Michigan asphalt company paves first US public roads containing recycled plastic | Hacker News Reader

Michigan asphalt company paves first US public roads containing recycled plastic

secondwavemedia.com

80 pointsrmason99 comments

They mention this as a way to recycle plastics, but for me this seems like a perfect way to get lots of tiny plastic particles out and into the environment once the road starts to wear.

Breathable micro-plastics doesn't sound nice.

I thought that’s happening anyways because we burn most of the plastic waste?

In a proper incineration plant it's so hot that there is no microplastics left over

But where does it go then? What’s the chemical reaction? Is there only CO2 and water left then?

Not an expert, but I assume remaining particles are filtered from the exhaust fumes and/or remain part of the remaining sludge.

Pyrolysis seems also like a thing that hopefully becomes viable: https://en.wikipedia.org/wiki/Thermal_depolymerization

Mostly, yeah. Of course polyamides also produce some nitrogen compounds and PVC also produces HCl that you have to deal with, etc.

But generally, plastics are very complex long-chain carbohydrates. Burning them at low temperatures produces all kinds of partially combusted horrible byproducts, but properly incinerating them results in just water and CO2.

I visited an incineration plan once and they showed how the make really sure the temperature is over 900 degrees Celsius st all times so that plastics and biological toxins are properly destroyed.

They also make sure there is lots of air available to the combustion process and thats done in an interesting way. They draw it in via the waste storage bunker solving two issues at once - the stinky air from all the waste gets effectively burned and the bunker is kept as negative air pressure so the smell doesn't get out.

And of course all the exhaust gases pass via a sophisticated fikter plant.

Aren't we then shooting ourselves in the foot then by being scared of burning trash/plastic waste? As an interim before solving all plastic waste, it seems like a much better solution than just stacking plastic into giant dumps.

You have to capture the CO2 and then figure out how to store it or turn it into pure Carbon and then you still have to landfill that.

Maybe. The CO2 going to the atmosphere is not great. You have to way that against the risks of plastic pollution from land filling.

If you are burning any fossil fuels for power, starting up waste incineration power plants to replace them is a pure win.

Perhaps burning trash would be the better solution. But it seems fairly unpopular with people in general, at least in the U.S. - you can imagine how easy it is to generate violent opposition to put a trash-burning facility in any place.

An acquaintance of mine from high school for some reason devoted much of his life to promoting trash burning technology. It seems like a good cause, but a futile one.

Trash incineration plants (referred to as “waste-to-energy” which sounds like an accurate euphemism to me) definitely generate very strong negative reactions in the U.S. I used to live just a couple miles away from one in Syracuse NY and I thought it was a great idea... recycle and reuse what you can, and everything else gets cleanly incinerated and generates electricity at the same time. There was no detectable smell either. Being supportive of the plant definitely put me in the minority based on all the negative feedback I read online and in the local newspaper.

I think burning PVC can produce dioxin, which would be very bad if it's not filtered out from the exhaust. Then it depends on how much you trust the facility to have an effective filter installed, and test and maintain it diligently. That costs money, so there will be a tendency to skip the maintenance.

No. Only partial combustion of PVC produces dioxins. Proper incineration plants do not produce any. So the solution is not filters, but hotter combustion.

Some countries have made that decision. For instance, Sweden recycles roughly half of all household waste, and burns almost all the rest.

https://www.nytimes.com/2018/09/21/climate/sweden-garbage-us...

This was my first thought as well. I’d rather discarded plastics be concentrated in dumps than thinly spread across the land.

Or why not use it just to make fundaments, underground insulation or just a ground water barrier. My understanding is that the underground environment causes less degradation to plastics than a one exposed to sun and constant friction.

But might affect ground water quality.

Micro plastics are terrifying, but I’m trying to think why exactly. If the road is shedding plastic dust along with the ground full of insoluble things like tar, rock, pebbles and stone; what’s a tiny particle of plastic any different from a grain of sand? I’m not asserting that micro plastics aren’t bad, just trying to understand what are the risks compared to a lot of dirt around us. I think dust on microscopic scale is inorganic insoluble solid particles and we seem to breathe/eat this stuff with no issue. Are polymers any different than dust particles when it comes to risks to humans in inhaling and ingesting it? Is it something else?

Microplastics can penetrate various biological barriers that were designed to keep dust etc. out. These biological barriers are already not perfect, things like heavy metals (lead, cadmium, …) do the same and can cause massive damages, which is why our only solution is to limit their uses and prevent them from leaking into the environment as much as possible.

TIL, thanks for the insight. It's remarkable already that human body can take so much abuse, and still survive.

Multicellular organisms are highly parallel, trillions of cells in a human. Even inside a eukaryotic cell (gigantic compared to far smaller bacteria) there is a huge amount of parallelism and non-linearity like in some assembly line.

The discussions about some health consequences always come up with "death" as the binary outcome measure. This is so useless. There already is an effect for tiny amounts of molecules. Functions in cells work worse, and cells work worse. This affects all of your functions. Since you are only ever exposed to tiny amounts even when it accumulates - e.g. for heavy metals - all those small problems are either not noticed or attributed to age, which of course also advances.

I had the "benefit" of diagnosed mercury poisoning (gray zone - enough to warrant chelation treatment, university clinic researcher doctor who always forgot to send his - very moderate - bills unless I reminded him several times for a year each time, so no over-diagnosis for profit).

From a disappearing nodule in my thyroid that I had had for decades, unchanging, that suddenly disappeared within weeks of chelation to the great amazement of an endocrinologist who had recommended surgery and who ultra-sounded me twice because he could not believe it, to a huge long list of "minor" ailments that I had increased over the decades and that I had ignored and also attributed to age (I never bothered doctors, far from hypochondriac, never thought much of it), to my returning ability for abstract thought, to digestion going from delayed and stinky to perfect (really), from sleep problems to easy and perfect sleep, to never tired, soooo much went away. With the doctors permission and supervision I chelated far longer and far beyond what would have been justified officially, since it kept helping even though measured amounts were getting really tiny.

Only because I saw the contrast, which rarely anyone ever does because for most people it's a very very gradual slope downhill, or they believe it's "genes" or age, do I even consider environmental factors. I once saw a webpage from a decades-long inner medicine clinic doctor who opened a private practice - in which she offered purely psychological bullshit "treatments" that you see from "alternative medicine". Her reasoning, explained on her (old, clinic-time) website: It's either genes or psychology in her clinical experience, meaning you can hardly ever really do anything but mitigation. Environmental factors never entered her mind. (I have no doubt any cases she diagnoses as "real" will be referred to a clinic by her right away, so not critic on her person from me.)

Which make sense, because the science behind the many, many each very tiny amounts of chemicals and their influence is very hard. Diagnosing it on an individual level, and not just on a population level (the latter does not help a doctor when there is a concrete patient in front of them), is even harder. So as a public health administrator allocating funds I perfectly understand why it flies under the radar. Because individual doctors working with individual patients can't really do much of anything. That is then equated with "there is no problem" (or they would do something about it). Oh and the "they didn't die so it can't be so bad" attitude.

Oh and by the way, completely non-scientific and my opinion after watching myself through many boring cycles:

- The common cold helps "getting stuff out". Significantly. I now wonder if eradicating it will have worse long-term outcomes for other issues. Also, not taking medicine to lower the symptoms for example for a good nights sleep might actually be better, the symptoms are part of that "getting stuff out". Yes it's very uncomfortable. It's horrible if you have to get up and go to work the next day.

- The best treatment by far are low stress (no alarms to wake you up to go to work when you would still sleep), sleep, rest as needed (during the day, just lying down and letting the mind go off somewhere - no reading or listening, the brain has to have "free time" to do things on its own - work from home is best!), walking (needed to get things moving, from my body experience the normal blood and ECF circulation is not sufficient.

- Changing sides left/right/left/right/... "I cannot find sleep" actually already is part of the brain's cleanup cycle! A lot of time spend in that phase may be an indicator that there is quite a bit. Clearly, having to get up for an early commute the next day adds stress and makes this hard to bear. But I recommend to accept it. It's a natural reaction, not something that should be suppressed. Yes it makes nights "work".

- The last 1-2 hours of sleep, that some (many) people find makes them more sleepy and groggy, are essential (okay, all phases are, but that's the one people like to skip).

- Being groggy after an afternoon nap is the same. Part of "getting stuff out".

You can call me out on any of this and I have no way to contradict you apart from anecdotes without any scientific value (nothing was measured, for example).

If true, this story convinces me even more that we must develop a superhuman at all costs, to at least overcome the current stupid and abusive societal and environmental formats, but something completely irrational to that cause (called ethics) forces us to tread water in the status quo.

I mean, we use plastic as implants in bodies like heart valves and joints. Hell, it’s a lot of Teflon. I think the jury is still out on the effect.

We also still use mercury amalgams in tooth fillings, that doesn't mean we should pollute the environment with random unrelated mercury compounds.

You missed my point. How toxic are plastics when we use them for implants?

The widely-used polymer molecules which the plastics are named of are mostly stable and harmless (actually, too stable, microplastics problems stems from that). But

1. plastics need other additives to have the required properties and these are sus

2. plastics over their lifespan dissolve/release other substances you don't want to keep in your body.

Dust is mostly chemically inert, while plastics aren't:

> Results

> Numerous animal studies have shown that exposure to nano- and microplastics leads to impairments in oxidative and inflammatory intestinal balance, and disruption of the gut’s epithelial permeability. Other notable effects of nano- and microplastic exposure include dysbiosis (changes in the gut microbiota) and immune cell toxicity. Moreover, microplastics contain additives, adsorb contaminants, and may promote the growth of bacterial pathogens on their surfaces: they are potential carriers of intestinal toxicants and pathogens that can potentially lead to further adverse effects.

https://particleandfibretoxicology.biomedcentral.com/article...

Every now and then I read something like this and wonder how long human lifespans would be if you combine modern nutrition, and healthcare but remove the toxicity of our modern environment.

Roman leaders often lived into their 60s/70s.

Biden is 78, Pelosi is 81, Trump is 74, and Bernie is 79.

US Life expectancy is 79.8 ... so we have basically made it so a good chunk of people, not just the leaders live into their seventies.

There's a good chance that there's something in our current genome that makes us get old and die ending in our 70s.

> modern nutrition

Uh...

Roads do contain asphalt which isn't significantly different from a long chain plastic. Even worse is the tire dust itself.

Oh, there are issues with breathing any kind of dust. Big issues. We should avoid adding dust into the air.

Plastics, unlike inorganic dust, bind to heavy metals and organic pollutants. Animals (of all sizes, but this concerns mostly plankton) mistake them for food and this causes pollutants to concentrate in the food chain.

Microplastics in soil also lower yield and have other adverse effects on crops (but this afaik needs to be studied more).

From what I have read plastics contain chemicals that interfere with our endocrine system.

> What’s a tiny particle of plastic any different from a grain of sand?

Here you go:

> The smallest microplastic particles are capable of entering the bloodstream, the lymphatic system, and may even reach the liver.

https://www.theguardian.com/environment/2018/oct/22/micropla...

And they're -- additionally to the above -- often endocrine disruptors, carcinogenic, causing male infertility, most probably playing a role in all sorts of chronic diseases.

> Micro plastics are terrifying

Micro plastics are in lots of cosmetics already.

Ready for another batch of "Scientists tracked down a mass killer of $SOMETHING"? See for example https://news.ycombinator.com/item?id=25431550

yeah... you're not wrong. Plastics are basically organic compounds and they screw around with organisms very easily.

Tho asphalt is already made with bitumen (a petroleum product) so it's not like it's THAT much different. Hopefully we aren't concentrating even more problematic compounds than what already existing in the asphalt.

>Tho asphalt is already made with bitumen (a petroleum product) so it's not like it's THAT much different.

Plastics generate microplastics. Does bitumen generate microbitumen?

Does bitumen bioaccumulate into food supplies? Why compare the two?

Here's one thesis that claims it probably does not:

https://core.ac.uk/download/pdf/20366224.pdf

Ran into this interesting factoid a couple days back:

"Kerogen is solid, insoluble organic matter in sedimentary rocks. Consisting of an estimated 10^16 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold.... Petroleum and natural gas form from kerogen. Kerogen may be classified by its origin: lacustrine (e.g., algal), marine (e.g., planktonic), and terrestrial (e.g., pollen and spores).... Kerogen is insoluble in normal organic solvents in part because of its high molecular weight of its component compounds. The soluble portion is known as bitumen."

[https://en.wikipedia.org/wiki/Kerogen]

All from the same (previously locked-up) family of goodies, it seems.

Do microplastics bioaccumulate? Or at least in the sense that we think of bioaccumulation?

Yea, it accumulates in the food chain.

yes. the road surface is abraded as it's driven over, which creates oily dust. essentially "microbitumen".

also, road usage already causes microplastic pollution in the form of tire wear, so while including plastic in the road surface might increase the overall volume of microplastic pollution, it won't increase the distribution of it - areas near roadways are already microplastic hotspots.

This is the right question. We talk about micro plastics, has anyone looked at concrete micro particles and the effects on humans? What about just the fine dust from top soil? What is the effect on humans?

Reminds me a little bit when people get overly worried about keeping things clean without realizing everything is covered in bacteria that you ingest on a regular basis.

Roads already have a lot of tire dust due to tire wear, I don't think this will be a significant extra source of pollution.

> The polymer solves a longstanding problem that the asphalt industry has encountered since the first attempts at using recycled plastics in roads, namely how plastic separates once it's melted into the hot asphalt.

I knew that this sort of comment was on top when I clicked the comment section :-)

PS: I’m not saying it’s wrong, it’s just fits the HN sentiment perfectly.

The article states that there is no advantage to the paving by having plastic mixed in. This begs the question why, other than landfill diversion of plastics, replace aggregate with plastic?

Greenwashing.

It's already everywhere

https://www.wired.com/story/plastic-rain-is-the-new-acid-rai...

Quantity and dosage also matter.

Future generations will see our use of plastic like we see asbestos, HCFCs, and leaded gasoline. Nobody denies its utility. It just kills people and wildlife. Once we ban at least single-use plastic we'll recoil with horror at what we did and how long we took after realizing what we were doing to stop ourselves.

I’ve recently come to see this truth. Like reading the vintage ads recommending cocaine to help your tooth ache.

I just hope the future finds a way to undo so much of the damage.

> Like reading the vintage ads recommending cocaine to help your tooth ache.

Cocaine didn't result in large scale environmental damage, to this day it's still in widespread medical use as a local anesthetic.

Imho a much more apt example would be something like "plutonium toothpaste" and the fact how humanity has irreversibly changed Earths biosphere by introducing large quantities of atmospheric plutonium 239 during the countless nuclear weapon tests [0].

Any acknowledgement of potential deadly consequences out of that mostly exist in some fringe awareness [1], and pretty much never comes up in any debates around the risks and dangers of nuclear as a source of energy generation.

[0] https://journals.sagepub.com/doi/10.1177/0096340215581357

[1] https://qz.com/1163140/us-nuclear-tests-killed-american-civi...

> I just hope the future finds a way to undo so much of the damage.

Future? We can undo it now -- just with life improvements and simplifications, I've dropped my emissions 90%, according to online calculators. I take two years to fill a load of trash at home, which used to be weekly. Many other changes. And one person changing is exactly what causes more people to change.

As a result, Mayors, Congressmembers, and other politicians, CEOs, champion athletes, and more have come on my podcast, helping lead large communities. The Hacker News community is particularly recalcitrant, believing that Mars and fusion are simple and will solve everything while flying less or having fewer children is against human nature and solve nothing, but there's variation.

Systemic change begins with personal transformation.

That sounds like work and inconvenience though. Let's just hit the snooze button and hope the mighty people of the future can figure it out se we don't have to make any changes to our lifestyle.

[deleted]

HCFCs are refrigerants that deplete ozone. They are not made from corn.

https://en.wikipedia.org/wiki/Chlorofluorocarbon

No doubt we’ll recoil I know horror, but we’ll probably recoil in horror at plenty of things we don’t know better about…that’s progress.

Thankfully we don’t judge we don’t judge people who made errors in the past out of ignorance. ;)

There’s already significant questions about playgrounds covered with recycled rubber and the suggestion that sports fields covered with such materials generate black cancerous dust.

I really would not want to live in a street paved with recycled plastics being ground into dust and distributed into the local environment.

All you’ll hear though about this sort of thing is how wonderful it is that use is being found for waste plastics.

I’d say “who are the companies financing these initiatives? Are they plastics manufacturers?”

https://www.theguardian.com/us-news/2019/jun/25/lawmakers-co...

Plastics are being incorporated into roads everywhere. It’s the next asbestos disaster and it’s completely obvious it’s coming.

I was playing on outdoor soccer field with artificial grass filled with lots of shredded rubber. When it got hot outside it was like plaing on tire dump and the smell made me sick.

Repurposing things should come with high scrutiny and strict regulations.

Seed oils were repurposed from varnishes to be “healthy fats” when petroleum based varnishes took market share, to likely devastating effect.

“50 years ago, paints and varnishes were made of soy oil, safflower oil, and linseed (flax seed) oil. Then chemists learned how to make paint from petroleum, which was much cheaper. As a result, the huge seed oil industry found its crop increasingly hard to sell. Around the same time, farmers were experimenting with poisons to make their pigs get fatter with less food, and they discovered that corn and soy beans served the purpose, in a legal way. The crops that had been grown for the paint industry came to be used for animal food. Then these foods that made animals get fat cheaply came to be promoted as foods for humans, but they had to direct attention away from the fact that they are very fattening. The "cholesterol" focus was just one of the marketing tools used by the oil industry. Unfortunately it is the one that has lasted the longest, even after the unsaturated oils were proven to cause heart disease as well as cancer.” [1]

Recycled toilet paper uses materials high in BPA.

[1] https://raypeat.com/articles/articles/unsaturated-oils.shtml

I found out about green chemistry but maybe we should have a big pole dedicated to green societies.

Center lifestyles around low rate of recycling (glass?) biodegradation potential, availability, etc

I care very deeply about the degree of harm done to living creatures by the exposure to toxic chemicals used in everyday products. Recycling plastic waste is indeed a good thing, however it's more pressing that we reconsider the safe use of plastics entirely. The road surface is subject to all manner of environmental exposure, and is a very direct vector into our drinking water.

> Recycling plastic waste is indeed a good thing

Is it? It seems increasingly like it isn't, it's just that we've now got entire generations of people for whom this idea is an article of faith. We were raised on a steady diet of greenwashing. We've been hearing it on a regular basis, from authoritative sounding sources, for so long - perhaps since before we can remember - that it's hard to imagine it not being true.

I'll further qualify my statement: "Recycling plastic waste _would be_ a good thing if it existed in some feasible, safe form".

India has been doing this since Nov-2015, when the central government made it mandatory for road-layers to use plastic waste. As of Oct-2018, 100,000 kms of roads had been constructed using plastic waste.

https://swachhindia.ndtv.com/plastic-waste-roads-one-lakh-ki...

So are we just going to ignore all the evidence on the harms of microplastics?

Where do you think your tire treads go?

Is rubber considered a microplastic?

edit: oh no, tyres use 24% synthetic rubber (which is a plastic polymer) :(

Yes, vehicle tires are a big source of microplastics.

Is there any research how to make tires shed less plastic and carbon black?

So because roads already involve microplastics, we don't have to care about there being even more?

We have an easy and better alternative to plastics road but we dont fore tire, so there's that.

the bike trail nearest me, when it first opened, proudly proclaimed about all the recycled glass that was used to make the trail....until - surprise surprise - cyclists started getting flat tires from the pavement.

Who could have predicted that?

It’s not the epic stupidity that bothers me - it’s the fact that it’s self evident - that’s what really bothers me.

It’s blindingly obvious this is a really bad idea.

What is so great about putting waste in surfaces that is driving this foolish rush to environmental disaster?

When something obviously stupid is happening and you just can’t see why, sniff to smell who’s money is behind it.

Actually the epic stupidity does bother me.

This is quite funny, thanks for sharing.

Part of me thinks this comes from the juvenile way that recycling is taught in our schools. Kids don’t leave with a good understanding of the conservation of mass/energy; everything we have around us is made from the earth, our goal has to be getting it back into the earth in as gentle a way as possible.

This really drives me nuts. How can it possibly be a good idea to introduce plastic in to the environment, even in the name of “recycling”? And it’s not like Dow has the world’s best record with environmental topics.

What's wrong with asphalt it's already quite recyleable

cracks and potholes form very quickly... unlike the plastic version according to this article: https://swachhindia.ndtv.com/plastic-waste-roads-one-lakh-ki...

Quote in the article: “It was neat to be on the forefront of something new”

Wikipedia: "In December 2019, India has built 21,000 miles of roads using plastic waste"

Different technology?

> It used to be that when dead animals were incinerated, the resulting black ash was mixed with bitumen and used as road surfacing.

https://www.theguardian.com/environment/2021/apr/13/the-knac...

I assume everyone is correct with their justification about microplastic fears. Every once in a while I wonder how much better everyones health would be if society greatly restricted automobiles and public transport including the structure of where everyone lives was being better engineered to handle multiple trains stopping periodically at walking distance of businesses and homes.

> Every once in a while I wonder how much better everyones health would be if society greatly restricted automobiles and public transport

The only large scale test of this I know of has been covid lockdowns, and, to an extent, 11 September 2001 air travel pauses. The effects were striking and the environment benefitted. There are plenty of downsides too, but it sure got me thinking.

Is there discussion on the lifecycle of this plastic?

Probably one winter?

Want a great green infrastructure project? Start taking down highways and roads. Don't build new ones or put plastic on old ones.

Building roads leads people to adjust and fill them with congestion. People will adjust to fewer roads too. The project will produce short-term jobs and long-term savings.

Roman workers with no degree made the roads last longer than 2,000 years, until the engineers came along.

(No puns, no sarcasm, just being sardonic)

Yes, we should pave our highways with cobblestones. It might help reduce traffic :)

Right and at 20 million per roadway mile we couldn't afford a billion miles of them.

This also ignores all the Roman roads that no longer exist.

I fully expect millenials and zoomers to all die at 50-60 years old from all the plastic we consume

They won’t die, they’ll solidify into mannequins.

As a resident of Michigan this road will be destroyed and needing replacement in approximately 8 months.

Apparently they are more durable then traditional pavements (if similar to https://swachhindia.ndtv.com/plastic-waste-roads-one-lakh-ki...)

I was being a little sarcastic, based on how horrible the roads are here. I wish they were engineered for longevity - if the plastic helps I’m all for it.

Holy crap, this is a pretty stupid idea considering the UV damage and abrasion that road surfaces have to endure.

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