Freezing Problems Associated with Spray Irrigation of Wastewater during the Winter.

摘要

During the winters of 1975-76, 1976-77 and 1977-78 biologically treated wastewater was applied to land in West Dover, Vermont. The wastewater was applied using the spray irrigation method at ambient temperatures as low as 0 deg F. During the first winter, freezing was a major problem. Modified spray nozzles that were less susceptible to freezing were installed at both the low points and high points of the aboveground spray laterals. During the second and third winters, ice buildup along the spray laterals, particularly in the vicinity of the spray nozzles, caused serious damage to the pipes. Many man-hours were required to continuously cut the ice from the laterals. As an experiment to alleviate the problem several 30- to 36-in. risers were installed at an angle of approximately 30 deg. from the vertical on two of the spray laterals during the winter of 1977-78. They functioned well enough to warrant future installation on the entire system of spray laterals. (Author)