The use of Phragmites for sludge drying is becoming more popular, especially with small municipalities, as a low-cost method of treatment. Wild plants are usually used for these purposes, but the Halophyte Biotechnology Center has been working to develop and test new varieties of Phragmites that would function more efficiently. The drying and organic decomposition rates of several operational reed beds were measured at two sites for over a full year. One site pours anaerobic sludge on two wild type reed beds and five traditional sand drying beds. At a second site, one bed was partitioned and one half planted with wild Phragmites and the other half with variegated Phragmites developed in tissue culture. A second bed at that site was used as an unplanted control. This site, which is only one year old, uses an aerobic sludge and the beds are enclosed in a greenhouse. The relative importance of various water loss pathways and the rate of decomposition (based on carbon dioxide evolution rate) were estimated for both sites. The evolution rate appears to be limited by oxygen at both sites, suggesting cracks and plant stems are important factors in determining decomposition rate. The evolution rate is also sensitive to temperature. Both types of Phragmites beds, including newly planted ones, can treat the same amount of sludge as the unplanted beds while saving a small treatment plant over a thousand dollars a year in worker hours and landfill fees. No significant improvement in efficiency has yet been measured for the variegated Phragmites over the wild Phragmites. Aphids, which have been reported as problem at other sites, were not a problem in the open beds but were a serious problem in the enclosed beds and had to be sprayed several times throughout the season.

Key words: municipal waste treatment, Phragmites australis, sludge, wetland plants