Micro sized drones will be invented by mid 2020s based on insect biology and mechanics. The military will want to weaponize it but international treaties will be quickly signed to prevent it. The future drones will be equipped with sensors and be used to turn garbage into micro sized particles. These particles will then be sprayed with an environmentally friendly chemical that will dissolve them. The technology will see great use with ocean rubbish and the third world countries where waste is a big problem. Drones deployed into sewage systems will clean them before solid waste reaches the ocean. Eventually local garbos will become obsolete as drones will break down your rubbish as soon as you bin it.