WATER QUALITY IN EAST END WATERSHEDS
Survey Introduction
Water quality on the East End is critically important – for drinking water and for the preservation of our marine habitats. There is a need for more measurement of the magnitude of the problem, and alternative cost-effective management solutions that can be applied as a community and as households. PGG and other community groups are sponsoring a survey to begin to measure the scope of the problem, with the goal to evaluate alternative solutions if the need and desire is there.
The Issue
The North Fork is surrounded by two estuaries of National importance. For our fresh water needs, we rely on a sole-source aquifer, which is recharged by rain and wastewater. Most of thewater that humans use reenters groundwater after passing through residential onsite wastewater treatment systems and often carries contaminants, pathogens and nutrients with it. After it hits groundwater, the effluent migrates toward either the Sound or Peconic Estuary.
Nitrogen and Marine Environment
Nitrogen is a nutrient of concern. The North Fork is considered by the Suffolk County Department of Health Services (SCDHS) to be highly susceptible to nitrates due to agriculture, land use, and soil characteristics. The nitrogen levels in groundwater potentially exceed drinking water maximum limits of 10 mg/l. Unfortunately, the marine environment is even more vulnerable to high levels of nitrogen, where upper limits for healthy waters are at the 0.3 to 0.45 range, being 20 times more susceptible to nitrogen loading impacts than humans. Along the shores of the East End, nitrogen mostly exceeds this limit.
When nitrogen enters the marine environment, it feeds algal blooms that reduce oxygen levels.When the algal blooms die, they contribute to the acidification of the sea, which in turn affects shellfish size and form. The algae, as in the case of Saxitoxin, can be toxic to humans. Saxitoxin was discovered in Mattituck Creek this year, the earliest it has ever been seen in NYS. Algal blooms only started appearing in 1985, when a brown tide nearly wiped out the scallop industry. Just when the industry was reestablished in 1994, the scallops were severely depleted again in 1995 by another brown tide. The Great South Bay has algal blooms almost every year now, and has lost 99% of its shellfish industry. Nitrogen is also a factor influencing eelgrass decline. Eelgrass provides a protective environment for shellfish, which in turn help to filter the water. Shellfish loss accelerates water quality decline.
Causes of Nitrogen Level Increases
The Peconic Estuary has experienced a rapid increase in nitrogen since 1960. The four main sources are stormwater run-off, atmospheric deposition (usually from combustion), wastewater effluent in groundwater and sediment flux -the accumulation of unprocessed nitrogen on the sea floor. A recent study sponsored by the Nature Conservancy determined that the greatest contributor to the nitrogen problem is sourced by humans. They weighed nitrogen isotopes in eelgrass to identify origins. The 15N, which represents nitrogen derived from humans, is clearly the major source, with a concentration evident on the North Fork.
Traditional Treatment of Human Wastewater
Decentralized human wastewater treatment systems include both on-site and community systems. Where densities warrant, central sewers are used, as in Greenport or Riverhead. Traditionally our on-site systems used cesspools.
On-Site Systems: Cesspools, Pre- 1973 Standards
Cesspools are single pits that gather all the waste collected from household uses from pipes from the home . The purpose of the cesspool is to slowly filter the wastewater into the ground. However, open joints or spaces in the cesspool wall leak both liquid and dissolved solids into the ground. As a result the soil’s ability to filter and treat is compromised and pathogens can enter groundwater. Houses built before 1973 are likely to be cesspools. Currently, it is not required by law to upgrade one’s system to current standards. Old cesspools leach nitrogen and pathogens into the groundwater
On-site Systems: Septic Tanks, Current Standards
Suffolk County Guidelines
Current standards require using septic tanks, which collect the wastewater and allow solids to settle out, where the sludge is treated anaerobically by naturally occurring microbes.
The liquids enter separate leaching pits, where the wastewater is dispersed into the ground. As water filters through soils it is further purified by filter and aerobic processes. Guidelines recommend between three and five feet of suitable soil above groundwater.
Next Steps to Assessing On-site Systems
Methodology by Peconic Green Growth
There are a few steps that need to be taken. First the pre-1973 cesspools need to be identified and receive priority for incentives and upgrades. If these systems are in areas with high water tables, they are likely to convey contaminants directly to groundwater. Both these conditions can promote pathogen as well as nutrient contamination. Significant damage to the environment can also be inflicted during temporary failure, such as in floods.
Much of our soil on the East End is considered unsuitable for septic treatment, usually because the leaching is too fast. Nitrogen levels exiting these systems are typically 40-60 mg/l. This is four to six times drinking water standards. The SCDHS uses minimum lot sizes to dilute these levels to the 10 mg/l acceptable for potable water. One acre is the current recommendation for a 4-6 mg/l goal, although half-acre lots are still legal in our hydrological zone.
Lots < ½ acre in size SCCWRMP
Since many of our neighborhoods are historic, development patterns are denser than current regulations allow or studies recommend. This means that all homes on lots less than one acre in size are providing nitrates at concentrations that exceed current recommendations for drinking water.And if we are talking about the marine environment, itis totally unbalanced.
What can we do?
So how can we protect both our historic settlement patterns and our marine environment? Luckily, the key conditions that impact failure tend to overlap, so by focusing on densely built communities close to the coast, we see results relatively quickly.
Courtesy Town of Southold
Land Conservation
Low lying areas are especially valuable as vegetation uptakes nitrogen in groundwater before it reaches the sea.
Advanced Treatment for On-site Systems
We can improve decentralized systems through advanced treatment. both for single, on-site installations and for decentralized community installations.
A Nitrex system, which basically adds sand and carbon filters to the process, is one of two systems recently approved by the SCDHS. It can be used for clusters up to 50 homes. Effluent nitrogen is reduced by 90% to levels acceptable for drinking water.
Community Systems
There are various types of community systems. A STEP (Septic Tank Effluent Pump) blends two approaches. First the wastewater goes into a septic tank on each site, just as our current systems do now. The liquid effluent is then transported in small diameter pipes to a central treatment facility. The septic tanks continue to treat the sludge anaerobically, which is hauled away periodically just as we do now.
Advantages of such a system include:
- Placement is where it makes most economic and environmental sense to do so.
- Wastewater is returned to the same watershed
- It is easy to make changes when technology improves
- Systems are designed to current need, avoiding the cost of building excess capacity
- The system can be easily expanded
- Installations are less intrusive for existing neighborhoods
- Treatment can take place outside of flood zones
The facilities are unobtrusive, being a pump house and covered pods containing filter membranes set into the ground or reconstructed wetlands. In Hillsdale, NY, a system serving 130 dwelling units costs each home owner $500 per year for both capital and ongoing maintenance costs, after grants reduced overall totals.
Living Machine
But we tend to forget that wastewater is a relatively inexpensive source of water and other byproducts. For instance, what is in the fertilizer we put on our lawns? Nitrogen. A Living Machine uses plants to process waste and uptake nitrogen. The water can be recycled and the plants harvested. The appearance of the facility can be a garden or greenhouse.
Peconic Green Growth has teamed up with Natural Systems Utilities for a grant sponsored by the Long Island Sound Study to work with neighborhoods interested in developing community solutions for wastewater treatment in the Long Island Sound watershed in Riverhead and Southold. Suffolk County is sponsoring a similar study for the Peconic Estuary. We will develop schematic designs for solutions best suited to conditions, and identify costs, regulatory issues, management and operational options. Natural Systems Utilities is a leading engineering firm that advocates environmentally sensitive treatment and reuse. Ed Clerico, the lead engineer, is a global expert on decentralized systems and wastewater reuse.
At the end of this exploration, we hope that communities will voluntarily apply for incentive funding the County and possibly the State have available for advanced wastewater treatment. The ultimate goal is to see cleaner waters in our lifetimes, maybe even 5-7 years. We ask you to fill out the surveys and return them or complete the survey on-line at www.peconicgreengrowth.org. Information will only be used to identify options for wastewater treatment and community receptivity.
The initial methodology was developed with a grant sponsored by Ed Romaine with Southampton’s GIS department. Patagonia has awarded us a grant to further knowledge of wastewater issues. We greatly appreciate your participation and welcome all feedback. This survey is being conducted in cooperation with local associations. We have also partnered with other environmental groups to form the North Fork Clean Water Action Group to help address this important issue collectively. If your home owners association or group would like to arrange a presentation, please contact us.
Sincerely,
Glynis Berry, Acting Executive Director
