KEEPING THE HOTBIN HOT
My HOTBIN has Stalled – It won’t go above 40C any more
Here at HOTBIN we are passionate about our brand promise that given the right volume and mix of waste everyone can hot compost at 40-60C.
We do not have many customers who struggle, and normally a combination of our Q&A database, email support or our unique composting photographic analysis service get their HOTBIN composting on track.
You can imagine therefore we get a bit hot under the collar when we find a customer where everything seems perfect, they have been hot composting for a while, all the settings are right (valve, door on, etc) the mix is right and there is nothing obviously wrong and yet the HOTBIN suddenly sticks persistently at 30-40C and will not rise. We have termed this “a stalled HOTBIN”.
Who is affected by stalling?
Firstly this is not to be confused with customers who have never reached 60C (if this is the case, please check out the FAQ: How to get to 60C check list. Stalled HOTBINs are where it has been working perfectly for months at 40-60 then suddenly it will not rise above 40C.
This is not a common occurrence and there are only a handful of reported cases. A dedicated customer (Andy U) wrote in and suggested an adaptation to help and this kicked off a summer of activity and research.
Why does it happen?
We have identified one central issue: restricted airflow through the base layer. (Think of the HOTBIN as a fire in the chimney, you add new waste onto the fire to fuel it. As the heat rises is ‘draws’ fresh cold air in at the base. This air is drawn up through the base layer. If not enough air flows, the bacteria are restricted and hence the heat produced is restricted.
What causes restricted airflow?
The HOTBIN works under many different waste conditions. However, we have identified the causes that can tip the balance and create restricted airflow:
- Base plate is ‘plugged’ (see below)
- Ultra compressed base layer
- Dense, compressed, wet layer of either paper or grass
Top tips for fixing A stalled HOTBIN
Prevention is better than cure and we will come onto product developments later.
If you are suffering from a stalled HOTBIN, here are our tips for fixing it:
- Check to see if your base plate is ‘plugged’ (check this post to understand what we mean by plugged rather than normal operation where the holes are covered with compost).
- Sprinkle a 1 cm layer of wood chip on the base plate after each emptying to –reduce the chance of plugging.
- Empty out the base layer at least every 6 months. Longer and it will lead to ultra compression of the base layer.
- Always add bulking agent – this is critical with Food waste, but it will also help prevent compression of any waste
- If stalled, stir the top half of bin to help aerate and break up any dense layers.
- Check for thick layers especially in lower half bin. – eg a solid layer of wet grass or compressed wet paper.
- Check mesh plate for leakage of water/leachate. If lots of leachate cross check to see if your real issues is that your waste is “too wet” for hot composting
We are seeking ten volunteers to test an addition to HOTBIN that will significantly reduce the chance of “stalling”. Andy U suggested the core of this amendment to us after he adapted his own HOTBIN and it appeared to stall less often. We have now tested a modified version of his idea that we believe we can fit to all HOTBINs.
We are now ready to test this device. If you are interested in helping undertake this test, send an email to email@example.com with ‘test helper’ in the title. You really need to be a victim of a stalled bin right now or be prepared to proactively stall the bin under our direction. You will need to dig out your HOTBIN to fit the revision and we need you to be flexible and tweak and mess around for a few weeks!
So if that sounds like composting fun for you and you have the time to give it a go please email us.