Sink me!

"They seek it here, they seek it there, they seek it everywhere. Is it in sink or is it it composter, that darned elusive, latest waste bit of bluster."

It started so innocently. One of the many forums/feeds I subscribe to mentioned in sink disposal.

In my quest for the best enviROI answers I decided to weigh in. As I speak it is ongoing. I must say, whilst still civilised, I am finding some of the retorts now a tad testy and pointed. My urge, naturally, is to kick back. When will these ardent 'greenies' ever learn about human nature:

Initial Post: A request for help please! I am working with a new team and we are looking for a range of exciting environment ideas to showcase at a major new exhibition.

· Theme: kitchen – just as a case study – what could be done in this room of a house? Ideas for what people can do in their own homes, and possibly work kitchens.


Ans 1: My friend has recently had an ‘Insinkerator’ installed (a waste disposal shoot fitted into a secondary, smaller sink next to the main sink). The idea is you put all your green waste in there; it gets shredded and washed down the drain by the water flow in the sink. It makes its way into the sewerage system and is eventually filtered and processed like the rest of the waste water in your house.
Reply 2: Obviously there are issues (water use, electricity use, increasing load on sewers), but it does seem to be a viable alternative to the brown box scheme we currently have in London for our green waste – you fill a brown box that is collected once a week by a lorry: a diesel lorry which drives around the neighbourhood, calling at every house…surely this is not the answer? The brown bins also smell terrible (which makes most of the public immediately switch off and vow never to have one in their home), and were recently labeled as ‘slop buckets’ by some newspapers. This hardly encourages take-up.

Reply 3: On balance, and as part of a suite of technologies in the home, the Insinkerator concept seems to me to offer a useful option for those wishing to recycle their green waste but who do not have the space or inclination to utilise a more hands on approach to composting their green waste, and who do not wish to use the Council’s collection scheme.

There are issues surrounding water and power use and the load on our sewers, and if anyone knows any more about these please let me know. People also need to know what can and cannot be put in there. But it seems a useful option to me, and should form a key part of the discussion about sustainable waste.

Me: My local council, Herefordshire, had an exhibition on this recently, and I'm a convert.

It seems a no-brainer, as this is a great way to get kitchen waste from the sink direct to a place where the energy is bio-extracted and the solid waste remaining reused.

I am currently assessing the half-dozen options on macerator offered, along with the grant funding in support.

My only wonder is that having done this it has vanished from the comms radar. To me it warrants a major national effort.

But then I have some doubts on the priorities applied in matters of enviROI by those who often look at targets and what will tick a Euro-box more than what's best for our kids' futures.
Reply 4: The use of an insinkerator has (like many environmental choices) trade-offs to weigh. The City of New York has been debating the use of these devices for decades and has, not surprisingly, generated a vast literature from proponents and opponents about the relative merits of managing food waste through the solid waste system versus the sewer system. A little bit of googling on insinkerator and New York City should lead you to many of the relevant studies. Note that in many parts of the US, the devices are called "garbage disposals" (pronounced dispose - Alls), so any searching should use both terms. All you are doing with one of these units is to pass the problem along the sewer to the Water Authority.

Reply 5: They have to treat and deal with it as sewage sludge and then find a disposal option for it. This may be anaerobic digestion or it may be putting onto non-food crop land. You’ll end up paying for it in higher water rates anyway. Much better to deal with it as close to source as possible, home composter, wornery , bokashi bin or kerbside collection.

Me: Forgive me, this was/is not my understanding.

As sold to me (at least, so far) they WANT this, and don't see it as a problem, but rather an opportunity.

As far as I can gather they have in place the means to deal with it - with luck on a enviROI+ basis.

It might be naive of me to hope such energy from 'free' waste may even reduce my rates, though.

And though my appreciation of the subtleties of composting, bio-degradability, etc is not that great (and I'd welcome more informed feedback), if the problem we face right now is C02 going into the atmosphere I would tend (with my limited science B/G) to prefer that the gasses of decomposition get captured and used rather than waft away

Reply 6: My reasoning was more of self sufficiency and not passing it on to someone else with all the embedded carbon in the transportation, processing etc. Another option is to community compost locally. I’m not sure that the water companies in the South and East will want extra solids in their sewerage system. With the push for reduction in water demand particularly in new homes build to Code for Sustainable Homes 4 and above, there may not be enough water flushed down the sewers to push it along and it will lead to blockages.
It seems to depend more on where you live and hence the council area.

Me: I am in South Hereford and Severn Trent seem to be OK with the solids.

Try this for more info. Reply 7: All kerbside collection schemes for anaerobic digestion and the methane produced is burnt to make electricity. That’s what I suggested, not putting it down the sink for the water company to deal with who might use AD or just bury the solids on non-food crop land.
Me: I don't know about all kerbside schemes, but ours takes just glass, metal and paper.

I wasn't even aware there were even such collections of matter for anaerobic digestion, which just shows the rather unhelpful diversity of options we seem to have countrywide.

I was told by my council that putting it down my sink would result in appropriate energy conversion and the solids would be used appropriately. I have to trust them that it's a bit more than 'might' on that... for now.

I do compost and bring major garden waste to the bring site by walking it there in a hand-towed trolley (it's flat en route, good exercise and then brambles don't kill the car fabric - plus I can take a nice big (volume) load, as oddly you need to pay for a trailer licence and hence most make multiple trips... in their cars).

But as I have no other option than a black bin liner and hence landfill for the rest of the organic matter, the sink system still seems good for where we are.

It would appear to be yet another case for some form of UK-wide, easy-to-assess, chart of the options and their relative enviROIs.

Reply 8: The reason for the diversity of collections is many fold, however it is mainly a mixture of the nature of the area, the aspirations of the Council through pressure from their residents and whether the private sector is willing to invest in processing facilities for different materials and take these from Local Authority collections. Why would a rural Local Authority want to collect green waste when most people practise home composting? Why would a Local Authority collect plastics, tetra paks, batteries when there are no processing facilities for hundreds of miles? Why would a Local Authority collect food waste when there are no AD or In Vessel Composting Facilities for hundreds of miles? Your Council would say put food waste down the sink as it divests them of the problem of collecting it. Councils are measured against a number of indicators and total waste arisings is one of them. The more they can divert away from what they collect whether it be to landfill or for composting, AD, etc. then the better their performance indicator looks. Also it improves the recycling percentage by decreasing the denominator in the calculation. The other main reason for diverting organic matter, particularly food waste away from collection and landfill is that it helps Local Authorities avoid the potential fines of £150 per tonne set by the EU if Local Authorities do not meet their ever increasing targets for diverting bio-degradable waste from landfill.

Reply 9 - I am confused. Where are the brambles and copious amounts of yard waste coming from? If you have enough outdoor space to produce so many trimmings, why can't you set up a composter or worm bin for your kitchen waste? It's dead easy, saves and recycles resources, and even gratifying when you remove the finished compost and feed it to your garden. As for assurances from Councils, well...it's been said already. There are unfortunately too many box-tickers and not enough creative thinkers in the average Council, and sending the problem waste downstream allows for better looking stats closer to the source.

Me - Golly you, and some others, don't sound the least bit confused. And that is to be envied.

I spent most of my time in a state of confusion on almost anything environmental.

Ever since I started up my little website, with its focus on practical at-home things to DO that can help the planet though reuse and repair, etc, I have also found myself very interested in all the other things out there that the general public can do to help. And as average family man and homemaker, in sharing my efforts many others have taken an interest in my various quests to find out more to do what one can for the best. Many have also been kind enough to contribute.

By doing a tad more reading and gaining exposure to the issues, I perhaps have become better informed than some, but of course a little knowledge can be a dangerous thing. Which is why I am careful always to caution on the limits of what I find or get told. All too often there are agendas, targets, boxes to be ticked and lucrative careers being forged that make what was on the surface so simple in fact a rather daunting hall of smoke and mirrors to get to my dream goal of a clear enviROI+. And it is so critical. As has been noted, the public does need to appreciate that collecting a Tetra-Pack may not make much eco-sense in Brighton if it has to be shipped to Fife for disposal, but then this should not be where it all stops. We have to then look at why there are not processing facilities and logistical systems for all potentially recyclable waste countrywide. And if there are local difference how these can be included to best national effect.

So be it man-made climate change to man-worsened climate change to climate change to global warming at government and/or major media level, to discussions as to whether Al Gore 'won' an Oscar or more the producer of a documentary featuring him did, or whether he won a Nobel prize or shared it with an entire scientific body (whose chairman once lambasted him) appropriately for Peace, I have often found myself stumbling through many issues (at least today the BBC did make a great point on insulation... so long as you have a cavity wall. I will however wait on the real figures of the solar they were plugging), with often strident exhortations from more committed and less questioning advocates on all sides.

So it seems, I have arrived at a similar point when it comes to insinkeration (neat term!)

To this point, it all made pretty good sense, because my council said it did and my local water board said it did. Indeed, at a county meeting (which involved the excellent Wiggly Wigglers lady ) this was all debated, and the result seemed quite clear.

Now, of course, I must look further, and deeper, to try and arrive a a 'better', or at least more informed view.

I was wondering if you guys who seem not so keen have any figures or sources pro/con to accompany your definitive advocacy against this system of disposal? And I will happily upload them on my site.

And on a a more personal note, yes, I am fortunate enough to have a garden. Though at this point I'd offer that not all do, especially in more urbanised areas, so again we have to look at the totality of the demographics when it comes to assessing the best enviROIs of systems. Often less ideal may be better than nothing, and according to usage more effective than 'the best'.

There's also the 'human' factor. I was actually keen on a green cone. But with kids playing out there and a stream nearby (a healthy source of water rats) my wife was not. Some battles are not worth fighting. Hence the sink-borne system seemed, to now, to be a good solution.

The net result is I am now not committing to either until I know more.

And finally, as a poor gardener with little interest in the practice, the only thing I grow is grass. Hence I am on my third composter. What would be neat would be to have a mechanism whereby I could give (or better yet sell) what I make to those who can and would use it.

Actually, I must add that to the list of things the JunkkYard postcode recognition system can facilitate.

Wow. That didn't take long. Within hours of the above I got this:

Reply 9 -

Some cities, including New York, have outlawed kitchen-sink garbage disposals, at least in homes foor good reason.
The cost and innefiency of combining non haserdous waste with water to transport it & then having to seperate it again for disposla is nuts!

Sink garbage disposals are not the greenest way to dispose of food waste. According to Mark Jeantheau of the popular eco-website Grinning Planet, conscientious consumers interested in returning food-based nutrients back to the Earth should bypass the garbage disposal in favor of composting.

“The ground-up waste [in a garbage disposal] does not go back to nature’s water supply to be gobbled up by fish and other life forms,” he says. Sewage-treatment and septic systems remove “any food value the waste might have had.” Indeed, most modern-day sewer filtration systems utilize chemicals to rid the outflow of any life forms, beneficial or otherwise. Plus, grinding food in a garbage disposal uses a lot of freshwater, which is becoming a more and more precious commodity.

Those on their own septic systems also might want to minimize their use of the garbage disposal. According to the U.S. Environmental Protection Agency (EPA), regular use of garbage disposals leads to a “more rapid buildup of scum and sludge layers in the septic tank and increased risk of clogging in the soil adsorption field due to higher concentrations of suspended solids in the effluent.” Jeantheau adds that even if a given septic system is designed to handle heavier, food-based loads, it still might not be worth the risk: “There are few homeowner nightmares worse than having your septic system go belly up.”

While composting may sound like a messy proposition, it doesn’t have to be. For starters, those doing the dishes should make sure to dump any and all food waste items into a kitchen-based composting bin with a lid that seals tight. Many municipalities now make such bins available to interested residents. A mesh strainer in the hole in the sink can catch smaller food scraps and be dumped into the composting bin when the dishes are done.

When the kitchen-based compost bin fills up, it can be dumped into a larger composting bin outside. After four to six months, you should have some nice compost to add to your garden and jumpstart the health of your soil. Companies such as The Compost Bin and Clean Air Gardening offer online sales of a wide variety of quality compost bins of different shapes and sizes, and provide a wealth of comparative information for the interested consumer.

CONTACTS: Grinning Planet, www.grinningplanet.com; The Compost Bin, www.compost-bin.org; Clean Air Gardening, www.cleanairgardening.com.

If you have to use this crazy appliance you should add another bit of plumbing to your disposal you can recapture the solids right away, for local composting. See the Kitchen Komposter

http://www.joneca.com/Komposter_Joneca.htm

Again this bit of hardware is just worthless They complicate plumbing substantially, are expensive, use electricity, and do indeed lose nutrients while increasing the load on waste water treatment plants and systems. The disposal collector I mention above is basically a
juicer for your drain, and lots of good stuff is lost in the process.

Now It looks like I have an issue on my hands to get to the bottom of. I have posted this as I said I would. However, it does seem to me that it is falling out (in every sense of the word) between two sets of 'passionate' advocacy.

What I would value is the opinion, preferably backed by enviROI relevant facts, of a more objective person with no eco-axe to grind.

ADDENDUM - In the spirit of discovery, I asked for some opinion from a very nice chap I met at a composting event. To be sure, his company is in the advocacy camp, but he has been kind enough to offer a comprehensive reply which is rich in data. I post his reply here:

Thanks for your email. It isn't an unusual subject, or to see the views polarised.

Water industry. None of the UK water companies like FWDs (Food waste disposers). because they think that they are being handed the bulk disposal costs of biodegradable municipal waste by the local government groups. Local gov has to reduce biodegradable waste going to landfill on a tapering limit. The taper is severe i.s >60% reduction is needed in a relativeley short time. For every tonne over they get fined £150. An average tonne costs £60 to dispose of, so the fines are huge. Water companies want to use FWDs as a mechanism to increase charges in their 2014 pricing settlement with Offwat. They say that if FWDs are allowed to expand in use, then their systems will need to be changed in order to handle it, and hence an increase in money will be needed. If they are not going to be allowed to get more money, then they will want to see their use curtailed.

Water UK is the trade body, and has entered into a 3yr research programme with WRC to establish the implications of FWDs on the sewer system.

There is already a body of evidence that says even in very high concentrated use that there is a negligible impact on sewer systemns and treatment processes. There is a town in Sweden where 30% of the homes were fitted with domestic FWDs and the impacts on the sewage treatment system measured. - I don't know the town's name or have a copy of the report.

If you want to think about the green issues of CO2 footprint and other greenhouse gases then you need to think about what happens to the Carbon atoms. Composting has a super following becuase it looks like the ultimate in get something for nothing. You can turn a tonne of waste into 200kg of fabulous compost. The old school scientists worked out some time ago that energy cannot be made nor destroyed. It just changes form - hence perpetual motion machines are unlikely. Energy also = mass (e=mc2) so a pile of waste material is an energy store. If the mass reduces say from 1 tonne to 0.2 tonnes, then the energy associated with the .8 tonnes has to be accounted for.

0.8 tonnes started life as chemical energy (i.e. carbon, nitrogen, oxygen, Hydrogen, and others bound together looking like an old tomato or onion, or whatever.)
Some will become heat
None will become light
None becomes kinetic
Some of it becomes worms and bugs - there is a great technical term for this but I can't remember what it is
Some of it was water and is evaporated and stays as water
The rest probably stays as chemicals, but in different forms/compounds:

Depending on where you are in the compost bin, there are bugs and worms. Where there is oxygen present (air) the bugs will be aaerobic. They will respire, using oxygen and generating CO2 - at the same time converting carbon in the waste into bug.
Where there is no oxygen, then the bugs are anaerobic and will be busy converting the waste into bug but will generate CH4 (Methane). A clue - if the compost is warm (heat being generated) then there is anaerobic digestion happening.
Worms it seems produce NOX.

All of this chemical activity goes unnoticed by the casual observer, so the process is considered to be something like a miracle solution.

There is a multiplier though: every ounce of CH4 is 23 times more agreessive as a greenhouse gas than CO2, and NOX is a frightening 296 times more agressive - see article below.

It is worth saying at this stage that sewage treatment processes are like big scale composters. The sludge is the byproduct compost. There are aerobic sections and aaerobic sections in any process. The trick is to capture the anaerobic output (Methane) in anaerobic digesters, because then you can do something with it that is positive - i.e. turn it into CO2 by burning it to get energy out - thus the Methane fraction doesn't act as a 23 times multiplier to greenhouse gas, but as a 1 times multiplier with a positive energy creation. If that is harnessed, then the energy might be used to offset CO2 generation in conventional power generation.

FWDs are one piece of technology in reducing landfill (CH4 is emitted in vast quantities at landfill). They have a role to play along with other things like composting. There actually needs to be a "live and let live" approach - it is a pity that there are folks around who want to ban this or ban that.

There are other manufacturers than Insinkerator.

He also directed to a Telegraph piece: Wormeries 'may add to greenhouse gases' , which actually validates (if true) my concerns from the outset on how anything that churns out greenhouse gasses can surely not be helping the immediate cause of a reduction of same. This would seem to suggets there may be soem value in looking at capturing the gasses from such composters, though on a domestic scale this might not be practical.

I have to say as I oscillate about, this latest certainly makes sense to me and I tend to stick with my initial views. But I am sure there will be more to come. This seems almost as charged as climate change!

ADDENDUM 2 - I have now had a reply - a most helpful one (well, bar the 53 page bit!)- from the local council:

You could point people towards our Environmental Impact Study for all this info, environmental and financial etc. It was funded by the County Surveyors' Society. It's 53 pages long so we've also published a 3-page synopsis.

REPLY 10 - A polite, if still rather dogmatic response from one who seems to be very much in the 'compost' camp. I could also cock an eyebrow at the first and last of his company's interest area: a CONSULTANCY on LIVING TECHNOLOGIES, SUSTAINABLE DESIGN AND CARBON OFFSETTING. Me, I do it all for free. Also he has missed, or avoided, some of my points. I do compost the garden waste. It's the few meat and non-compostable scrapings I am looking at. And it's between a green cone and FWD on an enviROI basis (I'm guessing the cone will be cheaper than the unit, and not incur any subsequent operating costs) I am interested in. There is really not a difference in effort between them. He also seems to again ignore the human element on a pragmatic basis, especially when thinking on flat dwellers. Worth replying to? Not sure. I have enough fun with such mindsets on Guardian CiF.

Peter, I am sure many can relate to and appreciate your dimemma and voyage of discovery. Thanks for sharing the process so openly, I think it helps the rest of us.

As for those with or without access to gardens, I believe that part of what we need to change about our strategies and cultural mindset is the idea that a solution is only viable when it is universal. One of the big lessons about sustainability is the importance of nurturing diversity. In this instance, it's about the diversity of situations, personal specifics, options and ideas. The fact that some have space for a composter and others do not does not minimise the value of a home composting solution. If you subtracted all the homes with garden or balcony space from the total kitchen waste production, it would have a significant and positive impact. If you subtract even a few, it's still worth doing.

If you limit your composting to grass clippings, bits of paper and cardboard (for the carbon balance) and uncooked vegetable and fruit scraps, the rats will have less interest. A wire cage around the composter would deter them anyway. A worm bin would happily dispose of pretty much all the cooked scraps, meats and other 'smellies', and if caged, would keep out the rats anyway. Finished compost can be raked into the lawn as a top dressing, or offered to gardening neighbours.

Don't forget that the value of compost making is much more than simply disposing of waste.

ADDENDUM 21/Nov: Press release (as is, at tad editted for space, but I really need to fight through the 'shock' copy a tad when I get a 'mo):

GREEN CONE TO LOBBY GOVERNMENT OVER NEW GREENHOUSE GAS EMISSION FINDINGS -centralised treatment of food waste produces between 10 and 40 times more CO2 emissions than garden food waste digesters-

According to garden Food Waste Digester (FWD) company Green Cone, transporting and treating food waste at a centralised treatment facility produces between 10 and 40 times more CO2 emissions compared to disposing of waste in a householder’s garden using a digester.

The shock statistics follow a recent paper by environmental consultant Dr Alan Knipe (previously group managing director of Nuclear Technology at international energy and environmental company AEA Technology), which has been peer reviewed by SLR Consulting.

Furthermore, the significant environmental findings are in addition to annual cost savings identified in earlier studies illustrating that by introducing FWDs, local authorities could expect to save between £3-4 million per 250,000 households.

In his latest study, Dr Knipe compared greenhouse gas emissions from the life cycles of specified centralised and household management strategies in terms of CO2 equivalents (CO2E). Whilst anthropogenic (manmade) greenhouse gas emissions associated with the manufacturing and end-of-life disposal of both treatment plants and FWDs were shown to be relatively small, emissions arising from the day-to-day operation of the treatment plant, and transportation of waste to the plants, were proven to be alarmingly high.

Dependent on household dispersion and waste management strategy employed, total emissions from the day-to-day operations of a centralised approach typically generated between 50 to 214kg of CO2 per tonne of food waste each year. This figures reduces by 14kg of CO2E per tonne if the resulting composting were to genuinely replace existing emission-intensive inorganic fertilisers, soil improves or peat.

By comparison, household treatment generates around 5kg CO2E per tonne of food waste annually and produces zero day-to-day greenhouse gas emissions.

The study’s findings based on the uncontaminated segregation of food waste and all significant components of the life cycles of both the centralised and household management strategies for food waste, were included in the calculations. A copy of the paper: “The Comparison of Greenhouse Gas Emissions from the Centralised and Household Treatments of Food Waste” can be found here

Link - Sink Your Waste

Let's Recycle - Ruddock backs anaerobic digestion for food waste - that settles it; it must be a con!

RWM - "Food waste disposal systems are like fly-tipping" says water company

MRW - Environment Minister says AD is the best process to tackle food waste