Managing Composting Odours

Bacteria do not decompose complex sugars and cellulose straight to carbon dioxide, they break waste into smaller chemical compounds first. Many all these intermediate chemicals are 'volatile organic chemicals' (VOCs) and they have an odour.

The intermediate chemicals are very different when decomposition is via aerobic rather than anaerobic bacteria.

What is the BIO Filter made from?
The filter is a mixture of activated charcoal (to absorb cabbage odour (VOCs), zeolite (to absorb ammonia) and mature compost (to host bacteria that will consume VOCs and NH3 and prevent the filter overloading and ceasing to be effective.
What chemicals cause the putrid (anaerobic) odours?
The chemicals that produce the gut wrenching reaction are dimethly sulphide, dimethly disulphide(putrid), butyric acid (sour milk), valeic acid (vomit), fumic acid, acetic acid (vinegar), sulphur dioxide, hydrogen sulphide (rotten eggs). Anaerobic heaps also produce methane but this is odourless.
what do I do if my compost smells rotten?
If the compost in the HotBin starts to turn anaerobic, immediately stir in small pieces (not sheets) of corrugated cardboard (to absorb excess water) and wood chip bulking agent (to help re-aerate the heap).
Longer term, check the amount of bulking agent being added, check you are chopping waste small enough (<4 cm), and prevent any sheets materials (e.g. paper, biodegradable bags) getting into the bin.
The grass in my HOTBIN smells, why?
Large amounts of grass in a compost heap tend to produce a distinctive whiff of ammonia. This is created when excess nitrogen leaves the heap as ammonia gas. You'll notice this when composting large quantities of 1-2 day old grass. To prevent / remedy, mix in several hands full of shredded cardboard or paper.
For more advice visit 'How to compost grass'.
What chemicals cause the cabbage odour/smell?
The range of volatile organic chemicals (VOCs) includes alcohols, ketones, terpenes and aldehydes. These chemicals are "natural" and in low concentration form the basis of many plant fragrances, e.g. the sweet smell of pine/leylandi is a terpene, the orange fragrance is made up from a reputed 300 volatile chemicals. The HotBin bio-filter reduces most smells below noticeable levels.


14 October 2016  |  HOTBIN Composting

The majority of food caddy bags in circulation today are both biodegradable and compostable. Can these be added to the HOTBIN?

10 October 2016  |  HOTBIN Composting

How the HOTBIN charcoal filter bag works and why it should'nt be removed from the bin.

5 August 2015  |  HOTBIN Composting

Vermin and other pests are largely attracted to the HOTBIN because they can smell food waste around the bin. By keeping the HOTBIN and the surrounding area as clean as possible (for a compost bin) this can help in reducing the attraction of pests. There are a couple of considerations for your HOTBIN hygiene.

14 October 2014  |  HOTBIN Composting

All composting produces odorous chemicals. The ability for the human nose to detect them depends on the concentration in which they are released. This in turn depends on how much waste is decaying and at what rate (i.e. cold or hot composting) and other factors such as temperature, humidity and wind speed.

2 October 2014  |  HOTBIN Composting

Your caddy is a ‘mini’ compost heap. Eventually it will develop composting moulds (fungi) and bacteria on the walls.

1 October 2014  |  HOTBIN Composting

The HOTBIN is designed to work using aerobic bacteria i.e. bacteria that use oxygen to decompose the waste to carbon dioxide and water. When your bin goes anaerobic, all the oxygen has been used up and is not being replaced so the anaerobic bacteria (those that do not need oxygen) take over.

11 February 2014  |  HOTBIN Composting

If your compost is starting to smell, it may be turning anaerobic - you need to take action fast.

8 March 2013  |  HOTBIN Composting

During the decomposition process, complex sugars and cellulose are broken into smaller 'volatile organic chemicals' which have an odour.