Spoiler alert… MABA’s Biosolids Research Update for April from Sally Brown will feature recent research into the use of biosolids in restoring degraded soils and landscapes. (Check it out at MABA Research webpage.) I have frequently opined that land reclamation is the highest and best use of biosolids, and I say it again here. I have a vision for restoring degraded landscapes.
I have a career’s worth of papers and presentations from my days at the Philadelphia Water Department on the topic of land restoration. I posted some on the MABA website . There is the amazing Rattler’s Run project (Lycoming County, PA), a biosolids-based restoration, involving the collaboration by a dozen groups, of a Pennsylvania Game Commission property gifted to it by a mining company after completion of deep and surface coal mining. You can read of the deep-row placement of biosolids at an Anthracite coal mine in Minersville, Schuylkill County, with its amazing growth of hybrid poplars. In 2003 I wrote the25-year history of biosolids-based reclamation, summarizing lessons learned in work at over 4,000 acres with 1 million tons of biosolids. The website also reports on the success of others, such as the work by Harrisburg with its biosolids used in a nearby coal mine site.
And it’s not only about coal mine reclamation. You can read of the restoration of a severely toxic soils caused by exposure of highly acidic, arsenic-bearing rocks, reclaimed by DC Water at the airport in Stafford County, Virginia. One of the best known reclamation site in the MABA region is the EPA Superfund restoration of a mountainside destroyed by toxic emissions from a zinc smelter in Palmerton, Pennsylvania, with biosolids work championed by USDA’s Rufus Chaney.
Importantly, restoration with biosolids is supported by sound science. William Sopper at Penn State was the early and eager scientist working with biosolids. His 1983 report, Guide for Revegetation of Mined Land in Eastern United States using municipal sludge, drew on 15 years of field research, and even as he approached retirement, Dr. Sopper prepared in 1993 a capstone textbook Municipal sludge use in land reclamation. Today’s senior scientists in the MABA region, Drs Rufus Chaney, Greg Evanylo, W Lee Daniels, Gary Felton, Richard Stehouwer, continue to provide the wastewater profession with scientific under-pinnings to reclamation practices.
My renewed enthusiasm for restoration stems in part from considering several positive contrasts to agricultural use of biosolids. Soil restoration beneficially uses the full suite of macro and micronutrients in biosolids, while in contrast most farmlands already have a sufficient storehouse of soil-borne phosphorus.
Biosolids used on disturbed landscapes restores a number of significant “ecological services.” One of these is a sink for carbon. New research demonstrates the very large capacity of reclamation sites to take in carbon source such as biosolids to permanently sequester carbon. Early conjecture was that the added organic matter would “burn off” and not contribute to a permanent storage of carbon, but this has proved not so. The research paper Soil Carbon Characterization 10 to 15 Years After Organic Residual Application shows that the application of organic residuals can increase soil C decomposition and thus improve long-term soil C stability. This was also shown to happen in over-used agricultural soils: Biosolids amendment dramatically increases sequestration of crop residue-carbon in agricultural soils in western Illinois: “We found dramatically greater sequestration rate of crop residue-C in biosolids-amended soil (32.5 ± 1.7% of total crop residue-C) versus unamended soil (11.8 ± 1.6%).” The authors of “Review Article: Soil Carbon Sequestration Resulting from Biosolids Application,” summarized their findings: “Many studies reported that mineralization rates of biosolids-borne C may not depend on soil texture and that slightly acid soils retained more biosolids-borne carbon than soils with a higher pH. Furthermore, amorphous iron and aluminum oxides usually found in biosolids would play an important role in soil organic C accumulation. Therefore, the capacity of soils to sequester biosolids borne C may not be finite.”
Biosolids can help recreate the ecological services of a healthy watersheds. In old mining districts, un-reclaimed mine lands continue to be a major cause of surface stream degradation through acid mine drainage (AMD). Reclamation of mines with a vigorous groundcover of grass and woody vegetation reduces to a very small percentage the proportion of annual rainfall that travels through underlying acidic rock to produce damaging AMD. In the journal article Revegetation of artificial grassland improve soil organic and inorganic carbon and water of abandoned mine, the authors wrote “results showed that artificial grassland markedly increased the biomass, canopy coverage and soil carbon content, but decreased soil bulk density and soil water content.”
But some of my enthusiasm for land restoration stems from avoiding our industry being implicated in damage to estuaries from excess nutrient losses. Despite aggressive study and regulation over several decades, the Chesapeake Bay, draining the central part of our region, still struggles to accomplish meaningful reduction in nutrients.
I firmly believe biosolids is a negligible part of the Chesapeake problem. Manure is a huge issue. Our region’s farms already have a mighty big job ahead to absorb in an environmentally responsible fashion the supply of nutrients available in the manure from animal production.
I used the 2012 Census of Agriculture to frame our biosolids challenges against that of manure production in the MABA region. The number of “animal units” of swine, cows and poultry (AU) in the 7 state MABA region (New York south through Virginia) is 8 million (an animal unit is 1000 pounds live weight). When expressed as AUs, the human “livestock” in the MABA region is 10 million, roughly equivalent. Using factors of manure production also available fromregional information sources, the average livestock AU puts out 3 tons of residuals annually, that is 24 million dry tons of manure in the region. But each human AU puts out only 0.15 tons annually, or 1.5 million dry tons of biosolids in the region. The difference in the proportion of organic residuals between animals and humans is striking, but it makes sense when you consider that humans are not being fed for maximum weight gain, and human excreta is highly treated before it is measured. The mass of organic matter, nitrogen and phosphorus coming from agriculturally-produced animals in the MABA region is easily an entire order of magnitude greater than the mass coming from humans (I invite readers to refine this calculation).
Tell me again, why do we biosolids managers want to play in the same box, farmlands, as the animal manure producers?
Let’s play instead with disturbed landscapes. In the mid-Atlantic region, some 400,000 acres of scarred, pollution-generating mine lands have existed for many generations. (By the way, I could not find a good source of acreage for this number, despite a website dedicated to this topic, and welcome help with this number). No economic engines nor regulatory or environmental programs are sufficiently compelling to cause significant changes to this number over the coming decades, because lands mined before 1977 are “grandfathered” out of requirements for restoration.
But we have resources in material and money to apply to these needy landscapes.
First, we have underused organic matter and nutrients. Nearly sixty million people live in the 7 state MABA region. Each produces a pound of recoverable food waste (wet) daily and a quarter pound (dry) of organic excreta. This is, say, 20,000 dry tons of organic matter daily within the region. If the target is to imbue degraded soils with 4% stable organic matter, 250 acres of lands could be recovered daily from these organic residuals.
Second, we have funds. The average cost today to collect, treat, transport and dispose of a dry ton of biosolids and food waste is on the order, roughly, of $400 per dry ton. Much of this money seems to be going currently to landfill disposal and incineration. In big numbers, our region’s populace is spending a grand total annually of $2,000,000,000 (yes, two billion dollars!) for organic matter disposal. So, why bury or burn this material if, for no additional money (maybe), you could use this material for land restoration?
Let me answer that, in part. The answer to this rhetorical question is the enormously steep slope that is the path to land restoration. Current regulations and utility operations are set up for disposal, and no economic or regulatory driver exists to change this current situation. The politics of large reclamation projects in the rural mine communities are a giant hurdle, as folks there have acclimated to the impacts of watershed impairment on landscapes and water, and do not see the opportunity for something new of benefit to them. Just as the global conversation about climate change and rising sea level has not moved the needle of society’s behavior significantly, how can you expect an easy path to deploying organic residuals for mine land restoration?
The wastewater profession could choose, I argue, to be take the lead in this project. We have the need for dependable long-range programs and we have the budget to drive programs. We have a natural alliance with the food waste collection firms to combine programs, as we provide an option to the nuisance and expense of landfill operations and the unreasonable enthusiasm and expense for anaerobic digesters. We can develop a customer relationship with mine operators, as we have capabilities to deliver a dependable, consistent quality material proven effective for land stabilization. We can draw on decades of successful projects to show communities, particularly the wildlife enthusiasts within them, the permanent environmental benefits of aquatic and terrestrial habitat restoration. This is a potentially quadruple win-win-win-win for wastewater agencies, solid waste collectors, outdoors-persons, and mine operators.
To make this happen, we need to overcome the major missing resource in this equation, a factor shared, sadly, with other worthy environmental challenges. That is visionary leadership.