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The Advantages and Disadvantages of Anaerobic Digestion vs Composting

Image illustrates the benefits of Anaerobic digestion vs composting: Making a Comparison. Anaerobic digestion pros and cons.

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What are the advantages and disadvantages of anaerobic digestion vs composting is a question asked by a large number of people. Many of our readers who are familiar with composting, but who are thinking more widely about the subject of recycling organic waste and have just heard about Anaerobic Digestion want to know the anaerobic digestion pros and cons.

If this is you, read on while we answer the question: “Which is best, anaerobic digestion, or the much simpler and lower capital cost method of composting?”

First of all the two processes are very much the same. The crucial difference is that composting is the decomposition of organic matter in the presence of air (oxygen) and anaerobic digestion (AD) is the decomposition of organic matter, without air (and most importantly oxygen) present.

Now we make the case for each process by listing the advantages and disadvantages of anaerobic digestion vs composting below:

Advantages of Anaerobic Digestion

  1. It is a net energy producing process which produces renewable energy in the form of biogas.
  2. It produces a liquid and a fibrous fertilizer.
  3. It sanitizes the feedstock/ waste which is put through it, as long as the temperature is held above a required temperature for a pre-defined time period.
  4. It reduces odour below unprocessed waste odour levels.
  5. It is much less likely to cause environmental pollution than spreading untreated organic waste on land.
  6. The effect of the fertilizer is longer lasting than for untreated organic waste.

Disadvantages of Anaerobic Digestion

  1. When carried out at a commercial scale on farms and at wastewater treatment works (WwTWs) it requires a high level of investment in large tanks and other process vessels.
  2. If run inefficiently AD can cause an odour nuisance.

Advantages of Composting

  1. Lower initial capital investment needed to start of composting facility than is needed for an AD Plant.
  2. A slightly lower level of training is needed to run a composting plant the is required for an AD Plant.
  3. It produces a solid output/ fertilizer only. For some this will be an advantage, but in general this digestate product is a neutral factor, neither positive or negative for composting.
  4. It has the same advantages as for AD (items 3 to 6 inclusive) over spreading untreated organic waste material on land.

Disadvantages of Composting

  1. Like anaerobic digestion, it is necessary to pasteurize the composted material to ensure that all infectious agents have been effectively removed. This requires very good operating practice and detailed monitoring to demonstrate to regulating bodies.
  2. This is the biggest disadvantage! Composting requires the input of quite large energy inputs to aerate and turn the compost piles. By comparison anaerobic digestion wins hands-down for “greenness”, and it makes no contribution to reducing the carbon footprints of businesses that use the composting process. By comparison AD Plants can assist businesses by reducing their carbon footprint.
  3. Like AD, if run inefficiently Composting can cause an odour nuisance.

We also found the following blog articles which discuss anaerobic digestion vs composting as follows, which you might find interesting to read:

Anaerobic Digestion – an Alternative to Composting (Ground To Ground Blog)

Similar to composting, in AD bacteria consume organic waste such as food scraps, silage, and animal waste and generate an environmentally benign byproduct that can be used as a natural fertilizer. Unlike composting, however, AD also produces biogas, which consists of about 2/3 methane (CH4). Natural gas is methane with a small amount of other trace gases, so biogas can be used as fuel like natural gas. … via.ADAlternativeToComposting

What’s the Difference Between Anaerobic Digestion and Aerobic Decomposition

Yes, one is with and the other without oxygen, and both divert waste from the landfill—but in terms of the end products, what is the advantage of anaerobic digestion? Simply put, does society face a shortage of compost or renewable energy?

In San Francisco, the green compost bins are ubiquitous. Even the food trucks are required to place bins alongside their trucks for compost, recyclables, and trash. Result: the city is diverting an enormous amount of trash from the landfill to help meet its zero-waste goal and producing lots of compost in the process – a process which also produces a lot of carbon dioxide, “the primary greenhouse gas emitted through human activities,” according to the EPA.

A few cities are taking an alternative, more expensive approach to diverting this organic waste called anaerobic digestion and in the process also producing biomethane that is captured for use in electricity generation or used as a transportation fuel. And from a “carbon intensity” perspective, this biogas, also called renewable natural gas, scores at the bottom of carbon intensity chart for California’s Low Carbon Fuel Standard, i.e. it is one of the cleanest of all transportation fuels…. Pop Quiz Difference

Anaerobic Digestion vs Composting: Another Way to Compare the “Aerobic” Process of Composting with “Anaerobic” Digestion is to compare the simplified process diagrams which we show below:

Aerobic digestion - known as composting

Fig. 1 – Schematic Diagram Showing the Aerobic Digestion Process

Anaerobic digestion schematic

Fig. 2 – Schematic Diagram Showing the Anaerobic Digestion Process

(Source: Advanced Biological Treatment of Municipal Solid Waste, Defra UK, 2007)

Anaerobic Digestion vs Composting – Conclusion

There are advantages to both anaerobic digestion and composting, and certainly applying either before green garden waste, or other organic waste is spread on the land, is better than not processing these materials at all.

On balance the preferred process is anaerobic digestion.

The primary reason that anaerobic digestion is considered more sustainable than composting is that composting requires an energy input to carry out the process. The energy is used in the power needed to turn the compost piles during composting. The fact that anaerobic digestion produces biogas is a renewable energy source which burns cleanly, and that biogas plants make more energy than they consume to operate, is generally the factor that makes anaerobic digestion the best most sustainable option.

We hope that you found this article useful. If so, and you have a moment to do this. We would greatly appreciate your comments.

Advantages and Disadvantages of Anaerobic Digestion eBook cover

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Anaerobic Digestion vs Composting - Which is Best?

More at: Where we provide a full article on the Pros and Cons of Anaerobic Digestion vs Composting.

The main disadvantage of composting is the energy it requires to achieve a good compost product.

This video has been developed to respond to the concern raised by many people in deciding their views about Anaerobic Digestion versus Composting.

This question is often asked by people that have an interest in where their local tax obligations are being invested by their local rubbish (garbage) collection service.

These individuals typically reside in a district where they have understood that their eco-friendly garden and vegetable waste is being sent out to a composting facility.

Alternatively, it may be being recommended that in future it will be sent to one, or this sort of waste can instead be sent out to an anaerobic food digestion (AD) plant.

In such circumstances, lower initial capital expense needed to begin a composting site than is needed for an anaerobic digestion facility, yet investing that money provides an AD center which is a lot more ecologically sustainable.

The factor that anaerobic digestion is a lot more eco lasting than composting, is because of the fact that it develops a kind of renewable energy that is incredibly useful. and also it does so with the littlest carbon emissions possible.

That energy is made in the biogas the process produces, yet in addition, much like composting, the AD procedure likewise produces a fertiliser and that fertiliser is as excellent or far better one, compared to that generated by composting.

The fibrous result from an eco-friendly waste AD plant still needs to be "composted" after it has actually passed through the anaerobic food digestion procedure, if it is to be used as a high quality organic garden or park compost for boosted crop growth.

Many people consider that composting is not eco-friendly considering that it eats a great deal of non-renewable fuel source, to create it. This fuel is needed is for its transportation and for energy made use of throughout the composting process to turn it over a number of times while it is sitting in the compost pile and after that after it has actually developed, and also to screen it as well as remove the large bits.

So in conclusion, the usual opinion held by people who study this subject is typically that, anaerobic food digestion is most ideal, however if it could not be done for any kind of factor, in that case composting is the second best.

A good strategy for an area looking to end up being more eco-friendly, may be to begin by developing a composting site, and after that when more funds become available, to add an anaerobic digestion plant to the facility later.

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13 Responses to The Advantages and Disadvantages of Anaerobic Digestion vs Composting

  1. Dana Sundby October 23, 2016 at 9:31 pm #

    I liked your site a lot. I’m taking an online course on Water Quality Technology from the UW-Moraine Park and I found this very useful in helping me write a paper on alternate methods of sludge stabilization. Thanks.

    • Stephen Last January 28, 2017 at 10:34 pm #

      Thanks for your feedback. It is appreciated, and it is good to hear that you found some useful information for your paper.

  2. sami January 2, 2017 at 7:21 am #

    why aerobic degradation is faster than anaerobic degradation????????????

    • radimin October 7, 2017 at 11:51 pm #

      I think that the normally given answer the AD experts will give you is that the methanogenic archaea that do the anaerobic degradation, are a lot slower growing (metabolising) than their aerobic equivalents. I hope that helps you.

  3. Peter Ogrady January 28, 2017 at 2:36 am #

    The reason that aerobic degradation is faster than anaerobic degradation is that the anaerobic organisms (methanogens) that do the degrading in anaerobic systems are slow growing at normal ambient (atmospheric) temperatures. They grow faster at higher temperatures. If you look on the web you will see that in hot tropical climates it is much more common to see small domestic biogas plants. Those un-insulated tansk don’t work so well in cooler climates.

  4. daniyan elijah October 26, 2017 at 12:29 am #

    tanks alot it of great help to my project work

  5. brodie January 8, 2018 at 6:25 pm #

    Thank you for posting this great article. I’m a long time reader however I’ve never actually left a comment.
    I’ve bookmarked your site and shared this on Facebook.

    Thanks again for a quality article!

  6. Ben Moore April 25, 2018 at 6:00 am #

    Your writing is very well received by me. At first my view was to say that anaerobic digestion was not preferable to composting, now I see that you are telling us the opposite. The fertiliser is a much needed product for farmers I am sure.

  7. Alice Araujo May 8, 2018 at 12:02 am #

    The Advantages of Anaerobic Digestion are many. Thanks to Brazilian-German Project on energy from Biogas – PROBIOGAS (DKTI). In May 2016, a biogas project based on agricultural residues with a capacity of about 21 MW won an energy auction for the first time. The energy will be priced at EUR 70/MWh, and it will start producing electricity from 2021.

  8. Aly Chiman August 17, 2018 at 2:15 pm #

    Hello there,

    My name is Aly and I would like to know if you would have any interest to have your website here at promoted as a resource on our blog ?

    We are in the midst of updating our broken link resources to include current and up to date resources for our readers. Our resource links are manually approved allowing us to mark a link as a do-follow link as well.

    If you may be interested please in being included as a resource on our blog, please let me know.


  9. Hanno Halonen August 28, 2018 at 10:44 am #

    Hi. Thank you for the informative writing and article. Some people are using the heat generated from composting to heat water/interior spaces, so perhaps that could be added to the advances of composting.

  10. Baz November 17, 2018 at 10:15 pm #

    Hello there,

    Would like to know if you would have any interest to have your website here at promoted as a resource on our blog. If so mail me to the email I just used for this post.

    We are in the midst of updating our broken link resources to include current and up to date resources for our readers. Our resource links are manually approved.

    If you may be interested please in being included as a resource on our blog, please let me know.


    • radimin November 18, 2018 at 11:13 pm #

      Baz – Yes. I mailed you.

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