Blockage of Drip Irrigation Filters and Emitters by Iron-Sulfur-Bacterial Products1

Abstract

Abstract Some drip irrigation systems installed in central and south Florida citrus groves have ceased to function properly because of filter and emitter clogging. The most serious clogging has been a slime formed by filamentous sulfur bacteria. The most abundant sulfur bacteria was Thiothrix nivea Robenhorst, a common inhabitant of warm mineral springs in Florida. The bacteria oxidize H 2 S to S and can clog small openings within a brief period of time. Beggiatoa sp., a sulfur bacteria, was also found in the slime although the organism occurred most frequently in emitter orifices. Another serious clogging factor has been Fe deposits in the form of filamentous, gelatinous ochre. The Fe deposits were associated with iron bacteria. The sticky sludge adhered to filters, grooves, and orifices of emitters. Iron sulfide clogged filter screens and accumulated in the grooves of some emitters.