Extent Of The Problem

Visually iron staining is easy to identify as the dark orange tinge that builds up where untreated bore water ends up.

External lab tests affirmed that iron was present at 37.5 milligrams per litre (mg/L).  This is among the highest concentrations in WA and can be seen in suburbs such as Joondalup, Mt Claremont and sections of the Peel region.

Iron becomes an issue at 0.25 mg/L when it hits the taste threshold and visibly starts damaging at 2 mg/Ls.
So at 37.5 mg/L iron was a major issue.

Fortunately the other minerals of bicarbonate, calcium and manganese that usually increase stain were within reasonable levels.

The Bore Water Treatment System

Upon completion this system was composed of:

• Dual standing sand filters
• A chlorine dosing unit
• Water conditioner
• Subsurface aeration chambers

It is a larger system to accomodate the greater daily flow rate and overall consumption. The average residential bore water treatment system only requires a single sand filter.

How It Works

It is both chemical and filtration system that removes all forms of iron. There is no settling tank as it is an on-demand system that filters bore water as it is required.

The general process is as follows;

Raw bore water is micro-dosed with chlorine and sent through a series of submerged aeration chambers. The purpose of the aeration chambers is to increase contact time for maximum oxidisation prior to entering the sand filters.

After that it enters the dual sand filters that separates out and captures the iron sediments. Each filter contains a specific mix of catalytic sand media that corrosponds to the exact mineral profile of the raw bore water.

Finally it comes out the other side ready use outside the house. While it has been treated, it is not potable.

System Management and Maintenance

The image of the pipe spewing out reddy/brown water is what comes out during the backflush of the sand filters.

The system needs maintenance periodically to replenish chlorine levels and expel captured iron from the sand filters.

Chlorine
In summer the system is used more frequently to irrigate gardens and lawns and in winter used far less. Chlorine consumption fluctuates based on seasons and consumption.

The average residential iron bore water treatement system consumes 20 litres every 4 – 6 weeks which is equivalent to approximately $200 per annum in chlorine.

Sand Filter Maintenance
Sand filters require regular maintence cycles to prevent excess iron captured from saturating the sand filters and reducing filtration performance.

Maintenance Steps:

1. Backflush until water is visably clear and there is red colouration
2. Rinse filters to resettle filtration media within filters
3. Set back to normal.

Maintenance is relatively straightforward but is very important because iron staining will occur if the captured iron isn’t regularly removed.

Home owners can carry out maintenance themselves or opt for Earth & Water to carry out regular services as is normal with commercial facilities.

Iron Stain Removal

Iron stain is removed by applying a specific acid based stain remover. 

Stain removal must be completed after installing an iron tretemnet system or after replacing sprinklers with subsurfce drip irrigation. If not the stain is highly likely to return.

Earth & Water sells iron stain removal solution in small quantities for home owners to apply themselves as well as supply and removal for commercial facilities. 

See Before and After photos of stain removal projects on our portfolio page.