Nature of Activity: This thesis considers the possibility of using effluent trading as a means to address low dissolved oxygen in the Providence and Seekonk Rivers in Narragansett Bay.   This study includes 22  wastewater treatment facilities in Rhode Island and Massachusetts (see Waste Water Treatment Facilities) in the Blackstone and Narragansett Bay watersheds (see watershed maps).

Environmental Problem: Acceleration of eutrophication resulting in low dissolved oxygen in the Providence and Seekonk Rivers and upper Narragansett Bay

Pollutant(s) / Pollution Type(s): Nitrogen

Trade Types: Point/point, but possible evolution to point/nonpoint once a high level of point source control has been achieved.

Stage of Implementation: Under study

Relation to TMDL: The nutrient TMDL [for the Providence and Seekonk Rivers] is in process.  The original schedule called for the process to be completed by December 2000. Alternative reduction scenarios were to be simulated during the winter and spring of 2001, and the draft TMDL document was to be issued for public comment during the summer of 2001. (305b report).  RIDEM has procured the services of Applied Science Associates to calibrate the hydrodynamics and water quality  models for the area.   A trading program should be designed within the TMDL, as the TMDL will specify the level of reductions necessary to achieve desired water quality goals.

Number of Potential Participants: There are 22 wastewater treatment facilities in Rhode Island that discharge directly or indirectly into the Providence and Seekonk Rivers and may be contributing as much as 66% of the nitrogen load to these waters.

Trading Ratios:   Since only point sources are being considered at present, unless water quality models indicate a difference in impact in different locations, the ratio may not need to be set high to result in an improvement.  However a ratio higher than 1:1 should always be set so that trades result in an improvement in water quality.

Estimated Cost Savings: 

Available Written Information: 

Innovative Aspects:  A wide variety of conditions was found among the facilities studied in both physical structure (age, size, technology, available land) and operation.  While analyzing the discharge data reported to the EPA's Permit Compliance System, it was discovered that some of the facilities were not performing nitrification before discharging, releasing large quantities of ammonia.  Because this can add significantly to the oxygen demand, trading oxygen-demand units, rather than nitrogen reduction units is considered.  This thesis calculates the maximum possible oxygen demand from each facility, assuming that all of the ammonia and nitrite released will be oxidized to nitrate and that all of the nitrate produced and released will be converted to biomass and then remineralized.