Forum Replies Created
atapene – some kind of wet air scrubbing system should work, as Dirk mentions. But I’d start by using a weak solution of sodium bicabonate in water. It should react with the acetic acid – and convert it to Sodium Acetate. This is non toxic, and shouldn’t cause any problems with disposal.
Interesting paper posted on ResearchGate.
BTW, I thoroughly recommend having an account on ResearchGate. Researchers regularly post copies of their own papers – so people can read them without having to go through university library accounts. That means that private researchers, who don’t have “institutional access”, are not excluded from obtaining the information they need.
That is utter madness.
They are just making huge quantities of PVC swarf.
Have you been in touch with any of the Repair Café people? Clothing & other fabric-based items are often included in the type of things that the cafes will repair. Some of the regular local volunteers could already have the right skills, experience, and interest to help with your project.
There is a list of Repair Cafes here – and half a dozen seem to be based in and around Eindhoven.
I think that is a good point Stan.
Near where I live there is a plastics factory that makes bathroom equipment (baths & shower trays) from glass reinforced polyester resin. Sometimes it is possible to smell fumes from the resin in nearby residential streets – but the fumes are presumably within limits, and I’ve not heard of any problems.
Without an objective outside measurement of toxicity, it is difficult to know how much of the various volatile compounds really need to be filtered out. It is impossible to go by aroma – as different people have different abilities to smell dilute chemicals. (e.g. I’m like a bloodhound, and smell everything. My partner has never once detected an odour from the plastics factory.)
Living Energy Farm (LEF) has developed two unique electrical technologies. The first is “daylight drive” whereby we power high-voltage DC motors during daylight hours. Early generations of off-grid energy systems used low-voltage DC electricity from PV panels. Increasingly, PV panels are tied together in strings that produce much higher voltages. At LEF, 90% of energy use is based on daylight drive application of high-voltage DC power from PV panels. This dramatically reduces the cost of providing basic services like pumping water, grinding grain, cutting wood, or accomplishing any of a myriad tasks that are needed in a village. Combined with thermal storage, daylight drive is a much cheaper, more durable method of suppling stationary power than AC power systems.
The second technology we have developed at LEF is the integration of nickel-iron (NiFe) batteries with LED lighting and charging systems. We are pursuing the deployment of this latter technology because it can be easily deployed to provide lighting and charging services for people all over the world who cannot afford grid power.
How is that LEF found these simple, cost-effective ways of using solar electricity while so many well-funded engineering organizations did not? Because we have been looking for answers that are simple, cheap, and durable, and they are looking for energy systems that mimic the AC grid power available to middle class consumers in industrial societies. The answer you get depends on the question you ask.
NiFe batteries are heavy and expensive. They were in significant use in industry 50 – 100 years ago. They faded out because the battery companies could not make enough money on them. But that predated both the arrival of both easily available photovoltaic (PV) solar electricity and LED light bulbs. (Incidentally, the old industrial NiFe batteries had high standby loss, modern ones do not. The price of NiFes is also coming down dramatically.) With the demise of NiFe batteries, the nascent off-grid movement of the 1970s and 1980s standardized around the use of short-lived lead-acid batteries. Off-grid technologies have been crippled by poor batteries.
Thanks @ratnag – it all seems more sensible now 😉
From your picture it also looks like quite a lot of your polymers are clear (so no fillers) which will improve your options when finding uses (or customers) for the waste.
Also – having a relatively large source of various good quality uncontaminated/decontaminated engineering plastics offers even more interesting possibilities. Usually items made out of the more exotic grades of polymer are not available in numbers that make any form of recycling cost effective. But the higher price of the engineering plastics, compared to the general commodity types, might mean that someone will be willing to pay for your collection.
But as you say, identifying some of these plastics could be a challenge. The manufactureres are not going to bother fully labelling them, as they don’t expect them to be recycled. And they also might not want to give away any manufacturing trade secrets, so may not tell you the full details even if you asked.
10 out of 10 for wanting to do something worthy and ethical with the byproducts of your healthcare 😉
However, you might have more of a problem than you anticipate – for a couple of reasons.
For a start, I’m quite amazed that the waste plastics you have can be simply placed in your domestic trash. In some countries that would be an offence – as a lot of it would be classed as “infectious waste” and would need to be sent to an authorised treatment site (possibly for incineration). Just leaving waste disposal up to the recipient of the care products seems a little bizarre.
This page at the World Health Organisation website has a handy summary of some of the issues.
This also means that anything you decide to make with the “blood contaminated” plastic could end up being classed as infectious, unless you can find a way to treat it to the satisfaction of the authorities. Washing methods (as being investigated by the PP team in the Netherlands) probably wouldn’t be seen as good enough – and full steam autoclaving might be too expensive for a home-based project.
The second issue, as you’ve already discovered, is the range of plastics that you’ve been left with. Many of them are classed as Engineering Plastics. As such, they fall outside of the rather simplistic “1 – 6 recycling code” system used for Commodity Plastics – and are essentially code 7 or “other”.
However, I’m guessing that most of these will be the most heavily contaminated plastics – such as the polysulfone membrane tubing – which might be beyond economical treatment anyway. Unfortunately, you might find that the HDPE fluid container is the only easily (and safely) recyclable item.
I like the idea of hunting and skinning a sofa… 😉
Story in this weekend’s Observer newspaper:
How melting plastic waste could heat homes.
The story is about a type of pyrolysis plant that takes the process further to produce hydrogen. The story doesn’t actually use the word pyrolysis, and by talking about clean hydrogen energy it taps into the current “hydrogen economy” rhetoric that is being used by some people.
The information appears to come from the University of Chester website. But there isn’t much extra there either. To me, it sounds like they may just be using a variant of the old coal syngas process – which requires steam and a carbon source to reduce water to H2 & CO. In this case they are using mixed plastics instead of coal, and may also get CH4, amongst other gases.
They are talking about collecting the H2, for sale, and burning the rest of the off-gases to make electricty. As such, this is basically an EFW (energy from waste) plant, that collects hydrogen as a byproduct. It looks like the combustion products (including CO2) will still enter the atmosphere – so, arguably, like all EFW plants it is just displacing an equal amount of fossil fuel use.
At least it will consume a lot of plastic – preventing it entering the oceans – even if it does pump out CO2.
I can see that any duckweed grown for food is going to need “clean” conditions, but the stuff grown for biofuels should also be good for wastewater remediation.
Many sewage treatment plants are currently building biodigester facilities to generate gas and make electricity. Another stage of water cleanup from duckweed might also help to provide extra feedstock for co-digestion – possibly enhancing the methane yield. The methane yield from pure sewage is not actually that good (although they process such a lot of crap that it is still worthwhile doing). Hence, at some plants they are also taking waste food to add to the digesters.
Unfortunately, some facilities seem to be using non-waste food, such as maize, for co-digestion – just because it is locally cheap.
If duckweed is to be used on a large scale, as a biofuel feedstock – then we do need to imagine what that would look like. One problem with current biofuel options is that people expect the crops to be grown “somewhere else” – so to not make any changes to their local scenery. But most of the good land situated “elsewhere” is already being used to grow food – and so biofuel crops simply displace food crops.
For biofuel crops, we need to use “marginal land” – such as hills and mountains. What would that look like? I’m guessing that for growing duckweed, terracing might just work – a bit like the way some rice paddy fields are arranged.
Try using the search function.
I guess this is one way of making a cold frame using bottles…
Have you read the reviews?
Maybe starting small, by making cloches, would be a good idea.
Having just had a healthy courgette plant demolished by the local wildlife – I think I’m going to have to do something to protect some of the more vulnerable plants in my garden, and cold frames or cloches are probably going to be the cheapest thing to build.
I’m guessing that wooden frames glazed with flattened panels cut from 2 litre PET bottles might just work. Alternatively, reclaimed clear polythene sheeting, or reclaimed glass (preferably toughened) could be used for glazing – with the side panels or framework made from re-moulded recycled HDPE.
Yeah, if the sun is entering the room, and hitting walls/furniture, then the overall heating benefit should be the same. You just won’t have a concentrated stream of warm air out of a can stack.
And yes, if PET doesn’t block UV, then I guess it might be possible to use such a bottle array to kill bacteria in tropical sunshine. I would think that you would need narrower bottles, though, so the UV can fully penetrate.
@donald – from a hot-surface-to-air heat transfer perspective, all that gluing of the cans is probably a waste of time, effort, and glue. If the whole glazed frame is sealed front and back, then you might as well scrunch all the cans, spray them black, and randomly fill up the framework with them.
That way, the surface area for heat transfer will be increased, as the air perculates (or is blown) up around the cans – and it will also create more turbulence. n.b. Surface to air heat exchangers are some of the most difficult to design well.
It looks like the plastic bottle ones are water filled – which might keep plastic surface temperatures down to manageable levels – if the flow is high enough. However, stopping all those bottle-to-bottle joints from leaking won’t be easy. And if the water temperature does get too hot, then the bottles will distort and shrink – which will definitely split the joints. 😉
And they have a verson 2 with some interesting joints made from plastic drainpipe. But, as discussed in other forum threads, drilling into the ends of the wooden beams is not a good idea – as bending loads are likely to split the wood.
Have a look at this thread. A number of the comments are about corrugated roofing sheets, mostly made from tetrapak waste (pulped, cardboard seperated, and the sheets moulded from the remaining polyethylene.)
I guess extra (low density) polyethylene could be also be added – such as waste plastic bags.
Hi @sarahg – after filling your survey questions, a little while ago, I’ve been pondering the geodesic dome greenhouse idea – so I might as well add some thoughts here.
I suspect a lot of people see geodesic domed structures and get a little buzz of enjoyment just from the way they look. I know I do – although I can’t exactly say why. Is it because of their geometric symmetry? Is it because most built structures tend to be rectangular cuboids – so the domes just look different? Is it the patterning of the framework that makes them look cool? I’ve no idea.
I’ve certainly always fancied the idea of having a geodesic dome greenhouse – and I’ve even looked into the possibility of building one – before various things put me off.
The first disadvatage I see is the circular ground plan. If you have the room for a circular structure, then fine – but in most small gardens, a rectangular greenhouse usually fits in better, without losing space. Even arched polytunnels have a rectangular ground plan – and so can be sited next to each other without creating any inaccessible external patches.
The other issue is the glazing. If using hard sheet material (e.g. agricultural glass, clear unplasticised PVC, polycarbonate) then cutting the triangular shapes could be quite wasteful. I guess there would be an optimum nesting scheme for cutting the different shapes of triangle from standard rectangular sheets – which would make certain sizes of dome more or less economical to build – and that would have to be carefully thought out at the design stage.
Sealing the glazing at the corners could get a bit tricky too – although for most greenhouses it wouldn’t matter too much if it was a little bit “leaky”, I guess.
The other method of glazing, by using flexible plastic sheeting is probably easier (and cheaper) – but that might also be a bit wasteful, compared to (say) covering a polytunnel.
But, yeah, geodesic domes are cool – which is why they turn up in all sorts of places. 😉
It was a bit of a disappointment, last night, when I saw that Fimo used PVC. I had always assumed it used some kind of thermosetting resin.
Looked at it many years ago, for home workshop rapid prototyping & ‘proof of concept’ purposes. But as you say @s2019 there might be more suitable materials.
There are filled epoxy “putties”, that start to cure after kneeding, and there are 2 pack polyester-based “fillers”, which might work too.
I guess people might have written about these before, in the forums.
How about using something like FIMO to create the mould? It should be malleable enough to form around your 3D printed “pattern” – and then you might be able to split it into two halves, using a sharp blade, and remove the pattern. The halves could then be fired (cooked) in an oven, whilst hopefully holding the detail of their shape. Fired Fimo is relatively strong, but you would have to see how it behaves during injection. My guess is that it would be better than silicone or plaster, as long as the heat of injection doesn’t soften it (which might happen).
PET bottle solar collectors?