D.O. Supplementation of Canal
Brooklyn, New York
Maintain 4 mg/l minimum D.O. throughout 7500 ft canal length
Dvirka & Bartilucci Consulting Engineers
330 Crossways Park Drive
Woodbury, NY 11797
The Gowanus Canal originally served as a navigable waterway prior to the development of efficient railroads and truck routes. Built in the 1860s, the canal served industries such as tanneries, cement works, paint, ink and soap facilities. As a result of years of discharges, storm water runoff, sewer outflows and industrial pollutants, the Gowanus Canal has become one of the nation’s most extensively contaminated bodies of water. Contaminants include PCBs, coal tar wastes, heavy metals and volatile organics. In 2010, the Gowanus Canal was added to the EPA’s Superfund National Priorities list for further investigation.
In 1911, a flushing tunnel was built to allow for artificial circulation of the water in the canal. This flushing tunnel had to be updated and a new pump station was needed to control Combined Sewer Overflows (CSOs) at the head end of the canal. During the 26 months construction period, the Gowanus Canal had to be able to support existing aquatic life. Without the flushing action from the Upper New York Bay, dissolved oxygen (D.O.) levels would quickly deplete. The New York City Department of Environmental Protection (NYC DEP) chose the ECO2 SuperOxygenation technology out of 5 investigated aeration technologies to maintain D.O. levels in Gowanus Canal.
Innovative and highly effective, SuperOxygenation technology is an eco friendly alternative to traditional chemical treatments for water and wastewater. Focusing on odor and corrosion prevention, ECO2 has helped cities across the country solve their needs in both municipal and industrial applications.
Design Considerations and Selection of ECO2 SuperOxygenation
The Gowanus Canal is 7,500 feet in length and 100 feet in width with a depth ranging from 4 to 16 feet at mean low water. The Gowanus Canal is an estuarine waterbody with a semi-diurnal tidal cycle varying between 5 and 7 feet. During a period between the mid-1960s and 1999 when the flushing tunnel was inoperable the median D.O. level was 2 mg/L resulting in discoloration, odors, and adverse impacts to aquatic life. After the tunnel returned to operation in 1999, the median D.O. level was 8 mg/L, considerably improving water quality.
The NYC DEP developed a facility plan to reduce the level of CSO occurring into the Gowanus Canal requiring the shut down of the flushing tunnel for a period of 26 months while construction occurred. Dvirka & Bartilucci Consulting Engineers reviewed a number of alternatives to maintain D.O. levels, including an interim flushing system, surface aeration, surface aspiration, venturi aspiration, diffused aeration, and side stream oxygenation.
Side stream oxygenation, using the Speece Cone developed by ECO2, was selected based upon several important considerations
- Efficient oxygen transfer rates (90-95%), regardless of canal water level
- Non-clogging / Non-fouling
- Low operations & maintenance costs
- No stripping of odors due to gas bubble action
- Versatile control of D.O. levels
- No interference with canal use
- Oxygen transfer performed in a centralized, controlled unit
Exposed Diffuser Pipe at Low Tide
ECO2 Speece Cone Installation
Installation of ECO2’s Speece Cone at Gowanus Canal
The ECO2 SuperOxygenation System is sized for a maximum oxygen feed rate of 3,250 lb/day and is designed to run continuously during the 26 month construction period. The oxygenated water is distributed along a 2,500 ft diffuser pipeline to ensure adequate lateral mixing of the water without undue disturbance of bottom sediments.
The system was commissioned in mid-July 2010 and quickly elevated D.O. levels to
12 mg/L. As the system could easily maintain 8 mg/L in the canal, the project team and contractor were able to shut down the flushing tunnel and move forward with the construction project according to schedule.
|Oxygen Dissolution Rate||700||lbs/day|
|Oxygen Transfer Efficiency||95||%|
Become a leader in water treatment.
ECO2 SuperOxygenation systems for water and wastewater treatment are designed and produced by Eco-Oxygen Technologies, LLC headquartered in Indianapolis, Indiana. The technology is the pioneering effort of Dr. Richard Speece, Centennial Professor Emeritus of Civil and Environmental Engineering at Vanderbilt University.
The ECO2 oxygenation method is a simple process based upon the scientific principle of Henry’s Law. No chemicals and no moving parts other than standard industrial water pumps are used. The result is a robust, reliable, economically competitive and environmentally friendly technology.
In municipal applications, ECO2 technology eliminates hydrogen sulfide odor and corrosion by dissolving pure oxygen in wastewater at high concentrations (50-75 mg/l) which prevents the formation of hydrogen sulfide and the associated “rotten-egg” odor. This approach saves money on alternative chemicals, provides pretreatment and does not increase total dissolved solids. ECO2 engineers are presently focused on wastewater projects in Maine, Indiana, California, Kentucky and Texas.