Organic Colour (Tannins) Reduction
Signs of the problem – Discoloured water from decayed vegetation or organic matter, usually from peatland, mires or bogs. The discoloration is usually worse after rainfall. The level of colour can be from a pale straw colour to deep yellow colour, similar to apple juice. Discolouration from tannins is not to be confused with iron presence in the water.
Solution. If the colour is very slight in some instances carbon filtration can be used. Carbon requires a very slow flow rate for colour reduction and can exhaust rapidly allowing the colour to pass again. The preferred approach to colour reduction is to use an organic scavenger/tannin filter. A tannin filter uses a specially selected anion resin which has an affinity to tannins, and regenerates on salt (using the chloride) to remove the colour.