If the city starts requiring residents to sort the materials that they put out for recycling, then many residents will put more recyclables in with their regular garbage.
Given
If the city starts requiring RSM → RWG residents to sort the materials that they put out for recycling, then many residents will put more recyclables in with their regular garbage.
This [more recyclables in ↑RG → ↑RL with the garbage] will result in more recyclables being buried in the city's landfill.
However, because of the SWB → RSM cost of having city workers do the sorting, the sanitation department will not stay within its budget unless the sorting requirement for residents [sort materials] is implemented.