My dad works for the DOT in a state that has a large homeless population. After the police remove everyone from the campsite, the DOT goes in to clean up.
And by clean up, I mean thely just throw literally everything into a big dumpster. Although apparently it can be pretty gross due to the unsanitary conditions (no toilets) and drug needles laying around, so they get 'hazard pay' and overtime pay for the job.
I'm sure the team of cops get 'hazard pay' and probably overtime as well. This usually takes a day or two and happens every few weeks. The cost of labor alone to temporarily displace these homeless people must be astronomical... I bet they could build so much temporary/transition housing with that money instead.
Oh, and I forgot to mention that the police usually only remove these encampments in wealthier neighborhoods and let the poor areas deteriorate.