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  • Wet, smelly results

    Hi all, I've had a read of the forum and I'm not clear on what the advice is in my situation - apologies if I've missed the answer on another post!

    We got our hotbin last autumn, and have struggled over the winter to get it up to the right temperature. We put in the container full of hot water to accelerate it, which worked until we accidentally punctured it with the themometer - oops! But it has been down below 20 degrees since Christmas.

    We opened up the bottom yesterday, and it is smelly, not compost-like at all and seems rotten.

    I think from reading we've made a few mistakes - too much wet waste and not enough dry bulking agent, plus the little hole at the top accidentally was closed for a while. We did put in a mesh of twigs in the bottom section, so while brown liquid is leaking out, I think there is quite a lot of air getting in there. I think we have a better idea of what to do to make it run properly.
    My question is: what do I do with the waste in it? Is it salvagable, or should I throw it all out and start again with new waste?

    I have attached a photo so you can see what it looks like.

    Many thanks

  • #2
    Hi Toppage,

    From your photograph it looks as though restricted airflow is the underlying cause of your HOTBIN operating consistently at the lower temperatures. Unfortunately there seems to be quite a few large pieces of torn corrugated cardboard which are creating impermeable layers in the unit.

    I would recommend that you empty your HOTBIN, salvage the material with a little reprocessing and restart it.

    Removing & Reworking Your HOTBIN’s Existing Contents
    • Empty the contents of your HOTBIN onto a ground sheet and removing the biggest pieces of the cardboard (I appreciate that this will be a labour intensive and messy job however, without it, unfortunately these problems are likely to be ongoing)
    • Add 3 large handfuls of bulking agent into the removed material and distributing it evenly through the material. This will ensure that sufficient air pockets are created within the waste to keep the bacteria oxygenated and operating optimally
    • Add 4 handfuls of torn up cardboard (<4cm pieces if possible) or shredded paper and distribute it evenly through the material
    • Next add in some fresh waste and mix this in with the removed material. If you have some ‘easy to digest’ waste such as vegetable peelings which you could add, these would be great addition as they should be digested quickly and help raise the internal temperature. With this new material, we would advise adding in the recommended ratios of both bulking agent and torn cardboard pieces

    The reason for this suggestion is that the removed material will, in its existing form offer a low nutritional value to the hot composting bacteria as the ‘easy to digest - fast food’ element of the waste has already been removed by bacteria during the initial part of the decomposition process. When fresh waste is incorporated within the older material, the bacteria will move through the material to reach the fresh waste and as a result of them digesting the waste will generate heat which in turn will further decompose the older material.
    • Allow the material to ‘air dry’ for a couple of hours until the excess moisture has been evaporated and the material just looks moist rather than saturated

    NB. Going forward I would strongly recommend that you tear/roughly cut cardboard into smallish (<4cm) pieces to meet the recommended ratio of paper/cardboard. To prevent your HOTBIN from developing operational difficulties, I would advise against adding in large ‘sheets’ of cardboard going forward as these would likely restrict airflow again.

    HOTBIN Checks prior to refilling

    With the HOTBIN empty, check the aeration holes in the base plate at the bottom of the unit have not become blocked. If they look to be filled with sediment, I would recommend giving the base plate a wash with the hose.

    Double check your HOTBIN's valve setting - it only needs to be opened by 2mm from the closed position. At this setting the valve should look barely open; if you turn to look at the HOTBIN side on, the valve should look almost horizontal with the top, flat surface parallel to the sky.

    Another reference point to use to confirm the valve is in the correct position is to align the series of small nodules around the centre of the valve with the front of the valve recess like you can see in the photograph below.

    I've included a photograph showing the ‘ideal’ valve setting below which I hope will help as a visual reference.

    Click image for larger version

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    Restarting your HOTBIN
    • To restart your HOTBIN, scatter a handful of bulking agent onto the internal base plate before reintroducing your waste
    • Return the material from the ground sheet back into the HOTBIN and close the lid
    • You may also wish to use the kick start bottle to give the bacteria an initial temperature boost and encourage them to accelerate the release of heat

    Once the material has been added back into the HOTBIN along with the kick start bottle, don’t open the lid for 48 hours – give it time for the bacteria to get to work and increase the internal temperature.

    Continue to add some fresh waste, shredded paper and/or torn corrugated cardboard and bulking agent into the HOTBIN every couple of days and keep an eye on the HOTBIN's internal temperature.

    As long as the height of material in the HOTBIN exceeds 40cm (roughly the top of the hatch height), you should be able to get your HOTBIN back up to hot composting temperatures in a couple of weeks.

    I hope that helps.


    • #3
      Thank you! That is so helpful. Yes, I think we've been doing a fair few things wrong as you've outlined. Must be more careful to get the cardboard into tiny pieces and shred the paper. I'll get going on following your instructions at the weekend, fingers crossed can get it going properly by being much more dilligent! Many thanks.


      • #4
        You're welcome! I hope that helps.

        Please let us know how you get on..

        If you have any other questions, please post them, I'm sure together the HOTBIN forum community can help answer them.