REDUCING PHOSPHORUS LOADING FROM ONSITE

WASTEWATER TREATMENT SYSTEMS IN THE

GREENWOOD LAKE WATERSHED, NEW YORK

Goshen, New YorkSeptember 23, 2013

Presented by: Dave Braun, Amy Macrellis, and Julie Moore

of Stone Environmental, Inc.

Collaborators: Fuss & O’Neill, Inc.

Sponsor: Orange County Water Authority

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Partners and fundingOrganization Person Title or Project RoleU.S. EPA, Region 2 John Mello Program Supervisor

NYSERDA Kathleen O’ Connor, P.E. Associate Project Manager

Orange County Water AuthorityDavid Church Executive Director

Eenika Cruz Administrator

Orange County Water Authority consultant

Simon Gruber Planner, Facilitator

Stone Environmental, Inc.

Dave Braun Project Manager/Water Quality Scientist

Bruce Douglas, P.E. Senior Wastewater Scientist/Engineer

Amy Macrellis Onsite Wastewater Treatment Scientist/Planner

Katie Budreski GIS Scientist

Julie Moore, P.E. Water Resources Engineer

Alex Huizenga Environmental Technician

Fuss & O’Neill, Inc.Kurt Mailman, P.E. Senior Project Engineer

Matt Jermine, P.E. Project Engineer

Village of Greenwood LakeBarbara Moore Mayor

Dodi Nichols Building Inspector

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Dedication

This project report is dedicated to Ron Bonnier, Caretaker of the Grace Lutheran Church in Greenwood Lake, NY, without whose steady engagement, negotiating prowess, and considerable patience the demonstration onsite wastewater treatment system at the Church may never have come to fruition; to Roxanne Lopilato, whose willingness to try new approaches enabled construction of a truly innovative system on her property; and to Barbara Moore, a strong advocate of improving the water quality of Greenwood Lake and always the champion of this project.

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Project goals

1. To demonstrate practices and technologies capable of reducing phosphorus pollution from OWTS in the New York portion of the Greenwood Lake watershed.

2. To utilize technologies that minimize electricity consumption.

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Contents

1. Introduction to Greenwood Lake and OWTS as Sources of Phosphorus

2. Wastewater needs assessment

3. Phosphorus management in onsite wastewater treatment

4. Demonstration OWTS monitoring results

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Greenwood Lake, NY, and NJ 15-minute quadrangle

■ Lake watershed = 25 sq. miles total (9.2 sq. miles in NY)

■ Lake surface area = 2.9 sq. miles

■ Our concern = NY portion of watershed

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Greenwood Lake−Lake is a valued resource−Elevated phosphorus (average = 0.031 mg/L) is

impacting water quality

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Eutrophication experiments

Aphanizomenon

Conclusion: Manage lakes for P!

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GREENWOOD LAKE NEEDS A PHOSPHORUS DIET

New York and New Jersey established plans: phosphorus TMDLs for Greenwood Lake

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1. Reduce P inputs instormwater

Greenwood Lake Phosphorus TMDL (NYSDEC 2005)

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Greenwood Lake Phosphorus TMDL (NYSDEC 2005)

■ ~2,700 developed parcels in the project area; 1,500 within 200 M of Greenwood Lake

■ Calculated P load from OWTS within 200 M: 710 kg/year (1565 lb/yr) (10% of total)

■ Required reduction from OWTS within 200 M: 309 kg/year (884 lb/yr) (43%)

2. Reduce P inputs from OWTS

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Groundwater transport of Pfrom OWTS

■ US EPA (2002) stated that older onsite systems pose “the potential for serious environmental degradation, as witnessed by the thousands of inland lakes where older, onsite development is increasingly being cited as the primary reason for lake eutrophication.”

■ A review by Curry (2000) found that 71% of 35 septic systems demonstrated transport to the water table.

■ Plumes may advance at the rate of inches to several feet per year.

Phosphorus plume from abandoned wastewater treatment plant discharges to Ashumet Pond, Cape Cod.Source: www.epa.gov/swertio1/tsp/.../leblanc_phos_prb_070808.pdf

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Soil chemistry

The phosphorus fixation potential in soil is finite. If the capacity of the soil to bind phosphorus is exceeded, a p-enriched plume will develop.

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Steep slopes/shallow bedrock Shallow groundwater

Part 2: Wastewater needs assessment--Challenging conditions

Small lots

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Wastewater needs assessment

1. Environmental sensitivities 3. Minimum depth to groundwater2. Minimum depth to bedrock

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■ Approximately 78% of developed parcels in the project area were constructed prior to 1970.

■ Typical systems consist of a septic tank and leachfield or seepage pit. Cesspools are also in use.

■ Components of older systems may be undersized for current uses.

■ Age of construction suggests that most soil absorption systems received higher P content wastewater prior to New York’s laundry detergent-P ban (1972).

Existing OWTS

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Walking through treatment train….

1. Source reduction

2. Source diversion

3. Removal in the septic tank

4. Post-septic tank treatment

5. Design/siting of the soil absorption system

Approaches #1 through #4 reduce P entering the soil absorption system, which should extend the time period before the soil absorption system reaches P saturation.

Approach #5 is geared toward enhancing P removal in the absorption field.

Part 3: Phosphorus management opportunities

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Phosphorus in domestic wastewater in Greenwood Lake, 2008 and present

Notes: The phosphorus contributions among the indicated sources are highly variable. The percentages indicated here assume:

1. Water is supplied by the Village of Greenwood Lake treatment plant. In 2008 the plant added approximately 1 mg/L of P for corrosion inhibition. By 2012, the plant had reduced the amount by roughly half.

2. In 2008, a brand of automatic dishwater detergent was used containing the maximum allowable amount of P (8.5% by weight). The ban passed by New York in 2010 reduced the allowable amount to 0.5 %.

3. A laundry detergent is used that contains 0.5 % P (the maximum allowed).

4. A garbage disposal is used to dispose of kitchen wastes.

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Source reduction

■ Emphasized because reducing P sources can have a broad impact across the community.

■ Since the early 1970s, New York has limited the P content of laundry detergents to 0.5%.

■ On July 15, 2010, New York passed a law prohibiting sale of automatic dishwasher detergents containing more than 0.5% P. Prior to this ban, the allowable concentration was 8.5%.

■ The Village of Greenwood Lake reduced by half the amount of P added to treated drinking water for lead & copper control/corrosion inhibition.

■ Eliminating in-sink garbage disposals reduces P and improves OWTS function.

Coke is it: 62 mg phosphorus per 12 fl. oz.

Reduce phosphorus entering wastewater.

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Source diversion

Divert phosphorus from OWTS

■ Microflush toilets (1.0 L or less per flush), with holding tanks for blackwater and separate treatment of graywater

■ Composting of feces and separate treatment of graywater

■ ”No-mix” or urine diverting toilets that keep urine separate from feces

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■ Separate bowls for urine and feces; and/or water-less urinals

■ Urine diverted to separate holding tank

■ Urine can be recycled to agriculture

■ Proven track record in Europe

■ Can remove 30-50% of phosphorus from waste stream

Urine diverting toilets

Urine-diverting toilet:

Wost Man Ecology DS Toilet

Source: Johansson 2000.

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Removal in the septic tank

Improve design or management to remove more phosphorus in the septic tank

■ First component of nearly all conventional onsite wastewater systems

■ A small percentage of the phosphorus (about 6%) that has entered the tank since the last pump-out will be removed when the tank is pumped again (assuming a 3-year pump out frequency as required in the project area)

■ P removal may be increased using a chemical flocculent, but this requires frequent maintenance and increases sludge accumulation.

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Post-septic tank treatment

Remove phosphorus from pre-treated effluent■ Aerobic treatment with chemical dosing

■ Sand and modified sand filters

■ Organic material-based filters

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Post-septic tank treatment options: Modified sand filters

■ Phosphorus removal of 90% or more for most methods(initially)

■ Large quantity of media required, which must eventually be replaced.

■ Reported P removal efficiency varies widely among media and tests. At 3 g P/kg media (very high, relatively speaking), roughly 900 kg media would be required to treat the P load from a single family residence per year.

■ Media considerations: availability, cost, hydraulic properties, effectiveness, effect on effluent pH, source (beneficial reuse preferred), and disposition of spent media.

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Phosphorus treatment media

■ Non-Proprietary Media− Wollastonite tailings

− Blast Furnace Slag

− Crushed Bricks

− Light Expanded Clay Aggregate

− Water Treatment Residuals

− Shell Sand

− Opaka/Polonite

− Fly Ash

■ Proprietary Media/Technologies− PhosRIDTM

− SorptiveTMMedia

− ACT-MX

− Filtra-P

− Wallax

Conclusion: Given the quantities of media necessary, we believe that locally sourced reused or recycled materials are preferable to manufactured and imported media.

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Design/siting of soil absorption systems

Methods for maximizing P removal in the absorption field■ Locate the absorption field as far as possible from

surface water bodies

■ Site in medium- to fine-textured soils high in iron and aluminum or calcium

■ Timed, pressure dosing: Maximizes soil contact time and uniformity and reduces the risk of soil saturation

■Narrow, shallow soil absorption systems: Places nutrients in the plant root zone where they are available for plant uptake (e.g., drip dispersal) and maximizes soil-volume utilization

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Part 4: Demonstration system results

■ Reviewed 31 applications and conducted site visits

■ Performed detailed characterization of three sites

■ Selected two demonstration sites:

− Single family home on Grove Street

− Grace Lutheran Church (cluster of three church-owned buildings)

■ Selection criteria included proximity to lake, year-round occupancy, type of water supply, existing OWTS malfunctioning, and more.

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Percolation test

Demonstration site characterization

Digging a soil test pit at the Grace Lutheran Church

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■ Soil morphology

− Texture, color, structure

− Redoximorphic features

■ Phosphorus sorption potential

■ Seasonal high groundwater determined by distribution of soil redoximorphic features (mottling)

■ Spring groundwater level monitoring at Grove St. residence

■ Topographic survey

Demonstration site characterization

Characterizing soil morphology

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Grove Avenue OWTS

■ The existing OWTS was malfunctioning due to groundwater inundation.

■ Phosphorus sorption in the existing leachfield was very low.

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Groundwater monitoring & percolation testing

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Grove Avenue replacement OWTS■ Urine diverting toilets installed in both bathrooms

■ 1,500 gallon urine holding tank installed

■ 2,000 gallon septic tank and Advantex AX20N textile filter

■ A second pump chamber pressure doses a contained raised bed (bottomless sand filter).

■ Restrictive soil layers in the bottomless sand filter excavated and replaced with C33 filter sand.

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Grove Avenue OWTS monitoring

■ Total P concentration of urine tank = 70-90 mg/L.

■ Total P concentration in the septic tank = 5.5 mg/L (typical range = 6-12 mg/L, U.S. EPA 2002).

■ 293 g total P accumulated in the urine tank in 567 days.

■ 1,467 g total P discharged from the septic tank in 567 days.

■ 1,761 g total P discharged with wastewater (1,467 g + 293 g)

■ Approximately 16.7% was diverted to the urine tank, substantially lower than expected.

■ Diversion rate does not consider settling in the urine tank.P in urine solids = 6.6 g/kg.

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Expected P reduction for the Grove Avenue OWTS

Approach Phosphorus Reduction

Source reduction1. Homeowner switched from automatic dishwasher detergent

containing 8.5% phosphorus to phosphorus-free brand25%(0.65 g/capita/d)

2. Village of Greenwood Lake Water Treatment Plant reduced use of phosphorus-containing corrosion inhibiter

5%(0.14 g/capita/d)

3. Reduced use of municipal water (containing P) not estimatedSource diversion: Urine diverting toilets will be installed in both bathrooms. Stored urine will be removed by a septage hauler

25-33%(actual 17%)

Septic tank: Larger tank will provide marginally increased removal not estimatedPost-septic tank treatment: Textile filter not expected to provide significant phosphorus removal beyond start-up period

~0%

Dispersal system: Bottomless sand filter (C33 sand) not expected to provide significant phosphorus removal beyond start-up period

not estimated

TOTAL >56-64%(>40%)

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Grace Church existing OWTS

■ The existing OWTS for the church consisted of a 50+ year old metal tank and possibly an undersized leachfield. The OWTS for the two smaller church-owned buildings were substandard.

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Grace Church site P absorption■ Despite approximately 4-feet of separation to seasonal high groundwater, the absorption field was insufficient for long-term removal of phosphorus.

■ Estimated P removal period: 6-12 years.

■ Rapid sorption ranged:B horizon: 537-1,525 mg P/kg of fine soilC horizon: 180-591 mg P/kg of fine soil

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Grace Church replacement OWTS

■ Faucets, showerheads, and five toilets replaced with modern fixtures.

■ New building sewers constructed to a 2,500 gallon septic tank and 3,000 gallon flow equalization tank with controls.

■ Effluent from the flow equalization tank passes to an Advantex AX20N textile filter, followed by a PhosTek™ phosphorus removal filter.

■ PhosTek™ developed by Wastewater Technologies Inc. of Milton, VT specifically for this project.

■ Effluent dispersed in a gravel drainfield with pressurized distribution piping.

■ O&M cost acceptable to the Church.

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Grace Church cluster OWTS site

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Grace Church cluster OWTS site

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Figure . Components of the onsite wastewater treatment system at the Church site

Figure . PhosTek™ filter media (water treatment residuals)

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Monitoring device installed at Grace Church

Installing a leachate collector in an absorption trench

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Sample clarity

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P removal by Grace Church OWTS

Figure . Mean concentrations of TP, TDP, and DRP through steps in the treatment progression

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Wastewater volume treated at Grace Church

Mean TP concentration in AdvanTex effluent (mg/L) 5.15 mg/L

Average daily water usage116 gal/d

439 L/d

Days from PhosTek™ start-up to 6/6/13 sampling event 594 daysTotal P input to PhosTek™ 1.3 kg PTotal P retained by the PhosTek™ 1.18 kg PTotal P mass retained per liter of media 2.5 mg P/L media

Filter media (bed) volume17 ft3

481 LWater usage from start-up to 6/6/13 sampling event 260,830 L

Bed volume of effluent treated 542 bed volumes

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Estimated phosphorus reduction for the Grace Church OWTS

Approach Phosphorus Reduction

Source reduction1. Village of Greenwood Lake Water Treatment Plant reduced use of

phosphorus-containing corrosion inhibiter5%(0.14 g/capita/d)

2. Reduced use of municipal water (containing P) not estimatedSource diversion: NA NASeptic and flow equalization tanks: Large tanks will provide marginally increased removal

not estimated

Post-septic tank treatment:1. Textile filter not expected to provide significant phosphorus removal

beyond start-up period. ~0%

2. PhosTek™ filter expected to provide 50-90% phosphorus removal 50-90%Dispersal system: Conventional absorption field expected to provide significant removal of remaining phosphorus

not estimated

TOTAL >55-95%

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Electricity consumption

Grove Avenue OWTS

■ 16.2 kWh/month ($1.80 per month)

Church site OWTS=

■ 26.7 kWh/month ($3 per month)

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More information:

Greenwood Lake (courtesy of the Village of Greenwood Lake website)

Dave Braundbraun@stone-env.com

Thank You!

Orange County Water Authority Website:http://waterauthority.orangecountygov.com/