How to pair a foot pod to a dumb treadmill

I am trying to find a way to sync my footpod with a dumb treadmill using an iPhone. Do I need to connect an ant+ dongle to my iPhone to do this?

An iPhone cannot support ANT+ even with a dongle. Only Mac, PC, and some Android devices support ANT+. If the footpod supports Bluetooth, use that. Otherwise you would need an ANT+/Bluetooth bridge device.