Instant pulp mill – just add water

Neil Smith

The following is taken from federal Environment Minister Malcolm Turnbull’s draft approval for Gunns pulp mill:

Effluent Impacts
17. The pulp mill must not operate if effluent from the pulp mill exceeds the discharge limits provided in the table below.
Parameter Monthly average effluent concentration
Dioxins and furans 3.4 pg TEQ/L
Chlorate (ClO3-) 1.9 mg/L
Total chloroacetic acids 237 ug/L
Total nitrogen 2.5 mg/L
Total phosphorus 0.8 mg/L
Total suspended solids 20 mg/L
Biological oxygen demand 11 mg/L

If Gunns’ engineers ever start thinking that they actually need to pay some attention to satisfying the conditions, but, whoops! the chlorate concentration is twice as big as it should be, what can they do?

Just add water.

Just pump an amount of pure, clean water equal in volume to the original effluent stream out along the pipe into Bass Strait, and, voila! (I’ll leave it as an exercise to the reader to work out the approximate effect on the pollutant concentration in Bass Strait itself).

Could this be why Gunns’ originally stated requirement for 26 gigalitres of water per annum now seems to have become rather fuzzy – up to 40 gigalitres?

By the way, 26 gigalitres is the contents of a lake just over 2.5 kilometres in diameter with an average depth of 5 metres. Considerably smaller than Great Lake, to be sure, but nevertheless, water availability is going to become more of an issue for all of us in years to come. Encouraging wanton wastage ill becomes the Minister for the Environment and Water Resources!

When I first saw the above “operating condition” in the first hours of the 10-day public comment period I immediately emailed the Department a comment – but I did so in a rather rude manner, so maybe it might help if a couple of polite, restrained individuals attempted to make a similar point in the next few days (my own suggestion was to express pollutant amounts in grams, milligrams, micrograms or picograms per day).

As to whether the State of Tasmania’s “Pulp Mill Permit” expresses effluent levels in terms of concentrations I don’t know. But it seems that no one can change that document anyway! If any Members were thinking of voting against it but need one more teeny weeny reason ……

Dr Neil I Smith
Electronics Engineering Services