Smallholder Composting: Can I Compost Alpaca Manure?
HOTBIN owner Clare has a smallholding with 50 chickens, 6 alpacas and is now about to open a cattery (www.clarescattery.co.uk). Following her success with her first two HOTBIN compost bins, she has asked us a number of “smelly based” questions over the past couple of months, the latest of which is HOTBIN’s ability to compost alpaca manure.
Clare asked us:
- Can I compost alpaca manure?
- Can I compost chicken poo with my food waste?
- Can I compost cat poo?
- Should I have separate compost bins for the alpaca, cat, and chicken/food waste?
Let’s begin with a cute picture of an alpaca before getting down and dirty with the issue of composting alpaca manure and other animal waste. Hopefully you are not feeling queasy and are ready to read on!
Can You Compost Alpaca Manure? (or Llama poo – its related cousin)?
The answer is yes. All animal poo (including dog and cat poo) can be composted. Clare has been successfully composting alpaca poo for 6 months in a HOTBIN compost bin. She reports just how easy it is: “The alpaca manure is largely free from any bedding additives, save for a bit of hay. I find that alpaca poo composts in no time at all, in fact many people say they use it neat, shall we say, as alpacas are ruminant animals and therefore poo is almost compost as it comes. However, I still prefer to compost it for a short while at least.”
Can I Compost Chicken Poo With My Food Waste?
Yes, chicken poo makes great compost fast. However the addition of bedding from chicken coops/houses can slow the composting process down so you may need to watch the amount of wood shavings added.
Different bedding materials compost at different rates: paper is the fastest followed by straw, sawdust and wood shavings. If you are using ‘pellet bedding’ – this can be either paper pulp or sawdust based. If you want to know more about the science of how lignin and surface area affect the speed of composing visit our woody material post.
Chicken poo is so fast to compost it acts as a compost accelerator and is more cost effective than commercial accelerators.
Can I Compost Cat Poo?
Yes, although many compost websites categorically say no to cat poo composting. There are however some health and safety issues to consider, but in our opinion with a correctly operating HOT home composting bin the risks are small. We do however broadly agree that adding cat poo to a cold compost heap should be avoided.
Should I Use Separate Compost Bins for Each Type of Waste?
We see no reason to separate the different wastes into different compost bins however the options below will give you some advice to make you own decision:
For a smallholder such as Clare we have two options to consider:
1) Separate the wastes into different HOTBIN’s, one each for food waste, alpaca manure, chicken poo and finally cat poo. This is essentially what Clare does now.
2) Mix all wastes together and fill the bins in rotation (e.g. bin 1-day 1; bin 2-day 3; bin 3-day 5; bin 4-day 7; bin 1-day 9 and so on).
We favour option 2 because it is easier to keep the temperature high (60C) with a mixture of wastes (soft, hard, green brown, etc). The easy to digest waste (e.g. alpaca manure and chicken poo) will help the harder waste (shavings and pellets) to rot down. There will also be less wood in one bin so it’s more likely each bin will compost at the same rate. You could set up a ‘square’ of four bins and ‘fill by rotation’, which would keep all the composting in one place and help reduce the heat loss as there will be less wall area exposed to wind chill cooling.
Method 1 would be better if you wanted separate compost, for example just “alpaca compost”. This option also suits separate locations – e.g. (for Clare) a bin by the cattery, chicken pen, alpaca field, and one near the kitchen door.
Whichever method is chosen keep an eye on the temperature and if they are not getting to 60C regularly then adjust the mix.
10 Interesting ALPACA FACTS
- The alpaca is a ruminant with three stomachs; it converts grass and hay to energy very efficiently, eating far less (as a percentage of its body weight) than other farm animals.
- Alpacas do not eat their afterbirths. Clare added 3 into the compost bin and they sent the temp dial spinning! No need to be squeamish about these things, it is what nature is giving us – thanks mother nature!
- Alpaca poo benefits from the addition of a bulking agent to improve its porosity. It is too heavy and dense to allow air to flow evenly through the mix.
- Raw (non composted) Alpaca manure is lower in organic matter (most of the plant cellulose id digested) than the manure from most other farmyard livestock (cows, horses, goats and sheep). Alpaca manure can generally be spread directly onto plants without burning them. Like all manure it is best to hot compost it as this reduces faecal pathogens and converts the organic matter to humic substances.
- The nitrogen and potassium content of alpaca dung is comparatively high, an indication of good fertilizer value. Nitrogen, phosphorus and potassium are the major plant nutrients. (They are the familiar N-P-K on fertilizer bags.
- South American Indians use the alpaca waste for fuel and local farmers apply alpaca’s droppings as a fertilizer when growing fruits and vegetables.
- A herd of alpacas consolidates its waste in one or two spots in the pasture, thereby controlling the spread of parasites, this also makes them popular pets and easy (ish) to housetrain (allegedly!).
- Alpacas originate from South America and have a life expectancy of around 20 years.
- Alpaca fibre lacks the roughness of some other types of wool, so is a popular material for making jumpers, socks, gloves and many other forms of clothing.
- The Alpaca is classified in the same animal group as Camelids, with Camels and Llamas as close family relatives.
Can I Compost…?
Got a question on what you can and can’t HOT compost? The HOTBIN composting team get all sorts of questions on what can be composted and how best to go about it – View our What Can I Compost Lists.
HOTBIN is diverting food waste
Waldringfield Community Composting scheme is successfully diverting food waste from landfill.
Last weekend we visited our friends at Waldringfield Community Composting to look at the results of the first 3 months of the HOTBIN use.
Everyone was keen to learn how much food waste the 12 households had actually diverted from landfill. The results are in and the weighing scales revealed: 5 Kg/week per household. (It was much higher in the B&B – but they have guests each week which accounted for the 10Kg/week.)
What a marvellous community composting effort.
How does this compare to other customers and the national picture?
Nationally the WRAP figures indicate that 5 Kgs per household per week is the average – I’m sure they will be happy to learn they are normal!
Our own HOTBIN customers survey is less rigorous in terms of weighing exact amounts, but it also indicates HOTBIN users divert around 3-6 Kg of food waste per week from landfill The main difference is between users who choose to really get stuck into what you can hot compost such as cooked food waste and chicken carcass etc. versus those that choose to only compost vegetable peelings.
What does all this mean? Does it make a difference?
If we take all the HOTBIN customers across the UK, the total diversion is still not that huge but as they say from little acorns….
There are 30 million households in the UK, if just 3% actively composted all food waste at home, that would remove 250,000 mt of waste from landfill. That also happens to be about the same amount of waste 10 major anaerobic digestion facilities to be built would process.
Clearly it works in our favour if more people have a HOTBIN but the figures speak for themselves!
What does this mean in terms of garden compost?
Each household is also composting garden waste. A total of 250-500 Kgs of starting material will give 75-150 Kgs of compost which is 5-10 bags of compost a year. That’s saving around £25-50 (maybe £10 more if we include car petrol) over buying from the garden centre.
Are there other benefits?
Yes. There are two huge, almost hidden, benefits of composting:
- More food waste results in more compost. More compost results in more humeric substances. More humeric substances means more fertile soil which means stronger plants and vegetables which in turn means more and better food.
- Humeric substances are ‘recalcitrant forms of carbon’ – they are resistant to further decay so they store carbon in the soil. Adding stable humeric substances to the soil results in carbon sequestration which off-sets the impact of global warming due to CO2.
What could be simpler, compost more!
Can I compost Horsetail (Mare’s Tail or Equisetum Arvense)?
Yes you can compost it. BUT!!
Problems will arise if the heap does not get above 40C – the seeds will survive cold composting and you will spread the seeds when the compost is used. A hot compost heap (40-60C) will kill the seeds.
However as this is such an invasive and tough weed, you need to check that the seeds/bits are only added to the top of a already hot pile, that they stay near the top (do not fork in or turn the pile/HOTBIN as seeds will fall down to cooler base). Finally, after hot composting, give your compost a ‘germination test’ – By this we mean leave the compost in an open maturation pile for a few months to check to ensure the Horsetail does not re-sprout. If it does, gently tease out all roots and rhizomes again and zap it through the hot compost again.
This may sound painstaking – but so will your efforts to remove it from soil in the first place. Are there any other options? Passing the waste on to your local authority to handle is not a great option. The seeds and bits can drop and disperse on roads and neighbours plots. If you are unsure, perhaps this is one case where it is better to burn the weeds (subject to local authority rules of course!).
- Horsetail or Mare’s Tail (Equisetum Arvense) is an invasive, deep-rooted perennial weed with fast-growing rhizomes (underground stems) that quickly send up dense stands of foliage that will spread quickly to form a dense carpet of foliage, crowding out less vigorous plants in beds and borders.
- Horsetail is easily recognised by its upright, fir tree-like shoots that appear in summer. In spring, fertile light brown stems, 20-50cm (10-20in) tall, appear with a cone-like spore producing structure at the end of the stems. In summer, sterile green shoots develop into fir tree-like plants, 60cm (2ft) tall.
- The creeping rhizomes of this pernicious plant may go down as deep as 2m (7ft) below the surface, making them hard to remove by digging out, especially if they invade a border. They often enter gardens by spreading underground from neighbouring properties or land.
You can also find more advice at: Garden Organic Website
Compost – What Should it Look Like? Looks can be deceptive!
Compost from you compost heap, compost bin and indeed your HOTBIN composter can vary an awful lot.
With many HOTBIN® composters coming up to their first autumn, there will be a lot of hot compost being taken out and used in the garden. We thought it would be good idea to let you know what to expect as ‘looks can be deceptive’!
To do this we will look at several batches of compost alongside some HOTBIN composts. Suggest how they might be graded based on common expert visual assessments. Then we will take you on a journey beyond the first look to give you some insight into compost stability and maturity tests (we’ve done them for you!), discuss what happens when you dry and sieve HOTBIN compost (don’t worry no-one is suggesting you need to do this) and finally do a bit of mud pie play to demonstrate a property called ‘colloidal behaviour’’. Finally we will tie these properties back to humeric substances and suggest that what you really need to look for in fabulous compost is high humeric substance content.
This blog is a little more scientific in nature than some of our others – so if you want the headline without the science it is this:
What a compost looks like can be deceptive. HOTBIN compost is often very sticky and very moist/wet and looks lumpy and perhaps even needing further composting. Tests show rather than it being ‘poorly’ composted, quite the reverse – it appears to have a very high humeric substance content and this is good news for your soil and plants – humeric substance is known as ‘black gold’ for a reason!
If your compost looks like (Fig 4&5), or even (Fig 6) below it is OK to dig in to your soil and does not need ‘more composting’. If you only want ‘fine’ particles of compost e.g. looking like (Fig 1) or (Fig 2) – the solution is fairly simple – dry your compost and then sieve it – you will surprised by how much fine material there is in HOTBIN Compost.
Our analysis tour includes;
1. Visual inspection
2. Carbon / nitrogen maturity test
3. Visual after drying and sieving
4. Pliability / colloidal behaviour
5. Humus test
6. Result to quality – is it fabulous?
1. Visual inspection – Below are 6 samples of compost
- (Fig2) Garden centre compost laid out dry
(Fig 3) Typical cold compost
- (Fig4) HotBin compost at 3 Months
(Fig5) HOTBIN compost that is it too wet
(Fig6) HOTBIN compost that has gone
anaerobicNow in our earlier blog (good, bad or fabulous compost) we outlined details on how different experts defined good compost. If we asked this group of experts to visually judge the samples above here is what we would expect:
(Fig1) Vermicompost – looks fine and rich, super
(Fig2) Garden centre compost laid out dry – looks very fine and free flowing, uniform and has probably been sieved
(Fig 3) Typical cold compost – looks mature, maybe 2 years old and as expected,
(Fig4) HotBin compost at 3 Months – looks ok, dark brown and a little lumpy
(Fig5) HOTBIN compost that is it too wet – looks water logged, lumpy, immature and soggy
(Fig6) HOTBIN compost that has gone anaerobic – definitely looks anaerobic, it’s black sludge not compost
2. Carbon / nitrogen maturity test
Industrial producers of compost (i.e. compost sold in garden centres) do a check to establish how active the bacteria are. Above a certain level and the compost is too active (i.e. not mature & stable) it needs to be left longer otherwise it can draw nitrogen from the soil as bacteria continue to use the carbon in the remaining compost. The maturity and stability test can be undertaken via the Solvita compost test method. You can do these at home, although it gets expensive!
Garden centre compost (Fig2) would not have gone on sale without passing the C/N maturity and stability tests. How did HOTBIN (Fig4&5) compare? Well they both fall in the stable and mature range. This will surprise a lot of experts as they look lumpy and lumpy normally means large pieces of non-composted material which is highly likely to result in an ‘active’ rather than stable result.
3. Visual after drying and sieving
We recently tested a range of compost sieves (see guide to compost sieves post). We know wet and sticky compost is a complete pain to sieve. When testing the Compostsifter it failed to sieve any of HOTBIN (Fig5). So we dried the compost and tried again. This reminded us of an old saying – ‘looks can be deceptive’. Below is the result of the sieving test.
HOTBIN compost sieved
The result was about 80% of all the compost went through the fine (8mm mesh) sieve. There is about 15% of wood chip pieces (0.8-1.5mm), and 5% oversize non-composted items (notably pampus grass roots – these are possibly going to take the record for the hardest most difficult material to compost – but that’s another blog!). I’d just like to say this sieve result is not a one off – we have seen it many times, same results.
If we visually compare the sieved HOTBIN compost with the sieved garden centre compost they now look very similar. So was the problem just that the HOTBIN sample has been stuck in the base and got wet? Is the difference just about one compost being very wet and another compost being dry? No!
4. Pliability / colloidal behaviour
When we sieve and handle HOTBIN compost we notice something else – it is very sticky. It rolls into balls in the sieves, when you grab a handful you can make a ball. It is ‘pliable’ just like a potter’s clay or children’s plasticine.
HOTBIN Vs Garden Centre on compost pliability
There are two common substances in soils and composts that create a pliable mix – clay and humeric compounds. Both these are ‘colloidal’ materials and it is this property and the resultant way they hold water that leads to the pliability.
We can take the pliability test a little further. If we make a ball of moist compost from Garden centre compost and HOTBIN compost (Fig5) and leave then to dry in the sun for 4 days. Now what happens when we try and squeeze each ball?
HOTBIN Vs Garden Centre – compost pliability after drying
The garden centre compost sample behaves more like peat – it sticks when wet, dries fast (i.e. looses water 2-4 times faster) and then the organic material falls apart when the dry ball is pressed. Whilst the HOTBIN sample is still damp and pliable, it forms a very hard solid outer layer material with soft inner. Even after 100% drying and re-wetting the pliability returns.
At this stage we should mention that HOTBIN composting (and certainly the batch of HotBin compost above ) had no soil added – hence the pliability is not believed to be due to soil clay.
5 Humus test
We think (and we mean ‘think’ because we have no laboratory proof) that it is possible that HOTBIN compost has more humeric substances than many other composts.
HOTBIN compost – Pliable humus
Can we test for humeric substances? The answer is yes but not easily outside a fully operational soil testing lab. There is a relatively simple humus soil test – targeted at measuring the concentration of humeric substances in soils. The HOTBIN samples are off the scale – but a note of caution – the test aims to give a reliable field test for soils with 0.5-6% humeric substances. It cannot be relied on for concentrations well above this.
6 Result to quality – is it fabulous?
We believe there is a real difference between compost and compost that contains very high amounts of humeric substances. Partly decomposed material (compost) will continue to decompose when added to the soil and eventually the carbon cycle completes and it is returned to carbon dioxide and a small amount of recalcitrant humus in the soil. Humeric substances do not decompose in the soil (to any great extent) so adding a concentrated form will improve your soil faster.
HOTBIN compost – drying out
As a company we are not into making claims about our products we can’t substantiate – to be clear – we believe we can explain the appearance and behaviour of HOTBIN compost. We believe we can trace (but not prove it yet!) this back to higher humeric substance content in HOTBIN compost. One day we will have the evidence – until then we believe our logic and science has merit, you can do your own testing, contribute to the debate or ignore our findings as just marketing waffle!
Worms and HOTBIN composting
A question we often get asked is; do I need to keep my Wormery now I have a HOTBIN?
The simple answer is no and the key benefit is that the HOTBIN can compost both food waste and garden waste. Therefore you can save space, reduce costs and still keep your food waste out of landfill.
So what is worm composting?
Worm composting is using worms to recycle food scraps and other organic material into a valuable soil amendment called vermicompost, or worm compost. Worms eat food scraps, which become compost as they pass through the worm’s body.
So what is HOTBIN composting?
The HotBin is a simple design that helps maximise what nature does by bringing together the right conditions to make hot composting easier. It does this by providing effective aeration between the bottom air inlet plate and the air outlet rotating valve, removing excess water through the valve as steam and allowing you to control the rate of heat loss. You can compost 100% of all domestic food waste in the HOTBIN without inherent problems with odour, vermin and flies. This includes left over meals, plate scrapings, meat, fish, small bones, bread, cakes, pasta and rice. Your food and garden waste will be turned into rich organic matter for the garden every 90 days.
Worms in the HOTBIN?
You do not need to add worms into the HotBin however you can – either directly by adding into the base layer (which is cooler) or inadvertently by adding worm eggs and worms into the bin via small bits of soil and old compost . Most of the worms and worm eggs will be killed by high temperatures (>45C) but a some will find there way down into the base layer and continue to work on the base layer compsot.
However, worms can be beneficial to composting and can be added if you want to. But a word of warning do not add them into the upper active layer (60°C will kill them) only add worms via the hatch panel where the compost will be cooler. Worms will help to decompose waste and leave mucus in the compost which is proving beneficial to soil fertility.
As the HOTBIN is no ordinary composting bin as you can use it to recycle than just vegetable kitchen waste in it. The hot temperatures achieved during hot composting make composting all food waste in the HOTBIN a safe home composting system that recycles a whole lot more than just potato peelings.
So if you were thinking about a Wormery as a form of recycling food waste why not consider a HOTBIN as it composts both your food and garden waste together.
Can I add Autumn LEAVES to compost in my HOTBIN
Leaves can go in the HOTBIN and they make great humus.
If you have a lot of leaves (>10 litres, a bucket load), you need to tweak the recipe to ensure they HOT compost.
If you only add thick layers of leaves into the HOTBIN, it is unlikely they will rise above 20-30C as the woody nature means they are hard for bacteria to digest and hence heat is released slowly.
To HOT compost autumn leaves, see the recipe below:
How to HOT Compost Autumn Leaves
There are two parts to successful composting of autumn leaves.
1) Adding a nitrogen source to balance the high carbon in leaves
2) Ensuring that there is enough ‘easy to digest’ waste (e.g. greens, food waste, shredded office paper’ (which creates heat quickly) to keep things hot whilst the hard to digest woody material (in which heat is released slowly) are also digested. In some cases solving (1) & usually solves (2).
Here’s what you need to do to ensure you get the best out of your HOTBIN
Step 1: Shred leaves
Leaves tend to form a dense matted layer that restricts air and oxygen flow within the HOTBIN. We advise shredding the leaves (e.g. using mower or a hedge trimmer).
Step 2: Mix leaves with easier to digest materials like food waste
Many people simply will not have enough food waste to mix with high volume autumn leaf fall. You can cheat a little by adding another easy to digest waste to go with the leaves such as chicken poo, chicken pellets, or a sprinkling of blood bone meal.
The ideal waste to mix with autumn leaves is grass lawn mowing – unfortunately, it is rare in UK to be able to get the mower out in Autumn as it is too wet and compacts the lawn soil. If you have room storing leaves in a wire frame box ready for spring and first grass cut can work really well . (Avoid sealing in black bags – the leaves will go anaerobic (see below for anaerobic method).
Step 3 – Do not add too many each time – little and often is best
More than 10cm (20 litres) of cold wet leaves in one go will “stall” the HOTBIN. The cold leaves will lower the temperature of the HOTBIN below 20°C and the heat production falls below that needed to re-heat. So store the leaves in a pop up bag, protected from rain and add over a couple of weeks – you’ll be amazed how fast they compost.
If you have a large garden with lots of trees and mounds of leaves then possibly doing a little bit each week in the HOTBIN is impractical. Try the following – shred the leaves (e.g. using lawn mower), store in a wire frame or cold compost heap until spring. Mix with first grass cuttings in large volume piles. Turn occasionally.
Leaf Mould Versus Composting
If you are collecting leaves into a wire frame then you might go down the route of just leaving them in the box and waiting 1-2 years for leaf mould.
Leaf mould versus ‘bagging’ i.e. anaerobic digestion
Many compost sites note that ‘bagging’ leaves in black plastic and tying off will create a black slime that can be used as compost. What this really means is you are anaerobically digesting the leaves down to compost. To an extent this is ok, our point would be AD creates methane and you are releasing a GHG that is 24 times more harmful than CO2. And we hope you would agree that every little bit avoided helps.
Aerobic composing is carbon neutral. Also to be honest – the black bags absolutely stink when you open then!
You can now successfully compost large amounts of Autumn leaves in your HOTBIN.
How do I prevent maggots and flies getting into the HotBin?
The quick answer is “Get your waste hot (>40C) as quickly as possible”
Flies and maggots in the HotBin are a real rarity. They can occur and it tends to be when the HotBin is in the ‘set up’ phase before the temperature has risen above 40C. Below we explain why and how to prevent this happening. House flies and fruit flies can lay eggs in the your composting waste anywhere from the kitchen, kitchen caddy / bags holding waste and possibly at any time when the lid is open or the door is not fastened tightly.
A hot (above 40C) HotBin will kill all fly eggs, maggots and flies.
In our customer surveys 99% state they are satisfied or very satisfied with how the HotBin reduces and prevents flies – but we do get the occasional issue with maggots and flies and it is a guaranteed sign that the waste inside has not risen above 40C.
We do not believe there is a 100% sure way to prevent flies laying eggs in your compost waste, but the following will reduce the chances of them laying eggs:
Ensure the lid is tightly closed at all times (unless filing!)
- Ensure the door hatch is on tight and the cam belts have been used to pull the door on tight
- Cover all waste at all times (eg kitchen caddy, collection bags)
- Clear up any waste dropped around the HotBin – it will be a fly magnet
It is often the case that your waste already has fly eggs in it. Accepting this is possible, the next step is to prevent the eggs hatching into larvae / maggots. You do this by getting your HotBin Hot (>40C) very quickly (within a few days). Heat prevents any fly eggs hatching.
The basic technique is to add lots (at least half full) of ‘easy to digest’ waste (eg grass, food waste, shredded office paper, corrugated paper).
Quick tips to help you do this:
1) Add a box of grass mowing and mix into the waste already in the HotBin
2) If no grass, add 2-3 cups of either chicken pellets or chicken poo
3) Check excess water is not seeping from the aeration mesh in base – if it is, add half a bucket of cardboard pieces and half a bucket of wood chip (from black bag supplied).
You can find more information on getting to 60C in the PDF ‘how do I get to 60C check list’
Please note: you might occasionally have flies hovering around the valve or crawling on the door hatch panel. We can’t stop this. There is always some residual odour around the valve, and often some old compost on the door. They normally give up and move on when they are unable to find the food source that generates the odour i.e. they cannot find the place to eat and lay eggs. If they bother you and you are not adverse to using chemicals, then any of the fly/crawling insect sprays can be spayed on the HOTBIN parts to keep them away – but outdoors this is a bit of a losing battle – it will wash off in the rain quickly. But do try to keep the area free of dropped food & compost.
Can you compost cigarette butts?
A number of composting advice sites indicate cigarette filters are made from synthetic plastics and do not decompose! We disagree – controlled hot Composting of cigarette butts is viable. Please read on to find out why!
Whether a material IS or IS NOT compostable (i.e. biodegradable) is a matter of scientific fact. We like to check the science and leave you better informed. It is rare for us to re-mind our readers our FAQ advice is provided on ‘without guarantee or indemnity’ – but on this occasion, as the topic is going to get people ‘hot under the collar’, a reminder that this is our reading of the science – we are only seeking to help inform your decision.
Searching the literature, we found that cigarette butts (the white filter bit) is made of ‘synthetic cellulose acetate’. That may sound non biodegradable but this is not the case. You can evidence this very quickly – a staggering 4.5 trillion butts are discarded each year (We can’t find a source for this number, but it is used widely on many sites, so let’s assume it is accurate). If these butts are not biodegradable – where are they now? Mass consumption Smoking has been around for 100 years or so. Despite the efforts of our Councils, if they did not decay, our sewers would be blocked and our streets piled high with cigarette butts. Now for the science proof!
The filters are mainly made from a synthetic polymer called cellulose acetate. All sounds a bit scary, but not really.
Acetic Acid (vinegar) is one of nature’s building blocks – life on earth needs it. Cellulose acetate is just lots of vinegar molecules joined together into a chain. Cellulose acetate is a short step away from cellulose (i.e. wood!). Most cigarette butts apparently still use natural cellulose acetate (i.e. tow from the wood pulp http://www.bat.com/group/sites/UK__3MNFEN.nsf/vwPagesWebLive/4572237B0C2D456CC1257314004EF667
). Even if they do not, synthetic (i.e. man made) cellulose acetate is man’s copy of nature’s science. It is used all around you – wrapped a present with cellotape recently, kept any photographic film (pre digital!) – that’s all cellulose acetate.
How fast cellulose acetate decays is directly related to the composting conditions – and principally the temperature of the heap (Q10 equation). You will often see quotes of 3,10 or 50 years as estimates for cigarette butt decomposition time. This is directly comparable the time it takes to decompose lignin (i.e. wood). Most of these tests are done outdoors (so an average of 10C is the temp for most tests). If you increase the decomposition temperature to 60C, you can divide this number by 32 and you’ll get the time it takes to hot compost it. So 10 years at 10C = 4 months at 60C (Again this is directly comparable to wood in an outdoor heap and wood in an IVC composting plant.
Even if we agree it is biodegradable, surely we do not want cigarette butts in our compost bins – they are full of toxic, carcinogenic tar chemicals the list of additives runs into 600 approved of by FDA for addition to cigarettes. If you really want to see some serious chemical names have a look at Wiki – http://en.wikipedia.org/Wiki/List_of_cigarette_additives
. Yes there are carcinogens in butt filters, but don’t forget – burning wood, fire smoke, the original tobacco plant, and much of nature – also has these nasty chemicals. Someone may have tested every single item and may challenge back, but looking through the list, from our knowledge of composting bacteria, they all look like readily biodegradable organic chemicals (i.e. bacteria food). These chemicals are built up in plants and broken down by bacteria all the time. (Take the logic to the extreme – if the carcinogenic chemicals made in plants were not biodegraded, then over the millennia they have been made by plants, they would have built up in soils – maybe even to a level that would have made soil toxic to humans?
What about the risk from “TMV – tobacco mosaic virus”. From our reading on the subject, claims are made that small fragments of tobacco carry the virus over from the tobacco leaf into the cigarette and onto the filter. TMV is known to be resistant to low temperature composting. However read wiki: http://en.wikipedia.org/wiki/Tobacco_mosaic_virus
. If your heap is hot (60C), the virus is going to outcompeted, die and be eaten by the thermophilic bacteria. If you add in the fact that remote chance TMV survives the burning process at 200C, a small chance a tiny fragment gets into filter and that a tiny fragment is not then eaten by bacteria – TMV from composting butts looks a really low risk.
Only you, as the composter, can make the decision whether to compost your cigarette butts. I do not smoke, but if I did, I’d be more worried about smoking than composting cigarette butts!
So finally – what’s the alternative? Leave them lying around, hope someone cleans them up and takes them to landfill! Then what? Well they will just decompose anaerobically and release methane!
Proper HOT Composting of cigarette butts looks sound!
A text book start for the HOTBIN
The Compost Woman, who knows an awful lot about composting, reviews the HOTBIN! And I’m pleased to announce she has had a text book start as she has already reached 60C!
She started with an very full HOTBIN having plenty of material available for her base layer.
After 24 hours there was already a noticeable difference as the the material started to decompose.
She is a freelance Forest School Leader and Environmental Educator who works with both adults and children on all sorts of things. As well as a volunteer Master Composter and Master Gardener, helping people make compost and grow veg at home or at school.
How to compost ALL food waste
Below we explain how to Compost ALL domestic food waste
(i.e. at home, in a garden, or via backyard composting).
Why do we need this blog?
Surely food waste is just like other waste for composting – we just add it to the compost heap and it breaks down?
What’s the big problem? Well to a degree this is true, food waste is carbon/organic and will compost. The problem is NOT that food waste does not compost, it’s just that more often than not, it creates a putrid stinky mush that attracts rats and flies.
What are the specific issues with food waste composting
Here at HOTBIN Composting we talk to a lot of people who compost – from Master Composters, Council Recycling Officers, expert gardeners to complete novices and we have also read hundreds of composting forums and blogs: the advice is near universal: ‘do not add meat, fish, cooked food waste, mouldy bread, left over bones, cakes, bits pizza, chip boxes, dairy products, gone off fruit, out of date fridge contents to your compost heap. If you do, they will rot, produce putrid odour which in turn will attract vermin and flies. Only add kitchen peelings and tea bags,coffee grinds’.
Kitchen peelings,tea bags, coffee grinds only account for 40% of domestic food waste.
The other 60% falls into the “do not” add to a compost heap.
[We know this because very detailed waste analysis of what goes in our disposal bins and onto municipal refuse collection and landfill was undertaken by the Love Food Hate Waste campaign in 2011 (recycle Now, WRAP) . Teams of people sifted and weighed the contents of 1000’s of household waste bins over many months (nice job!). So we know on average, a UK household produces 250Kg/year of food waste. Every item wasted was listed and weighed (what they call a composition analysis), so it is easy to look at the list and reclassify per the compost “in/out” list.]
So even those with a compost bin, will most likely still be sending food waste to landfill.
They might still have stinky food waste sitting in a kitchen or wheelie bin for two weeks. (We accept there is a growing number of councils rolling out kerbside collection to be used in AD/EfW recovery plants – but this is a small part of the total).
Millions of home composters want to add ALL food waste to their compost bins.
This is what why the HOTBIN was invented: ‘to create a compost bin and method that enables millions of existing home composters to compost ALL food waste without the inherent problems of odour, vermin and flies’
Why does food waste rot and go putrid
As food waste starts to breakdown it forms a thick slimy mush. This soft mush prevents airflow and so the waste quickly turns anaerobic. As soon as anaerobic bacteria take over, the waste releases putrid gut wrenching odours. From here it is all downhill – the smell attracts vermin and flies and everything becomes unpleasant. As food is composted, the structure/fibre of the food weakens and water is released. There are three places the water can go – it can drain to the ground, it can be driven off as steam (water vapour) or it can remain in the waste. Under most composting conditions the water stays in the waste until it becomes saturated and then it will start to drain into the ground. Composting soft food waste naturally produces a mushy slime.
The alternative is to use heat produced by the bacteria to drive of water as steam vapour. This happens when we hot compost.
The golden rules for successfully composting ALL food waste are:
- Remove excess water
- Keep the waste aerated
What is composting?
The biggest part of the composting process relies on bacteria and if you refer to our post So What is Composting? you will note their requirements are not dissimilar to what humans need to survive and grow!
So how do we get rid of excess water and keep the waste aerated?
We take a lead from industrial composting and apply the science and engineering they use to a domestic compost bin.
(If you want to look up the science and engineering, have a read through Haug – Practical Handbook of Compost Engineering) on Amazon book review.
Let’s cut to the chase
- To remove excess water
You need lots of heat i.e. you need to be ‘HOT composting’
- To aerate you need to keep adding lots of oxygen/air
Unless you have the means to force airflow (e.g. a pump / blower), or you can constantly turn/tumble (yes we mean constantly), then you are reliant on “buoyant airflow’ or the chimney principle of hot air rising creating a pressure drop that pulls cold air through from below. You only get buoyant airflow if there is a temperature gradient – i.e. you need heat.
- To maintain buoyant airflow (even with heat)
You need to a heap structure that maintains buoyant airflow. To get a structure that stops food waste collapsing into a mush you need to add what we refer to as a bulking agent (typically this is wood chip).
In summary to compost food waste, you need to get the waste hot, aerate it (via buoyancy airflow) and ensure it stays aerated by adding a bulking agent. It sounds technical and it would be easy to achieve where it not for nature’s laws on heat production and heat loss!
Nature has a law on how much heat is produced
Bacteria release heat as a by-product when they ‘eat’ the waste– just like humans release heat when we eat and exercise. The amount of heat is capped by the calorific value – the more calories the more energy and potential heat. The rate of heat released varies by food type.
Think of it like this human analogy – eat coke and sweets (sugar!) for breakfast and you’ll be on a sugar high for a few hours, then hungry again. East oats/muesli and it will be digested more slowly but over a longer period – you’ll make it to lunchtime.
Bacteria are the same – they digest and release heat from sugars and carbohydrate food very fast, from cellulose (plant material) slower, and from lignin (wood) even slower. The amount and rate of heat generated is determined by what goes in and how much goes in. For most households – it is a challenge to create a hot compost heap, you need about X10 more food waste than most households create.
Nature has a law on how much heat is lost
Heat transfers from a hot place to a cold place until they both reach equilibrium, i.e. the same temperature. This law is scientifically defined by Newton’s law of cooling. Let’s simplify it for a compost heap – even in summer (25C), a compost heap will not stay hot (40-60C) for long as the heat rapidly moves to the cool air. If you want to keep your waste hot, you need to reduce the rate of heat loss ie you need to insulate it. There are two ways of doing this – by having a large heap so the outer metre of waste acts as insulation or use a specialist insulation material.
Oh, one last thing – odour, vermin and flies
Lets assume we are now hot composting away. All composting creates odour and food odour attracts rats and flies. Unless you want a heap infested with rats and flies then you are going to need to control odour so it does not attract vermin and control access the compost heap just in case. In other words, compost in a container that won’t attract rats or let flies in.
Successful food waste composting needs heat (for water removal), oxygen (to ensure aerobic bacteria active), which in turn needs a heat gradient, which needs bulking agent to allow airflow. We need to balance the heat produced with the rate of heat loss (insulation, protection from wind) to keep the bacteria warm and composting fast and then protect the whole operation from infestation with rats and flies.
Achieving the above without a specialist bin is very hard.
The HOTBIN was specifically designed to achieve HOT composting to allow ALL Food Waste to be composted. To find out more please visit our extensive FAQ