Reclaimed Water ASR Permitting

Transcription

1 Reclaimed Water ASR Permitting Presented by Mark B. McNeal, P.G. February 11, 2004 Presented at the Environmental Permitting Short Course Sponsored by Florida Chamber of Conference Rosen Plaza Hotel Orlando, Florida

2 Today s Presentation Introduction ASR Feasibility Technical Issues Summary

3 Mature reuse systems face supply and demand imbalances Increasing Demand Reclaimed Water Supply Reclaimed Water Demand Potential Supply Deficit Potential Excess Supply Jan Feb March April May June July Aug Sept Oct Nov Dec

4 Many storage options are available Surface Reservoirs????? Above Ground Storage Tanks ASR Wells

5 ASR is most feasible in many cases Problem: 600 MG storage needed 6 ASR Wells $5 to 6 million cost 3 acres of land 120-5MG Storage Tanks >$100 million cost 100s of acres of land

6 Reclaimed Water ASR The seasonal storage of high quality reclaimed water in a suitable aquifer during periods of low demand, for subsequent recovery during periods of high demand for beneficial use Different from deep well injection which is designed to dispose of effluent that does not necessarily meet reuse standards

7 Conceptual Reclaimed Water ASR Well Public Access Reuse System Public Access Reuse System WRF or AWTP Class V, Group 3 Injection Well WRF or AWTP Class V, Group 3 Injection Well >1,000 mg/l TDS Low Permeability Zone Moderate Permeability Zone Zone of poor quality water Typical Recharge Operation (Excess Supply) Low Permeability Zone Typical Recovery Operation (Excess Demand)

8 Reclaimed water ASR programs are developing quickly along Florida s west coast Clearwater Largo Pinellas County St. Petersburg Southwest Manatee County Sarasota County Englewood Northwest Hillsborough Central Hillsborough South Hillsborough Manatee County North City of Sarasota Cycle Testing Initiated (2) Lehigh Acres ASR Well Drilled (5) Construction Permit Issued(7+) Feasibility Study Bonita Springs Marco Island WWTP

9 Florida is out in front nationally in development of reclaimed water ASR Other states are less comfortable with reclaimed water use Artificial recharge and indirect potable reuse are more active elsewhere Other areas appear to be lagging in matching the quality of water to intended use ID-1

10 Reclaimed water ASR will become more widespread in the near future Similar projects are underway in Arizona - Australia California - Washington Other states recognize the need but must develop regulatory framework South Carolina -- North Carolina Georgia --Texas Yet other states must still become more comfortable with reuse

11 ASR will be the key to successful optimization of many reuse programs Reuse is often limited to 50 to 60 percent of annual ADF without seasonal storage for many Florida reuse systems ASR development in many cases is the lowest cost option to expand reuse has the lowest land requirements is environmentally sensitive has no negative aesthetics

12 Reclaimed water ASR programs take several years to implement Feasibility Study (3 to 6 months) Permitting (10 to 15 months) Well Construction (6 to 12 months) Operational testing (2 to 4 years) August 1996 January 1997 July 2001

13 A feasibility study is important to address ASR preliminary issues Supply and demand issues Well siting Reclaimed water characterization Existing wastewater infrastructure and reuse system Existing groundwater users Native water quality and hydrogeology Drilling and testing program

14 Native water quality and hydrogeology drive selection of optimum storage zone and permitting strategy Permitting Not Feasible Proper Storage Zone Selection Maximizes Recovery And Aids in Permit Approval Limited Recovery

15 Permitting for Reclaimed Water ASR Systems Similar to Potable Water ASR Technical Advisory Committee Formed FDEP local and Tallahassee Local WMD EPA County DOH Other County agencies WMD Water Use Permit still required Truly a Zero-Consumptive-Use permit Should be relatively straight forward

16 Quality of Aquifer Dictates Effluent Quality Requirements Greater than 10,000 mg/l TDS Secondary treatment only (BOD and TSS limits) Similar to Deep Injection Wells Between 3,000 and 10,000 mg/l TDS All primary DWSs Secondary DWSs waived Minimum criteria ( free-froms ) Between 1,000 and 3,000 mg/l TDS As above, but Secondary DWSs also regulated Less than 1,000 mg/l TDS (62-610, FAC) Same as above plus additional TOC and TOX limits

17 The reclaimed water must meet all primary Drinking Water Standards Phthalate concerns may have to be addressed Disinfection by-products can be successfully addressed through chloramination TTHMs reduced from 175 ppb to 30 ppb at NW Hillsborough Co. Nitrogen series may also require process changes Nitrate of <10 mg/l Nitrite of <1 mg/l Ammonia is not regulated

18 Coliform standards must be met at the well Total coliform of 4 cfu/100 ml; not a reuse - but a groundwater discharge - standard Reuse systems are not sterile conveyance systems, not constructed/operated as a drinking water system Chloramines are more persistent than free chlorine, but generally not as strong a disinfectant; maintaining elevated TRC at wellhead should control TC Fecal coliform must be (and have been) absent UV Alternative disinfection such as UV may be needed at the wellhead Capital $80-$150k/well O&M $3-$5k/year/well

19 Secondary Drinking Water Standards must also be met Secondary DWSs are aesthetic rather than healthbased standards Color -- Manganese -- TDS --ph Odor -- Iron --Chloride --Sodium Ambient groundwater is alternative standard Exemptions are available and relatively easy to obtain WQCEs, ZODs, Chapter 120 Variance Regulated as average concentrations, rather than single sample exceedence

20 Initial test results from EWD are encouraging Storage zone is saline 20,000 mg/l TDS No other beneficial use 90 MG was recharged during first cycle Only 12 MG was recovered Due to lack of reuse demand not water quality Recovered water quality approached 1,100 mg/l TDS Approximately 450 mg currently in storage 10 mg recovered with TDS approximately 500 mg/l Recovery efficiency showing improvement w/ increased storage

21 Blending of ASR water with reclaimed water will help meet irrigation quality mg/l TDS ASR Well 2000 mg/l TDS Chlorine Contact Basin Water Reclamation Facility mg/l TDS mg/l TDS (400 mg/l chlorides)

22 Cycle testing is an important phase of the ASR program Operational testing necessary to justify FDEP operating permit issuance Defines recovery potential of the stored water Allows demonstration that drinking water standards can be maintained during recharge events, and reuse standards during recovery

23 Sufficient reject pond capacity provides flexibility during cycle testing Existing Blowdown Pond TPW-1 High turbidity observed for 1 to 2 hours following recovery startup Existing pond sited for 15 to 20 minutes of recovery Larger pond will allow longer blowdown period during multiple ASR well startups

24 Reclaimed water ASR projects should be easier to develop than potable ASR Source water costs pennies per 1000 gallons (pumping costs), therefore investment is minimal to develop bubbles Recovery to approximately twice the salinity of drinking water for many irrigation applications No re-treatment should be required prior to placing into the reuse system, following water quality demonstration

25 Major hurdles have been cleared over the past several years in Florida Permitting Feasibility Recharge Water Quality Issues Native water quality characterization Authorization to Use Operating Permit One hurdle remains...

26 Summary Sustainable dry season supplies are becoming increasingly critical for reuse reliability ASR allows the reuse utility to maximize use and minimize disposal of this resource Substantial progress has been made in Florida to recognize the benefits of reclaimed water ASR Further progress is needed to streamline implementation of these programs

27 Summary (cont.) Reclaimed water ASR is a new use of a proven technology to maximize reuse Favorably received by FL regulatory agencies May allow utility to transition into a zerodischarge facility Economical approach to large volumes of seasonal storage Future saltwater intrusion barriers or indirect potable reuse applications may develop, but additional treatment is likely required

28 Reclaimed Water ASR Permitting Presented by Mark B. McNeal, P.G. February 11, 2004 Presented at the Environmental Permitting Short Course Sponsored by Florida Chamber of Conference Rosen Plaza Hotel Orlando, Florida