Developing a Sustainable Water Supply Strategy for the City of Plantation, Florida

Transcription

1 Developing a Sustainable Water Supply Strategy for the City of Plantation, Florida Water and Energy Sustainability Symposium Pittsburg, Pennsylvania September 29, 2010 Courtney S. Licata, Hazen and Sawyer Michael Wengrenovich, Hazen and Sawyer Hank Breitenkam, City of Plantation

2 The City of Plantation the Grass is Greener Broward County, FL Approximately 85,000 residents Committed to water conservation to promote community involvement and water stewardship Source: City of Plantation

3 The Biscayne Aquifer is the principal water supply in South Florida Regional water system: Urban growth Environment Agriculture Industry Source: SFWMD

4 Water management focused on protecting the Biscayne Aquifer

5 The SFWMD is responsible for managing water resources in South Florida Lower East Coast (LEC) Planning Area Source: SFWMD Lower East Coast Water Supply Plan Update

6 Competing water needs have prompted recent legislation Regional System Water Availability Rule No additional withdrawal from the Biscayne Aquifer over levels that existed prior to April Lower East Coast Water Supply Plan Update ( LEC Plan) Encourages Development of Alternative Water Supply (AWS) Projects

7 Several options presented to satisfy future water demands Demand Management Alternative Supply Conservation Reclaimed Water for Irrigation Captured Stormwater Floridan Aquifer (Brackish) Biscayne Aquifer Recharge (Wastewater Reuse) Seawater

8 The City of Plantation is proactive about conservation Demand-not-Met (DNM) = Amount of water needed to support future demands which cannot be supplied by the Biscayne Aquifer

9 The City investigated several options to address the 2018 DNM Floridan Aquifer Development Canal Recharge Golf Course Irrigation Source: SFWMD

10 The Floridan Aquifer Alternative involves reverse osmosis treatment of raw water Key assumptions: Long term viability of the Floridan as source 75% reverse osmosis process recovery N

11 The Floridan Aquifer Alternative requires the following process components: Floridan Aquifer Supply Well Cartridge Filtration Reverse Osmosis Degasification / Odor Control Distribution System 1.1 mgd Reject Clearwell High Service Pump Station 0.8 mgd Deep Well Injection Reverse Osmosis Water Treatment

12 The Canal Recharge Alternative involves advanced wastewater treatment Studied in the City of Plantation AWT Pilot Project

13 The Canal Recharge Alternative involves advanced wastewater treatment Surface water discharge of reclaimed water under FAC and Broward Co , 196 Key assumptions: Direct hydraulic connection between canal and Biscayne Aquifer (1:1 offset) 90% ultrafiltration process recovery 85% reverse osmosis process recovery N

14 The Canal Recharge Alternative involves advanced wastewater treatment Parameter Broward County Standard Florida State Standard CBOD 5 10 mg/l 5 mg/l Total Suspended Solids (TSS) -- 5 mg/l Total Nitrogen (TN) 1.5 mg/l 3 mg/l* Ammonia (unionized) 0.02 mg/l 0.02 mg/l Total Phosphorus (TP) 0.02 mg/l 1 mg/l* Water Quality Based Effluent Limitations (WQBEL)* No Yes

15 The Canal Recharge Alternative requires the following process components: Traditional Wastewater Treatment Influent (18.9 mgd capacity) Screens Grit Primary Clarification Primary Sludge to Digesters Aeration Basins RAS Secondary Clarification WAS to Sludge Thickeners To Deep Well Injection Advanced Wastewater Treatment 1.3 mgd Denitrification Filter Ultrafiltration 1.2 mgd Reverse Osmosis Reject Deep Well Injection UV / AOP 1.0 mgd East Holloway Canal Membrane Softening Water Treatment Biscayne Aquifer Supply Well 1.0 mgd Cartridge Filtration Deep Well Injection Nanofiltration Reject Degasification / Odor Control Clearwell 0.8 mgd High Service Pump Station Distribution System

16 The Golf Course Irrigation Alternative involves tertiary wastewater treatment Land application of reclaimed water under FAC Key assumptions: Termination of golf course CUPs resulting in a 1.0 mgd offset credit for 1.4 mgd applied Based on preliminary modeling Source: City of Plantation

17 The Golf Course Irrigation Alternative involves tertiary wastewater treatment N

18 The Golf Course Irrigation Alternative requires the following process components: Traditional Wastewater Treatment Influent (18.9 mgd capacity) Screens Grit Primary Clarification Primary Sludge to Digesters Aeration Basins RAS Secondary Clarification WAS to Sludge Thickeners To Deep Well Injection Tertiary Wastewater Treatment Deep Bed Filters Chlorine Contact Reclaimed Water Storage Distribution Pump Station 1.4 mgd 1.4 mgd Delivery to Golf Course Ponds Membrane Softening Water Treatment Biscayne Aquifer Supply Well 1.0 mgd Cartridge Filtration Deep Well Injection Nanofiltration Reject Degasification / Odor Control Clearwell High Service Pump Station 0.8 mgd Distribution System

19 Carbon footprint assessment gaining acceptance as measure of sustainability Carbon footprint is a term used to describe the amount of greenhouse gas (GHG) emissions associated with a particular activity Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own needs (WCED, 1987) Pillars of sustainability Social Economic Environmental Source: SFWMD

20 Defining the functional unit an important step in carbon footprint analysis Functional Unit: Production of 0.8 mgd of finished water to meet DNM in 2018 for one year of operation Result: nanofiltration water treatment included for reuse alternatives

21 Carbon footprints were developed based on project operation System Boundary: Includes all processes required to produce the functional unit Includes nanofiltration treatment for reuse alternatives Excludes existing wastewater treatment systems as these are deemed fixed regardless of additional treatment needed

22 Carbon footprint analysis focused on Scope 2 emissions Scope 1 emissions released into the atmosphere directly from a given process Scope 2 emissions released into the atmosphere indirectly from a given process due to the purchase of energy Scope 3 emissions released into the atmosphere indirectly from a given process due to the transport or manufacture of process components

23 Model developed to predict power consumption for all processes Direct Computation Literature Product data Water supply Cost studies System Boundary Canal Recharge and Golf Course Irrigation projects credited for power consumption Qγh p P = 550η Source: SFWMD

24 Power consumption relates to emissions released EPA egrid database used to convert power consumption (KW-h) to emissions released (lbs) Global Warming Potential (GWP) used to relate global warming impacts of emissions to that of carbon dioxide Result: carbon dioxide equivalents (CO 2 e) Gas Carbon Dioxide GWP 1 Methane 23 Nitrous Oxide Source: IPCC,

25 Results indicate CO 2 e emissions vary considerably for the project alternatives Alternative Floridan Aquifer Canal Recharge Golf Course Irrigation Carbon Dioxide Equivalents Produced (tons/year) Water Treatment Wastewater Treatment Total Combined 1, , ,

26 Results indicate CO 2 e emissions vary considerably for the project alternatives Carbon Dioxide Equivalents Released in Operation of Alternative Water Supply Projects 1,750 1,500 CO2e Released (ton/yr) 1,250 1, Floridan Aquifer Canal Recharge Golf Course Irrigation Project Scope 2 Emissions

27 Results classified by treatment category illustrate relative contributions Carbon Dioxide Equivalents Released in Operation of Alternative Water Supply Projects 1,750 1,500 CO2e Released (ton/yr) 1,250 1, Floridan Aquifer Canal Recharge Golf Course Irrigation Tertiary Wastewater Treatment Water Treatment

28 Cost considerations are important in examining alternative water supply options AWS Option Capital Cost Range ($/gal) Floridan Aquifer 6-9 Canal Recharge 10+ Golf Course Irrigation 6-8

29 Conclusions related to alternative water supply and beyond City able to demonstrate that the Golf Course Irrigation Project is most favorable in terms of cost, feasibility, and global warming impacts caused by operation of the facilities Study illustrates how a carbon footprint analysis can be used as a tool in the development of water resources projects Source: City of Plantation

30 Questions? Source: SFWMD