This paper describes the Gulf Island Pond Oxygenation Project, a unique, cost-effective solution adopted by three paper companies and a power company to a difficult environmental problem. Gulf Island Dam in Lewiston, Maine, forms an impoundment--Gulf Island Pond--on the Androscoggin River which the state has designated as Class C waters. At times, during summer low-flow, critical temperature periods, dissolved oxygen conditions in the Pond do not meet the Class C waters minimum requirement of 5 milligrams per liter.
Three large pulp and paper mills-- International Paper in Jay, Maine; Boise Cascade in Rumford, Maine; and James River Corp. in Berlin, New Hampshire--discharge treated wastewater effluent to the river upstream of Gulf Island Pond. Central Maine Power Company owns and operates Gulf Island Dam. These four companies joined together to solve this problem.
Water quality modeling showed that the state’s dissolved oxygen goals for Class C waters could not be met throughout the Pond, even with the complete elimination of biochemical oxygen demand (BOD) from the mill effluents, due to other organic discharges to the river; oxygen demand from sediments in Gulf Island Pond; and characteristics inherent to the impoundment, i.e., deeper depths of water, a reduction in the flow velocity, and a reduction in the reaeration capability. Thus, reducing mill BOD discharges would not solve the problem.
Section 125.3f of the Clean Water Act allows NPDES permit holders to consider alternatives to simply reducing discharges to achieve water quality goals in receiving waters. The three paper companies were able to demonstrate, based on environmental, economic, and technical considerations, that direct injection of oxygen into Gulf Island Pond, along with reductions in mill BOD effluent limits, was the preferable method of meeting the dissolved oxygen requirements.
This paper describes the results of the feasibility study used to evaluate four oxygen injection systems, the design of the diffused oxygenation system, the permitting and construction of the system, and initial effect of the system on the dissolved oxygen concentrations in Gulf Island Pond. The project was accepted by all federal, state, and local permitting authorities. The project was constructed during the summer and fall of 1991 and completed its first season of operation on September 30, 1992.
Gulf Island Pond Oxygenation Project - A Unique Cooperative Solution to an Environmental Problem, 19