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Screen filter Photo: L SchwanklThe degree of filtration is expressed as mesh size or equivalent mesh size. The mesh size is the number of openings per inch. For example, a 200-mesh filter has 200 openings per inch.

Flushing of a drip tape lateral Photo: L. SchwanklPeriodic flushing is required to prevent clogging from sediments, particularly along the lower part of the drip line. A 200-mesh filter will not remove particles of fine sand, silt, and clay or fine particles of algae.

Filtration Guidelines for Irrigation Water Filters...

Self-flushing lateral line end caps, used on a subsurface drip system in tree crops Photo: L.

Manifold flush valves for a row crop subsurface drip system Photo: L.

Storage reservoir with organic contamination Photo: L. SchwanklBiological growths in drip lines and emitters can be a serious problem when the irrigation water contains organic sediments, iron, or hydrogen sulfide. The primary contributors to biological growths are algae and bacteria.

Water in an irrigation reservoir with a high organic contamination level Photo: L.

Storage tank for chemicals injected through the microirrigation system Photo: L.

Double-venturi injection system Photo: L. SchwanklTreating irrigation water with a biocide will minimize the growth of organic contaminants and often destroy the organic material, minimizing the clogging hazard. Three biocide methods are commonly used to treat irrigation water.

Venturi injector with small pump. Photo: L. SchwanklChlorine is often added to irrigation water to oxidize and destroy biological microorganisms such as algae, fungi, and bacteria.