Sunday, October 25, 2015

Anaerobic Digestion vs Composting - Which Is Best? A Westerners' Opinion*

This article has been created to answer the question Anaerobic Digestion vs Composting, which is best?

As videos are so popular now, we also created a video which has the same text as this article. If you prefer to watch a video, you are welcome to watch the video below. 

This question is often asked by people who are interested in what their rates (local taxes for household waste collection and disposal) are being spent on, and whether there are better options.

These people often live in a district where they have known that their green garden waste is being sent to a composting facility, or it is proposed that in future it will be sent to one. They may also have heard that this type of waste can also be sent to an anaerobic digestion (AD) plant.

Either method is better than sending this waste to a landfill, but which of these two alternative methods is really best?

* "A Westerner's Opinion"; refers to the fact that what circumstances vary so much in the developing nations that what may be "best" in the developed west may not necessarily be best in the developing nations.

Anaerobic Digestion vs Composting - Our Opinion

In such circumstances, lower initial capital investment needed to start a composting facility than is needed for an AD Plant, but spending that money provides a facility which is much more environmentally sustainable.

The reason that anaerobic digestion is much more environmentally sustainable is due to the fact that it creates a form of renewable energy that is extremely valuable. and it does so with the smallest carbon emissions possible.

That energy is produced in the biogas output, but in addition, just like composting the AD process also produces a fertiliser and that fertiliser is as good or better than that produced by composting.
In fact, the fibrous output from a green waste AD plant still needs to be "composted" after it has passed through the anaerobic digestion process, if it is to be used as a high quality organic compost for improved crop growth.

Many people consider that composting is not environmentally friendly because it consumes a lot of fossil fuel, to make it. This is for its transportation and for energy used during the composting process to turn it over regularly and then after it has matured, to sieve it and remove the large particles.
So to conclude, the common view is usually that, anaerobic digestion is best, but if it cannot be done for any reason, composting is the second best.

In fact, a good strategy for a community seeking to become more environmentally sustainable, may be to start by building a composting facilty, and then add an anaerobic digestion plant to the facility later.

We found some other articles on this subject, which you might find interesting, below:

Several states and major metro areas recently implemented bans on food Anaerobic Digestion Benefits With rapid population growth and industrialization, the amount of organic waste we produce has greatly increased. Organic waste is produced in many forms like food waste, human and animal waste, and agricultural waste. Organic waste is not actually a 'waste' if handled properly. ... Kitchen waste may contain non-organic material like plastic-packaging, which cannot be digested or composted. Human and animal fecal waste; Agricultural waste: It ... Credits: Organic Waste Recycling by Anaerobic Digestion - Energy Recyclers

Anaerobic digestion can be used to prevent waste going to landfills and, instead, indicated sending the discarded food to composting or anaerobic digestion operations. Wasted food is typically an excellent source of energy in an ... only simple pre-screening often make their way into wet digesters. One such scenario could involve screened and pulped waste collected from a university kitchen or a grocery store's prepared foods kitchenCredits: Containing Food Waste Contamination Essential for Anaerobic ...

This portable anaerobic digestion system can accept a wide variety of organic waste materials, ranging from kitchen scraps and yard waste to paper products, and generate both liquid fertilizer and energy in the form of biogas ... Credits: This HORSE converts food waste into fertilizer and energy ...

That is our view of anaerobic digestion vs composting, if you think differently, or agree, we would welcome your comments below.

Anaerobic Digestion Community Website