Rusty red sediment clogging emitters and filters is a common problem for growers using drip and other types of micro-irrigation.
Iron is abundant, composing up to 5% of the earth’s crust. Iron is present in water in soluble form as ferrous iron (bivalent iron: Fe+2) or insoluble form as ferric iron (trivalent iron: Fe+3). Iron fixing bacteria react with soluble iron, Fe+2, through an oxidation process that changes the iron to an insoluble form, Fe+3. When Irrigation water has iron levels above 0.1 ppm, clogging of drip irrigation emitters may occur.
Concentrations above 1.5 ppm are considered severe. Practically any water that contains concentrations higher than 0.5 ppm of iron will need treatment to be used in drip irrigation. The bacteria colonies surround the insoluble ferric iron and create the sticky iron slime gel and hard sediment that is responsible for clogging the dripper and filtration system.
Iron in irrigation water can be reduced by the use of a sedimentation pond. Water is held before being used for irrigation allowing the iron to precipitate out of the water. For many irrigation systems however a sedimentation pond alone is insufficient and a cleaning treatment must be used.
Treatments such as peracetic acid or chlorination have been used in the past however they are frequently only moderately effective and pose severe risks to either the workers handling the chemicals or the soil ecology.
Phyto-Cat is completely non toxic and the most effective irrigation cleaning treatment currently available. See our previous blog post for a comparison of irrigation cleaning treatments and learn more about Phyto-Cat.