Protecting circuit from piezoelectric disc voltage spike
Please post a circuit when asking questions. A parallel resistor with a proper value is what you need. The current isn't high. The first circuit is with Arduino. The second circuit is recommended.

The circuit shows a 1MR resistor.
More complex option:

And the best way, but you have to reduce the voltage to 5V or 3.3V, depending on your MCU.

You can always use a standard sonar sensor, but they are expensive.
Sources:
http://www.learningaboutelectronics.com/Articles/Piezo-knock-sensor-circuit.php
http://www.robotoid.com/appnotes/sensors-piezo-disc-touch-bar.html
https://www.homemade-circuits.com/simplest-piezo-driver-circuit-explained/
https://www.homemade-circuits.com/diy-contact-mic-circuit/