IoT gabage monitoring system with my own Android application
Does your campus have WiFi? If so, go with EPS8266 if its pins are OK for your sensors.
ESP Pinout

You'd want to keep an eye on power consumption; you'd sample your sensors per desired interval and deep-sleep at all other times. Check out available sleep here. It also has en example of how to sample and send a sensor, and sleep afterwards.

On the application end, you could either use a ready service such as Blynk, or go for a custom solution and send the data on your server. Of course, you would then need to write an API and some sort of application to present your data. 

Let me also point out that for measuring garbage level, you should calculate the total volume of your bin and subtract the volume of garbage your sensor detects. Having non-uniform trash would give you some trouble, but it's a good technique for an estimation of garbage volume. Also, if using ultrasonic distance sensors, given the fact that you have temperature readings available, you should compensate your measurements; check this out.