Pneumatic Barrier and Beach Pollution

The feasibility of improving the bathing conditions of certain beaches by using pneumatic barriers both with and without chlorination was determined by an experimental system consisting of four parallel lines (three air and one water-chlorination) encompassing approximately 355 ft (108 m) of beach, under a mean tidal value of 7.2 ft (2.2 m), a complete cycle of approximately 12 hrs 15 min and a net water exchange of 1,600,000 gal (6,000 cu m). Air was supplied by two 100 scfm (2.8 standard cu m/min) compressors and was sparged through 1/64 in. or 1/32 in. (0.4 mm or 0.8 mm) orifices spaced at 30 in. (76.2 cm) intervals, at conditions assuring critical velocity across the orifices. The conclusions of these studies were: (1) Aeration alone had no statistically significant effect in lowering bacterial levels or acting as a bacterial barrier; (2) chlorination effectively reduced all bacteria levels in the basin; and (3) pneumatic curtains appear effective in containing surface debris and contamination such as oil spillage.