Well one reason is that garbage disposals are insanity to begin with. It makes no sense to burden the sewage system with food scraps it was never intended to handle. It’s not that it can’t handle them at all, but it wasn’t designed for it. However, new wastewater treatment plants designed to produce and capture biogas actually benefit from garbage disposals, so the situation may change in the long run.
Nowhere outside of USA has significant use of garbage disposals. We may see this change due to the biogas aspect.
Maybe it's just a cultural thing? Everyone has a garbage disposal here, even apartments. Occasionally you see a house built in the 1950s or earlier that doesn't but it's pretty rare, the Insinkerator is as ubiquitous as the microwave oven, common enough that the brand name has become a colloquial term like Kleenex or Hoover to describe similar units made by other companies. The house I grew up in had a septic tank so my dad always discouraged using the disposal for anything other than crumbs but I've never heard anyone suggest there was any issue with them in homes that are on a sewer connection. I suppose it could be an issue if you produced a tremendous amount of food waste but for the occasional off-cuts, scraps and crumbs I don't see it being an issue. I have a compost pile out in the corner of my yard where I dump grass clippings and stuff I prune off the trees so occasionally if something like a whole fruit or vegetable goes bad I'll toss it in that pile but I can't be bothered to trek outside for small scraps so into the disposal it goes. My mom used to keep a compost bucket in the kitchen sink, still does in fact and I've always hated it. Even with a lid on it attracts fruit flies and if you open the thing to put something in it stinks up the whole kitchen, blech. Probably would be ok if it was emptied daily but that didn't happen.
We can get yard/food waste service here too but it costs a significant amount extra on top of garbage pickup, at least our recycling is free. There's a ravine at the edge of my back yard so for me it has always worked to have the compost pile back there, it helps compensate for the erosion that takes place.
Wiki says about 50% of US homes have garbage disposals. I never had a place with one. But yeah, I think it is cultural. Swiss people have never heard of them, they’re absolutely shocked when they visit USA and see them for the first time! :p
Contrary to Alec's (Technology Connections) comments on Bosch dishwashers, the system is far superior to American dishwashers, in my opinion!
Bosch machines use a filter to catch big waste, which means the biggest waste can be siphoned off and cleaned every 30 or so uses (~3 months) into the general waste. This big waste is not macerated and recirculated within the machine, which clogs pipes and adds dirt to dishes being rinsed. You should remove big waste from dishes before loading them; I think this is true of all dishwashers. And while pre-rinsing is a waste of time (why people still do this baffles me), you should make some effort to take the largest waste off the plates as the machines are not designed to remove these effectively.
He didn't give the impression to me that one system is clearly superior. But anyway I agree, filter system is better. The issue is consumers don't want to perform basic maintenance. So the filter will fully clog after ~12 months and then customer will complain to the manufacturer that their dishwasher stopped working. Instead of with the macerator that clog or self destruct after ~3 years at which point, customer will buy a new dishwasher or pay someone to come clean it out, less calls to the manufacturer.
Ummmm... what? Bosch dishwashers work like pretty much every European dishwasher: filter screens of various mesh sizes are placed ahead of the recirculating pump, such that debris is trapped and doesn’t clog the spray arms. Then, when draining, water back-flows across the screens, releasing the debris into the wastewater, where it is pumped out. Only massively large debris like stays behind. Nothing to do with siphons. (Stuff like paper jar labels will sometimes be caught on the outer mesh strainer.)
The fine mesh filter needs to be cleaned periodically, definitely far more often than yearly! I do it about every two months, since I live alone and don’t need to run it super frequently.
I follow the rule of “scrape, but don’t rinse” that is recommended by experts.
Nowhere outside of USA has significant use of garbage disposals. We may see this change due to the biogas aspect.
Can't see it changing, too many issues with fats clogging up sewer pipes: https://en.wikipedia.org/wiki/Fatberg
An eco friendly city would have a food/organic waste pickup stream: https://environmentvictoria.org.au/resource/organic-waste/
That is not a hypothetical. The wiki article mentions a Swedish town that is encouraging people to get garbage disposals to improve the yield of their new biogas wastewater treatment plant. It being Sweden, I’m pretty sure they already have robust organic waste recovery.
And there’s no correlation between fatbergs and disposal waste, as far as I’ve been able to find. In my experience, most people only use them for vegetable waste, not for greasy meat scraps, since you can’t but bones into them anyway.
Can't see it changing, too many issues with fats clogging up sewer pipes: https://en.wikipedia.org/wiki/Fatberg
An eco friendly city would have a food/organic waste pickup stream: https://environmentvictoria.org.au/resource/organic-waste/
I thought that was mostly about the marketing of disposable wipes as "flushable" which they most certainly are not? Obviously oil and grease are a problem as well, but I always assumed that was people who just poured their frying pan of oil or bacon grease directly into the sink rather than use of garbage disposals. I haven't heard any claims that the US has dramatically more fatbergs than other industrialized countries, despite our use of garbage disposals, but perhaps that is just because most of our sewers are newer and in better condition than those in the London.
Yeah, fatbergs are thanks to “flushable” wipes. I find it appalling that the manufacturers are allowed to make that claim, when they demonstrably do not dissolve in water. (And why would they? They’re engineered for long-term storage in aqueous cleanser, after all!) I’m not against the wipes, I am just baffled at why the manufacturers are so vehemently opposed to just saying “do not flush, throw into trash” on the package, like baby wipes.
FYI, while pouring grease down the drain is a huge no-no, it’s not the source of most of the fat in sewage. Most of it mundanely comes from dishwashing, because even what’s dissolved with soap eventually separates out again, and the chemical reactions with soaps and cleaners cause the fats to solidify into waxy substances.
As for bacon grease, I wish they sold the grease coagulant that’s apparently commonplace in Japan: you just add some granules to the grease in the pan, and a few minutes later it’s a gel you can toss in the trash with no mess!!
This reminds me that I have a few bottles of used frying oil that I need to take to the recycling... and all the other recyclables too... sigh...