Solid Waste & Recycling

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The Aerobic Landfill

Aerobic operation of a modern landfill offers a cost effective and environmentally sound opportunity to eliminate the liability of waste while sustaining resources.


Aerobic operation of a modern landfill offers a cost effective and environmentally sound opportunity to eliminate the liability of waste while sustaining resources.

Accelerated Biological Organics Processing (ABOP) is a quantum leap forward for the treatment, utilization, and the sustainability of organics. Aerobic processing is the Best Available Control Technology (BACT) for organics in a landfill or a source-separated organics digester, and shortens the leachate-contaminating lifespan of a landfill. Municipalities must decide between risking groundwater resources or not. The short cycle time (40 days) of ABOP makes it easy to define performance and convert detractors.

Systems old and new

The “aerobic” landfill systems of the early 1990s failed because the operations led to landfills catching on fire. By forcing air or oxygen into the wastemass air of “dry aerobic” landfills, aerobic processing occurred, but spontaneous combustion started fires (something that doesn’t go unnoticed).

Other waste conversion technologies can be expensive and controversial (e.g., waste-to-energy incinerators or gasifiers, and purpose-built anaerobic digestion plants).

Utilizing a landfill as a “wet” anaerobic digestion system is less expensive and very effective at degrading putrescibles with modern strategies.

To start with, a modern landfill liner represents a well designed and effective waste and water containment system. However, an anaerobic waste mass will outlast the competency of the liner system meant to contain it. (If someone tells you different, they likely have never built a landfill and dug into an anaerobic wastemass.)

Using a modern lined “cell” to process waste — rather than just store it — allows a landfill operator the chance to aerobically digest the organic portion of the wastemass. It makes sense to to digest the components of waste that foul water and kill organisms, wile preserving the  multimillion dollar containment “vessel.”

Wet aerobic digestion contradicts several principals that most compost experts hold dear. Windrows, forced aeration, and static piles fail to utilize much of the power of microbial processing. ABOP does a much better job harnessing the awesome power and flexibility of exponential biological growth. (See figure.)

Wet aerobic processing relies on water to move heat, nutrients, organisms, and processed materials within the wastemass. It also eliminates fires, methane emissions, and the majority of the long-term liability associated with leachate formation.

The science

The ABOP breakthrough is easily observed as massive aerobic digestion. Observations of the macro work of the 4.7 sextillion organisms that can be produced from a single organism in one day can be observed when it’s combined with the offspring of a sextillion other starter organisms.

These amazing numbers can’t be sustained without manipulation of conditions in the wastemass. ABOP aerobic digestion allows nature to reach a larger fraction of its potential — a stabilized level that hasn’t been achieved before. The organisms found in the wastemass are nurtured and evolve at amazing speed. A new, better acclimated-generation organism is “born” and doubles its population every 20 minutes (in theory). It might be ten minutes per generation in a million-tonne wastemass; the potential number of variables (and opportunities) is staggering.

Aerobic digestion relies on water to bring nutrients, new generations of microbes, and oxygen to the wastemass. The water also removes excessive heat, digested materials, and other constraints to the microbiology.

The organisms tear apart the wastemass by opening up the materials as they digest. Surface area increases as the organisms access the shrinking organic component. The exponential population growth and the associated digestion continue until the plateau of the system capability is achieved. Digestion reaches a stable level of biological activity that’s not achieved in nature.

Aerobic processing releases the energy of the organics in the form of heat and carbon dioxide. Methane emissions in the active phase of the landfill are aerobically eliminated. Natural and safe mesophilic bacteria already present in the feedstock are utilized to process the organic material to an inert state.

Leachate is processed aerobically onsite such that it can be utilized beneficially as “compost tea” discharged to surface water or groundwater. Most undesirable odors associated with anaerobic purification are eliminated (the feedstock stinks).

ABOP can also be used to process source-separated organics (SSO), where the lined system is far less expensive and safer than conventional composting. The evolved biology necessary to digest a landfill can also be utilized to attack toxic compounds from industry and municipal settings. Wet aerobic processing can assist in the remediation of contaminated materials and human and animal biosolids.

Richard Aho is Principal of EWS LLC in Marquette, Michigan. Contact Richard at raho@ewsview.com


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