I doubt that you are on the next political scandal, but in fairness to you there is a public element to bin charges: levies for disposing of waste at landfill site.
They can be, like cigarette taxes, increased on the back of public policies: who will oppose increased landfill waste disposal levies?
But that will be very visible, and cannot cover the amounts at play with the water charge or household tax.
Plus it would hardly be discreet if part of that money went to water...
See what happened 3 years ago: http://www.irishtimes.com/news/environment/collection-firms-to-ra etc ...
Collection firms to raise bin charges
Move follows levy increase of €10 per tonne for disposing waste at landfill sites