ASP composting – penny wise and dollar smart

There was a time in composting’s history when a method or technology based on anything more sophisticated than simple turning might have been considered risky and experimental.

A basic window operation was also cheap.  So choosing this low-tech option seemed like smart thing to do.  But that was long ago, and that penny wise start-up may now be a dollar foolish facility.

Nowadays, the outdoor windrow is composting’s equivalent of a pedal car trying to keep up on a highway populated with Teslas.

And as for the price tag, by the time the owner wastes an inordinate amount of time and money battling –

  • flies,
  • leachate,
  • failed lab tests,
  • equipment issues,
  • Mother Nature,
  • and a mountain of unsellable or low value product,

…that bare-bones facility doesn’t look like such a bargain.

Time-tested, proven technologies now exist that best the outdoor window in almost every production category, delivering rapid, predictable processing and high compost quality.  

Save time.  Save money.  Generate significant dollars from the sale of compost products.  What’s not to like about ASP composting? 

Yet, the majority of all composting operations in the US are still outdoor and low tech.  Nearly 60% are yard waste only facilities.  Not food waste and yard waste.  Not biosolids and yard waste.  Just yard waste.

They may have been cheap to build, but they’re not designed or equipped to handle the modern urban waste stream.  They’re not generating maximum revenues for their owners.  In short, those beleaguered owners are leaving money on the table.

When a region is not composting all of its organics (W/WTP sludge, FOG, food waste, yard waste, etc.) and professionally marketing a quality compost, it could be spending too much for multiple organic management and disposal systems, too.

To be at their most efficient and cost effective, public, private, and nonprofit operations can reduce costs and improve revenue generation by upgrading that tired, under-performing windrow system. 

And even if your windrow operation is chugging along without major headaches, it is possible to add more dollars to the bottom line while whittling away at operating costs.

Step 1 – Upgrade to ASP

Outdoor windrow composting is such a cheap and easy way to get started in the business.

But it’s only that – a start.

At some point, anyone who is serious about taking on a feedstock stream that includes high-moisture and/or highly-putrescible organics will want to consider a faster, more predictable technology for converting waste into a salable product.  And that often points to some sort of aerated static pile (ASP) system.

ASP composting is not one size fits all.  These systems can use fans to pull or push air through a compost pile.  Some might passively aerate by embedding perforated piping in the composting mass to improve air flow.

This natural or forced movement of air replaces the windrow turner.  Aeration speeds up biodegradation by keeping the microbes happy, creating and maintaining ideal oxygen and temperature levels within the composting environment.

When feedstocks are properly blended, ASP also ensures even degradation rates throughout the composting mass, making the process (including throughput rates) more predictable.

The same air movement also removes excess moisture, eliminating leachate issues, too.

Process control options range from manual to fully computerized temperature logging and aeration management.

Converting to ASP composting is one of those expansion activities that can be completed incrementally as time and budget permit.

Set up a test unit, tweak until everything is right for your operation, then build out the system.

Step 2 – Eliminate weather as a process influence

Unless you are operating in a perfect-for-composting climate, sooner or later you’ll want to put yourself in control of your process, not Mother Nature.

Yes, we are talking covers, enclosures, buildings, encapsulation … anything that will lessen weather’s influence over the process and the product.

The more control a manufacturer can have over the composting environment, the greater the potential for the production of top quality, high-value compost.

Make note of the fact that we used the word “potential,” because humans can manage to muck up just about anything.  In truth, most problems at composting operations of any type are the result of human failure, not design or technology issues.

Therefore, each preemptive design or operational choice that removes both weather and the human factor from any composting phase takes the entire process one step closer to reliable perfection.

This means stationary piping and fans beat a windrow turner, a building is better than open air, automated monitoring and airflow control is superior to manual thermometer readings and passive aeration.  

And as the processing environment becomes tighter and more secure, compost quality improves.  So does a manager’s ability to predict and control throughput.  Composting becomes a true manufacturing process.

Who should consider ASP?

These days, it’s possible to find aeration features on home composting units.  So it would seem composting projects of all sizes and descriptions can benefit from ASP augmentation.

From the 3-cubic-yard pile at the community garden to a 100,000 TPY super-sized facility, ASP could make sense for your operation if you want to –

  • Simplify the system,
  • Take the guesswork out of processing,
  • Reduce management time/labor costs,
  • Reduce equipment acquisition and maintenance costs,
  • Cut space requirements or process more in the same footprint,
  • Add biofiltration,
  • Minimize nuisance issues and complaints,
  • Improve compost quality, and/or
  • Improve environmental protection.

If a community project has a cadre of volunteers showing up every few days, turning shovels in hand, ASP could spoil all the fun.  But if the project coordinator finds him/herself standing there all alone on turning day, contemplating the purchase of a skid steer loader to help with the heavy lifting?  ASP could get the job done at a fraction of the cost.

An outdoor windrow operation may be able to accommodate a few small loads of food waste every week.  But what happens in a few years when that volume turns into several loads day, then several loads an hour?

And consider the “perfect” windrow composting site.  Years ago, it was sitting in the middle of nowhere surrounded by cows and cornfields.  But today, owners of those facilities may see the roofs of yet another new housing development peeking through the trees.

Like it or not, populations are growing and more folks now live in metro areas than rural.  Urbanites are spilling out into the countryside.

Why wait for the inevitable nuisance complaints to start rolling in when you can easily reduce the active footprint and increase vegetated perimeter buffers to keep your operation off your new neighbors’ radar?

Get yourself a kick-ASP system

With ASP composting comes serious control over the composting process.  The delivery of air to the composting mass makes it ideal for processing high-moisture feedstocks like food waste.

But there are many options that should be considered before settling on the specific elements of an ASP composting unit.

Because no single system is right for everyone, matching the system to the operation ensures those improvements will meet processing goals without overspending.

For a small, low throughput project, a good USCC workshop might be all that’s needed to set the owner on the path to success.  But for anything larger, a knowledgeable consultant or system designer could be a valuable member of the conversion team.

But a few words of caution:

In the early days of the composting industry, there were a handful of notorious examples of facility failures triggered by a lack of composting knowledge on the part of the design firm.

Composting is a biological process, and everything – including the engineering – must support the biology.  Do not engage a consultant or designer without a number of successful ASP composting projects under his or her belt. 

There’s an ASP composting system for every budget

Upgrading to ASP processing needn’t be an expensive proposition.  In fact, at $2000-$10,000 a pile, installing fans and piping could be one of the most cost-effective decisions you’ll ever make for your composting operation.

Converting will also dramatically reduce the size of the facility.  McGill estimates its plants can process 10 times the volume of an outdoor windrow operation within the same size footprint.

The numbers for your facility may vary, of course, depending on factors like the specific aeration technology and monitoring system, level of process containment, etc.

But with that extra space, an owner can intake more material, add an anaerobic digestion unit at the head of the plant, install a small solar farm, or simply expand its perimeter buffers.

It’s hard to find a downside to ASP composting systems.  They’re penny wise and dollar smart, the best choice for operations ready to take on the challenge of today’s urban organics.