SECTION 7.0 RECLAIMED WATER 7.1 Introduction The use of highly treated wastewater effluent, or reclaimed water, has expanded greatly in Florida over the past several decades. In particular, the use of reclaimed water for irrigation of golf courses, parks, medians, and other public and private landscape areas is very popular. This type of reuse is termed unrestricted land application. Reuse of effluent in this manner has two major benefits: 1. It reduces the volume of effluent to be disposed by other means. 2. It reduces the consumption of potable water for irrigation. Other benefits include some nutrient value in the reclaimed water, cost savings for end users because of generally lower price for reclaimed water compared to potable water, and public perception of conservation of a resource. Negatives include reduced revenue to the water utility because rates for reclaimed water are lower than for potable water, and the need for a back-up means of effluent disposal (or a large capacity for long-term storage of reclaimed water) because of the high seasonal variation in the demand for reclaimed water. Although reclaimed water can be used for a variety of uses besides public access irrigation, such as for industrial processes (cooling water or process water), or other non-potable uses, the opportunity for these types of uses are generally quite limited and often not cost-effective due to the need for higher levels of treatment and separate pumping and piping facilities. Reclaimed water for agricultural irrigation is practiced in some places, however, its use for this purpose is limited by potential health concerns and the fact that often the supply of reclaimed water is not close to the end user. In Florida, the vast majority of reclaimed water is used for public access irrigation. This will be true in Hernando County as well, since the majority of the County is residential and commercial, with little major industry or agriculture. Therefore, this section will focus on opportunities for public access irrigation, while other potential uses will be identified where feasible. 7.2 Regulatory Requirements The Florida Administrative Code (FAC) Section 62-610 addresses the regulatory requirements for reclaimed water use. The following is a summarized list of the major requirements: Reclaimed water must have less than 5.0 mg/l suspended solids, which requires filtration, and must receive high-level disinfection. The treatment plant must have Class I J:\00313\00313006.01\DOC\Reports\Final.doc 157 August 2005
reliability. (Required treatment levels are addressed more fully in Section 5.0 of this report). The treatment facility must be manned whenever it is producing reclaimed water. An alternative disposal method or storage for reclaimed water that does not meet regulatory quality requirements must be provided. An alternative disposal method or adequate storage (minimum of 3 days at average daily flow) must be provided to accommodate flows during wet weather when reclaimed water demand is low. Three days storage is only required if there is no alternative disposal method for effluent that can handle the plant s design flow. All proposed SWWTP expansions for Hernando County include providing RIB capacity to handle the full design flow capacity. As such, no reject storage is required. The utility must have a cross-connection control ordinance in place, which includes periodic inspections to ensure compliance. Additional construction, operating, and monitoring requirements are specified in FAC 62-610. 7.3 Seasonal Variation in Reclaimed Water Use As noted in the introduction, the demand for reclaimed water is highly variable depending on the time of year. Several studies of the annual demand pattern for reclaimed water used for irrigation show that demand is lowest during the cool and wet months of December through March, then increases sharply to a very high demand during April and May. Demand drops somewhat during the summer months, then reaches another peak during October before dropping again in late fall and winter. Because of this high seasonal variation in demand, a typical public access reuse system in Florida can dispose of 50 to 60 percent of the total effluent on an annual basis. In order to dispose of a larger percentage, the system must either have a large volume of long-term storage (typically up to 100 days of plant flow), a source of supplemental water for high-demand periods, or the ability to limit or remove users during high-demand periods (demand management). A brief discussion of each of these options is listed below: Long term storage. As noted above, approximately 100 days of storage is typically required. Therefore, for a system with a 2 MGD capacity, 200 MG of storage would be required. This volume of storage is not economically feasible in tanks. Lined or unlined storage ponds have occasionally been used, but they require a large land area, have significant maintenance issues, and the water needs to be retreated when it is withdrawn for use. The use of Aquifer Storage and Recovery (ASR) wells is currently being investigated by some utilities, but these are very costly, and to date no reclaimed water ASR system has been permitted for normal operation (some wells have been permitted J:\00313\00313006.01\DOC\Reports\Final.doc 158 August 2005
for testing). At this time, the use of long-term storage is not recommended for Hernando County due to the above negative factors. Supplemental water. A source of supplemental water may be used during high demand periods to augment the reclaimed water supply. Supplemental water may include surface water, stored stormwater, groundwater, or potable water. The supplemental water source must be available during dry periods, which generally precludes the use of potable water. The use of supplemental water sources should be investigated during design of each system. Demand management. The use of demand management to reduce peak demands can allow the utility to maximize the percentage of effluent used for reclaimed water. However, it is unlikely to completely offset the seasonal demand variation. Hernando County should keep the option of demand management open in any future reclaimed water agreements or promises for service. 7.4 Required Facilities The facilities required to produce and distribute reclaimed water consist primarily of the following: Additional treatment required to produce reclaimed water suitable for public access irrigation (see above and Section 5.0). Reclaimed water storage for diurnal variations in demand, generally equal to about 1 day average daily flow. Reclaimed water pump station and transmission main to transport the reclaimed water to the end user. Reclaimed water distribution system which may be owned by the end user (such as a golf course or park). The most cost-effective use for reclaimed water is to supply a large volume end user already equipped with a distribution or irrigation system. Golf courses usually fit these criteria very closely and therefore have been, and are, primary recipients of reclaimed water. Other popular users include parks, common areas, and individual residences. The cost to supply individual residences is generally fairly high because the utility must install the distribution system to each lot. Generally the larger the lots, the more cost-effective the system will be. J:\00313\00313006.01\DOC\Reports\Final.doc 159 August 2005
7.5 Available Flows The five SWWTPs that will potentially provide wastewater treatment in the study area were given an initial assessment of their potential for providing reclaimed water. Upgrades required at the plant to provide reclaimed water (or to continue to provide reclaimed water) are presented in Section 5.0. The initial assessment showed the following: Spring Hill SWWTP. This plant is currently providing reclaimed water to the Timber Pines golf course and other public areas. This should continue into the future, with excess reclaimed water being provided to other users if available. Berkeley Manor SWWTP. This plant is a relatively small plant and has adequate disposal capacity for the projected flows for the planning period. Primarily for these reasons, this plant should not be upgraded to provide reclaimed water. Brookridge SWWTP. This plant currently has adequate effluent disposal facilities on-site to accommodate its flow until 2025. Also, there are no large volume users in close proximity to the plant. Primarily for these reasons, this plant should not be upgraded to provide reclaimed water. The Glen SWWTP. This plant has two golf courses within reasonable proximity to the plant, and will be one of the larger SWWTPs in the system by 2025. Therefore, reclaimed water production should be considered at this facility. Airport SWWTP. The Airport SWWTP already is identified to provide reclaimed water to the Silverthorn golf course, and is in reasonable proximity to two other golf courses. The facility will also be one of the larger SWWTPs in the system, and therefore should be considered for reclaimed water production. Table 7-1 shows the flows by planning year for each plant with each alternative. Table 7-1 Alternative 1 Wastewater Flow Summary (gpd) SWWTP 2005 2010 2015 2025 Spring Hill 1,917,133 2,219,423 2,618,043 3,026,353 The Glen 570,931 980,768 1,692,838 2,520,508 Brookridge 273,830 443,600 546,290 699,410 Berkeley Manor 176,290 178,840 181,730 189,720 Airport 493,203 1,348,683 1,675,588 2,277,918 SWWTPs Total 3,431,387 5,171,314 6,714,489 8,713,909 J:\00313\00313006.01\DOC\Reports\Final.doc 160 August 2005
Alternative 2 Wastewater Flow Summary (gpd) SWWTP 2005 2010 2015 2025 Spring Hill 1,603,023 1,217,014 1,445,140 1,606,576 The Glen 570,931 1,735,498 2,589,906 3,627,493 Brookridge 273,830 443,600 546,290 699,410 Berkeley Manor 176,290 0 0 0 Airport 807,313 1,775,202 2,133,153 2,780,430 SWWTPs Total 3,431,387 5,171,314 6,714,489 8,713,909 Alternative 3 Wastewater Flow Summary (gpd) SWWTP 2005 2010 2015 2025 Spring Hill 1,603,023 1,217,014 1,445,140 1,606,576 The Glen 570,931 1,556,658 2,408,176 3,437,773 Brookridge 273,830 443,600 546,290 699,410 Berkeley Manor 176,290 178,840 181,730 189,720 Airport 807,313 1,775,202 2,133,153 2,780,430 SWWTPs Total 3,431,387 5,171,314 6,714,489 8,713,909 Because of the seasonal variation in reclaimed water use previously discussed, for planning purposes it is assumed that 60 percent of the annual average daily flow from any plant will be reused in any given year. 7.6 Existing Commitments Silverthorn Summer Properties, Inc., developed the Firethorn Country Club, now known as the Silverthorn Country Club. In September 1989 Summer Properties entered into an agreement with the Hernando County Water and Sewer District, which indicated that Summer Properties would provide for the disposal of 1 MGD of effluent from the Airport SWWTP through irrigation of the golf course and other common land. Summer Properties will receive and store the effluent in its golf course ponds, and will not be charged for delivery of the effluent for the first ten years of the term of the agreement. After ten years, Summer Properties shall pay rates similar to those of other like users of effluent in the County. The agreement stipulates the terms for apportioning the cost between Summer Properties and Hernando County for the reclaimed water treatment, storage, pumping, transmission, and distribution facilities. In October of 1998 the terms of this agreement were assigned to Golf Trust of America, the current owners of the Silverthorn J:\00313\00313006.01\DOC\Reports\Final.doc 161 August 2005
Country Club. To date, no effluent has been delivered under this agreement. However, the Silverthorn Country Club manager has expressed interest in receiving effluent for irrigation of the golf course. To meet the full commitment of 1 MGD (annual average) to Silverthorn, the Airport SWWTP will require an annual average daily flow of approximately 1.67 MGD. Under Alternative 1, the Airport SWWTP total effluent flow will reach this amount by 2015, while the flow will be 2.28 MGD by 2025. A total flow of 2.28 MGD will support an annual average reclaimed water use of 1.37 MGD, or approximately.37 MGD above the Silverthorn use agreement. Under Alternatives 2 and 3, the plant flow will reach 1.67 MGD slightly before 2010, and the total flow will be 2.78 MGD in 2025. This flow will support an annual average reclaimed water use of about 1.67 MGD, or approximately 0.67 MGD above the Silverthorn use agreement. Timber Pines Timber Pines Community Association, Inc., entered into an agreement with Southern States Utilities, Inc. (the predecessor to Florida Water Services) in April of 1995 to deliver an annual average of 1.7 MGD of reclaimed water from its Spring Hill SWWTP. When Hernando County acquired the Spring Hill SWWTP from Florida Water Services they assumed the terms of this agreement. Reclaimed water was provided at no charge until December 31, 2004, and currently a flat monthly charge is assessed. The monthly rate is pro-rated if less than 1.7 MGD (monthly average) is provided in any given month. Under the agreement, the County must provide minimum wet weather storage as required by FDEP. Also, Timber Pines has the right of first refusal to meet any third party offer to purchase reclaimed water from the Spring Hill SWWTP in excess of 1.7 MGD. Hernando County is required to maintain all necessary reclaimed water lines from the plant to the points of delivery. Timber Pines will store the reclaimed water in a storage pond and be responsible for all irrigation facilities. To meet the full commitment of 1.7 MGD for the Timber Pines Community Association, the Spring Hill plant will require an annual average flow of 2.83 MGD. It will reach this flow sometime after 2015 under Alternative 1. However, under Alternatives 2 and 3, Timber Pines will not be able to receive the full 1.7 MGD, since the Spring Hill SWWTP capacity will be limited. Except for in the later years under Alternative 1, the existing Timber Pines demand will account for all the reclaimed water produced by the Spring Hill SWWTP under all the alternatives. 7.7 Additional Potential Reclaimed Water Uses Since Timber Pines will use virtually all the available reclaimed water from the Spring Hill SWWTP, additional reclaimed water users for this plant will not be considered further. Therefore, only the Airport and the Glen SWWTPs will be considered for additional users. J:\00313\00313006.01\DOC\Reports\Final.doc 162 August 2005
Airport SWWTP As noted above, the Airport SWWTP will only be able to meet the Silverthorn commitment until 2010 under Alternatives 2 and 3, and until 2015 under Alternative 1. Therefore, the immediate focus for this plant is to begin supplying the Silverthorn commitment of 1.0 MGD. The Silverthorn Country Club is located approximately 3 miles from the Airport SWWTP site, and will require about 14,000 feet of 12-inch main to deliver the reclaimed water. Additional potential users for the Airport SWWTP reclaimed water include: Spring Hills Golf Club Seven Hills Golf Course Green space areas around the airport Glen SWWTP The Glen SWWTP currently does not reuse any effluent, nor does it have any agreements in place to supply reclaimed water. Based on Table 7-1, the Glen SWWTP currently has about 0.3 MGD of reclaimed water available, and will have about 1.0 MGD available in 2015 under Alternative 1. Alternatives 2 and 3 will create approximately 1.5 MGD of available reclaimed water by 2015. The closest golf courses to the Glen SWWTP include the Glen Lakes Golf and Country Club and the Heather Golf and Country Club. The Glen Lakes Golf and Country Club is approximately three miles south of the SWWTP, while the Heather Golf and Country Club is approximately five miles past the SWWTP. Both of these are 18-hole courses, which with some associated green space and median irrigation can generally use approximately 0.5 MGD of reclaimed water each on an annual average basis. Therefore, a 1.0 MGD system will accommodate the Glen SWWTP through the year 2015 for Alternative 1, while Alternatives 2 and 3 will provide an additional 0.5 MGD of reclaimed water. For this analysis, a 1.0 MGD system will be assumed. The length of transmission main required is 14,000 feet of 12-inch main to Glen Lakes Golf and Country Club, then 9,500 feet of 8-inch main to the Heather Golf and Country Club. 7.8 Costs Both the Airport and the Glen SWWTPs will initially have 1.0 MGD reclaimed water systems. Facilities required for each system include the following: 1.0 MG ground storage tank 1.0 MGD high service pumping station (variable speed) Transmission main to deliver reclaimed water to end user J:\00313\00313006.01\DOC\Reports\Final.doc 163 August 2005
Since storage and high service pumping was included in the treatment facility expansion costs, they are not included here. In addition, the distribution system cost is not included, since the golf courses have their own irrigation systems. The associated costs for each plant are shown in Table 7-2. Since the County does not necessarily have to provide reclaimed water beyond the existing agreements, these extra costs are not included in the Capital Improvements Plan (CIP) discussed in Section 9.0 Table 7-2 Reclaimed Water Transmission Costs Unit Price Cost (2005 Dollars) Description Quantity Unit Glen SWWTP 12-inch RCW Transmission Main (Glen Lakes) 14,000 LF $ 85 $ 1,190,000 8-inch RCW Transmission Main (Heather) 9,500 LF $ 65 $ 617,500 SUBTOTAL $ 1,807,500 Engineering (15%) $ 271,200 Construction and Contingency (15%) $ 271,200 TOTAL $ 2,350,000 Airport SWWTP 12-inch RCW Transmission Main to Silverthorn 14,000 LF $ 85 $ 1,190,000 Engineering (15%) $ 178,500 Construction and Contingency (15%) $ 178,500 TOTAL $ 1,547,000 J:\00313\00313006.01\DOC\Reports\Final.doc 164 August 2005