Saturday, May 19, 2007

How much do we recycle?

Australian towns and cities have been developing water recycling schemes for a couple of decades now. The pressure to do so initially came in the late 1980s with the establishment of the various state-based Environmental Protection Authorities (EPAs).

The EPAs set limits and increasingly strict quality criteria for wastes that could be discharged to waterways. This had a considerable effect in causing many inland sewage treatment plants to be upgraded and/or find alternative means for disposing of effluents. Among the most common solutions was to begin to use the treated effluent to irrigate the local airport, golf course or timber plantation. By the late 1990’s, Australians were reusing around 7 % of our treated municipal effluents.

However, in the current decade the major impetus for water recycling has changed significantly. The last six years has been one of the most sustained dry periods across Australia since records began. The pressure for water managers has shifted from a need to dispose of used water to a more urgent need to find new water sources. What was previously considered to be ‘waste water’ has never before looked like such an intrinsically valuable resource.

The aim of most developing Australian water recycling schemes is now to treat and use recycled water in such a manner as to either directly supplement potable water supplies or to replace the use of potable supplies for some specific applications. This additional pressure has brought the national water recycling average up to around 12 % during 2005/06. And as regular readers would know, this growth is not about to slow anytime soon.

I got this ‘12 %’ from the National Performance Report 2005/06 released this week by the National Water Commission and the Water Services Association of Australia. There are two parts of the report, -one covering the major urban water utilities (Sydney Water, Actew, NT Power & Water, Brisbane Water, Water Corporation, etc), and the other covering the non-major urban water utilities (Kempsey Shire Council, etc).

One very clear trend is that the little guys are generally much better water recyclers than the big guys. An average of 9% was recycled by the major utilities (total volume recycled was 125,000 ML), while 23 % was recycled by the non-major utilities (total volume recycled was 42,000 ML).

The reason for the discrepancy is clearly that it is easier for the smaller towns and cities to recycle the relatively smaller volumes of effluent that they produce compared to the much larger cities. In many cases a decent sized golf course or plantation can use a significant proportion of what is produced and commonly only secondary or tertiary treatment levels are required.

For large cities to recycle significant proportions of their effluent, they will commonly need to consider industrial, horticultural, or household reuse where increased levels of treatment and management are generally necessary.

So who are the real individual water recycling champions?

The National Performance Report indicates that there are five utilities that recycle at least 75% of their treated effluents. These are Dubbo City Council (NSW), Western Water (VIC), East Gippsland Water (VIC), Goulburn-Murray Water (VIC), and Wide Bay Water (QLD).

However, the proportion recycled doesn’t give any indication of whether the water was recycled for a high-value application or a low-value application. Furthermore, it doesn’t indicate whether any potable water was saved by having its use substituted by the recycled water.

While the data appear to be a bit more sketchy, the National Performance Report identifies 5 utilities where recycled water contributes to at least a 10% savings of the potable water supply. These are Bega Valley Shire (NSW), Orange City Council (NSW), South East Water (VIC), Western Water (VIC), Power & Water (Alice Springs, NT).

So it seems that on these two combined (somewhat arbitrary) measures, Western Water appears to be the 2005/06 water recycling gold medallist. We’ll have to take a closer look at exactly what they’re doing some time.


Anonymous said...

If all goes well, the new winner for water recycling will be south east Queensland by late 2008 or early 2009.

Joie Carine Ukunzwe said...

can you please tell me what kind of materials you use to treate the water very well.

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