Treatment Wetlands: Facilitating the Beneficial Use of Reuse

Transcription

1 Treatment Wetlands: Facilitating the Beneficial Use of Reuse May 16, 2017 State Information Exchange Webcast 2017 by the WateReuse Association

2 A Few Notes Before We Start Today s webcast will be 60 minutes. There is one (1) Professional Development Hours (PDHs) available for this webcast. A PDF of today s presentation can be downloaded when you complete the survey at the conclusion of this webcast. If you have questions for the presenters please send a message by typing it into the chat box located on the panel on the left side of your screen. 2

3 Today s Speakers Chris Keller is President of Wetland Solutions, Inc., located in Gainesville, FL. Chris has over 20 years of experience specializing in the design and operation of constructed wetlands for water quality improvement, habitat creation, public use, and ancillary environmental benefits. Chris received his bachelors and masters degrees in Environmental Engineering from the University of Florida. Chris has worked on more than 120 wetland projects across 22 states and countries. The Moderator Rick Hutton is a professional engineer who oversees water and wastewater planning at Gainesville Regional Utilities. Prior to working with GRU he spent 10 years doing environmental engineering consulting for a variety of municipal and industrial clients. He received his bachelors and masters degrees in environmental engineering from the University of Florida and has been engaged in water supply planning, water and wastewater treatment, and water quality protection for over 25 years. Amy Tracy Director of Regulatory Programs England-Thims & Miller

4 Types of Treatment Wetlands Natural Treatment Wetlands Constructed Treatment Wetlands Surface Flow or Free Water Surface Subsurface Flow Horizontal Vertical (upflow or downflow) Tidal or Reciprocating Hybrid Systems Infiltrating (recharge) Intensified Systems Aeration Chemical Addition Exotic Media

5 Wetland Water Quality Processes

6 Treatment Wetlands are Engineered Systems Q i Q 1 Q 2 Q 3 Q n P-k-C* Model (Kadlec and Wallace 2009) C i Q i W u C 1 ET P C 2 Water Slope = -dh/dx C 3 Stems occupy volume fraction 1 = Ɛ C n CC 2 CC CC 1 CC = 1 + kk PPPP C 1 = inflow concentration (mg/l) C 2 = outflow concentration (mg/l) C* = background concentration (mg/l) k = 1 st order rate coefficient (m/yr) P = apparent number of tanks-in-series q = hydraulic loading rate (m/yr) PP H i x h(x) B(x) H(x) L H o Q o Outlet Weir Bottom Slope = Sb = -db/dx datum Total Phosphorus (mg/l) Fractional Distance

7 Sources of Design Guidance and Performance Summaries

8 General Wetland Performance Limits Parameter BOD TSS TN NH 3 -N, NO X -N TP Coliforms Heavy Metals Organic and Synthetic Hydrocarbons Emerging Contaminants Lower Performance Limit 2 mg/l 2 mg/l 0.8 mg/l < 0.01 mg/l < 0.02 mg/l < 100-1,000 col/100 ml BDL Varies Varies

9 Wetland Capital Costs 1,000,000 Capital Cost (thousands of dollars) 100,000 10,000 1, Cost = 194*A 0.69 r 2 = 0.79 Unit Costs Area (ac) $/ac 1 $100, $50, $25, $12, Area (ha) Capital costs for 84 surface flow wetlands (Kadlec and Wallace 2009)

10 Wetland O&M Costs Percentile Median $700/ac/yr Y = 0.247Ln(x) r 2 = ,000 10, ,000 O&M Cost ($/ha yr) O&M costs for 21 surface flow wetlands (Kadlec and Wallace 2009)

11 Wetland Applications for Water/Wastewater Utilities As an upgrade for secondary treatment or alternative to conventional highercost AWT processes As cost-effective add-on unit processes for tertiary treatment prior to surface water discharge, or in some cases, discharge to recharge basins As beneficial reuse projects designed to achieve multiple benefits such as water quality improvement, wildlife habitat creation, and public access opportunities As environmental buffers for Indirect Potable Reuse applications

12 Orlando Easterly Wetlands, FL Project Facts: Operational 1987 Size 1,200 ac Flow 16 MGD Cost $21.5 M ($18k/ac) O&M $450k/yr ($375/ac) Visitors 15,000/yr

13 Orlando Easterly Wetlands Performance 6.0 Total Nitrogen (mg/l as N) Wetland Inflow Wetland Outflow Permit Limit Total Phosphorus (mg/l as P) Wetland Inflow 0.60 Wetland Outflow Permit Limit Parameter Standard Average TN (mg/l) TP (mg/l)

14 Wetland Applications for Water/Wastewater Utilities As an upgrade for secondary treatment or alternative to conventional highercost AWT processes As cost-effective add-on unit processes for tertiary treatment prior to surface water discharge, or in some cases, discharge to recharge basins As beneficial reuse projects designed to achieve multiple benefits such as water quality improvement, wildlife habitat creation, and public access opportunities As environmental buffers for Indirect Potable Reuse applications

15 Talking Water Gardens, Albany, OR Project Facts: Operational 2011 Size 37 ac Flow 12.3 MGD Cost $13 M ($350k/ac)

16 Wetland Applications for Water/Wastewater Utilities As an upgrade for secondary treatment or alternative to conventional highercost AWT processes As cost-effective add-on unit processes for tertiary treatment prior to surface water discharge, or in some cases, discharge to recharge basins As beneficial reuse projects designed to achieve multiple benefits such as water quality improvement, wildlife habitat creation, and public access opportunities As environmental buffers for Indirect Potable Reuse applications

17 IPR North Texas Municipal Water District Project Facts: Operational 2009 Size 1,840 ac Flow 90 MGD Cost $280 M ($152k/ac)

18 IPR Clayton County Water Authority Huie Wetlands Project Facts: Operational 2010 Size 263 ac Flow 17.4 MGD Shamrock Lake/ Blalock Reservoir

19 IPR Conceptual Wetland/Wellfield Recharge

20 What s Next - One Water Treatment Wetlands Comingling reclaimed water and stormwater management Challenge with stormwater wetlands is maintaining adequate hydration between storms Supplementing with reclaimed water maintains biological processes and increases performance Maximize infrastructure investment and functionality Encouraging recharge-based reclaimed water management to replenish potable supply aquifers Use infiltrating wetlands to cleanse and recharge aquifers (may require recharge enhancements for well-confined aquifer systems) Combines wetland treatment processes with soil aquifer treatment (SAT) processes Demonstration projects show viable infiltration rates can be maintained

21 What s Next - One Water Treatment Wetlands Closing the gaps between permitting processes for potable water use and reclaimed water management Eastern vs. Western U.S. water accounting practices Multi-agency permitting can be required Recognizing and maximizing project functions and benefits Total Maximum Daily Loads Supporting environmental flows and water levels Wetland mitigation credits Ancillary benefits (human use and wildlife)

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23 Sweetwater Wetlands Park Project Area

24 Historical Impacts 1800s to present: Urbanization of Gainesville Stormwater runoff Trash & sediment WW Effluent Septic Tanks 1930s:Sweetwater Branch channeled directly to Alachua Sink 1,300 acres of wetlands impacted. Direct flow path from Gainesville to Alachua Sink 1930s: Portion of Prairie Creek flow diverted away from Paynes Prairie

25 Project Drivers and Alternatives Alachua Sink TMDL 2006 TMDL Adopted by FDEP 55% N reduction in Point Sources 45% N reduction in Non-Point Sources Upgrade Main Street WRF to AWT Plant currently 7.5 mgd Activated Sludge w/ tertiary filtration MSWRF could meet 4 mg/l TN w/ $41M upgrade Would not meet TMDL of 1.5 mg/l TN Would not address stormwater Expand the Reclaimed Water Program Divert 75% of effluent flow $40M to $60M cost Would not address stormwater

26 Conceptual Plan Upgrade Main Street WRF P Removal (TP < 0.3 mg/l) Enhancement Wetland Reduce TN from all sources in SWB (TN < 3.0 mg/l) Fill in Sweetwater Canal Additional Nutrient Removal on Paynes Prairie TP < 0.09 mg/l TN < 1.42 mg/l

27 Design Elements Sediment Basin And Trash Removal Area 1.3 Acres

28 Design Elements Forebay Attenuation and Flow Distribution 5 Acres

29 Design Elements Overflow Channels Storm Events

30 Design Elements Wetland Treatment and Prairie Rehydration 125 Acres in 3 Wetland Cells 1.1 Mile Long Sheetflow Distribution Channel

31 Design Elements Public Access 3.6 mile berm systems to create/contain the wetland areas serve as walking paths and maintenance access. 1,800 linear feet of wooden boardwalks over shallow wetlands, over deep open water pools and onto tree islands. Berm walking paths containing 7 wooden platforms/shade structures that provide resting places and wildlife viewing opportunities. Interpretive signage throughout the public access areas.

32 Environmental Benefits Water Quality Exceeds TN TMDL Achieves background TN and TP on Prairie Removes sediment and trash Hydrologic Restoration Removes 2 miles of drainage canal Restores sheetflow and rehydrates 1,300 acres Conservation Adds 184 acres to Paynes Prairie Preserve State Park

33 Funding Partners GRU/COG - $20 M FDEP - $3.2 M - Legislative, Section 319, TMDL & RTP SJRWMD - $1.4 M - SWIM & Land Acquisition Programs FDOT - $0.6 M - NPDES Cost Share FWC - $0.5 M - AHRES Cost Share Alachua County $0.5 M Land Conservation Program

34 Project Site - Before

35 Project Site - After

36 Questions Chris Keller President, Wetland Solutions Rick Hutton Professional Engineer Gainesville Regional Utilities Please type your questions into the chat box Amy Tracy Director of Regulatory Programs England-Thims & Miller