Aquifer Recharge Using Reclaimed Waterin the Tampa Bay Area

Phil Waller, P.E.

Project Overview – SWUCA and MIA

Project Scope of Work

• Technical Memorandum 1- Hydrogeology, Water Quality and Permitting– Previous Project Review – Regulatory Review – Reclaimed Water Quality – Hydrogeology and Aquifer Water Quality – Indirect Aquifer Recharge Feasibility Mapping– Permitted Groundwater Users – Aquifer Contamination Site Review – Evaluate Indirect Recharge Technology Issues

– Evaluate Direct Recharge Technology Issues

Project Scope of Work

• TM 2- Water Level Improvements/Impacts– SWFWMD Rule Summary – Direct Recharge Groundwater Modeling – Indirect Recharge Groundwater Modeling

• TM 3- Economic Analyses

• Final Report

Project Schedule

Summary of Similar Projects

• 75 reclaimed water recharge projects were identified globally

• Projects were identified by:– Reclaimed water as recharge source water– Groundwater credits or exchange– Wastewater treatment processes– Ultimate recharge purpose

• Groundwater level mitigation• Groundwater replacement• Salinity barriers• Long term storage• Indirect potable reuse

Summary of 16 Relevant Projects

Indirect Recharge Projects

• Water Conserv II RIBs - Orange County and the City of Orlando

• Old Winter Garden Road South WRF RIBs - Orange County Utilities

• Beardsley Road and Butler Drive WRF RIBs - City of Peoria, AZ

• Tucson Sweetwater Wetlands and RIBs - Tucson Water, AZ

• Oak Hill Estates RIBs - Polk County Utilities

• Lake Marden Recharge Project w/wetland - Orange County Utilities

• Project RENEW Irrigation – Orlando Utilities Commission

• Wetlands-Based Water Reclamation Project - City of West Palm Beach

• Orlando Easterly Wetlands - City of Orlando• Green Cay Wetlands - Palm Beach County Water Utilities Department

Summary of 16 Relevant Projects

Combined Indirect and Direct Recharge Projects• Arrowhead Ranch Recharge Facility ASR System, Vadose wells,

and RIBs - City of Glendale, AZ• GW Replenishment District RIBs and Salinity Barrier - Orange Co

Water District, CA

Direct Recharge Projects• Kanapaha WRF Injection Well - Gainesville Regional Utilities, FL• West Basin Reclamation Project Salinity Barrier - West Basin

Municipal Water District, CA• Hueco Bolson Recharge Project Recharge Wells - El Paso Water

Utilities, TX• Bolivar Reclaimed Water ASR System - Adelaide Water Works,

South Australia

Conclusions Derived from Projects

Florida - Reclaimed water has been used for groundwater exchange:– SJRWMD and SFWMD have approved projects for permitted

groundwater exchanges– Level of treatment predominantly is secondary treatment with

filtration and high level disinfection– Providing reuse water for irrigation to minimize surficial aquifer

pumping for irrigation– RIBs that recharge the surficial aquifer to offset future surficial

aquifer withdrawal impacts– RIBs that recharge the surficial aquifer to restore/mitigate

wetlands from Floridan withdrawals– Wetland recharge where excess wetland sheetflow water can be

used for surface water supply augmentation

Conclusions Derived from Projects

Arizona Groundwater Recharge

– Arizona Water Banking Authority established in 1980 to restore basin groundwater supply with Colorado River surface water and reclaimed water

– Deep unconfined aquifer and recharged reclaimed water undergoes Soil Aquifer Treatment

– Reclaimed water meets reuse and AWT standards

– RIBs, Vadose wells, wetlands, and injection wells are used

– Wetland restoration and treatment

– Groundwater recharge for intentional recovery by drinking water wells

– Long term storage credits to be used for withdrawal during drought conditions

Conclusions Derived from Projects

California Groundwater Recharge– Colorado River is a major component of water imported to Southern

California. River allocations are being reduced due to low river flows.

– California uses reclaimed water for salinity barriers and aquifer recharge for water supply well withdrawal (Groundwater Replenishment Project, West Basin Reclamation Project)

– RIBs and injection wells are used– Reclaimed water meets Full treatment standards

• Membranes (multiple barriers)• UV disinfection• AOP (hydrogen peroxide)

– Groundwater recharge for intentional recovery by drinking water wells.

– Recharged water retention time is a minimum of 6 months before being captured by drinking water wells

Applicable Aquifer Recharge Regulations

• 62-4, FAC – Permits • 62-40, FAC – Water Resource Implementation Rule• 62-520, FAC – Ground Water Classes, Standards, and Exemptions• 62-521, FAC – Wellhead Protection Rule• 62-522, FAC – Groundwater Permitting and Monitoring Requirements• 62-528, FAC – Underground Injection Control• 62-532, FAC – Water Well Permitting and Construction Requirements• 62-550, FAC – Drinking Water Standards, Monitoring, and Reporting• 62-600, FAC – Domestic Wastewater Facilities• 62-601, FAC – Domestic Wastewater Treatment Plant Monitoring• 62-610, FAC – Reuse of Reclaimed Water and Land Application• 62-611, FAC – Wetlands Application• 62-620, FAC – Wastewater Facility and Activities Permitting• 62-621, FAC – Generic Permits

– 62-621.500(2)(b), FAC – Generic Permit for Rapid Infiltration Basins

Groundwater Recharge Treatment and Disinfection RequirementsType of

Recharge System

Required Treatment Level Comments and Applicable Rules

Injection to G-II in the Floridan aquifer or Biscayne aquifer (<500 mg/L TDS)

Secondary treatment & filtrationTOC: The lesser of 5 mg/L average or background; 9 mg/L maxTOX: 0.2 mg/L average, 0.3 mg/L max.TN: 10 mg/L (average)Drinking water standards and HLDMultiple barriers (for organics & pathogens)Mutagenicity testing approved by FDEP. Activated carbon adsorption or approved alternative.Full scale operational testing for 2 years.Approved standby disposal or storage facilities.Additional pollutant reduction for parameters reasonably expected to pose a risk to public health due to acute or chronic toxicity (Rule 62-610.562(3)(b), FAC).

Rule 62-600.540(3), FAC.Rule 62-520.420, FAC at a minimum.Possible pilot testing reductions are outlined in Rule 62-610.564(5), FAC.ERC will hold a public meeting following pilot testing or full scale operational testing.Full-scale operational testing complete and national expert review before any permit is issued.

Injection to G-I, F-I, G-II (<3000 mg/L TDS)

Secondary treatment & filtrationTOC: 3 mg/L average, 5 mg/L max.TOX: 0.2 mg/L average, 0.3 mg/L max.TN: 10 mg/L (average)Drinking water standards and HLDMultiple barriers (for organics & pathogens)Pilot testing for 1 year.Additional pollutant reduction for parameters reasonably expected to pose a risk to public health due to acute or chronic toxicity (Rule 62-610.562(3)(b), FAC).

Alternate TOC and TOX limits can be obtained if all public supply wells within 1 mile are owned by applicant, and other users are prohibited or have RO treatment in place (Rule 62-610.563(3), FAC).Possible pilot testing reductions are outlined in Rule 62-610.564(5), FAC.

Groundwater Recharge Treatment and Disinfection Requirements (continued)

Type ofRecharge System

Required Treatment Level Comments and Applicable Rules

ASR using G-I, F-I, G-II (<3000 mg/L TDS)

Secondary treatment & filtrationTOC: 3 mg/L average, 5 mg/L max.TOX: 0.2 mg/L average, 0.3 mg/L max.TN: 10 mg/L averageDWSs and HLDMultiple barriers (for organics & pathogens)

Lesser standards (principal treatment; see >3000 mg/L below) if applicant can demonstrate that the groundwater is between 1,000 and 3,000 mg/L, not currently used as a source of public water supply and is not reasonably expected to serve as a future source of public water supply. Secondary DWSs, TN limit, and HLD fecal coliform standards shall not apply in this case.(Rule 62-610.466(9), FAC).Recovered water must demonstrate standards for BOD5 (20 mg/L), TSS (5 mg/L), and FC (absence).

Injection for salinityBarriers (G-II having TDS 1000-3000 mg/L & not used for potablepurposes)

Secondary treatment & filtration Primary DWSs and drinking water disinfection ZOD for secondary DWSs TN: 10 mg/L average)1000 ft. setback from potable supply wells

Treatment requirements are consistent with injection to G-II having TDS > 3000 mg/L.

Groundwater Recharge Treatment and Disinfection Requirements (continued)

Type ofRecharge System

Required Treatment Level Comments and Applicable Rules

Part IV systems (e.g., RIBs) in unfavorable conditions such as highly karstic or over-lying public water supplies

Secondary treatment & filtrationPrimary and secondary DWSs and HLDTN: 10 mg/L average

Rule 62-610.525, FAC.Also applies to RIBs with loading rates >9”/day.Projects are considered as reuse for groundwater recharge.Allows ZOD for secondary DWSs with affirmative demonstration (Rule 62-610.525(8)(b), FAC).

Discharge towetlands that percolate to ground water

Wetlands discharges are regulated under Chapter 62-611, FACPercolation can be regulated under ground water rules.

Chapter 62-611, FAC.

RIBs and other rapid-rate systems with favorable conditions

Secondary treatment (BOD5 and TSS <20 mg/L)Basic disinfection (FC <200 cfu/100 mL; CR >0.5 mg/L)Nitrate: 12 mg/L (max. as N).

Demonstration of <10 mg/L nitrate at edge of ZOD may allow nitrate limit of 12 mg/L to be waived (Rule 62-610.510(1), FAC).

Projects Ranked by Permitting Difficulty

• Projects ranked from simplest to most complex– Direct recharge or ASR into a G-IV aquifer containing greater than

10,000 mg/L TDS– RIBs located in areas without direct connection to the Floridan aquifer

with no potable water supply expected in the underlying aquifer– RIBs located in areas with direct connection to the Floridan aquifer

and with potable water supply occurring or expected to occur from underlying aquifers in the project area

– ASR completed into an aquifer containing between 3,000 and 10,000 mg/L TDS

– ASR completed into an aquifer containing between 1,000 and 3,000 mg/L TDS that are not reasonably considered to be used for public water supply

Projects Ranked by Permitting Difficulty

• Projects ranked from simplest to most complex (continued)– Direct recharge into an aquifer containing between 3,000 and 10,000

mg/L TDS (e.g., salinity barriers)– ASR in an aquifer containing less than 1,000 mg/L TDS– Direct recharge into an aquifer containing between 500 and 3,000

mg/L TDS– Direct recharge into an aquifer containing less than 500 mg/L TDS

• More complex permitting projects generally require more stringent water quality standards

SWFWMD Groundwater Permitting

• Minimum aquifer level in most impacted area of the Southern Water Use Caution Area

• Net Benefit concept• Other regulatory requirements

Level of Treatment from Area Utilities

• Hillsborough County - Advanced Wastewater Treatment– Falkenburg AWTP – Valrico AWT – South County AWTP

• City of Tampa - Advanced Wastewater Treatment – Howard F. Curren AWTF

• City of Plant City- Advanced Wastewater Treatment – Plant City Water Reclamation Facility

• Polk County - Secondary Treatment – Many WTFs (11 in all)

• City of Lakeland - Secondary Treatment – Northside WWTP – Glendale WWTP

Direct Recharge Project Areas

Direct Recharge Projects – 40 MGD Coastal Scenario

Direct Recharge Projects – 40 MGD Coastal Scenario

Direct Recharge Projects – Model Summary Table

Old Scenario

#

New Scenario

#

Recharge Area

Recharge Rate

(MGD)

Well Spacing

(Feet)

Model Simulation Completed

MIA Monitor Wells Average

Water Level Change (Feet)

MIA Area Average Water Level Change

(Feet)

Peace River Monitor Well

Average Water Level Change

(Feet)

Peace River Area Water

Level Change (Feet)

1-2 1-1 1 10 2,500 X 2.04 1.08 0.17 0.171-1 1-2 1 20 2,500 X 3.48 2.23 0.33 0.321-3 1-3 1 40 2,500 X 4.74 3.57 0.45 0.43

2-3 2-1 2 10 2,500 X 1.12 0.96 0.29 0.282-1 2-2a 2 20 2,500 X 2.51 N/A 0.61 N/A2-2 2-2b 2 20 5,000 X 2.25 N/A 0.59 N/A2-4 2-3 2 40 2,500 X 4.62 4.32 1.21 1.17

3-2 3-1 3 10 2,500 X 0.77 0.79 0.38 0.383-1 3-2 3 20 2,500 X 1.77 1.77 0.76 0.753-3 3-3 3 40 2,500 X 3.62 3.74 1.51 1.49

4-2 4-1 4 10 2,500 X 0.32 0.29 0.76 0.824-1 4-2 4 20 2,500 X 0.67 0.66 1.52 1.634-3 4-3 4 40 2,500 X 1.43 1.39 3.08 3.26

Direct Recharge Projects - Withdrawals

Floridan Aquifer Vulnerability Assessment

• Evidential Theme (data layer)– IAS thickness– Hydraulic head difference (UFA-SAS)– Proximity to karst features– Soil permeability

• Training points (occurrence)– Wells with WQ data indicative of vulnerability

• Response Theme (output map)– Model output of relative vulnerability

FAVA Evidential Themes

Soil Permeability

Proximity to Karst Features

Intermediate Aquifer System Thickness

SAS-FA Head Difference

Model Output = Relative Vulnerability

FAVA Response Theme – Floridan Aquifer

• An output map of the probability of vulnerability

• Calculated by estimating the combined weights of the data layers

• Output theme is displayed in classes of relative vulnerability (one area is more vulnerable than another)

Floridan Aquifer Favorability Assessment

Indirect Recharge Next Steps

• The Lakeland and Lake Wales Ridges in the north may be sites of interest for indirect recharge.

• Availability of land will affect the selection of sites.• Potential opportunities to use mining lands as recharge sites• Conduct groundwater modeling on selected sites

Indirect Recharge Site Selection

Recharge Feasibility Next Steps

• Technical Memorandum 2 will summarize numerical groundwater modeling of recharge and withdrawal to quantify the net aquifer benefits to the Upper Floridan aquifer.

• Evaluations will be made to rank the recharge scenarios based on the improvements in water level and the additional withdrawal available to be captured.

• Technical Memorandum 3 will summarize estimated costs for projects that are identified to have a greater aquifer improvement and additional groundwater availability.

• Final report summarizing findings on study.

Aquifer Recharge Using Reclaimed Waterin the Tampa Bay Area

The End

Phil Waller, P.E.