Control of Fouling in Irrigation Systems

Irrigation Systems


A common problem encountered in all irrigation systems is growth of microorganisms in the irrigation pipes causing poor flow, blockages and the potential for the spread of disease-causing organisms throughout the irrigated area, particularly fungal diseases.

The microorganisms flourishing in irrigation pipes include bacteria and fungi and, if sufficient light is present algae. Irrigation pipes provide an ideal environment for the establishment of biofilm on the inside of the pipes.

Other than mineral build up, the presence of biofilm is the single most likely cause of reduced flow and blockages in irrigation systems. The presence of biofilm also creates a permanent reservoir of potentially harmful microorganisms throughout the irrigation system.

Control of Microorganisms in Irrigation Pipes


Conventional chlorine, bromine and non-oxidising biocides are very poor at controlling microorganisms in irrigation pipes because of short contact times unless dosed at very high concentrations. Even at high dose rates, these disinfectants do not control biofilm.

High concentrations of disinfectant in irrigation water are also potentially harmful to the plants being irrigated. Most non-oxidising biocides are unacceptable for spraying onto food crops.

Chlorine dioxide overcomes all these problems. It is effective against algae, bacteria, bacterial spores, fungi, protozoa and viruses and is the only method of disinfection that is effective at controlling biofilm. Chlorine dioxide remains effective over a wide pH range from about 4 to 10. It does not react with ammonia or organic matter in the water and at the recommended dose rates is not phytotoxic. Any residual chlorine dioxide on plants rapidly breaks down to harmless inorganic compounds. In addition to these benefits, chlorine dioxide when used at high enough dose rates will disinfect hard surfaces preventing the spread of disease-causing bacteria, fungi and viruses.

CleanOxide 75 is a 0.75% solution of chlorine dioxide in water containing only a small amount of sodium sulphate and sodium chloride as by-products of mixing. When dosed into the irrigation system at the recommended rate, CleanOxide 75 will control bacteria, fungi, viruses, algae and biofilm. Higher rates will allow the control of microorganisms on hard surfaces contacted by the irrigation spray such as workbenches, pots and glass in greenhouses.

Advantages of CleanOxide 75


  • Clean Oxide 75 is 100% bio-degradable.
  • Clean Oxide 75 is a sustainable, environmentally friendly product.
  • Clean Oxide 75 leaves zero residues in the soil.
  • Clean Oxide 75 is safe for plants.
  • Clean Oxide 75 restores failing irrigation systems.
  • Clean Oxide 75 restores water flow rates.
  • Clean Oxide 75 increases the life of irrigation systems.
  • Clean Oxide 75 controls bacteria, fungi, viruses, biofilm & algae.
  • Clean Oxide 75 removes iron & manganese.
  • Clean Oxide 75 removes foul odours from water.
  • Clean Oxide 75 is effective over a broad pH range of 4 to 10.
  • Clean Oxide 75 is 10 times more powerful than chlorine.
  • Clean Oxide 75 is effective at lower dose rates than chlorine & hydrogen peroxide.
  • Clean Oxide 75 does not contain free chlorine.
  • Clean Oxide 75 is non corrosive at the recommended dose rates.
  • Clean Oxide 75 does not react with ammonia & does not produce toxic compounds in contact with organic materials present in water.
  • Clean Oxide 75 is so effective against biofilm because it exists in solution as a dissolved gas. The dissolved gas is able to diffuse into the biofilm where it can destroy the micro-organisms responsible for the biofilm.
  • Micro-organisms do not develop resistance to Clean Oxide 75.

System Maintenance


Regular maintenance is essential to maintain the efficiency of irrigation and drip systems as well as ensuring the maximum possible life of the system.

Water quality plays a big part in determining the optimum maintenance schedule for any system. There are three sources of clogging hazard to be considered in the design of a maintenance programme – physical, chemicaland biological.

Physical hazards are principally sand and silt and are best dealt with by filtration. As a guide, particles one tenth the size and above of the smallest diameter aperture in the system must be removed to ensure that clogging due to bridging does not occur. Biological activity often exacerbates clogging by fine silt and clay particles in the system.

There are numerous possible chemical causes of blocked systems. The most commonly encountered problems are:

  • Bicarbonate concentrations above 2meq/L and pH above 7.5 leading to precipitation of calcium carbonate.
  • Calcium concentrations above 2-3 meq/L causing precipitation of calcium phosphate when using phosphate fertilisers.
  • High concentrations of sulphide ions causing precipitation of iron and manganese sulphides.
  • Water containing more than 0.1mg/L sulphide promoting growth of sulphur reducing bacteria.

Biological clogging hazards arise from:

  • Growth of bacterial slimes (biofilm).
  • Growth of algae wherever there is sufficient light available, especially around drip taps and emitters.
  • Biological growth on clay particles contributing to physical clogging of spray nozzles by bridging.
  • Adhesion and agglomeration of fine particulate matter as a result of biological activity.
  • Precipitation of iron and sulphur caused by biological activity.

Filtering particulate matter and, as far as practicable, eliminating organic matter from the water before it enters the irrigation system are essential for eliminating physical blockages due to sand and silt. Specific chemical remedies may need to be applied if some of the chemical problems outlined above are present. For example acidification of the water may be necessary to control bicarbonate levels if this is causing problems.

For control of biological problems CleanOxide 75 is by far the best choice. CleanOxide 75 controls bacteria including sulphide reducing bacteria, biofilm, algae, fungi and viruses. Problems such as clogging due to biological material accumulating on particulate matter will be eliminated, precipitation of iron and sulphur due to biological activity will be reduced or eliminated and algal growth around spray nozzles and emitters will cease.

Chlorination is often used to control biological activity in irrigation systems. However, chlorination does not remove biofilm; it is very poor at controlling algae and can lead to increased problems when manganese is present in the water. Chlorination is ineffective if the pH of the water is above 7.5.

Flushing


Before attempting to use CleanOxide for the first time, the system should be thoroughly flushed with clean water to remove any accumulated organic matter or sediment. Flushing several times throughout the year should be carried out as a routine part of any maintenance programme.

Maintaining a record of system flow rates using a water meter will prove useful for determining if clogging is occurring at any point in the system. Ensure filters are clean and pressures set correctly. Begin flushing from the pump onwards. Flush the mainline, sub-mains, laterals and flushing manifold. If necessary, increase pressure in the inlet water in order to achieve adequate flushing of the laterals.

Control of Fouling in Irrigation Systems

A common problem encountered in all irrigation systems is growth of microorganisms in the irrigation pipes causing poor flow, blockages and the potential for the spread of disease-causing organisms throughout the irrigated area, particularly fungal diseases.

The microorganisms flourishing in irrigation pipes include bacteria and fungi and, if sufficient light is present algae. Irrigation pipes provide an ideal environment for the establishment of biofilm on the inside of the pipes.

Other than mineral build up, the presence of biofilm is the single most likely cause of reduced flow and blockages in irrigation systems. The presence of biofilm also creates a permanent reservoir of potentially harmful microorganisms throughout the irrigation system.

Conventional chlorine, bromine and non-oxidising biocides are very poor at controlling microorganisms in irrigation pipes because of short contact times unless dosed at very high concentrations. Even at high dose rates, these disinfectants do not control biofilm.

High concentrations of disinfectant in irrigation water are also potentially harmful to the plants being irrigated. Most non-oxidising biocides are unacceptable for spraying onto food crops.

Chlorine dioxide overcomes all these problems. It is effective against algae, bacteria, bacterial spores, fungi, protozoa and viruses and is the only method of disinfection that is effective at controlling biofilm. Chlorine dioxide remains effective over a wide pH range from about 4 to 10. It does not react with ammonia or organic matter in the water and at the recommended dose rates is not phytotoxic.

Any residual chlorine dioxide on plants rapidly breaks down to harmless inorganic compounds. In addition to these benefits, chlorine dioxide when used at high enough dose rates will disinfect hard surfaces preventing the spread of disease-causing bacteria, fungi and viruses.

CleanOxide 75 is a 0.75% solution of chlorine dioxide in water containing only a small amount of sodium sulphate and sodium chloride as by-products of mixing. When dosed into the irrigation system at the recommended rate, CleanOxide 75 will control bacteria, fungi, viruses, algae and biofilm. Higher rates will allow the control of microorganisms on hard surfaces contacted by the irrigation spray such as workbenches, pots and glass in greenhouses.

  • Clean Oxide 75 is 100% bio-degradable.
  • Clean Oxide 75 is a sustainable, environmentally friendly product.
  • Clean Oxide 75 leaves zero residues in the soil.
  • Clean Oxide 75 is safe for plants.
  • Clean Oxide 75 restores failing irrigation systems.
  • Clean Oxide 75 restores water flow rates.
  • Clean Oxide 75 increases the life of irrigation systems.
  • Clean Oxide 75 controls bacteria, fungi, viruses, biofilm & algae.
  • Clean Oxide 75 removes iron & manganese.
  • Clean Oxide 75 removes foul odours from water.
  • Clean Oxide 75 is effective over a broad pH range of 4 to 10.
  • Clean Oxide 75 is 10 times more powerful than chlorine.
  • Clean Oxide 75 is effective at lower dose rates than chlorine & hydrogen peroxide.
  • Clean Oxide 75 does not contain free chlorine.
  • Clean Oxide 75 is non corrosive at the recommended dose rates.
  • Clean Oxide 75 does not react with ammonia & does not produce toxic compounds in contact with organic materials present in water.
  • Clean Oxide 75 is so effective against biofilm because it exists in solution as a dissolved gas. The dissolved gas is able to diffuse into the biofilm where it can destroy the micro-organisms responsible for the biofilm.
  • Micro-organisms do not develop resistance to Clean Oxide 75.

Regular maintenance is essential to maintain the efficiency of irrigation and drip systems as well as ensuring the maximum possible life of the system.

Water quality plays a big part in determining the optimum maintenance schedule for any system. There are three sources of clogging hazard to be considered in the design of a maintenance programme – physical, chemicaland biological.

Physical hazards are principally sand and silt and are best dealt with by filtration. As a guide, particles one tenth the size and above of the smallest diameter aperture in the system must be removed to ensure that clogging due to bridging does not occur. Biological activity often exacerbates clogging by fine silt and clay particles in the system.

There are numerous possible chemical causes of blocked systems. The most commonly encountered problems are:

  • Bicarbonate concentrations above 2meq/L and pH above 7.5 leading to precipitation of calcium carbonate.
  • Calcium concentrations above 2-3 meq/L causing precipitation of calcium phosphate when using phosphate fertilisers.
  • High concentrations of sulphide ions causing precipitation of iron and manganese sulphides.
  • Water containing more than 0.1mg/L sulphide promoting growth of sulphur reducing bacteria.

Biological clogging hazards arise from:

  • Growth of bacterial slimes (biofilm).
  • Growth of algae wherever there is sufficient light available, especially around drip taps and emitters.
  • Biological growth on clay particles contributing to physical clogging of spray nozzles by bridging.
  • Adhesion and agglomeration of fine particulate matter as a result of biological activity.
  • Precipitation of iron and sulphur caused by biological activity.

Filtering particulate matter and, as far as practicable, eliminating organic matter from the water before it enters the irrigation system are essential for eliminating physical blockages due to sand and silt. Specific chemical remedies may need to be applied if some of the chemical problems outlined above are present. For example acidification of the water may be necessary to control bicarbonate levels if this is causing problems.

For control of biological problems CleanOxide 75 is by far the best choice. CleanOxide 75 controls bacteria including sulphide reducing bacteria, biofilm, algae, fungi and viruses. Problems such as clogging due to biological material accumulating on particulate matter will be eliminated, precipitation of iron and sulphur due to biological activity will be reduced or eliminated and algal growth around spray nozzles and emitters will cease.

Chlorination is often used to control biological activity in irrigation systems. However, chlorination does not remove biofilm; it is very poor at controlling algae and can lead to increased problems when manganese is present in the water. Chlorination is ineffective if the pH of the water is above 7.5.

Before attempting to use CleanOxide for the first time, the system should be thoroughly flushed with clean water to remove any accumulated organic matter or sediment. Flushing several times throughout the year should be carried out as a routine part of any maintenance programme.

Maintaining a record of system flow rates using a water meter will prove useful for determining if clogging is occurring at any point in the system.

Ensure filters are clean and pressures set correctly. Begin flushing from the pump onwards. Flush the mainline, sub-mains, laterals and flushing manifold. If necessary, increase pressure in the inlet water in order to achieve adequate flushing of the laterals.