The waste system in Japan tends to be confusing to foreigners, and each town, city, or prefecture has their own rules. This page outlines the waste system rules for Sendai city.
You can install an official app on your phone where you can search for specific items to know how to throw it away. It can also notify you when something goes out on that day, so you won't forget. You can find a link to the app here.
Sendai city encourages residents to follow the 3Rs when it comes to waste:
Reduce - Refuse excess packaging and shopping bags, use all food ingredients when bought, buy in bulk as much as possible
Reuse - Carry reusable bags, use your own chopsticks when eating out, buy refills of items like shampoo and soap and reuse the dispenser, carry your own refillable drink container for water and coffee etc.
Recycle - properly sort plastic, cans, glass bottles, PET bottles and paper, and dispose of food trays, milk cartons, and batteries etc. at stores
Below is a quick summary of what you must separate. Please see the above resources for more details. Please take this seriously, as we want to honour our neighbours, the city, and protect the environment.
Small electronic devices (under 30cm in diameter) can be taken to a collection point at the city office.
The city does not take larger electronic devices (besides printers and scanners). These will need to be taken by the manufacturer.
Large items and furniture are collected by booking in advance. After booking, you will need to purchase a sticker at a convenience store and take the item to the collection point on the day of collection.
Paper & Cardboard¶
Tie up cardboard into bundles. For loose paper, either collect it in a paper bag if you have one handy, or put smaller pieces instead of a larger piece and tie it up. This is collected every two weeks.
PET & Glass Bottles, and Cans¶
Remove any plastic packaging or paper labels (separating them correctly) before rinsing them. Place them loosely (without a bag) in the provided yellow crates at the collection point. These are collected once per week.
Any plastic packaging that carry a プラ icon should be separated, and rinsed if necessary. You will need to place them in a special red rubbish bag which is specifically used for this plastic waste. You can purchase these at many stores. This is collected once per week.
All Other Waste¶
Any other household waste can be thrown away into special green rubbish bags which are specifically used for this waste. You can purchase these at many stores. If you have separated your waste correctly, there should not be much in these bags besides food and sanitary waste. This is collected twice per week.