Biosolids and the Care of Our Common Home

I had an “Aha!” moment at the WEF/IWA Residuals and Biosolids conference last week in DC.

I was attending a technical session on phosphorus. Dr. Lakhwinder Hundal, the senior scientist at Chicago’s MWRDGC, made a point that surprised me: “Most of the P in biosolids is not from human excreta.”

How does Lak know this? He knows this because he and his colleagues conducted a major study to track down sources of P to Chicago’s treatment plants. Their interest was in answering a policy question about whether the agency should impose controls on sources of P as part of an effort to meet P limits in their discharge. Chicago researchers determined (get the report here) that 28% of influent P was from human excreta. The next largest source was industrial discharges at 23%, followed by storm water.

When all was said and done, Lak reports, Chicago chose not to reduce P coming into the treatment plants, but rather to remove it during the treatment process. The P harvesting project at Stickney will be the largest for Ostara.

Chicago will be undertaking the important task of being a barrier to the flow of phosphorus and of recovering a non-renewable nutrient resource. What is more, because Chicago’s biosolids is very ordinary with respect to P, they will be example to us all.

Why is this important?

The Pope knows why. At least that’s my reading of his encyclical, ”Praise Be To You, Laudato Si:, On Care of Our Common Home.”. I will get back to the Pope.

After learning of the importance of non-human P sources in wastewater, I did some of my own sleuthing on sources of phosphorus.

One significant market for P is the food industry. This is in the form of phosphoric acid addition to soft drinks and processed foods. One interesting angle is the concern that consumers are exposed thereby to unhealthy levels of phosphorus. Check out the Dietary Phosphorus Excess and Health, describing how excess dietary P can “disrupt hormonal regulation of phosphorus, calcium, and vitamin D, contributing to disordered mineral metabolism, vascular calcification, impaired kidney function, and bone loss.” Eke!

The biggest market, of course, is fertilizers, some 80% of all P sold in the United States for its essential role in food and feed crop production. We have likely all heard of the looming crisis of P fertilizer depletion. For instance, in Yale University’s Environment 360 you can read “Phosphate: A Critical Resource Misused and Now Running Low”, and in Wikipedia, as good as any source of “truth,” you can read about “Peak Phosphorus.” Academicians, it comes as no surprised, are also engaged in this issue, as exemplified by the Sustainable Phosphorus Futures project of the Global Phosphorus Research Initiative.

I was interested in finding what may be a contrary viewpoint. At the International Fertilizer Industry Association website almost all of the good stuff is behind a “members only” wall, but you can scan the titles. One intriguing title was: “Planetary Boundaries: Concept and Boundary for Nitrogen and Phosphorus.” I “googled” this title, but no alternative source popped up.

Planetary Boundaries? That was a new term-of-art to me, so I “googled” it. Am I the last to hear about this?!!

Wikipedia is a great place for demystification of hot topics. It says at its article on Planetary Boundaries: “Planetary boundaries is the central concept in an Earth system framework proposed by a group of Earth system and environmental scientists led by Johan Rockström from the Stockholm Resilience Centre and Will Steffen from the Australian National University. “

Planetary Boundaries is, I discovered, a huge new tool for sustainability investigation and debate. Rockstrom’s initiating article is Planetary Boundaries: Exploring the Safe Operating Space for Humanity. He and his 28 co-authors identified nine “boundaries,” each with an index against which current human impacts are measured for whether humanity has crossed the boundary, to the peril of our future. These boundaries are: climate change, biodiversity loss, biogeochemical, ocean acidification, land use, freshwater, ozone depletion, atmospheric aerosols, and chemical pollution. Rockstrom proposed (and other have continued to evolve) indices for 7 of the nine boundaries, with two still under development; one group of scientists has proposed a 10th boundary involving human justice. The Climate Change Boundary is only one element, albeit listed first, in the full picture of environmental risks confronting humankind.

Why was the fertilizer industry interested in planet boundaries?

Fertilizers are in the crosshairs of the Biogeochemical Boundary. The impact of fertilizer nitrogen and phosphorus loadings have indices that have been, or which may soon be, crossed. The fertilizer industry apparently is taking seriously the growing prominence of Planetary Boundaries in the international debate on global sustainability.

Under the “Biogeochemical Boundary,” the nitrogen boundary has been crossed: “the Earth's nitrogen cycle has been disturbed even more than the carbon cycle. Human activities now convert more nitrogen from the atmosphere into reactive forms than all of the Earth´s terrestrial processes combined. Much of this new reactive nitrogen pollutes waterways and coastal zones, is emitted back to the atmosphere in changed forms, or accumulates in the terrestrial biosphere.”

The second index for the “Biogeochemical Boundary” is phosphorus releases. In Rockstrom’s original paper, humankind has not yet crossed the boundary in P loadings. But this finding was disputed by others in the new Planetary Boundary community, specifically “Reconsideration of the Planetary Boundary for Phosphorus.” The authors write: “Current conditions exceed all planetary boundaries for P. Substantial differences between current conditions and planetary boundaries demonstrate the contrast between large amounts of P needed for food production and the high sensitivity of freshwaters to pollution by P runoff. At the same time, some regions of the world are P-deficient, and there are some indications that a global P shortage is possible in coming decades.”

What I saw in these discussions is the significant role that we in the wastewater profession ought to be playing in mitigating loadings that take humanity across the Biogeochemical Planetary Boundary. As the authors state, “More efficient recycling and retention of P within agricultural ecosystems could maintain or increase food production while reducing P pollution and improving water quality.”

The Biogeochemical Boundary is only one of several boundaries that the wastewater industry can serve to mitigate. For the Freshwater Usage boundary, the report says: The good news is that the potential for savings, without hurting human health or economic productivity, is vast. Improvements in water-use efficiency are possible in every sector.” We can do this.

For the Land Use Boundary: ”We can avoid losing the best agricultural land by controlling land degradation, freshwater depletion and urban sprawl.” In this I hear the message that recycling of organic matter and nutrients back to farmlands at the urban periphery is a mitigation measure, one which we are expert at doing.

For the Chemical Pollution Boundary, the 9th on the list, one proposal is to have the boundary set on an index of limiting loadings of PCBs. I have personal experience with biosolids as a barrier to illegal PCB discharges to the environment, and I am not alone in the biosolids profession in this. Wastewater treatment is a barrier to chemical pollution of all sorts, in the way that persistent bioaccumulative pollutants are trapped in, and ultimately degraded when biosolids are managed. In the future, we could become an even more effective barrier to chemical pollution.

Planetary Boundaries as a policy tool is now warmly debated within the global sustainability community. It was proposed, but not adopted, as a tool for the Rio+20 United Nations Conference on Sustainable Development in 2013. Delegates were concern that this tool could be used to stop economic progress in developing countries, a social justice concern. Nevertheless, I see Planetary Boundaries’ deployment expanding.

I believe the holistic paradigm of Planetary Boundaries just got a big morale boost yesterday from the Pope.

Nowhere has the call for a comprehensive response to Earth’s health been more powerfully made than in Pope Francis’s so-called Climate Change Encyclical. The scope of the Pope’s encyclical is far, far more comprehensive than that of a call to reduce greenhouse gas emissions. It engages agriculture, forestry, mining, biodiversity, land use, pollutant emissions and all environmental aspects as they effect living conditions and health of peoples, and of all nature, non-uniformly and adversely across the entire globe.

The Pope’s encyclical is very long, but please read it, or at least skim it for those passages that can motivate and enliven the mission of the work we do in the world.

For instance, go to paragraph 164, where the Pope writes: “Yet the same ingenuity which has brought about enormous technological progress has so far proved incapable of finding effective ways of dealing with grave environmental and social problems worldwide. A global consensus is essential for confronting the deeper problems, which cannot be resolved by unilateral actions on the part of individual countries. Such a consensus could lead, for example, to planning a sustainable and diversified agriculture, developing renewable and less polluting forms of energy, encouraging a more efficient use of energy, promoting a better management of marine and forest resources, and ensuring universal access to drinking water.”

Let’s set our daily work in the complex and intriguing work of the Planetary Boundaries, and in the vast, noble context laid out for us by Pope Francis. Our wastewater profession wields important tools for accomplishing the task of lessening loadings of nitrogen and phosphorus, of reducing greenhouse gas emissions, of providing distributed energy, of erecting barriers to chemical pollution, of allowing intensification of agriculture, and of returning freshwater to safe human use.

We are a core aspect of achieving Planetary Boundaries, and, even more so now, of responding to the Pope’s challenge for the Care of Our Common Home.


For further exploration of Our Planetary Boundaries, check out "Fitting Sewage Treatment into Our Planetary Boundaries".