Reducing P by 0.02 grams per litre will cost $100 million

25 August 2012

Droplets readers should, by now, be fully up to speed about why we need to reduce the amounts of nutrients being discharged into our rivers and streams, ending up in our lakes and dams.  Its all about eutrophication and the very negative economic consequences that not paying attention to this problem can have.

Reducing the levels of phosphorus in, for example, wastewater effluents, to levels that will not impact negatively on our water resources, is relatively easy to do but, depending on what needs to be done to bring about the necessary changes, may cost a lot.  In South Africa, a recent application to bring a single wastewater treatment plant into line was estimated at costing an almost-insignificant ZAR23 million (approx US$3 million) – but this was turned down.  I am not sure why but I would hazard a guess that if the national regulator admits there is a problem that can be fixed at just one treatment plant, what about those at hundreds of others?  Of course it is not going to get any cheaper.

For decades one of the central reasons why eutrophication is not managed at source, i.e. at the wastewater treatment works, has been due to a lot of whining from municipalities and treatment engineers about how much it will cost the poor ratepayers.  Now, in this case, the ratepayer (think about where human faecal waste comes from), is both part of the problem and of the solution.  When you use your toilet you put nutrients into the system.  If you want healthy lakes and rivers and all the benefits these provide, then you need to be prepared to pay for the services needed to achieve this.  The fact that doing so is going to cost you a lot now is because your public representatives have ducked the problem for so long, plus they probably kept you in the dark about it as well.  Ultimately, though, its your fault for being too accepting of letting elected officials manage your environment for you, without question.

Lets have a look at the case of the City of Barrie, Canada, a town that currently dumps its wastewater effluents into Lake Simcoe:  Barrie already has a very low limit for the concentration of phosphorus (P) it discharges, 0.12 mg P per litre.  By South African standards (OK we don’t really have any but if we did…) this is phenomenally low!  For Barrie, though, they need to drop this by 0.02 mg per litre, to 0.1 mg per litre of P, which amounts to 555 kgs per year.  Its this seemingly minor reduction that will amount to the need to spend $100 million – or $22500 per ratepayer!   If they delay doing anything, it may just become even more expensive!

In Cheshire, Connecticut, a $31 million upgrade to the treatment works will include new filter technology to remove phosphorus from the effluent flows. State permits require Cheshire to lower its phosphorus levels from 0.7 milligrams per liter to 0.2 milligrams per liter.

Of course phosphorus does not only originate from human waste streams.  Fertilizers are a huge source and, as everyone knows, eutrophication is a outcome of trying to feed the world’s rapidly growing population – phosphorus fertilizer production keeps pace with population growth.  In Boston a new bill to ban fertilizers containing phosphorus is before the governor (hope he or she knows what eutrophication is all about !).  Boston’s Charles River is at the centre of a $500 000 nutrient management strategy for the City.

In the UK, the cancellation of the annual Strathclyde ‘Great Scottish Swim‘ has angered many.  This is the second cancellation in three years – brought about by worsening water quality in the lake.


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