Considering the pros and cons of waste management technologies?

Evaluations of waste management technologies can be riddled with inaccurate, incomplete, and outdated information – and the full dollar value of compost use is rarely included.

Elected officials making decisions on behalf of taxpayers may be experts in their respective fields.  But most lack knowledge in many areas specific to municipal governance, especially waste management technologies.  Consequently, staff and consultants are often asked to do some research and provide a report of findings, including recommendations.

A couple of articles released last month aimed a spotlight on inherent weaknesses in a process that relies on published research and interpretive reports for decision-making.

One piece focused on a study out of North Carolina State University.  It concluded the best use for compost was as landfill cover.  The other, from the University of Washington’s Dr. Sally Brown, said those research assumptions were off.  Many benefits of compost use weren’t considered.

No matter which viewpoint seems right to those who read the articles, the fact that there are two different takes on “best use” for compost – both from very reputable sources – focuses attention on one of the biggest struggles engineers and consultants face as they attempt to develop meaningful recommendations for policy-crafters and lawmakers.

A never-ending information stream floats about in cyberspace.  Available facts and bits of data are of sufficient quantity and quality to support almost any position one chooses to promulgate.  Adding or subtracting just one factoid in the mix of observations can result in a very different conclusion.

And the sad-but-true fact is that too many studies involving waste management systems fail to include the full range of economic and environmental benefits of composting.  Conspicuous by their absence are those elusive “dollars saved” numbers resulting from compost use.

Level playing fields for waste management technologies are hard to find  

Decisions related to organic waste management options present unique challenges.  Credible research comparing all four of the modern commercial technologies in the same study is rare.  Landfill gas-to-energy, thermal waste-to-energy, anaerobic digestion, and high-rate composting – finding a level playing field for technology comparisons feels like the impossible dream.

A researcher must wade through an ocean of irrelevant and often conflicting studies to find the few that fit the bill.  Volumes and types of materials may differ from one study to the next.  The specific parameters and amount of data collected won’t match up.  One report might focus on energy generation while skipping over input costs.  Others fail to include industrial composting and/or anaerobic digestion along with landfills and incineration or base conclusions on data that is now decades old.

Unfortunately, staff/consultants hired by municipal governments to gather information for these kinds of reports must rely on this mishmash of published data.  Rarely (if ever) does that consultant or in-house specialist have the budget to conduct new economic research comparing four different technologies at field scale using identical waste streams under real life conditions.

Hunting for needles in haystacks

A literature review may require the researcher to sort through a hodgepodge papers and websites to find information.  The hunt can include bench-scale studies, computer modeling outcomes, masters theses, field trials, magazine articles, and published budgets from public record projects. 

From this jumble comes the reviewer’s analysis, report of findings, and recommendations.  But proprietary information like construction and operating costs from privately-owned composting facilities is rarely available in the public arena.  As a result, a consultant’s report may not reflect an accurate picture of a technology’s true potential or the latest innovations.

In the real world, research scientists are limited by budgets, people power, time, personal knowledge, and the expectations of funders.  And while that may be the nature of the beast, the resulting scientific paper merely represents a snapshot of conditions and available data as they existed within the framework and specific timeline of the investigation – nothing more.

Scientists understand this.  But the elected officials using those study results to guide their decisions may not, taking those studies as gospel.  They don’t see inconsistencies or information gaps.  They don’t ask the right questions.

But if all of those studies ignored compost use, do any of their only-halfway-there conclusions really matter?

Getting waste management comparisons to the finish line

Just to see if it could be done, we took a stab at stitching together a balanced comparison of organics management options. Pulled the most recent data we could find from multiple studies.  Adjusted dollars for inflation.  Converted all energy input/output to a common unit of measure.  Cobbled together bits and pieces from a slew of research papers, municipal budgets, and other web resources.  

Tipping fee revenue was assumed for all technologies.  Commercial composting was compared instead of municipal operations because [1] we had a pretty good idea of the costs for building and operating a big, industrial composting plant and [2] many of the published costs we’ve seen over the years for municipal construction and/or operations for similarly-sized or smaller facilities were far higher than our own experience.

Based on a 100,000 TPY operation, annual revenue calculations included tipping fees and sale of products like energy and compost, minus debt amortization for facility construction (without interest) and operating costs per ton processed.

Admittedly, the resulting numbers were very, very crude.  But the grand total of those figures?  All options netted about the same dollars per ton.

Yeah.  We were surprised, too.  However, what none of the studies calculated – including our own investigation – were all the additional economic benefits to be had through compost use. 

Compost use tips the scale in favor of organics recycling

Sadly, the oversights of these reports were not unusual.  The full dollar value of compost use was missing from almost every published economic evaluation of waste management technologies for organics.  The absence of this highly relevant data represents a glaring hole in the big picture, one that can negatively impact an entire region for decades.

Mostly, these benefits represent dollars saved, which are much more difficult to identify and calculate than dollars spent.  But that doesn’t mean those dollar values should be ignored:

  • There is a dollar value for carbon sequestration through compost use.  
  • There are dollar savings in water treatment costs when runoff is cleaner because of compost’s filtration abilities.  
  • Construction projects save when they use compost-based controls for erosion.  
  • Turfgrass managers save when there is compost beneath players’ feet.  There is also a reduction in the severity of sports injuries … more avoided dollars.
  • When compost use is specified as part of a communitywide stormwater program, stormwater systems and their construction costs can shrink.  
  • During times when synthetic fertilizer costs are high, the NPK content of compost can represent a real bargain.  There are also avoided costs related to transatlantic shipping and synthetics’ reliance on natural gas.
  • Compost helps soil combat weeds and control some plant diseases, reducing chemical use on lawns and sports fields.

When a government body responsible for the general well-being of hundreds (or millions) of people is not provided with all the facts, their decision-making suffers.

Granted, it’s devilishly hard to assign dollar values to some of these benefits.  This article by Dr. Brown demonstrates how involved the calculation of even one aspect of compost’s advantages can be.

Yet, the greatest value of organics recycling comes not from composting, but from compost use.  Ignoring this fact serves no one and significantly undervalues composting as an option for mainstream waste management.

If a municipality wants to be assured of choosing the very best technology option for its organic waste stream, issuing agencies and departments will include those important “dollars saved” calculations on the list of deliverables required of their consultant or engineer.