire manifold system and provide system reliability. Modifications to the W WTP has been recommended to provide the necessary facilities to meet the new federal requirements for sludge stabilization prior to land application. 1.3 Both of these options will require additional treatment facilities at the Manly Avenue plant, such as an additional clarifier, filters, additional chlorine contact tankage and effluent storage and pumping facilities. The grove irrigation options are estimated to be most cost effective, however, negotiations and agreements with land owners have been historically difficult and time consuming. The golf course option appears desirable due to the large available capacity and control of the operation, due to City ownership, however, the costs to pump to the golf course are relatively expensive. The costs associated with the ten (10) year planning period (1995-2004) as identified by the consulting engineers reveal the requirement for additional municipal bond financing. The State of Florida has not provided a general law that mandates residential homesite or commercial mandatory water hook-up except as required by the Department of Health and Rehabilitative Service (HRS). However, there are provisions that require mandated hook-up for wastewater. We do not calculate water impact fees into our Utility revenue stream when calculating debt service payments. The following table provides some insight into the dollar requirements for complying with the Utility Masterplan. A. The possibility always exists regarding a change to the quality of the current water processed by the water treatment facility. In the event the quality should decrease and operational costs increase or that the City should elect to build a new 1.0 MGD plant at the Airport property instead of a modular expansion to the current plant, the anticipated costs utilizing 1995 dollars for construction during the 2000-2003 planning period is estimated at $4,566,230. (Page 9-38, Table 9-4, Water & Wastewater Master Plan) B. Capital Improvement costs for the water system during the 1995-1999 planning period is estimated at $1,143,533. (Page 9-35, Table 9-3, Water & Wastewater Master Plan) C. Capital Improvement Costs for the water system during the 2000-2004 planning period is estimated at $5,900,232. (Page 9-41 and 9-43, Water & Wastewater Master Plan) 1.4 WATER RECAP Treatment Plan (Reverse Osmosis) $ 4,566,230 Capital Improvement Costs (1995-1999) 1,143,533 Capital Improvement Costs (2000-2004) 5.900,232 TOTAL: $ 11,609,995 (Less R/O Plant) - 4,566,230 $ 7.043.765 WASTEWATER RECAP D. Current treatment capacity for the City wastewater treatment plant is 300,000 gallons per day but the current disposal capability is only 142,000 gallons per day or approximately one-half of the current treatment capacity. Recommended Solutions from the Consulting Engineer: #1 Grove Irrigation (Page 10 -23 -Table 10-6 $ 576,450 #2 Golf Course Spray Irrigation (Page 10-24 _ 742.950 Table 10-7) Costs for both Recommendations $ 1319.400 1. Capital Improvement Costs for the wastewater system during the 1995 - 1999 planning period. a) Plant Expansion $ 1,803,600 (Page 10-30, Table 10-9) b) Disposal System Upgrade 461,100 (Page 10-32. Table 10-10) c) Recommendation #1 (Above) 576,450 $ 2.841.150 1.5 WASTEWATER RECAP (Continued) 2. Capital Improvement Costs for the wastewater system during the 1999-2004 planning period. a) Wastewater Treatment Plant Improvement $ 2,247,660 b) Miscellaneous Capital & R & R Costs 72.454 TOTAL COSTS( 1+ 2) RECAP Water treatment, transmission and distribution improvements for the period of 1995- 2004.. $ 11,609,995 Wastewater collection, transmission, treatment and disposal system for the period of 1995-2004.. $ 5.161264 10 YEAR TOTAL: 1.6 $ 6.7