Project Renew: A Regional Approach to the Distribution of Reclaimed Water

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ABSTRACT
The Orlando Utilities Commission (OUC) has been granted a 20-year permit to use the Floridan aquifer as a source of potable water. In addition to providing for the continued use of groundwater, the permit also requires that OUC make use of alternative water supplies. One of the most innovative of the alternative water supply projects is referred to as project RENEW. The OUC Consumptive Use Permit (CUP) provides a general definition of project RENEW as bringing reclaimed water from the Iron Bridge Regional Water Reclamation Facility (WRF) to the Northwest Orange County Area (NWOCA). The CUP requires that 3 million gallons per day (mgd) of reclaimed water be delivered to the NWOCA by 2011 and 9.2 mgd by 2015. The fundamental assumption driving this requirement is that the availability of reclaimed water in these volumes will offset expected future withdrawals of groundwater that would be used for irrigation. This, in turn, will mitigate drawdowns in the Floridan aquifer that would potentially occur without these offsets.

The RENEW alternatives analysis report considers various means of implementing RENEW within the guidelines established in the CUP and selects the most cost-effective solutions. Given the requirements of RENEW, the primary alternatives for delivering reclaimed water to NWOCA are: 1) from the city of Orlando’s Iron Bridge Regional WRF, 2) transferring wastewater to the city of Orlando’s Water Conserv II WRF, 3) transferring wastewater to the Altamonte Springs WRF and 4) a combination of the Water Conserv II and Altamonte Springs alternatives. Subalternatives to the primary alternatives address whether the RENEW flow is a constant delivery or one that fluctuates as a function of the bulk customer’s demands. Consideration is also given to the use of seasonal storage and supplemental water to manage differences in supplies of reclaimed water and demands for irrigation. Figure 1 provides an overview of the project area and facilities of interest.

SUMMARY OF BULK CUSTOMERS’ SYSTEMS
Meetings were held with each potential bulk customer in the NWOCA to discuss project RENEW and to gain an understanding of their reclaimed water needs. Copies of current reuse studies and master plans were obtained which provided data for the existing and proposed reuse systems.

The city of Apopka projects a very large reuse water deficit of 13.5 mgd by the year 2015. The supplies and demands for the cities of Winter Garden and Ocoee are relatively balanced. However, they have each requested reclaimed water from the jointly owned Water Conserv II system in order to meet their localized reuse demands.

DEVELOPMENT OF RENEW ALTERNATIVES
Factors influencing the development of RENEW alternatives included the following:

  • Identification of viable routes for reuse transmission mains.
  • Determination of the potential use of existing reuse facilities to facilitate the implementation of RENEW. This included the Water Conserv II transmission system as well as the existing and proposed reuse facilities of the bulk customers.
  • Determination of modifications required to existing pump station and force main systems required to re-direct raw wastewater from one facility to another.
  • Quantifying the need to expand the treatment capacity or avoiding the need to expand plant capacity as a result of the transfer of raw wastewater from one service area to another.
  • Determination of how RENEW flows would be delivered to the NWOCA, either as a constant flow of 9.2 mgd or a flow that varied according to the needs of the bulk customers. The primary use of reclaimed water will be for irrigation. As such, the demands for water will vary significantly throughout the year as a function of temperature and rainfall. Delivering water at a constant rate increases management requirements for the bulk customers, while variable deliveries according to demand shifts the management burden to the supplier.
  • Determination of the requirements for supplemental water to ensure that water for irrigation would be available with a reasonable level of reliability to reclaimed water customers of the city of Orlando Eastern Regional Reclaimed Water Distribution System (ERRWDS) and RENEW.
  • Determination of any additional wet weather management by the bulk customers required due to the implementation of RENEW.
  • Determination of the potential to use the existing Conserv II rapid infiltration basins (RIBs) and freeze protection wells to help manage seasonal differences in reclaimed water supplies and the demand for irrigation.

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