Sieving Compost From HOTBIN Composter
The best & most cost effective way to sieve your HOTBIN compost!
There are plenty of options available to sieve compost, some better than others. Here at HOTBIN composting we have certainly tried a few, as you can see from our previous post. It might be worthwhile mentioning that how compost looks and feels can vary a lot. Take a look at the post which talks about how HOTBIN compost will look . Remember you are recycling a variety of organic matter to great something wonderful for your garden!
To make an effective sieve for next to nothing
What you need is:
Some squirrel wire (that’s the 1 cm x 1 cm mesh) and a wheel barrow
How it works:
Simply place the mesh over wheel barrow and then just tip a bucket on top and brush/rake it a few times
How do we rate it:
As long as the compost is reasonably dry it works a treat. In fact, for £6.00 for the wire (get it places like Yorkshire trading, garden centres) and using an old wheel barrow I already had, I’d say it has become the HOTBIN favourite method!
Set Up: (slight delay on this occasion due to visit from feathered friend!)
The bits that are left:
How your HOTBIN compost will look afterwards:
HOT TOPIC – TEA BAGS!
Can I compost tea bags? There is something about this composting question – it keeps coming back – it was on the Radio’s 2 Simon Mayo Drivetime today. Here is an answer that deserves reading our a cup of tea!
You may remember the HOTBIN composter featured on Simon’s Drivetime innovation slot back in February last year.
Toby Buckland (BBC gardening expert) gave Simon a quick summary of ‘hot’ and ‘cold’ composting.
We were interested to hear Toby Buckland noted that some tea bags do not degrade because they have plastic fibres in so you should go for the more ‘expensive’ paper ones with strings.
HOTBIN composting checked composting out tea bags sometime ago. After checking several manufactuirng sites, we found most of the fibre used is paper. Some manufacturers add a small amount of polypropylene fibre to make the bags stronger and allow them to create a heat seal after the bag has been filled. This appears to be a minuscule amount of PP fibre.
In cold composting the bags tend to present in the final compost. In the HOTBIN composter and hot composting they are degraded fast and usually completely within 3 months. Occasionally a bag will need to go through again – more so with the pyramid bags!
In summary – the tea leaf and paper is composted, the inert PP fibres remain but are invisible within the compost and do not affect the soil.
The Guardian did a feature on this three years ago – A report published a few days ago by Which? Gardening reveals that teabags produced by top tea manufacturers such as Tetley, PG Tips, Twinnings, Clipper and Typhoo are only between 70-80% biodegradable. As a result, gardeners are finding the net part of teabags – caused by the inclusion of heat-resistant polypropylene – left on their compost heaps.
Which? Gardening contacted the major tea manufacturers to check the content of their products. PG Tips responded: “‘Like most of the teabags in the UK, our teabags are made with about 80% paper fibre, which is fully compostable along with the tea leaves contained in the bag. The remaining packaging includes a small amount of plastic which is not fully biodegradable.”
HOTBIN IN THE TELEGRAPH
The HOTBIN was in The Telegraph this Saturday and you can read it on-line too.
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!
Tumbler versus HOTBIN
Tumbler compost bin versus HOTBIN with no turning
If you have landed on this page, you are probably trying to decide whether to buy a tumbler compost bin or the HOTBIN. We offer you a quick ‘expert’ recommendation and a more detailed list of items so you can evaluate the type of compost bin for yourself. Alternatively jump to over and read what HOTBIN customers say
Our expert recommendation: As soon as you set a goal to compost all food waste (including meat, leftovers, bread, pasta, etc), and you want to compost all year round (through winter), with no vermin, flies or odour, then you need to opt for a specialist ‘hot composting bin’. Many tumblers are not capable of hot composting. If you hot compost and use a bulking agent there is no need to turn your compost.
Decide for yourself (list of things you should review):
To establish if a product is “better” you need to take a step back and ask – ‘What am I trying to achieve?’
There are two sets of features to look at. The first group looks at whether you want to hot or cold compost, and the second group look at how easy the compost bin is to use.
Group 1 – Hot or cold composting?
Do you want to:
- Compost ALL food waste from a typical domestic home
- Compost all year round (i.e. through winter)
- Compost faster typically less than three months
- Compost difficult garden wastes (e.g. weed seeds, couch grass, etc.)
- Compost without rats, flies or odour
- Compost without turning (fork over the heap)
Vendors will try and persuade you their bin will do ‘a lot’ and you can ‘control things’. To a degree this is true – but there is a huge performance gap between a bin designed to hot compost and a tumbler that holds waste while it cold composts.
- Feed it the right mix of chopped up waste
- Retain heat – ie insulate it by using specialist insulating materials
- Aerate – harness the science of buoyant airflow to get air to each bacterium at microscopic level
- Control water – remove excess water from the mix
- Enclose the waste, remove odours and control vermin and flies
The items are connected – get all five right and it is a virtuous circle, get one wrong and it can quickly form a vicious circle, spiralling downwards out of control.
Feed it: Some materials compost faster than others. Feeding chopped up, ‘easy to digest’ waste allows fast digest and hence fast heat release.
Retain heat through Insulation:
All things compost faster as a function of temperature (read about the Q10 equation here)
. No compost heap will compost faster unless
it retains heat. Plastics are very poor heat insulators – do not get fooled by names like ‘thermo’ and a few extra mm of plastic. You need a top quality, waterproof insulated material/ Just like your loft insulation ask for U or R value rating! Most tumblers have no insulation of any significance so they do not retain heat. The HOTBIN is designed to control both conductive heat loss (via insulated walls) and convective heat loss (hot air flow). If your goal is to hot compost; walk away from non-insulated bins. If you goal is to compost typical amounts (2-5Kgs) of food waste through winter, check the insulation works – look for user endorsements offering time & temperature graphs using on known amounts of waste (Kgs/week). We are NOT aware of any insulated tumbler guaranteeing winter hot composting of 2-5Kgs per week.
Aerate the waste:
You can hot compost without turning! The science (ref in T Huag, Compost Engineering) states air introduced via turning will last only a short time. If you have twiggy/woody material that maintains ‘free air space’ structure and a temperature gradient, it will aerate via buoyancy air flow. To learn more about the theory of “no turning” visit our buoyancy airflow and free air space faq
Plus you need to take into account spinning or turning a compost tumbler is not always easy.
100 litres = 50 Kgs, 200 = 100 Kgs.
Even with levers this can be hard and it places huge stresses on plastic and metal joints.
Control moisture: This is critical to the composting process. Kitchen scraps are wet, as is grass clippings need to be balanced with dry materials. Some tumbler models have drain holes in the drum, and also a collection chamber in the base to receive the “compost tea”.
Wet waste: Wet waste tends to rise and then slumps to bottom – it churns into a solid sludge- the last thing you need! Wet waste is the norm when composting all food waste. This is really easy to handle in the HOTBIN – you just add shredded paper and bulking agent to balance the system.
N.B. Leachate: most of the excess water is driven off as steam in hot composting. Some excess will drain down. Look for a bin/tumbler that has some form of leachate collection
Control Odour: All composting produces odour. Aerobic composting avoids anaerobe pungent putrid odour – but it has a cabbage odour. You need to filter odour and reduce the any possible chance of attracting flies and vermin. Check if your tumbler has any odour filter mechanism – the HOTBIN does!
Pest control: Do not get sucked in by statements like “compost tumblers are 100% pest proof since they are fully sealed”. We believe no domestic compost bin is rat proof. Rat experts will tell you they will eat through all plastics (be it 3, 15mm PE or 50 mm EPP as in the HOTBIN) if there is any gap. Understand vermin – what attracts them (odour, warm and quite nesting sites), then look for design that makes the bin highly rat resistant. If you bins has ANY open holes of 0.5cm or larger and odour you will have problems sooner or later. Always look for off the ground, and look for a filter that removes residual odour to a very low non-nuisance level.
Group 2 – Usability factors
What are the key items that make it easy to use;
- Loading and unloading
Assembly: Bit of a preference – we suggest you look for bins that come ready assembled or at least require very little self assembly. HOTBIN requires none.
Loading and unloading: Small loading and unloading hatches panels are fiddle and difficult to use – it is a big issue for some composter. Some tumblers are good – others are hopeless. The HOTBIN is OK.
Batch or continuous: You can fill the HOTBIN to the top and leave a batch to mature (batch) or more commonly, you keep filling at the top and take out the compost from the bottom without stopping (continuous). With most tumblers there is the issue of when to stop adding new materials so that the whole composter can “finish” and the compost can be removed. Dual chambers are better than single so you can swap compartments, otherwise you may be looking at two bins. (This is a bigger issue if your goal is compost food waste over winter as you cannot stop for 2 months.
Durability: Choose carefully! Tumblers tend to be more heavily constructed since they need to be strong enough to hold the full weight of the composting materials. This does not always work – many fail at the joints and stands. Inspect the supporting legs and the central axis connection – they should be built to last years of use (Check for customer’s reviews after years of use!). The HOTBIN has no moving parts – and only a door to take on and off.
Size & Capacity: Avoid thinking bigger is better. Hot composting is typically 10-30 times faster – so you need vastly less capacity. When hot composting, match the size to the amount of waste – it is harder to get a big tumbler hot with a small amount of waste – the laws of physics do not support small amounts of waste getting or staying hot in large empty bins!
Price or rather value for money:
- The HOTBIN = £120-150
- Non-insulated tumblers = £70-500
- Insulated tumblers = £170-£450
HOTBIN composting supply a compost bin. If you are wondering how and why we are open about offering the secrets of buying the right bin – well its straight forward – our product is excellent, the customer’s reviews say it is excellent, we have used robust composting science and engineering for the design and operation. We have confidence you will choose the right product.
Jump back to HOTBIN products page. Jump back to your shopping cart
Grass composting in the HOTBIN
How to compost grass in the HOTBIN composter. What can you expect when you add grass into the HOTBIN
As we explained in our previous grass post there are advantages to adding cardboard (or shredded paper) plus bulking agent (wood chip) to the HOTBIN to help you compost grass most successfully; it helps calm the ammonia smell and creates extra structure.
Here’s what happens to grass in your HOTBIN through a series of pictures.
Grass added to the HOTBIN
One hour later …
24 hours later…see how it has shrunk already!
48 hours later…
4 days later…this picture speaks for itself
7 days later…It’s almost gone and is steaming away!
Our control experiment!
We put some grass in a bag outside with no insulation… the temperature never gets above 30C
After 24 hours…
After 48 hours…We added some insulation on the top to see if this helps?
After 4 days…The insulation hasn’t made a difference!
After 7 days…there is still no real drop in volume
How to compost grass lawn mowing
To get fast superb results when composting grass lawn mowings in the HOTBIN:
Add 40 parts grass with 20 parts shredded paper and 1 part wood chip (bulking agent)
Typically this is a medium sized lawn mower collection box (40 litres) with a full carrier bag of shredded paper (20 litres) and 4 hands full (one 2-litre measuring jug) of bulking agent.
If you want to view a photographic sequence of grass compost stages, you can jump to our post on steps / stages of grass composting.
Below we explain why this recipe works, why just adding large amounts of grass can be problematic and offer 6 different options for handling large volumes of grass cuttings
The problem often seen when composting grass is you end up with a black slimy layer that stops the compost heap working.
In a HOTBIN you should get brown mulch in 7 days
Grass is one of the quickest materials to compost. In the HOTBIN you can typically convert grass to mulch within 7 days. Grass is so quick to heat up to 60-70C, the HOTBIN team recommend it to help accelerate and increase temperature quickly.
BUT! You can end up with a black anaerobic slime
In traditional compost heaps, it is one of the most troublesome materials to compost. Grass often heats up for 2 days and produces a very distinctive whiff (ammonia/urine). After 2-days it then ‘collapses’ into a cold, wet, slimy black mass that smells horrible (anaerobic mush).
Funnily enough we don’t have a picture of this as if you do it correctly in a HOTBIN it shouldn’t happen!
Composting grass successfully requires a little bit of extra composting knowledge but the real secret is matching the amount of grass you generate with the time and effort you have available.
Why does grass turn into a slimy putrid mess?
The ‘black slime’ is due to anaerobic conditions, i.e. excess water and too little airflow. Grass (lawn mowing) has a high water content (>80%) and no lignin (i.e. no woody stalk). As grass starts to decompose, the plants cells break down and become soft; water is released. The grass collapses and forms a thick impervious layer and airflow decreases. This in turn means the water is trapped, the process slows and a vicious circle is created where water is not removed, all oxygen stops flowing and aerobic bacteria cease to release heat. The heap cools and anaerobic bacteria take over releasing obnoxious odour and resulting in a ‘black slime’.
The golden rules for successfully composting grass are:
- Remove excess water
- Keep the grass aerated
- Balance the mix to avoid ammonia odour
So how do we get rid of excess water, keep the waste aerated and avoid both ammonia and or anaerobic odour?
- To remove excess water
You need lots of heat, i.e. you need to be ‘HOT composting’
- To keep the grass aerated (i.e. get air/oxygen into the grass layer)
You need buoyant airflow which requires a temperature gradient and a structure with spaces and gaps so the air can flow up.
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 via the chimney principle” – and this requires the grass to maintain a structure with small air spaces (ie not a thick wet slimy mass!).
To get a structure that stops grass collapsing into a slimy heap, you need to add what we refer to as a bulking agent (typically this is wood chip). The bits of wood chip act like ‘stacking blocks’ and the air flows around them. Simple but essential!
- To avoid ammonia odour
To prevent excess ammonia, you need to be adding a fast/easy to digest carbon material like shredded office paper or chopped up corrugated cardboard.
The odour is caused because grass has an excess of nitrogen which the bacteria are unable to use as fast as it is released. So it forms ammonia gas and evaporates away. You are most likely to notice this when composting and/or turning large quantities of 1-2 day old grass lawn mowing. After 3 days things slow down and the nitrogen is no longer in excess. Turning grass heaps does not prevent the odour – it enables the trapped gas to escape ‘all in one go’. (If you have done this job, you may well come back inside the house and realise your clothes smell of ammonia!).
The HOTBIN does have an odour filter in the lid that does remove ammonia odour. But, when you add a whole box of grass in one go without anything else, the filter gets temporarily overload for 2-3 days. To prevent the odour during the initial 2-3 days you need to balance the carbon/nitrogen ratio.
You achieve this by adding a dry high carbon waste. The key here is to add ‘easy to digest carbon’ such as corrugated cardboard or paper shredding. Woody items like sawdust, shavings, wood chips are high carbon – but they are not easy to digest, so will not balance the C/N during the critical 2-days of intense activity. Here is the challenge – you need a lot of dry carbon! A 40L grass box (a typical mower box), needs 20L of paper – that’s a whole carrier bag full. It also needs to be mixed with the grass. Not everyone wants to do this, especially after cutting the grass. Below we outline a few options about different methods you might want to follow.
Large amounts of grass waste need extra steps to compost quickly, without ammonia and without turning putrid. Is the extra effort worth it? We think so! Each year fertilising grass lawns consumes considerable inorganic fertiliser – adding the nutrients back via compost is environmentally better.
Below are six options/choices for composting grass. Often you can ‘mix ‘n’ match’ routines at different seasons and times of the year to cater for the varying grass volumes.
1) Small to medium lawns – add grass into your HOTBIN each week
The HOTBINn will easily compost grass from a small-medium lawn (approx 40 litres/week or 1 large grass box per week, filling about a quarter of the bin each time).
This will generate some odour that you may well notice for 2 days. If this bothers you, there are a couple of methods to solve this:
- add shredded paper or corrugated cardboard in ratio 2 parts grass to 1 part paper
- Only add half a box, then return 3 days later add the other half
|Grass volume / Weight
||To Avoid wet slime
||To Avoid Ammonia
|40 litre (approx 20 Kg)
||Add 2 litre (a measuring jug) of bulking agent. Mix in well
||Add 20 litre (a full carrier bag) of shredded office paper or chopped up corrugated cardboard).
Results in approx 1.6 Kgs of compost in 30-90 days
2) Large lawn – use a dedicated HOTBIN for grass
If you have a large lawn and generate 3, 4 or more boxes each week, then you will need to consider a dedicated HOTBIN. It will cope with 2-4 boxes (about 60-80L) per week.
The same rules apply – but adding and mixing in large amounts of paper is intensive and requires a high degree of commitment – perhaps not what you want straight after cutting the lawn! Large lawns allow the HOTBIN to be located away from your seating area – so we suggest you save your effort of adding shredded paper to eliminate ammonia odour – just leave the HOTBIN down the garden and reap the benefit of fast compost without anaerobic slime.
|Grass volume / Weight
||To Avoid wet slime
||To Avoid Ammonia
|80 litre (approx 40 Kg)
||Add 4 litre (a measuring jug) of bulking agent
||Leave remotely and accept ammonia for 1-2 daysAdd 40 litre (a full carrier bag) of shredded office paper or chopped up corrugated cardboard).
Results in approx 1.6 Kgs of compost in 30-90 days
3) Leave the cuttings to compost on the lawn
Many gardening sites now actively promote leaving grass cuttings on the lawn. Normally you use an adapted/special mower blade that chops the grass into very small pieces (2-5 mm) and thoroughly spreads them. The method is to weekly trim of top third of grass and spread this evenly so it composts quickly, adding nutrients back to soil, but not creating thatch. If you have the grass ‘trail line’ down side of mower, then this will rot into mulch that blocks light and growth and does create thatch. Please refer to manufacturer for correct mower blades/settings. If you walk regularly on your lawn – you may find bits get on your shoes and are walked back into the house!
4) Best of both worlds’
Add the first few cuts of the year which tend to be large (say 3-4 boxes) into your empty HOTBIN. The bin is full for a week or so, and then rapidly becomes half-empty allowing ongoing use with food. After the spring cut, leave grass cuttings on lawn. Occasionally (e.g. when cutting hedges) add the grass box back on the mower and collect grass to complement garden ‘browns’.
5) Transfer grass to Local Authority
This is unlikely to interest HOTBIN users, but it is possible to have grass collected at the kerbside and taken to the council recycling centre. We are strong believers in home composting and believe in the environmental benefits of saving fuel and transport.
6) Allocate a large, remote area of garden to build smelly grass mounds
The mounds will tend to be smelly and go anaerobic, but it is fast to empty and dump lots of grass. We had rave reviews on how fast and efficient the HOTBIN is with grass – so maybe you do not need this option anymore!
So in essence it is easy to compost grass in your HOTBIN but depending on the amount you need to consider which methodology is best for you.
Running A Successful School Composting Project – HOTBIN Composter Case Study
We have a number of schools using the HOTBIN to compost food and garden waste. Below we share how they got started and our hints and tips for success.
First decision: decide if this is an “adults only, reduce waste collection” or an “educational tool that will fully involve the children”. It is obvious which option most schools go for – but do not walk into this without planning ahead. Know what to expect and have a plan in place for what to do when things go wrong.
We often hear one or more of these comments: we bought a couple of dalex cones from the council – they were really cheap and we have a bit of garden so we thought we would do our bit. Two years down the line – the bins are overflowing, nothing is breaking down, we now have four bins (they are taking over the place). The children put the wrong things in, no-one wants to clean out the compost. We have masses of flies, our heap got a wasps nest in, we had rats. We can go on!
Do not be put off by this: all the Council Waste Recycling officers and Master Composters across the country will say the same – composting is not a “toss it in and walk away project”. It is not hard, nor is it time consuming – BUT it does require a method and care (“TLC”) to get the right results.
Scale: are you just going to compost left over sandwiches, fruit cores/skins? Is it going to include kitchen peeling? Or indeed all leftover food waste from lunches? (Please call for advice – the HOTBIN has a maximum fill rate and is not suitable for large schools with significant volumes of food waste).
Which compost bin: the HOTBIN is not the cheapest – but it does hot compost ALL food waste. (Find out more about how to choose a compost bin)
Funding: try all the normal routes: trusts, charities, governors, LEA, Council, Headmasters discretionary spend. You can also get creative – our friends at Waldringfield have got lottery funding for their community composting scheme!
Engage the children – recognise they want to touch, open/close and play – get this out of the way during set up!
Choose the site carefully – close enough to be practical, but not along a main through way.
Learn about composting – decide on your in/out list, who is collecting, when added, who adds it. You will need to look at the HOT vs Cold composting list.
Know your recipe – when composting food waste add shredded paper and bulking agent.
Always have a ‘compost monitor’ – who will take ownership and check progress.
Have the gear on hand – pair of gloves, caddy, stirring stick. Have a place to store them (by the bin is best).
Engage – experience to date shows the children love to record, measure and chart. So take temperature reading weigh the waste added, compost out, work the savings/impact, observe to compost, use the compost, track what happens with/without compost in garden.
Use the science – you will need to relate this to age, but things like recycling, landfill, C/N cycle, through to deeper GCSE/A Level – chemistry (enzymes biocatalysts, rates reaction, Q10), physics (Newton’s law cooling, heat transfer, convectional vs conductive), IT (how do we do set up a remote wireless temperature monitoring). WRAP (recycle now) has a number of resources for keystage1 and 2, our friends at Garden Organic also have resource packs for schools.
Watch for warning signs and intervene early – It is easy to correct and get back on track when using the HOTBIN – the earlier you intervene the easier it is. Have your materials on hand to fix things – shredded office paper, bulking agent, either grass or chicken pellets. Ensure the person who owns this fixing it if it goes wrong is ‘compost friendly’ Be realistic: they should not be squeamish about a bit of odour, have a phobia about flies, unable to cope with the thought of mixing compost or even worse case digging out compost.
Other resources & help: if you are unsure and need help, often you can find a Master Composter to come around and help – they are not there to manage the compost bin for you, but they will help you learn how to do it. Plus we do have a great HOTBIN FAQ
Health & Safety: staff have a duty of care for children at school so H&S and risk assessment figure prominently. You can find composting H&S advice at going at our website www.hotbincomposting.com. Life is not risk free, composting has risks – follow the basic hygiene guidelines and these are minimal. It is undertaken the world over and has been a recorded practise as far back as Roman times;
- Wear gloves
- Wash hands after composting
- Keep composting tools, implements away from food preparation areas
- Cover cuts to skin
- Children may not be aware – but do not eat place anything in mouth once gone into compost bin (so no taking a sweet out – even if still in wrapper)
- Take care asthma those with breathing difficulties – eg wear dusk mask and do not stand over active compost heap.
Above all have fun and enjoy composting! Compost is nature’s way of recycling!
COMPOST ALL FOOD WASTE
How To Compost All Food Waste – And Save The World!
It is easy to home compost vegetable peelings, tea bags, coffee grinds – but they typically only account for 35% of domestic food waste. The other 65%* (meat, fish, cooked food leftovers, mouldy bread, plate scrapping, chicken bones, cakes, bits pizza, chips, etc) falls into the “do not” add to your compost bin list. (*calculated from the 2011 Recycle Now, WRAP waste analysis figures)
It is not easy to compost all food waste. As food breaks down, the cell structure weakens and water is released. The food collapses into a thick slimy mush. This mush prevents airflow and the waste quickly turns anaerobic. As soon as anaerobic bacteria take over, putrid gut wrenching odour is released. From here it is all downhill – the smell attracts vermin and flies and everything becomes unpleasant.
Millions of home composters want to compost all food waste. Not only will this divert it from landfill, it will produce loads more quality compost to grow more healthy plants and vegetables.
Top tips for successfully composting ALL food waste
Keep it hot – insulate you waste – bacteria release heat as a by-product when they ‘eat’ the waste. Heat transfers from a hot to a cold until equilibrium (same temperature) reached. Even in summer when the air temperature might hit 25C, a compost heap will not stay hot (40-60C) for long as the heat rapidly moves to the cooler air. If you want to keep your waste hot, you need to reduce the rate of heat loss i.e. you need to insulate it. There are two ways of doing this: a very large heap (at least 1XX1m) where the outer metre of waste acts as insulation around a small hot core, or by using a bin made from a highly insulating material.
Shred – it is often said that one million bacteria can fit on a pin head. Give them a break! A whole potato wrapped in sheet of newspaper (a woody hard to digest lignin material) is a gargantuan challenge. Chop things up – let them get into the soft easy stuff inside
Remove (or manage) excess water – you need lots of heat to drive off excess water as steam – i.e. you need to be ‘HOT composting’. You will almost certainly need to add dry shredded office paper or corrugated cardboard (not newspaper!) to balance ‘wet’ food waste.
Aerate – you need to keep pulling lots of oxygen/air into the waste – Unless you have the means to force airflow (e.g. a pump / blower), or you can constantly turn/tumble (I mean constantly), then you are reliant on “buoyant airflow’ – 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 and a structure through which the air can move.
Add a ‘Bulking Agent’ to maintain 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).
Manage residual odour – you need a filter – be this a layer of compost of a specialist bio filter – and all air leaving the heap needs to pass through this. Even hot composting creates odour – it might not be putrid, but rats will still be attracted. Unless you want a heap infested you need to enclose it without cutting off the flow of air/oxygen.
Protect from vermin and flies – you need to enclose the heap in a protective closure that will not rot, allow heat loss, yet still allow air flow
I spent 2 years attempting to build a food waste hot composting system. I followed numerous online composting sites. I went from cold too hot, too stalled to anaerobic. He lost count of the number of stinky, pungent ‘test’ bins I had to sort out. Eventually in frustration (I don’t like to lose!) I purchased a mega composting engineering handbook (T. Haug – great book if you have a strong chemical engineering bent).
It’s not easy to create a domestic hot composting system. Look carefully and most descriptions of hot composting and they almost all refer to very large (+500Kg) piles of garden waste and an awful lot of turning. Most food waste comes in small lots of 2-5Kg per week.
Composting food waste without a specialist bin is hard. With a specialist bin it’s much easier!
What about saving the world! If you are unsure how humus (the important ingredient in compost) will save the world – then research the following: no compost = no humus = no soil fertility = no plants = no food = a whole heap of trouble for us all. Then double back and look up what causes soil erosion, desertification, acidification and the current health of the world’s arable farm land bank. Let me know if you agree!
The HOTBIN was specifically designed to achieve HOT composting to allow ALL Food Waste to be composted.
HOTBIN in TOP 50
My Green Directory has announced the Top 50 voted for companies in the ‘PEA-ple’s Favourite Award’ and the HOTBIN is delighted to be in that list.
The TOP 50 includes – 100% Organics, Akamuti, Akuawood, Bareskin Beauty, Black Sheep Inn, Bohohemp, Climate North East, Cred Jewellery, Coulson Macleod, Daisy Green Magazine, Daniel Field, Dr Organic, Earthwise Girls, Eco Dog Company, Flute Office, Frugi, Greenhills Cleaning, Green People, Green Pomelo, H2 Eco, Hotbin Composting, iec connect, Indica, Jurys Inn Brighton, Low Impact Living Initiative, Mama Pack, Mazzard Farm, Method, Mi Naturals, Moon Times, Myakka, New Age Music Garden, Organic Holiday, Permaculture Magazine, Piccalilly, Plush Pants, Po-Zu, Shangri La Organics, Soel Boutique, Sustainability Centre, Suma, Suzanne James, Tamman, The Nappy Lady, Thrashion, Weleda, Wild Thyme Farm, World Land Trust, You Gen and Zaytoun.
The new ‘PEA-ple’s Favourite Award’ will be presented by My Green Directory at the third annual PEA Awards in October 2013, an award ceremony that celebrates inspirational individuals already making a difference and honours those who have demonstrated the importance of sustainability.
Voting will continue until 18 June to find the Top 10 voted for companies, with the final round being a twitter vote to find the winner. All Top 10 companies will attend the The PEA Awards in London, with the Winner receiving the accolade of becoming ‘The PEA-ple’s Favourite’.
HOTBIN still needs your support and votes to get to the next round.
As a thank you to voters they will be entered into the prize draw to win 4 tickets to attend the Awards themselves.
Vote for your favourite green company – visit www.mygreendirectory.info