Water futures

It will also integrate a HACCP risk management and quality assurance system for the whole water cycle (HACCP is recognised and used all over the world as a system for ensuring the quality and safety of food products). Toowoomba City Council already has an independently certified and audited HACCP system to ensure drinking water quality.

The seven barriers of Water Futures - Toowoomba

Barrier 1 - Wetalla Water Reclamation Plant

First, the wastewater goes through the Wetalla Water Reclamation Plant. Here the wastewater treatment plant combines several different processes to purify water. The physical process of screening removes all large particles and material that will not dissolve. A biological process follows, where a population of small organisms such as protozoa and bacteria feed on the dissolved organic material in the water. Oxygen is supplied at controlled rates to create zones ranging from high oxygen to none at all, to encourage specific types of organisms to grow.

The water then flows through large settling tanks where the organisms and their feed (organic matter) are separated out and returned to water at the beginning of this process to do their job all over again. The solid by-product of this process, called biosolids, has excellent nutrient value and is used as a soil additive in agriculture. To ensure that there are no dangerous bacteria or viruses remaining, the water to be discharged down Gowrie Creek is disinfected using chlorine or UV light. The water to be purified for potable reuse then continues to the next barrier.

Barrier 2 - Ultrafiltration

The next stop for the water is at the Advanced Water Treatment Plant where it will undergo ultrafiltration. This involves the use of polymer or ceramic membrane filters, with a pore size of 0.01 micron, to remove very fine colloidal (very small suspended) particles from water.

At this stage in the process parasites such as Giardia, Cryptosporidia and bacteria such as E coli (Escherichia coli), and any other disease-causing microbes that might have been present in the water are removed.

Barrier 3 - Reverse osmosis

Our third barrier is the use of reverse osmosis (RO). During the RO process, pressure is applied to squeeze the water across an extremely fine membrane filter. The pore size of the RO membrane is so small (0.0001 micron) that bacteria, viruses and chemicals cannot pass through.

The membrane traps small pollutants such as salts, drugs (for example, chemotherapy drugs, anti-inflamatories, antibiotics and other pharmaceuticals), chemicals (such as personal care products), hormones, and importantly, viruses, while allowing the water molecules to pass through.

Very small amounts of some organic chemicals may pass through a RO membrane, but these are safely destroyed at one of the next two stages in the process.

It is important to note that, to begin with, not many hormones enter our water system. Hormones are large organic molecules (more than ten times the size of water molecules). This makes them relatively easy to remove through membrane filtration. Current Australian research shows more than 90 per cent of the hormones in raw sewage will be destroyed in the water reclamation stage (barrier 1).