The problem is that standard trash bags do not fit in those bins. You have to find oversize trash bags that are a lot more expensive than needed. Usually people do not use liners for these bins. Whenever their kitchen trash bin are full, they bag it up nicely and dump it in the big collection bins, resulting in inconvenience and waste.
For example I have a single family / detached house with a huge trash bin on wheels. It should be quite handy for dumping vacuum cleaner dust, and for non-recyclable garage and yard waste. But without a lining I can't use it, having to carry the waste back into the house. I also have to empty the bagless vacuum cleaner bin into a plastic bag, tie it up nicely, before dumping into the collection bin.
I do not want to waste trash bags for my kitchen bin. So I only empty the bin when it's full. Because of this it's not easy to tie up the bag nicely so I use bags with a draw string, which is significantly more expensive than the ones without strings. Also, carrying a full trash bag in and out of the house isn't that nice. A stretchable bag will prevent breaking up and leaking trash. This is more expensive.
The idea is to make an adapter inside the collection bin so smaller trash bags can be mounted easily. I invented one.
Basically it's an almost square wooden frame, which sits nicely inside the bin as shown. Opposite two sides are taller than the others for the trash bag to mount on. For the next version, there will be four wooden bars about a few inches long, rising up vertically at the four corners. It will be easier to mount the bags without touching the bin, and increase the trash volume a little.
The improvement will be to use square arcylic tubes or plumbing tubes, which would be washable and weather proof. You can get arcylic tubes from eBay, cut them using common electric saw and glue them using arcylic glue. The cutting will not be prefect because the edge tend to melt a little due to heat. Arcylic glue can be used on PVC plumbing tubes but I don't know if the reverse is true. Because plumbing tubes are circular, you need to use T's and corner elbows, and you cannot use complicated structures.
You can also use custom wood pieces to block off the small gaps between the adapter and the collection bin, to avoid accidents of making the collection bin dirty. You can have arcylic shapes laser cut for you, at a high cost. 1/8 arcylic sheets are rather solid and strong.
For the moment we use about 3 kitchen trash bags a week. With the adapter, the minimum will be one large trash bag per week, or every 2 weeks, because of the more efficient packing of household trash we may not need the trash to be collected every week. The large trash bags actually cost less because of the lack of drawstring.
Imagine how much the city saves and how much the world saves if collection bins are designed for fitting trash bags, and allow smaller sizes to be used?
Of course the kitchen bin still need lining. At the moment the draw string fits tightly on the tip of the bin. Whenever I like I take the whole bin to the yard and dump the content into the large one. The kitchen bag will stay on because of the tight fit. So the kitchen bag needed to be changed perhaps once a week or once a month.
Engineering and many other things are about saving material, time, and labor. It's all about money but it's also about happiness. You can add the ecology dimension but it's really long term material cost - cheaper materials that cost your health isn't saving at all.
PS Fold down the trash bag at the corners and it's hard to remove the bag without ripping out the corners. The bag is very securely in place.
Having a much bigger bin feels a lot better than the dingy little tall kitchen bin.
Empty the full kitchen bin into the larger bin is a rather bad experience. You don't want to churn garbage around. So saving trash bags by using it again and again is not difficult but you don't feel great about it.
Certainly I save money by using trash bags without the need for draw string. To save trash bags I will have to put bigger things straight to the big outdoor bin instead of the kitchen bin. So each bag will last longer. Or I can always use a smaller kitchen bin and hence smaller bags.
