Soundkeeper's Filter Project

Polluted runoff from our streets remains a critical problem for the health of Long Island Sound. This toxic runoff is a persistent and pervasive pollution problem. Soundkeeper's Filter Project has undertaken the task of resolving polluted runoff through an innovative yet non-invasive and cost efficient technology.

Every time it rains millions of gallons of rain water flushes down our streets to nearby storm sewers. In fact, our roads and highway systems are superb water collection systems. The rain water becomes polluted with hydrocarbons, grease and oil that drip incessantly from our cars and trucks, animal feces, decaying rodents and birds along with packaging material of every description. This poison concoctions flows freely to our waters.

Soundkeeper's Filter Project is designed to stop this toxic runoff from reaching Long Island Sound.

Terry Backer, Soundkeeper

Project Area

The project area encompasses 275 storm drains in the South Norwalk area.

The part of the city selected for the project includes two drainage areas in Norwalk that have a similar land use – residential, industrial, marinas, and nurseries. The first is a basin with 275 drains, equipped with Smart Sponge Plus antimicrobial UUF, which empty through one pipe into Norwalk Harbor on the way to the Long Island Sound.

The second, the ‘control’ basin, does not have UUF’s and also flows through one pipe into the harbor.

Project Technology

Over the past seven years, AbTech has developed the Smart Sponge technology based on its proprietary blend of synthetic polymers aimed at removal of hydrocarbons and oil derivatives from surface water.  AbTech's process creates a very porous structure with hydrophobic and oleophobic characteristics capable of selectively removing hydrocarbons while allowing high flow through rates for water.  As hydrocarbons are absorbed into its structure, the Smart Sponge® swells and maintains porosity and filtering capabilities.

Field and laboratory tests have confirmed the Smart Sponge capability to absorb, depending on the type of oil contaminant, up to five times its own weight and removes 75% to 95% of the hydrocarbons present in stormwater runoff, typically in the range of 5 to 30 mg/liter (ppm).  The absorption is permanent and the saturated product does not leach or leak contaminants, transforming the contaminant - in most cases - into solid waste with lower disposal costs.

During the past couple of years, AbTech has worked on the development of an antimicrobial technology.  Smart Sponge Plus features a proprietary antimicrobial agent chemically and permanently bound to the Smart Sponge polymer surface and therefore does not leach or leak, avoiding any downstream toxicity issues.

The antimicrobial mechanism is based on the patented agent's interaction with the microorganism cell membrane, causing the microorganism disruption but no chemical or physical change in the agent.

Antimicrobial activity does not reduce the agent capability or cause its depletion and, therefore, maintains long-term effectiveness.  Additionally, the hydrocarbon absorption capability is not inhibited.

Filter Maintenance

The Ultra-Urban Filter should be serviced as needed to remove sediment and debris, according to expected debris accumulation.  The sediment and debris can be quickly vacuumed out of the modules through the opening of the drain with conventional maintenance equipment.  For example, a curb inlet with four to five Ultra-Urban Filter modules can be typically serviced in 10 minutes or less.  Under normal operating conditions the Ultra-Urban Filter should be replaced every 1-3 years.

Pollution Defined

A pollutant is generally understood to be anything in the air, water, or earth that is harmful to life or makes the air, water, or earth unfit for a specific use. Mostly, we think of pollutants as manmade, but that is not always the case. Metals and silt washed from the land and decaying animal or plant waste can also pollute the water.

Pollutants may harm living things by killing them, causing disease, causing genetic changes that produce impaired offspring, or upsetting the balance of a habitat. They may also just be unsightly and spoil the view.

Sources of water pollutants are conveniently classified into two types: point sources and nonpoint sources. Point sources are easy to identify - you can see them. Any pipe or ditch spilling wastewater into the Sound or any river or stream is a point source of pollution.

Nonpoint pollution sources are not so easy to identify or to control. They are, in fact, everywhere. They include contaminated groundwater, overfertilized lawns, and runoff from construction sites, farms, paved surfaces, marinas, and garbage dumps. Stormwater runoff from developed land is a major nonpoint pollution source for the Sound. It can originate anywhere in the watershed and may flow directly to the Sound or to rivers and streams that flow to the Sound. It can carry all types of dissolved or suspended pollutants, including eroded soil. Certain pollutants, for example, heavy metals and nitrogen, enter Long Island Sound mainly in rivers that drain Connecticut and the rest of the mainland watershed.

Your home is a nonpoint pollution source, too. Whatever you spread or spill in your yard, flush into your septic system or dry well, or send to the municipal landfill can reach the Sound via a river or stream, surface runoff, or groundwater seepage.

Project Expansion

Soundkeeper's Filter Project is a real solution to combat the real threat to Long Island Sound toxic runoff has become.

The filters included in the South Norwalk project area are merely a fraction of the hundreds of thousands of street drains contained in Norwalk, Fairfield County and the State of Connecticut.

On every streetm in every town, in every county, in Connecticut there's a storm drain sending an untold volume of poison into the Long Island Sound Estuary.

Now, we have the technology to change that.

Let's expand Soundkeeper's Filter Project, swim in cleaner water, catch heathier fish and protect our quality of life that is so inextricably linked to the Sound.

Yankee Doodle Bridge

Interstate 95 crosses the Norwalk River via the Yankee Doodle Bridge. There are more than 30 drains that flush the water contaminated with the grease, oil and spills of 130 thousand cars and trucks per day. 

The polluted water flushes, unimpeded, through eight inch drain pipes to the river below.  There has been speculation that the grossly contaminate sediments now being dredged and sequestered in a containment cell under the rivers bed stem form this discharge.  It’s a costly taxpayer-funded fix. 

Currently, Soundkeeper’s Filter Project does not include the dozens of drains on the Yankee Doodle Bridge.  Soundkeeper hopes to find additional funding and work with the State of Connecticut to develop a system of storm water filters for this egregious pollutant source.

Long Island Sound

From the headwaters of the Connecticut River, through the farmlands of Vermont and the industrial heart of New England, and onward to the coastline, a vast and abundant natural resource exists: the Long Island Sound watershed.

Each and every one of us benefits from recreational, manufacturing, and economic activity made possible by resources in the watershed, along the coast, and in the Sound itself. Yet many of us take these resources for granted, rarely considering how fortunate we are to live in such a plentiful environment.

All too often we think of ourselves as independent from our natural surroundings. We don't pay enough attention to the relationships among ourselves, plants and animals, and the land and water that support us all. Such neglect, whether from ignorance, apathy, or lack of true awareness, cannot continue. If we don't take steps now, the beauty and economic value of Long Island Sound could be destroyed.

Virtually all threats to the Sound are population-driven. As everyone knows, we like to live and work near the water.  It's been estimated that one of every ten Americans lives within 50 miles of the Sound. To grasp fully the impact of human activity on the Sound, add the thousands of cars traversing 1-95 in Connecticut every day and the more than one million people who live away from the coast but still in the Sound's watershed.

Our uses of the Sound often compete with each other and with the interests of the Sound's marine life. As cities and towns expand, the need for housing, offices, factories, parking lots, waste disposal sites, sewage treatment plants, and other trappings of society forces us to alter the land.

The time has come to seriously evaluate what damage we have done and are still doing. There will be no quick fix for the problems we have created. The situation, however, is not without hope. Numerous municipal, state, and federal programs are now aimed at water quality protection and improvement in general, and the Sound in particular. Technology has provided means to better understand the problems and repair them.

Cleaning up the Sound will not be accomplished independently by either the private sector or government action. It is essential that we all work together. We can make simple changes in our daily lifestyle and in our own backyards that will diminish pollution of the Sound. We must be vigilant and speak out against threats to the Sound. We must also inform legislators that there is widespread support for protective action at the city, state, and federal level.