SHELTER ISLAND SEPTIC SYSTEMS AND WATER QUALITY.pptx

John C. Cronin, Jr., P.E.
Shelter Island Town Engineer
jccronin@shelterislandtown.us
631 252 1167 cell and text
Office located next to the Building Dept, and behind
Town Hall
Median Home Prices (to the nearest $100000)
 National: $200000
 New York State: $300000
 Shelter Island: $700000
IS A HOLE IN THE GROUND
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PHYSICAL – separate the solids
BIOLOGICAL – reduce the organic content
CHEMICAL – gas transfer and disinfection, along with
other chemical processes
The first two are often called primary and secondary
treatment in the world of sewage treatment.
The third process is sometimes referred to as tertiary
treatment and, while it is increasingly being done, is not
a widespread practice.
Sometimes you will hear the term “denitrification” as an
aspect of tertiary treatment.
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That chemical side can include inclusion of nitrogen and phosphorus compounds that
remain in the effluent (the liquid leaving the system).
Any doubt about the effectiveness of sanitary waste material encouraging the growth of
things, ask yourself why manure is added to flower beds, and why fertilizer contains
nitrogen and phosphorus compounds?
Bags of fertilizer display three numbers. These are the nutrients it contains. The first is
nitrogen, the second is phosphorus, and the third is potassium (N-P-K).
Because nitrates and phosphates occur in the sewage process, ideally we’d like to see the
nitrates broken down to include gaseous nitrogen (which can be released to the
atmosphere), and phosphates possibly removed as precipitates.
For instance, we want to take NO3 and break off the three oxygen molecules, leaving free
nitrogen (a gas). This is denitrification (or tertiary treatment) and is not easily or cheaply
done.
When these constituents are not removed, they make their way into the environment
where, as the quantities ever increase, they begin to do harm because they help all sorts of
things grow – many undesirably, or contaminate our drinking water supply.
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A typical Shelter Island summer day will find 10000 residents producing
about 750000 gallons of wastewater daily. Some 50000 gallons of that
heads into the channel between Shelter Island and Greenport (just north of
the ferry slips) after being treated in the Shelter Island Heights Property
Owners Corp sewage treatment plant. The remaining 700000 ultimately
heads to the aquifer that supplies our drinking water.
750000 gallons is about 18 typical residential swimming pools
Annual rain fall on Shelter Island is 45 inches and average snowfall is 27
inches (which adds another 2.7 inches to the rainfall total). So let’s say 48
inches of precipitation on about 12 square miles. If 50% of that recharges
the aquifer (a reasonable estimate from the civil engineering standpoint),
roughly 13,711,000 gallons of water on average enters the aquifer daily.
700000/(13711000+700000) amounts to about 5% sewage injection into
the the aquifer on a daily basis during peak season.
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Nitrate pollution of the aquifer has been a known issue on the
island at least as far back as the 1980s, when elevated levels
in the Center caused the school to post warning signs about
consuming water in the building
It was alluded to as a developing problem in the Town’s
Comprehensive Plan in the 1990s
10 mg/l nitrates is the maximum allowed for potable water
Levels in the Center are known to be over 5 mg/l
Nitrate pollution was suspected and even implicated in the
early outbreaks of “Brown Tide” in West Neck Bay in the
1980s
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The sole source of drinking water on Shelter Island is the water in
the ground and under our feet. John Hallman has discussed
aspects of it in his presentation earlier.
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Substances and fluids migrating into it
Topography
Sea level
Water pumped from it
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Suffolk County Department of Health Services
Office of Wastewater Management
Siting of on site sanitary waste disposal systems
Design of on site sanitary waste disposal systems
Construction of on site sanitary waste disposal
systems
Local building department (or code enforcement
officials) adherence to county regulations
Local motivation to ensure health, safety, and welfare
of citizenry is guarded
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General awareness of issues, and
acknowledgment that regulations exist
Ensuring that proposed property alterations
consider what is expected through the regulations
Appropriate maintenance practices for sewage
disposal systems
Routine well water testing to ensure a healthy
supply of drinking water
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Educational outreach initiated approximately one year ago
Summer Engineering Intern began database entry of computed
latitude and longitude location of all septic systems and wells on
island (for which there was a record), funded with a grant from The
Group for The East End. Coordinates will be handed off to GIS
consultant for mapping
Approached County Executive Steve Bellone about piloting one of
the lottery based systems here on Shelter Island
Sought WQPRP (Water Quality) Grant Funding from County to
upgrade the Legion/Youth Center System
Sylvester Manor also sought WQPRP Grant Funding from County to
do a demonstration project at the Manor
Both the Legion/Youth Center and the Sylvester Manor projects
were approved for grants
Aggressive participation by the Supervisor in East End based efforts
with other town leaders involving all 5 eastern Long Island towns
MS4 (Municipal Separate Storm Sewer System)
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We could spend time discussing emerging
technologies, but it is more appropriate to look at
the overall strategic effort suggested by the EPA
The EPA has issued Voluntary National
Guidelines for Management of Onsite and
Clustered (Decentralized) Wastewater Treatment
Systems
A summary is next presented…
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• Management Model 1 - “Homeowner Awareness” specifies appropriate program elements and activities where
treatment systems are owned and operated by individual property owners in areas of low environmental sensitivity.
This program is adequate where treatment technologies are limited to conventional systems that require little
owner attention. To help ensure that timely maintenance is performed, the regulatory authority mails maintenance
reminders to owners at appropriate intervals.
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• Management Model 2 - “Maintenance Contracts” specifies program elements and activities where more complex
designs are employed to enhance the capacity of conventional systems to accept and treat wastewater. Because of
treatment complexity, contracts with qualified technicians are needed to ensure proper and timely maintenance.
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• Management Model 3 - “Operating Permits” specifies program elements and activities where sustained performance
of treatment systems is critical to protect public health and water quality. Limited-term operating permits are issued
to the owner and are renewable for another term if the owner demonstrates that the system is in compliance with the
terms and conditions of the permit. Performance-based designs may be incorporated into programs with
management controls at this level.
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• Management Model 4 - “Responsible Management Entity (RME) Operation and Maintenance” specifies program
elements and activities where frequent and highly reliable operation and maintenance of decentralized systems is
required to ensure water resource protection in sensitive environments. Under this model, the operating permit is
issued to an RME instead of the property owner to provide the needed assurance that the appropriate maintenance is
performed.
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• Management Model 5 - “RME Ownership” specifies that program elements and activities for treatment systems are
owned, operated, and maintained by the RME, which removes the property owner from responsibility for the system.
This program is analogous to central sewerage and provides the greatest assurance of system performance in the
most sensitive of environments.
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Provide a means for septic system effluent to be further treated in a
manner consistent with nitrogen compound removal
Recirculating systems
Vegetation based systems
Commercially available systems
Costs have been cited at as little as $8000 for systems that might be
“piggy-backed” on top of existing systems
Costs have also been reported as upwards of $30000 for highly
advanced systems
More typical costs are expected to be in the range of $15000 to
$19000
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Because public health, the environment, and
considerable costs are involved all efforts to
control contamination from septic system effluent
ultimately involve decisions by elected officials.
SCDHS Office of Wastewater Management has
been evaluating revisions to regulations for some
time, and are continuing to do so.
Last year Suffolk County sponsored a lottery with
19 winners to pilot “experimental” waste water
treatment systems for residences.
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Some complained the lottery requirements were too
restrictive, but in actuality they were crafted to provide
the best scientific test scenarios for such systems.
The Town of Shelter Island approached the County
Executive about piloting a system here on the Island in
a commercial application.
While a favorable answer was not forthcoming, Shelter
Island was successful in obtaining two (2) Water
Quality grants from the County to pilot a commercial
application at the Legion / Youth Center and at
Sylvester Manor.
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Property tax abatements have been discussed
that might be structured to relieve a part of the
property tax burden to permit those funds to be
used for new septic systems
At the state level, $5 million has been earmarked
for the Long Island Nitrogen and Mitigation Plan
$100 million has been specifically sought by East
End Supervisors from the state to address
ineffective septic systems
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$200 thousand goes to the Peconic Estuary
Program
Discussion is on going about use of Community
Preservation Funds (the 2% real estate transfer
tax monies) for preserving water quality
There continues to be various sources of grants
for very specific projects (the Suffolk County
Water Quality grant program in which both the
Town and Sylvester Manor have participated)
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The first step starts with awareness and
education. Hopefully we’ve accomplished that
today.
THANK YOU!
Now if there are questions or discussion, let’s
open the floor to them for the next few minutes…