>The mealworms are able to do this due to their gut bacteria (Exiguobacterium sp. strain YT2) that actually breaks down the polystyrene.
> The fact that these worms are converting about half of the styrofoam they eat into carbon dioxide and the rest into mineralized organic material suggest that it has come full circle.
The bacteria breaks the molecules and shouldn't harm the animals that eat them.
I don't know about industrial processes involving bacteria, but the mealworms might be providing a lot of value. First they chew up the styrofoam, and then they provide an environment (pH, nutrients, enzymes) for the bacteria to be effective. Mealworms are also fairly easy to breed.
If you isolated the bacteria, you might need to provide those other functions in an alternative way that's more cost effective than putting some worms in a bucket.
Would you need to feed the mealworms anything other than just styrofoam? i.e. can you just have a giant vat of mealworms that you through styrofoam into?
My recollection of the original stanford writeup was that you actually couldn't feed the worms anything else. If given any options, they picked styrofoam last.
True, but at industrial volumes it might be more space/cost/time effective to directly use the bacteria, combined with a mechanical or chemical pre-processing step.
How are you defining efficiency? Time to “disappear” the styrofoam? If yes, that’s not the problem to solve here. Health concerns are to be reduced from used styrofoam. Burning reacts it with air, and as another has commented, that produces harmful byproducts. Decomposing into CO2 (perhaps which can be captured) and manure is perhaps a better alternative?
> It does not. Burning in an incinerator is completely clean and releases only water and CO2. If you burn it badly you can make smoke, so don't do that.
I suppose I should have been more careful with my terms - "burning" was meant as a layman's "making fire" rather than in a controlled process within an incinerator as you mentioned.
If this is clean, why are people so motivated to look for alternatives for its disposal, giving up and resorting to landfill? Is incineration cost-prohibitive? Or is the transport to the incinerators inefficient?
Because people are not rational and incineration "seems" dirty somehow, even though it is - by far - the mostly environmentally friendly way to deal with plastic. Far outclassing recycling.
It just looks bad, and recycling is about feeling good, not the environment.
Incineration not only disposes of the plastic, it also gives you back the energy embodied in the raw material used to make it. Then you can avoid burning some other oil, and use that other oil to make fresh plastic.
You can think of it as recycling with extra steps :)
The danger from Styrofoam comes when the smoke from burning it releases harmful amounts of PAH (Polycyclic Aromatic Hydrocarbons). According to the Illinois Department of Public Health, it is known that PAH stays in the environment for years; has been linked to short-term symptoms like eye irritation, nausea, vomiting, diarrhea and confusion, and long-term symptoms like kidney and liver damage and cataracts.
> The fact that these worms are converting about half of the styrofoam they eat into carbon dioxide and the rest into mineralized organic material suggest that it has come full circle.
The bacteria breaks the molecules and shouldn't harm the animals that eat them.