My original plan was to step from Nutrients to Energy to Water week by week in thinking through resource recovery from wastewater treatment plants, but I want to dwell a little longer on Nutrients as this past week I attended the WEF/IWA Nutrient Removal and Recovery 2013: Trends in Resource Recovery and UseIt was a very good conference. Just the fact that this annual conference that started out looking at nutrient removal now includes significant space for recovery of said nutrients is an excellent step forward. Last Blog I listed what I thought were 3 significant hurdles to nutrient recovery, namely Money, Focus and Knowledge. This past week certainly brought Focus to the topic and considerable Knowledge too... to be honest there was so much knowledge shared I need to go back through the proceedings to see what I missed! This is excellent news in our move toward a sustainable future.
So that's the good news, but still there is the significant hurdle of Money. I want to offer the suggestion that we need to broaden our perspectives when it comes to looking at the finances of nutrient recovery projects. One very obvious example is the benefit that comes from removing phosphorus from a treatment facility that is suffering from pipe blockages and equipment failure due to struvite. I have heard of a couple of utilities that have decided to do phosphorus recovery in order to remove phosphate from their sludge liquors where struvite was a major problem. There is also evidence that sludges rich in phosphorus (due to enhanced biological phosphorus removal) are more difficult to dewater. Finally, the content of P in most biosolids produced in a treatment facility is much higher than it needs to be for agronomic use. Connect all of these factors together, estimate the cost benefits of them and then add this to the economic analysis for P-recovery and it will significantly shift the balance.
And all this is can be acheived without considering the true value of phosphorus as a non-renewable resource. Throw in this factor, and the fact that it's doing the right thing, then I think the case for nutrient recovery is much stronger than many may realize. I'm excitied to be working on a P-recovery project at Stickney in Chicago over the next several months. I strongly encourage others to consider doing it - the financial aspects are much better than you'd expect if you take an holistic view, and it's just the right thing to do, so do it!