The fate of bacterial indicators, bacteriophages and enteroviruses was studied in a forested cypress strand treated with primary effluent from the town of Waldo, Florida. Experimental corridors (40m × 10m) were installed in a strand and were treated with pumped primary effluent. Bacterial indicators (total and fecal coliforms, fecal streptococci), bacteriophages and enteroviruses, were removed following 40m travel of sewage through the corridors. The results indicated that fecal streptococci accumulate in the sediments.
The levels of bacterial indicators, phages and enteroviruses were monitored in another strand that had been receiving sewage for 50 years. Microbial numbers were determined at stations situated at increasing distances from the sewage outfall (up to 230m). It was observed that the bacterial indicators were reduced approximately by 3 log10 units at the 230m-station. Fecal streptococci were shown to accumulate in the sediments. The reduction in the number of phages was less and was approximately one log10 unit. Enteroviruses and Salmonella spp. were detected in the cypress strand water. They were often undetectable in the sediments.
The results demonstrate the potential use of wetlands for low-energy treatment of sewage effluents.