Fluid will be bearing solids. Discharge is to atnosphere.
A spring loaded pinch valve would do but Red Valve limit their pressure to 150psi.
The rigs that these will be mounted on do not have compressed air.
(1) You could use the Red valve if you find a place 10M higher to mount it. Thereby subtracting enough head to get the internal pressure to less than 150 psi.
(2) An electrically controlled system: Pressure switch to monitor system pressure, solenoid valve, and a rack-and pinion actuator on a ball valve.  Drive the system with process water pressure.  Filter and regulate the water after the pressure switch.  If the water contains corrosives, the actuator and solenoid could be stainless steel.  Make the pressure switch normally closed, open to alarm.  Make the actuator on the ball valve "fail open" so on any loss of electrical supply, the relief opens and dumps pressure.
I did not suggest a pure electrically operated valve because electric actuators are so slow a damaging pressure spike may not be adressed.  A fast electric actuator on a small valve takes at least 6 seconds to stroke.  By then, the damage is probably done. 

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