Extent of the Problem

People became accustomed to the look of iron staining because the accumulation of iron and calcium isbarely noticable on a daily basis.

Each day, the stain is marginally worse than the day before.

This picture of Joondalup Primary School shows a wall that has been exposed to sprinklers three times a week for several years.

We applied an acid-based wash that removes iron stains to see how deep the stain actually was.

It is always best to install a bore water treatment system before the stain accumulates but in this case Joondalup Primary didn’t have that option.

The iron stain had crept up on them.

Bore Water Treatment

Preliminary water tests showed that the school’s bore water had abnormally high iron concentration in its ground water.

External laboratory test results from our water samples confirmed this and were the basis of the water treatment system designed.

The goal of the system is to simply remove iron out of the water and capture it in a separate tank. This stops iron from ever being used in the school’s irrigation.

These are the technical components in this particular bore water treatment system: 

1. Dual tank sand traps that oxidise and separate the iron from the water.
2. Water conditioner that improves the ionic structure of water in increase flora’s nutrient aborption rate and reduces the negative effects of salt.
3. Chlorination injection that delivers miniscule amounts of chlorine to reduce bacteria, organic particles and to oxidise out iron.

Leftover Iron

All iron that is removed from the bore water has to be captured somewhere. In this picture you can see dark brown water filling up a water tank.

That brown colour is iron that would otherwise be distributed across school grounds and buildings. Instead the iron is backflushed out of the irrigation system and into its own separation tank.

Iron is heavy and settles quickly. After eight to twelve hours the iron will sit at the bottom of the tank and the water above can be filtered out into ground sumps next to the tank.

Over time the iron will accumulate at the bottom of the tank. It is a heavy and dark sludge which is removed and taken elsewhere for disposal.

It is easier and cheaper to catch and remove iron in this way than allow it stain buildings and property.

The Visual Impact of Iron Staining

The aerial from Google Maps shows how buildings, roofs and paving next to sprinklers change colour due to iron staining.

Overspray is always the reason unwanted staining occurs. 

The iron stain has since been removed on the roofs and buildings next to the ovals.

In smaller areas it is more water-wise to replace sprinklers with subsurface drip irrigation. The same untreated bore water with high concentrations of iron and calcium will water plants and leave property untouched and clean.