Susan Rask Barnstable County Department of Health and Environment

1. Projected Use of Innovative/Alternative On-site Sewage Treatment Systems in Eastham, Under Current Regulations and Policies Susan Rask Barnstable County Department of Health and Environment

2. Project funded by Barnstable County Wastewater Implementation Committee (WIC)

3. Project Goals • Examine existing regulations and Board of Health policies that require or encourage use of I/A systems • Use this information to project how many I/A systems might be installed over next 20 years, and where these might be installed • Provide information about initial and long term costs of I/A systems, so these can be compared to other alternatives

4. Project Methodology • 6152 lots in Eastham • Could not examine on case-by-case basis • Use of reasonable assumptions to compensate for missing information • Use of GIS to analyze parcels and graphically show results • Analysis linked to Eastham drinking water quality database

5. Criteria for Installation of I/A • Criteria 1: Board of Health policy • For new construction or upgrades of existing systems • When SAS < 100 ft. to any drinking water well • When SAS < 75 ft. to edge of wetland resource

6. Criteria for Installation of I/A • Criteria2: Public Water supplies A public water supply is any well that serves more than 25 people for more than 60 days per year In Eastham, most are Transient, Non-Community wells at restaurants and motels • 39 in Eastham, primarily on Rt. 6

7. Criteria for installation of I/A • Criteria 3: Title 5 requirements • I/A required • For NEW CONSTRUCTION on residential lots with well and septic, if design flow exceeds 440 gpd/acre • Title 5 and DEP policy that BOHs consider requiring I/A • For existing systems at time of upgrade, if design flow > 440 gpd/acre and nearby wells showing elevated nitrates

8. Criteria 1: Board of Health policy • When SAS <100 ft to any drinking water well • Could not be directly determined, due to lack of information on septic and well locations • Surrogate: • All parcels <10,000 s.f. were likely not to be able to meet 100 ft setback, and were projected for I/A • Parcels > 20,000 s.f. were assumed to generally be able to fit well and septic • Parcels >10,000 but <20,000: examined wetland coverage on parcel, size of surrounding parcels, bedroom density, and well water quality and made decision on lot-by-lot basis

9. Criteria 1: Board of Health policy • When SAS <100 ft to any drinking water well RESULTS:I/A projected on Parcels <10,000 s.f. = 276 I/A projected Shown in pink on Map 2 Parcels >10,000 but <20,000 s.f. := 282 I/A projected Shown in blue on Map 2 Parcels > 20,000 s.f. = 0 I/A projected but these parcels were examined under Criteria 3 to see if they met 440 gpd/acre standard

10. Criteria 1: Board of Health policy • When SAS <75 ft from edge of wetland • Could not be directly determined, due to lack of information on septic and house footprint • Surrogate: For each parcel • Mapped wetland coverage • Mapped 75 ft buffer zone beyond wetland boundary (BOH setback criteria) • Mapped 10 ft property line offset • Knew house foundation size from assessor data • Created “House Footprint” by adding foundation size plus a 20 ft border around foundation, to meet septic setbacks

11. Criteria 1: Board of Health policy • When SAS <75 ft from edge of wetland • Area available for SAS = Total lot size –(area of “House Footprint” + area covered by 75 ft wetland buffer + area covered by 10 ft lotline setback) • If Area available for SAS < 3000 s.f., projected I/A

12. Criteria 1: Board of Health policy • When SAS <75 ft from edge of wetland • RESULTS: I/A projected = 482 • Shown in green on Map 1 • Recognize that some of these are likely all wetland and unbuildable, more realistic number is probably 382

13. Criteria 2: Public Water supplies • Regulated by 310 CMR 22.00—Drinking Water regs • Zone I: area immediately surrounding a well • For small volume wells, is minimum 100 ft radius • IWPA: “zone of contribution”, land area that may contribute water to well • For small volume wells, is minimum 400 ft radius around well

14. Criteria 2: Public Water supplies • 310 CMR 15.00—Title 5 requires I/A • When design flow >2000 gpd and septic system will be located in IWPA or Zone II of public drinking water supply well • When septic system is in IWPA and design flow exceeds 440 gpd/acre • For upgrades of existing systems, when septic components cannot be located outside Zone 1 of the well

15. Criteria 2: Public Water supplies • Most businesses with a public water supply well are located on relatively small parcels • 400 ft IWPA radius usually covers most or all of the parcel, making it difficult to locate septic outside this radius • Most have septic design flows > 440 gpd/acre • Most businesses will fit into one of the categories in previous slide • All are projected to have I/A systems installed = 39. Shown in blue on Map 1

16. Criteria 3: Title 5 requirements • I/A required • For NEW CONSTRUCTION on residential lots with well and septic, if design flow exceeds 440 gpd/acre • DEP and Title 5 suggest that BOHs consider requiring I/A • For existing systems at time of upgrade, if design flow > 440 gpd/acre and nearby wells showing elevated nitrates

17. Criteria 3: Title 5 requirements On residential lots with well and septic, Title 5 allows 440 gpd/acre = 4 bedrooms/acre or 2 bedrooms/0.5 acre, etc. i.e. 1 bedroom per 10,000 s.f. lot size

18. Criteria 3: Title 5 requirements • Why does Title 5 limit septic design flow to 440 gpd/acre in areas served by private wells? • Nitrogen loading model predicts that 440 gpd/acre results in groundwater nitrogen concentration of 7.1 mg/L on lot-by–lot basis • Protective, based on human health standard of 10 mg/L nitrate in drinking water • Does not address N loading to coastal embayments

19. Criteria 3: Title 5 requirements • I/A required for NEW CONSTRUCTION on residential lots with well and septic, if design flow exceeds 440 gpd/acre • Installation of these systems is usually voluntary, i.e. owner wants more bedrooms and is willing to install I/A system • Not predictable, so unable to project • Could result in a significant number over time Note: New Construction = addition of new design flow

20. Criteria 3: Title 5 requirements • DEP and Title 5 suggest that BOHs consider requiring I/A • For existing systems at time of upgrade, if design flow > 440 gpd/acre and nearby wells showing elevated nitrates

21. Criteria 3: Title 5 requirements • To approach this problem, we mapped: • Most recent water quality data for each lot • Bedroom density on each lot • Equivalent to 4,5,6,7,8+ BR/acre • Shown on Map 3

22. Criteria 3: Title 5 requirementsBedroom density and nitrate levels • Results: Map 3 • Lots showing elevated nitrates (> 2 mg/L) are widespread, esp in northern end of town • Number of water samples showing nitrates > 2 mg/L constitute 50.4% of all samples • Bedroom density is not directly correlated with nitrate level on its own lot • Wells showing nitrate > 5 mg/L are likely due to “short circuiting”

23. Leach field Downgradient well NO3 Nitrate

24. Drinking wells intercepting plume at different distances from plume source and therefore showing different concentrations of nitrate

26. Criteria 3: Title 5 requirementsBedroom density and nitrate levels • “Short circuiting” is occurring due to small lot size and large number of wells and septic systems; • High number of samples > 2mg/L validates that entire groundwater system is showing nitrogen impacts from septic systems

27. Current Eastham Drinking Well Results

28. Historical Trend of Nitrate levels in Wells, 1981-2006shown as percent of total samples

30. Criteria 3: Title 5 requirementsBedroom density and nitrate levels • Results: Map 3 • Lots showing elevated nitrates (> 2 mg/L) are widespread, esp in northern end of town • Lots showing nitrates > 5 mg/L appear to be randomly distributed • Bedroom density does not appear to be correlated with nitrate level on its own lot • Many lots exceed 440 gpd/acre

31. Criteria 3: Title 5 requirementsBedroom density and nitrate levels • How to deal with this information? • Developed scenarios for installation of I/A • Lots with >6 BR/acre and nitrates > 5 mg/L 147 lots shown in light blue on Map 4 • Lots of 10-20,000 s.f. with > 4 BR/acre and nitrates > 3 mg/L 90 lots shown in pink on Map 4

32. Criteria 3: Title 5 requirementsBedroom density and nitrate levels • Results in very random distribution of I/A systems • Not recommended way to use these systems because • Does not address groundwater N loading in a coherent way • Will likely not solve problem of lots with elevated nitrates • Expensive for homeowners • Management issues with single family I/A s

33. Bedroom Density 45% of total parcels in town exceed 4 BR/acre or 440 gpd/acre guideline (this doesn’t include analysis of commercial flow vs. lot size)

34. Criteria 3: Density vs. lot size 45% of total parcels in town exceed 4 BR/acre or 440 gpd/acre guideline • If 440 gpd/acre = 7.1 mg/L N in groundwater, its not surprising that Eastham has a number of lots showing elevated nitrates • Unlikely that groundwater quality will improve

35. Summary of Projected I/As • 93 Currently permitted • 276 Criteria 1A: parcels <10,000 s.f. • 372 Criteria 1B: insufficient setback to wetlands • 39 Criteria 2: public water supplies • 90 Criteria 3: parcels 10-20,000 s.f. with > 4BR/acre and nitrates>3 mg/L • 147 Criteria 3: parcels with >6 BR/acre and nitrates >5 mg/L • 1017 TOTAL

36. Summary of Projected I/As • 1017 Projected • Shown on Map 4 • Randomly distributed around town • Random distribution will do little to address groundwater nitrogen in a coherent way

37. I/A Systems: Considerations • Perception that I/A systems are quick and inexpensive fix • Not True • Costly over life of system • Stringent O&M and sampling requirements when used for nitrogen reduction • Variable performance • At best, remove 50% of nitrogen • Impose management burden on town

38. I/A Systems: Economics • Individual I/A on-sites are not inexpensive • Installation cost: $10,000 above cost of Title 5 system • Significant Annual Costs • Operation and Maintenance contract ($1200) • Electricity costs ($350) • Effluent Sampling ($400, included in cost of O&M) • Total annual cost to operate= $1550

39. I/A Systems: EconomicsPresent value cost of I/A system • Present value analysis brings all costs associated with system installation, maintenance and operation of the system, over the entire life of the system, into present dollars i.e. How much money would I have to set aside today to cover all costs associated with the system over it’s life span?

40. I/A Systems: EconomicsPresent value cost of I/A system • Assumptions: • Installation cost $10,000 • Annual O&M contract $1200/yr • Electricity to operate $350/yr • Quarterly inspection and effluent sampling • 20 year life of system • 5% interest rate Yields present value of roughly $35,000.

41. I/A Systems: EconomicsPresent value cost of I/A system including Title 5 components Initial costs: I/A unit $10,000 Title 5 components $10-20,000 Brings total initial cost to $20-30,000 Brings present value cost to $45-55,000

42. Economics of I/A systems • Assume present value for each I/A system is $45,000 • Use conservative assumption of 1000 I/A installed • Total projected wastewater infrastructure cost present value =$45,000,000. • Is this the best use of $$$?

43. Economics of I/A systems vs. sewering to small collection plant • Falmouth New Silver Beach Project: • 220 homes, gravity collection system to small treatment plant; plant and effluent disposal on town owned property • Total cost estimate: $12.2 million • Per home cost: $55,000 • Payable as betterment over 20 years at 5% interest

44. I/A Systems Individual Residential Use Performance • Most I/A systems remove nitrogen and organic matter (BOD) from wastewater, but are only somewhat effective in removing pathogens, unless additional components—such a UV treatment—are used. • I/A systems are not a substitute for meeting Title 5 setback requirements.

45. I/A Systems Individual Residential Use Performance • How well do various systems work? • Only 2 technologies have been granted General Use Approval for nitrogen reduction by DEP— recirculating sand filters (RSFs) and RUCK systems • 2 technologies (Bioclere, FAST) that had Provisional Use Approval for nitrogen reduction may no longer be installed and DEP has not granted them General Use Approval for nitrogen reduction.

46. I/A Systems Individual Residential Use Performance • At present, only 2 technologies may be installed, under Piloting Use Approval, for nitrogen reduction—Amphidrome, Waterloo Biofilter. • Only a small number of these systems will be allowed, per the terms of Piloting Approval

47. I/A Systems Individual Residential Use Performance • To keep costs low and to keep maintenance minimal for homeowners, most are designed to be as simple and as passive as possible • Gravity flow where possible • Water flows through system by hydraulic displacement i.e. Water In = Water Out

48. I/A Systems Individual Residential Use Performance • No Surge Capacity results in varying amounts of residence time and therefore treatment of individual “slugs” of water • Results in inconsistent levels of treatment

49. I/A Systems Individual Residential Use Performance • Residential Wastewater is highly variable in strength and composition • From residence to residence • From hour to hour and day to day within one residence • Results in inconsistent levels of treatment