I’d calculate this in liters of waste and collection cycles, not just people per bin. Start with a planning formula:
Cans needed = (attendees × waste per person per day × event days) ÷ (bin capacity × fill factor × empties per day) × (1 + buffer).
For a one-day, 10,000-person festival, assume about 1.5 L of general waste per person and 0.75 L of recycling per person. That gives 15,000 L of general waste and 7,500 L of recycling. If you use 240 L wheelie bins, fill them to 75%, and empty them three times a day, each bin handles about 540 L per day. So general waste needs about 28 bins; recycling needs about 14. Add a 25% buffer for peak eating periods, messy food areas, and unexpected crowds: roughly 35 general waste bins and 18 recycling bins, or about 53 bins total. If you’re using smaller 120 L urban cans, the same assumptions point to roughly 70 general waste cans and 35 recycling cans—about 105 total—unless you empty them more often.
Don’t spread that number evenly. Put bin clusters where people queue, eat, enter, exit, and use toilets. Use clear signage, separate recycling and organics, keep lids and liners stocked, and schedule extra pickups during peak hours. Also check local event rules and vendor waste plans, because food vendors can change the volume a lot.