TUHH Anaerobic MSW Process

Anaerobic Digestion of Municipal Solid Waste

Anaerobic Digestion of Municipal Solid Waste (MSW) refers to either:

  • the anaerobic digestion of “black bag or mixed waste” where no source separated or kerbside recycling is in-place. In which case the Dry Anaerobic Digestion” process can be used to reduce the organic activity of the waste, and generate some useful biogas, before it is landfilled.
  • the anaerobic digestion of the organic fraction of “source separated waste”, usually done in CSTR (Continuous Stirred-Tank Reactor) biogas plants.

Before the organic fraction of the waste can begin, the mixed waste requires the separation of the organic material (organic or biological fraction) from everything else.

Anaerobic Digestion of Municipal Solid Waste is carried-out in so-called “MBT” plants on the organic fraction of the residual waste (i.e.”black bags”) collected from households, and businesses on behalf of Municipal Solid Waste Management bodies (I.e. local authorities and businesses). In the developed nations a significant amount of food waste is present.
“MBT” plants, or “Mechanical Biological Treatment Plants” in full, are where the organic matter is separated from the other garbage.
Once that has been done the MBT plant is usually provided with its own biogas plant (Anaerobic Digestion (AD) Plant). Here we introduce the MBT Plant concept, and how MBT Plants improve recycling. Plus, help avoid greenhouse gas emissions by diverting organic waste away from landfill as required by the EU landfill Directive.
Image shows the options for anaerobic digestion of municipal solid waste. (TUHH Anaerobic MSW Process)
The decision flowchart above, illustrates the design options for the anaerobic digestion of municipal solid waste.
For many people, they have have a pretty fair understanding of what an incinerator is, and they visit their local Household Waste Recycling Centre (HWRC) quite regularly to dispose of their own waste items, so are reasonably knowledgeable about what happens there. But, would ask…

What is a Mechanical Biological Treatment Plant (MBT)?

It's a combination of a recycling plant, which in most instances, also carries out the anaerobic digestion of municipal solid waste (MWS). However, some Mechanical Biological Treatment Plants  (MBT Plants) simply compost the organic fraction so that the material can be considered to have been “processed”. This is done to make it a lower environment risk once it is inside the landfill.
When MBT plants are built with only aerobic composting this is a huge missed opportunity, because AD plants are capable of generating renewable energy (biogas). This renewable energy, when used instead of fossil fuels is highly beneficial to the planet. It reduces fossil fuels which when burnt emit carbon dioxide which in-turn is blamed as being a source of climate change, due to its greenhouse gas properties.
[box type=”alert”]Watch our video at the bottom of this page. We talk you through a flow chart – don’t expect a lot of pretty pictures![/box]

The Difference Between STWs MRFs and MBTS

Most people are able to grasp the concept of Waste Transfer Stations (WTS). The name says it all, as a WTS is simply where the small loads from the refuse trucks are made up into large “bulk” loads for cost effective transport to the landfill.

Using a WTS avoids having to transport the waste out to landfills over increasingly large distances.

It is worth pointing out that while an RCV is transporting waste, the waste collection operatives (bin) either sit in the cab and enjoy the ride, or need to wait for the RCV to return before resuming their bin collection round.

In the UK and Europe most WTSs have been extended to include sorting facilities for recycling, and are now called MRFs (Material Recycling Facilities).

But, there is little public knowledge of MBT.

The Difference Between a WTS a MRF and an MBT Plant

An MBT Plant is a WTS with not only added sorting equipment recycling for recycling, but also a biological treatment stage such as composting or anaerobic digestion.

The MBT is one of the waste management technologies which are being increasingly used by the local authority waste disposal contractors. By transferring the relatively small loads of waste in each Refuse Collection Vehicle (RCV) into much larger trucks, money can be saved.

MBT facilities are an extension of the task of a WTS. That means that there could be quite a lot of MBT facilities built, within the next 10 to 15 years.

“Many Mechanical Biological Treatment Plants are being wee built in the UK during the period 2000 – 2010”.

Also, here are quite a number in the EU states already, and the Germans and the Austrians are the leaders in introducing them.

In Germany there are about 50 MBT plants, which were built and operating (January 2008), and clearly the local people have no concerns about them, or at least, very few, objections.


MBT Plants are designed for maximum recycling, and usually include a composting and/or an Anaerobic Digestion stage.

They also are intended to make the quality of the much reduced quantity of waste, which is the remaining fraction of municipal solid waste (MSW) which cannot be re-used or recycled much less damaging when the residual quantity eventually arrives at the landfill.

An alternative to an MBT Plant is an incinerator.

MBT plants are much more popular with the general public than incinerators.

Green pressure groups argue that incinerators, once built, reduce the incentive for the staff to recycle. The more they burn in an incinerator the more electric power they can generate and the bigger the income to pay for the Incinerator.

In contrast to that, there is no question that a MRF or an MBT plant operator would not absolutely maximise re-use and recycling of the incoming materials. After all, the income for such plants comes from the sale of the recycled materials.

Does the Presence of an Incinerator Tend to Reduce Local Recycling?

The author of this article is not convinced that such an argument against incinerators, is a real one.

He considers it likely that, that incinerator operators re-use and recycle to the maximum in accordance with the requirements placed upon them. That means that if the community which the incinerator serves takes measures to ensure that contractually the incinerator operator must recycle to a set level, and checks are in-place. There is no problem. However, the local community/ Council Officers do need to inspect the incinerator records regularly. The intention must be to ensure that the recycling targets are being met the incinerator manager.

However, the public and environmental pressure groups don’t always see it that way.

In fairness to those people that run incinerators, though. Once built, they do need to pay-back their initial investment cost. Recycling rate targets are continuously being raised.

This can lead to older incinerators, having been designed for lower recycling rates than currently required, lacking the equipment to comply with the newer higher recycling rates. In such cases, those plants tend to act against raising recycling rates, until they reach end-of-life and are refurbished to cope with the new recycling rate requirements.

How Does a Biogas Plant Work?

Watch our video below to find out!


    • Jeremy Jordan
    • June 21, 2017

    Write more, thats all I have to say. Literally, it seems as though you relied on the video to make your point. You definitely know what youre talking about, why waste your intelligence on just posting videos to your site when you could be giving us something informative to read?

    • Phyllis Holmes
    • June 21, 2017

    Hi there! Would you mind if I share your blog with my myspace group? There’s a lot of folks that I think would really appreciate your content. Please let me know. Many thanks

      • biogasman
      • September 23, 2017

      Yes. No problem.

    • Govind Bhargav ji
    • September 19, 2017

    I discovered your blog web site on yahoo and checked some of your posts.

    The source separation of the digestible fraction of household waste and of other similar wastes from municipalities, prior to anaerobic digestion (AD) is a topic of increasing worldwide
    relevance, as nations seek sustainability in the management of their organic wastes.

    There is an interesting report at https://www.iea-biogas.net/files/daten-redaktion/download/Technical%20Brochures/source_separation_web.pdf

    Thank you Sir.

      • biogasman
      • September 23, 2017

      Hi! Govind. Thanks for the heads-up on that report. Looks like an interesting one.

    • David Helman
    • September 29, 2017

    Our Council want us to put our food waste in a separate container and put all this food in our green waste bin with our garden waste. Then they will only collect it once a fortnight. Is this reasonable? Is it hygienic. I doubt it very much. I am against the anaerobic digestion plant for this reason.

    • scarlet
    • September 29, 2017

    You should advise against the use of compostable plastic bags for municipal organic waste. “They are indistinguishable from other plastics and usually are not made from corn starch, some may not even be compsotable”. We recommend paper bags. The paper bag is what should be used, not so called compostable.

    • Tabitha
    • May 25, 2018

    Where is your evidence that the emission of carbon dioxide is a source of climate change? You guys just keep repeating this dumb idea without a shred of real evidence. when will you STOP. Listen to Trump, he knows.

    • Berry Alton
    • October 21, 2020

    Hi there to everyone. I am actually keen to be reading this, however, to move to more incineration is not the right way to go. Incineration destroys so much organic material when it should be recycled for sustainability, and carbon dioxide flows out of the chimney. Why not carbon capture that C)2 and use it. You must be able to sell CO2?

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