Posts

Whatever happened to aiming for the best waste management option? 

If it’s easier to do, then it’s the thing to do.  If the job can be done faster by cutting corners, go for it.  If it’s the cheapest option, buy two.  Somewhere along the path of societal evolution, easiest-fastest-cheapest has become synonymous with best.  This linguistic transmogrification is so pervasive, society no longer takes notice of its shortsighted slide down a spiraling path toward all things inferior.

When did easiest-fastest-cheapest become synonyms for best? When did we stop aiming for the best waste management choices and settle for inferior? 

There are good, affordable options out there that can strengthen/support recycling mandates and result in better waste management systems.  But progress toward zero waste is s-l-o-w and too many communities are still stuck in their comfortable ruts.

Progressive leadership looks to the future, ever-steering its constituency toward that proverbial “brighter tomorrow.”  For waste management, that horizon does not include landfills or incinerators. But it does include high-rate industrial composting … if public and private facility owners aim for the best and not the cheapest.

What are the best options for biodegradable wastes, the best organics collection strategies, the best composting technologies, the best facility designs, the best uses for compost products – who asks these questions before plunging head first into a development project?

Or, if someone asks the questions, do they really mean what’s the cheapest technology, design, and collection strategy? 

As for the resulting compost product, is the real objective to put it to highest and best use or to get rid of the stuff as easy and as fast as possible?

‘Best use’ is hard to achieve with an inferior product

Stormwater management, erosion control, carbon sequestration, turfgrass management, landscaping – these rank among the best uses for compost products.

They represent markets that place high dollar value on stable, quality soil amendments with no odor, high organic matter content, macro and micro nutrients, and other characteristics linked to a high-performance product that can be safely used by anyone, anywhere, at any time.

Poor quality compost cannot meet this minimum standard.  For the most part, its sale and distribution is restricted to low-dollar markets like farming and landfill cover.

The catch here is that, when managing mixed organic wastes, it usually requires a combination of the best facility designs, composting technologies, and management protocols to produce a really good compost product.

To achieve top quality, keep product moving out the gate, and ensure the highest possible revenue stream, a facility owner must match those aspirations with a high-quality manufacturing process and competent management that includes a professional sales effort.

Shortsighted strategies won’t meet long-term goals

Many communities are waking up to the fact that their long-range plan needs to include a viable strategy for organic waste management that keeps biodegradable materials – especially, food waste – out of landfills and incinerators.

Composting certainly fits the bill, and it’s often possible to modify an existing yard waste windrow permit to include other organics.

But what happens a few years down the road when that one load of food waste per week turns into a load per day, and then two loads per day, and then 10 loads per day?

When the entire city is source-separating organics curbside, and the vast majority of those garbage trucks are headed for that crowded, outdoor windrow composting facility, what happens then? 

Historically, facility owners (public and private) can struggle through years of banned feedstocks, failed lab reports, public complaints, unsellable product, fines, and/or legal fees before finally facing the facts. Their antiquated composting system simply isn’t up to the challenge of today’s urban waste streams … and their bargain basement facility wasn’t such a bargain after all. 

Successful high-volume processing of urban streams that include highly putrescible materials and biodegradable plastics requires tight environmental control and a high-rate composting process. 

If a facility owner wants to process in the least amount of space, taking the least amount of time, using the most reliable, predictable process, then that owner is going to convert that lesser system to the best system for mixed urban organics.  A covered and/or encapsulated aerated static pile (ASP) system, preferably with computerized control/monitoring and biofiltration, meets those expectations.

But how much might that region or business have saved/earned by investing in an expandable, high-rate facility in the beginning?  Remember, we’re not just talking composting, but all the dollars saved associated with compost use, too.

While Nero fiddled, Rome burned

Fiddling about while the city buries itself under a mountain of garbage is not an example of good governance.  In the private sector, failing to invest in upgrades and new technologies sets a company up for obsolescence.

Both depict outcomes resulting from failure to act when the time is right.

Unlike even 10 or 15 years ago, when most people were clueless about the many benefits of organics recycling on a municipal/industrial scale, today’s taxpayers are aware of composting as a waste management strategy.

Large volume waste generators in the private sector have been using commercial composting services for decades for one reason only – it’s more cost-effective than landfills.  As a bonus, it also gives corporations green points to use in their marketing messages.

Is it right for governing boards to continue to expect taxpayers to pay more simply because those who made the decision failed to be proactive in their decision-making?

No single option will be right for every community.  But giving serious consideration to organics recycling is always the right thing to do.

Starting at the top and working down is a lot easier than trying to claw one’s way up from the bottom.  So, aim for the best solution first, even if it’s not the easiest, fastest, or cheapest option.  

Then, use easy-er, fast-er, cheap-er tweaks to mold that system into the perfect waste management approach, customized to meet the unique needs and expectations of each community or business. 

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.

True sustainability requires a system, not marketing-speak

Sticking a bird’s head on a spider does not transform that organism into a creature capable of flight.  Adding energy generation to incinerators and landfills doesn’t make them sustainable systems for organic waste management, either. 

“Sustainable” is one of those words that has been co-opted by Madison Avenue, slapped on everything from dog food to baby toys, and flung about willy-nilly like insults on nighttime reality TV.

It seems every product, process, and entity with even the smallest claim to the word uses it, because “sustainable” has finally caught the attention of the general public.

But the term, when applied to waste management choices, may be just as misleading as the words “natural” and “organic” on supermarket shelves.  What’s behind the label can still be the environmental equivalent of junk food. 

Admittedly,  people have become so adept at generating waste that the world has a never-ending supply have the stuff.  Ergo, any disposal or recycling technology could legitimately claim its feedstocks are sustainably sourced – even landfills without methane capture and plain, old incinerators.  

But that doesn’t make the total system sustainable or economically prudent or environmentally sound.

If pears are grown in compost in South America, shipped to Asia for processing, and transported back across an ocean to the U.S. for distribution and consumption, are those pears a sustainable choice?  

Using compost is better than not using compost.  But, c’mon, folks.  Did that pear earn the right to call itself sustainable?

Of course not.  Neither do disposal options that burn or bury compostables … even if they do result in energy generation.

Currently, only technologies that recycle or divert organics for use as a soil amendment (in farming, landscaping, turfgrass management, etc.) can claim true sustainability.  They close a loop, and when properly managed, do no environmental harm in the process.  

It remains to be seen whether some of the emerging re-uses for organic waste like building highways and formulating cleaning products will help or hurt the effort to recycle biodegradables back to the soil. 

Making new products from waste can be a swell idea.  But if those products can’t find their way to recycling at end-of-life, if the reclamation process renders them too toxic or otherwise inappropriate for composting, or if that reclamation generates a waste stream that cannot be efficiently returned to the soil, these types of reuse projects will likely – albeit indirectly – contribute to further soil depletion, more polluted runoff, increasing stormwater problems, and atmospheric carbon overload.

When government decision-makers are asked to evaluate new systems for organic waste management, marketing-speak has no place in a serious discussion.  One or two sustainable components does not make a sustainable system.

True sustainability cannot be conferred by feedstock source alone.   For organics, returning nutrients, organic matter, carbon, and beneficial microbes to the soil in an efficient, cost-effective manner makes composting and compost use a true sustainability choice – no marketing-speak required.

Lab test lingo:  How much is 1 PPM?

Test results — compost analytical reports included — often convey constituent concentrations in parts per million (ppm) or milligrams per liter (mg/L).  Both state the fraction of the tested substance found per one million units of gas, liquid, or solid.

But what does that really mean?  Is 1 PPM a drop in the bucket or a thimble of water in an ocean?

Such infinitesimal amounts can be difficult to visualize, but here are a few examples found on the web that may help:

PPM

PPB

Sometimes, even smaller concentrations may be reported as parts per billion or micrograms per liter (μg/L).  When you see this term, correlate to:

Know the limits

One of the best analogies is 1 ppm equals one large mouthful in a lifetime of eating.  But it must be said:  just a small bite of the wrong thing can be one bite too many.

That’s why it’s important to always correlate reported concentrations  with the limits deemed safe by regulators and other jurisdictional entities.  Typically, for easy comparison, these ceilings will be reported in an adjacent column on the lab report.

FAQ: Do I have to rake fall leaves?

Nature drops fall leaves for a reason, and it’s not to give sightseers an excuse to tour the countryside.  Those red, yellow, and gold gems will eventually decay to help fertilize the soil for the coming season.   So, no, leaf raking is not a necessity. 

Know, however, that the fall leaf drop can wreak havoc on stormwater systems.  One should, at the very least, make the effort to keep those leaves well away from stormwater inlets and  flow pathways.

Use a mulching mower to break up the leaf mat and accelerate biodegradation once that colorful blanket starts to fade.

If you can’t get through October or November without grabbing a rake, rough chop some of those leaves and use them to mulch planting beds and gardens.

The remainder can go to composting, of course.  Add them to your backyard compost pile, or prep them for curbside collection following your municipality’s guidelines.  And, please, do remove plastics, metal, glass, and other contaminants before moving those leaves to the curb. 

Estimating organic waste volumes for composting 

Imagine you’re the facilities manager for a large commercial building or institution, staring at a row of overflowing carts or roll-off boxes sidled up to the wall in the alley or back parking lot. 

They’re filled with crumpled paper, reams of old reports, food leftovers, used coffee pods, an avalanche of plastic bottles and aluminum cans, and pizza boxes with paper napkins stuck to the remnants of a variety of cheese toppings.    

You know all of those discards can be recycled and/or used as compost feedstocks.  Since most of that waste is compostable, diverting the organics from the landfill to composting could save money.   

The problem is, few composting operations will accept mixed waste loads.  The resulting compost is just too contaminated to use and winds up in the landfill anyway.  And if you want to develop an on-site composting project, knowing the volume/weight of compostables influences everything from sizing to siting to process selection. 

Source-separation – removing recyclables and compostables from the disposal stream at your location – is not as difficult as it sounds.  A good education program supported by a healthy dollop of (re)enforcement usually does the trick.   But before investing time, money, and brainpower in the project, you know the decision-makers will want to talk dollars and sense.  They’ll want assurances that the economics work.   

The first step is to determine how many pounds or tons of compostables are being generated each year.  Then, you can begin the planning process and start to gather cost estimates. 

Routes available for developing estimates all come with advantages and disadvantages, mostly related to things like people-power, total generation volumes and required degree of accuracy.  A web search will offer lots of ideas.  Here, we look at 3 broad categories: 

Route 1 – Develop estimates based on published norms and averages 

The easiest, fastest, and cheapest method to estimate compostable volumes is to glean “typicals” and “averages” from the web.   

The U.S. EPA says about 61% of the total MSW stream is made up of food, paper and cardboard, wood, and yard trimmings.  If your commercial or institutional stream is similar, this method could work for you.  Couple this percentage with known weight capacities of the specific receptacle in use, and the result is a baseline number you can use to calculate weekly or annual tonnage.   

Simply convert those gallons or cubic yards to pounds (based on container weight limits), divide by 2,000 to get tons, then multiply that number by .61 or 61%.  This is the estimated weight of all compostables. 

There are also sources that will provide weights based on generation rate per defined unit.  Example: 41 pounds MSW per week per household or 200 pounds per week for each fast food restaurant employee.  Again, convert pounds to tons and multiply that number by .61 for a rough estimate of compostable tonnage. 

Want to count bins or carts?  Contact your waste hauler for specific container sizes/weights or use a more generic number like 180 pounds for a 96gallon cart (from one online resource). 

Just focusing on food waste?  A cubic yard of food waste weighs about .5 tons. 

This method of estimating volumes for composting is probably best for low volume generators, because the total volume and weight of any “error” will be relatively small.  For everyone else, use this type of generic data for rough estimates only. 

You can find charts to help with weight estimates in our SlideShare title:  Estimating volumes of food waste and other organics for composting. 

Route 2  the DIY waste audit 

This method relies on statistically representative random sampling to develop a picture of the total waste stream.  There are several sample size calculators available online to help you get it right, and they come in handy for evaluating validity of other types of surveys, too. 

The following examples were calculated using the SurveyMonkey tool: 

Let’s say you counted a total of 40 trash cans in your office building.  Using a confidence level of 95% and a 5% margin of error, the calculator suggests a sample size of 37 trash cans. 

If you have a larger building with 400 trash cans, using the same confidence level and margin of error, the sample size is 197. 

Trying to pin down the generation volume of a city of 40,000?  The sample size is 381. 

Once you know how many units you need, identify a representative subset for sampling.  A human can do this, but to be totally unbiased in the choice of trash cans, let a computer randomize the list.  Using the 40-can building as an examplecreate a list of all trash can locations in a spreadsheet.  Then randomize the list Randomizing is easy … this site is just one of many with step-by-step instructions.   

Once the list is randomized, use locations 1-37 for your audit: 

  • Assemble supplies (gloves, aprons, scales, etc.) and identify helpers. 
  • Pull all 37 trash cans at the same time on the same day and move to your audit location. 
  • Provide training to any helpers who might not be able to distinguish compostable from non-compostable.
  • Separate can contents into those two piles.  If conducting a full waste stream audit, further subdivide the non-compostables into glass, metal, plastic, etc. 
  • Weigh the compostables pile and divide by 37 (sample size) to get an average weight per can.  Multiply that average by 40 cans (total building) for a daily average.  Multiply the daily average by the number of workdays per year to arrive at an annual weight and divide by 2,000 to convert pounds to tons. 
  • If you’re just doing compostables, you’re done.  Otherwise do the same calculations for each waste group you wish to audit. 

Advantages of this method are improved accuracy and the fact that audits can make good group projects.  But the audit is only as accurate as the volunteers, and auditor safety (masks, gloves, etc.) must be a top priority.  

Also consider, as an alternative to the internal DIY, the resources of a local university where a researcher, class or student may be looking for a project.  Some private companies and governmental entities also offer free audits.  Just make sure they understand the focus is compostables, not just the more traditional recyclables like plastic and glass. 

Route 3 – professional waste audits 

Sometimes, only a professional audit will do.  This will include sizeable and/or toxic waste streams where the expense of professional expertise is warranted.  Typically, these will be engineering firms and other specialists with experience in waste management. 

Professionals can charge by the hour or by the contract.  If taking this route, choose a reputable firm and make sure there is a clear set of deliverables, as well as a timeline, spelled out in the Scope of Work agreement. 

As might be expected, this option can require a healthy budget.  But on the plus side, using professionals can be more accurate than any other when estimating volumes for composting.  If composting costs less than landfilling in your region, the audit may well be a money-saver in the long-term. 

READ MORE: 

Good compost starts with a good recipe 

Whether making a small batch or a big one, following basic instructions will get composting done right. 

While baking relies on an external heat source to trigger a myriad of chemical reactions, and composting generates heat as a result of biological activity, both processes have a great deal in common – including the end result. 

Whether baking cupcakes or making compost, a quality product starts with quality ingredients added in the right amount, at the right time, and in the right order.   

Mess up even one step of the process, and the end product may never be right. 

Ingredients 

Adding a pinch of sugar and 2 cups of salt to a cake recipe (instead of the other way around) could become an inedible disappointment.   

Composting is no different.   

For the process to work as it should, the carbon to nitrogen ratio must be right (25-30:1 by total C and N content, not “brown and green” feedstock volumes) and moisture levels must be in the zone (40-60% by weight). 

Blending 

In baking, improper or incomplete mixing of ingredients can result in gooey or dry pockets within the finished treat.  Batches must be thoroughly blended to distribute ingredients evenly throughout the mixture. 

Goof up a compost blend, and the same thing happens.  Wet or dry pocketsmarbling, and other mixing mishaps mean microbes will not have equal exposure to target compounds, air, or moisture.   

This can create zones of uncomposted materials in an otherwise completed batch, failed laboratory tests, smelly finished product, etc.   

When blending, focus on achieving uniformity in moisture distribution, texture, and porosity. 

Processing 

Convection ovens, equipped with fans that move heated air during the baking process, have become a favored appliance for bakers who once struggled to achieve even baking in older, conventional models. 

But the latest and greatest in kitchen gadgets are no help if temperature settings are wrong.  Heat levels must still be correct to bake a cake or casserole to the center without drying or burning the edges. 

For composting, that zone is 113-160 degrees for initial composting and 70-113 degrees for curing.  The time it takes to complete each processing stage depends on the level of control applied … which is where those fans come to the fore. 

It is possible to compost (and do it well) without an automated aeration system – it just takes more time and trouble.  But it’s not possible to compost without any aeration.  

In nature, it doesn’t matter how long a pile of yard waste or a dead squirrel takes to decompose.  Sometimes, it can take years for nature to work its recycling magic. 

But most composting operations don’t have the luxury of unlimited time.  Speed and effectiveness of the process impacts everything from acreage requirements to the cost of operations.  Managing air flow through the composting mass must be a top priority for any municipal or commercial composting facility that needs to meet both throughput and budget targets. 

Here’s why: 

Remember that 70-160-degree temperature range?  Two types of composting microbes live and work within those zones.  Mesophiles are most active at the lower temps, while thermophiles dominate the higher levels where microbial activity and the resulting biodegradation is quite robust. 

Air flow is the primary mechanism for temperature control within the composting mass.  If temps are allowed to exceed 160 degrees F, thermophiles die off, the entire process crashes, and heat (generated by biological activity) must rebuild to productive levels. 

Every “crash” slows the process.  It’s like opening the oven door every five minutes to check the rise of a souffle — does more harm than good. 

But by using fans to move air through the composting mass, temperatures can be controlled.  More air cools the pile; less air allows warming.  By using sensors linked to microprocessors to automatically adjust those fans to meet specific time/temperature goals, a composting batch can meet regulatory requirements for pathogen kill in a matter of days instead of weeks or months.   

Of course, a manual probe will work, as well, if the budget allows for a person to walk around all day monitoring pile temperatures and making the necessary fan adjustments. 

Cooling/curing 

Food is rarely at its best when consumed straight from the oven.  Most dishes require a cooling/resting period prior to consumption, allowing sauces to thicken, juices to be absorbed and starch retrogradation to “happen.   

Compost, while it can be used fresh once PFRP/VAR requirements are met, is best when allowed to cooltoo. 

This is compost’s curing phase, when temperatures drop into the lower, slower zones preferred by the mesophilic organisms that will finish off the last of the food and bring the composting mass to a stabilized state. 

Farmers may prefer an immature compost because it can offer a slightly higher nutrient value than a more mature product.  But fair warning:  Use a compost before it’s fully cured only when destined for agriculture or other application away from sensitive noses.  Otherwise, wait until the pile offers only the sweet smell of rich, fertile soil before distribution.   

Depending on the initial feedstocks and technology used, the curing phase can last anywhere from a few weeks to several months.  Technologies used during curing can range from controlled aeration to occasional turning of a windrow to static pile. 

What is composting and how does it work? 

Composting is the managed degradation of plant and animal matter under aerobic (with air) conditions.  The process mimics natural decay in a controlled environment to speed up the breakdown of these organics. Composting results in a safe and easy-to-use soil amendment — compost.

Insects and bacteria are examples of the types of creatures that feed on discards like food waste and leaves during composting.  The larger animals tend to use mechanical methods, while the microscopic rely on chemicals to degrade these materials.

This feeding activity reduces complex compounds into simple molecules that are benign and odor free. Compost is used to build and replenish soils, closing the recycling loop for organic matter.  

The only byproducts of composting are CO2 and water;  the process produces no waste requiring disposal.  The CO2 is considered “carbon neutral” since its release during composting is the same as if decomposed by nature.

Most municipal, commercial, and non-profit composting facilities rely on microbes to do the bulk of the organic decomposition.  There are mancomposting methods in use, although outdoor windrows are among the most common.  Earthworms are the primary agents of decomposition in the controlled process known as vermicomposting. 

However, some other processes that have the word “composting” attached to their name in the vernacular may not be true composting processes.

Bokashi composting, for example, is an anaerobic (without air) fermentation process. Anaerobic composting is another misnomer.  Because neither is aerobic, neither is true composting.   Both can biodegrade organics, however.  Unfortunately, anaerobic decomposition may generate unpleasant odors since anaerobes produce mercaptan during biodegradation. (Mercaptan is added to odorless natural gas to give the gas its distinctive rotten egg smell.)   

Composting digestate, the by-product of energy extraction using anaerobic digestion, increases both the market value and uses for this waste material if managed for quality compost production.  

While neglected composting piles have been known to “go anaerobic,” too, a well-managed composting process — one that keeps the piles aerated — will not generate unpleasant odors.  Any odors present in the incoming feedstocks will be quickly neutralized, too.

Food waste collection: Thinking outside the trash can

Food waste collection can be a major hurdle for communities hoping to recycle curbside.  But might the real problem be not the what, but the how?  Is it time to think outside the trash can?

Let’s ponder this a minute.   

Waste 360 recently spotlighted grassroots recycling as a viable alternative to mainstream systems.  The article pointed out the actions of municipalities that, years ago, may have been too eager to turn successful, local recycling efforts over to “big waste haulers.”

The entrepreneurial efforts and business models of food waste collection outfits like CompostNowNOPE, and Compost Cab seem to be working in their respective service regions.  Instead of disrupting existing “Trash Day” collection systems and practices to include source-segregated food waste, these types of operations bypass the big trash truck with a service built on local-centric collection models that are meeting with success in multiple jurisdictions.   

Commercial composters, both large and small, have already demonstrated profitability in providing direct services to high- and low-volume waste generators, too. This success certainly proves that bypassing conventional collection systems is viable.

Looking at the world’s most successful bottle/container bills, we see return and recovery systems totally divorced from trash collection with capture rates approaching 100 percent.  While bottlers and other manufacturers of containerized products have been known to fight these types of programs, deposit and return systems do work. And they appear to work best when deposit amounts encourage those returns.

So, as the U.S. scrambles to rebuild and reshape its recycling infrastructure in the wake of the China debacle, could the long-abandoned local route to resource recovery of recyclables – residential food waste included – actually offer the better solution?  

Should food waste collection be a local thing?

Maybe, the decades-old struggle to integrate recycling within a system designed for mass disposal indicates the entire approach is flawed. Closely associating food waste, plastics, etcetera with trash as a first step to recovery means recyclables must be rescued from the waste stream before recovery can take place. Is this logical?  Is it efficient?  

Adding methane capture systems to landfills in an attempt to neutralize the damaging impacts of anaerobically-degrading organics just adds complications and expense for managing a material that shouldn’t be landfilled.  Similarly, for plastics and other recyclables, the better solution may lie in diversion at the source, not the transfer station.

Minus putrescibles/recyclables,  curbside collection of the real trash might be reduced to once a month (or less).  This disposal stream would be much, much smaller than current volumes … and clean.   With lower fill rates, existing landfills should last longer and cost less to manage, too.

When recyclables are funneled through and filtered by trash systems, does it make diversion more difficult than it needs to be?   Have we been going about recycling all wrong?

What are your ideas for getting recycling right?

Attract professional composters to your city’s waste management table 

Composting high volumes of source-separated organics (SSO) is not for the faint of heart.  It takes skill, experience, and science to recycle one of the messiest urban waste streams.  But while composting done right doesn’t come cheap, it is possible to build modern composting infrastructure without public financing. 

Instead of bemoaning a lack of composting infrastructure and doing nothing about it, municipalities and regional authorities can set the stage for organics diversion.   

The result?  Some of the biggest and most experienced composting companies will compete for that business. This delivers a big win for the host community: 

  • No well-intentioned but flawed “solutions” from designers and technology providers with no knowledge of biochemistry and no hands-on experience in the day-to-day operation of industrial composting facilities.  
  • No major issues with regulatory permitting when other facilities of the same type are running successfully elsewhere. 
  • … and here’s the biggie – no public financing required if the population base within 40-60 miles is large enough and the local landfill tipping fees are at or above national averages.  A community/region of around 50,000 could generate a sufficient volume of organic waste to make commercial, high-rate composting economically viable.  (View: Estimating volumes for composting) Private ownership means private financing.  Public/private ownership can also result in private financing if the public entity brings enough to the table to make joint ownership attractive to the private entity.   

But what about – 

  • Facility failure?  Structure the contract to include an option for public takeover should the owner fail to make a success of the project.  
  • Odors?  No matter the technology choice, most climates will require an indoor operation with a good biofiltration system — combined with preventive/preemptive management practices — to solve the odor problems associated with composting putrescibles.  Consider containment, collection, and treatment of air from all active work zones — off-loading to curing.  Typically, if the product has been properly composted and cured, it can be stored outdoors.  However, to preserve product quality, some manufacturers may opt for covered storage here, as well. 
  • Leachate?  Correct blending and indoor processing all but eliminate leachate as a management headache.  But do require RFP respondents to address the issue in their respective proposals. 
  • Product stockpiles?  Make sure the successful respondent has a proven track record in marketing compost in similar markets.  Just remember the sale of soil products tends to be seasonal.  Suitable acreage for large stockpiles must be included in the site plan.  Those stockpiles should dwindle significantly during the planting season(s).  But as a safety net, require a provision for distribution of volumes exceeding market demand after a reasonable market development period. 

Foster and promote compost use 

Composting is efficient, cost-effective, and the only technology offering true sustainability for biodegradable waste.  Returning organic matter to the soil to complete the recycling loop is what makes composting and compost use a sustainable system.   

But policymakers tend to get so caught up in the diversion of organics that they neglect correlating mandates for compost use. 

Compost isn’t just for farmers.  A quality compost can be used by anyone, anywhere – even urban/suburban areas: 

  • Lawns, gardens, and greenspace 
  • Parks, sports fields, and other recreation areas
  • Roadside and rest stops
  • Utility easements and rights-of-way
  • Rainwater catchment zones and pathways 

Parallel to composting infrastructure development, craft internal and external guidelines, policies, and programs to encourage regionwide compost use.   This will not only help build a product market, but also reap financial benefits to the municipality in the form of reduced costs related to stormwater management, synthetic fertilizer use, etc.