The Conservation Foundation recognized the urgent need for a central sewage system, but was concerned that the island might not be able to assimilate the effluent discharge into the ground. Certainly the area of the interior wetlands and river adjacent to the present disposal site for the Beachview plant is grossly polluted. Higher levels of treatment may help, and better receiving areas may be found. Nevertheless, the ocean disposal option should not be dismissed at this time.
Federal requirements appear to permit ocean disposal of secondary effluent under certain conditions.
The combined effects on Sanibel's surface waters of runoff pollution and leaching of sewage have been estimated by G.K. Young. Young has calculated that, with the best expected levels of treatment of sewage effluent, the combined effect would overwhelm the assimilative capacity of the wetlands - leading to unacceptable water quality when the total island population approached 20,000. Thus, there is a definite water quality limit to the occupancy of Sanibel. Direct discharge of wastes as concentrated point-sources is not now a major problem on Sanibel and should not become so in the future. It appears that neither sewage effluent nor industrial wastes are discharged directly into Sanibel waters at the present.