Table A-1-1. General summary of micro-irrigation problems and possible solutions (Burt et al., 1998).
|Small slimy bacteria
- Continuously apply chlorine at low dosage. Free chlorine at the far end of the system should measure 1 ppm.
- Superchlorinate to 200-500 ppm free chlorine at the far end of the system: Thoroughly flush system, inject chlorine, allow to sit overnight, flush system the next day.
|Iron and manganese bacteria
- If the bacteria inhabit the well, injecting acid or chorine directly into it may minimize the problem. Check for legality of this procedure in the local area.
- Pump well water into a reservoir and aerate it before pumping it to the irrigation system. The oxidation will cause precipitation of iron and manganese.
- Inject a long chain linear polyphosphate or polymaleic acid into the irrigation water to sequester iron and manganese, keeping them suspended while they move through the irrigation system.
- Inject chlorine gas (1.4 parts chlorine for each 1.0 part iron in the water) prior to a fine media or disc filter to precipitate the iron from the water and trap it in the filter. This technique will not work for manganese.
|Calcium and magnesium carbonate precipitation
- Neutralize the carbonates by injecting phosphoric or sulfuric acid into the irrigation water such that the pH decreases below 6.5.
- Inject a very long chain linear polyphosphate into the irrigation water at a rate of 1 to 2 ppm to sequester calcium and magnesium, keeping them suspended while they move through the irrigation system.