A system for treating water comprising: an electrochemical cell having an inlet and an outlet, the inlet of the electrochemical cell fluidly connectable to a source of water comprising at least one contaminant, the electrochemical cell comprising: a cathode comprising a catalytic material for electrochemical generation of persulfate free radicals, wherein the cathode catalytic material comprises a metal selected from the group consisting of iron, copper, nickel, cobalt, and metal alloys; and an anode; a source of a persulfate positioned upstream of the electrochemical cell and fluidly connectable to the source of water; a first contaminant concentration sensor positioned upstream of the electrochemical cell and fluidly connectable to the source of water; and a controller operatively coupled to receive one or more input signals from at least the first contaminant concentration sensor, the controller operable to generate a control signal that regulates at least a rate of introduction of water from the source of water, a rate of persulfate introduction to the source of water, and a potential applied to the electrochemical cell based on the one or more input signals, characterised in that there further comprises a second water flow rate sensor positioned downstream of the electrochemical cell, and wherein the controller is further operable to receive at least one input signal from the second water flow rate sensor to generate a control signal that regulates at least the rate of introduction of water from the source of water, the rate of persulfate introduction to the source of water, and the potential applied to the electrochemical cell. an electrochemical cell having an inlet and an outlet, the inlet of the electrochemical cell fluidly connectable to a source of water comprising at least one contaminant, the electrochemical cell comprising: a cathode comprising a catalytic material for electrochemical generation of persulfate free radicals, wherein the cathode catalytic material comprises a metal selected from the group consisting of iron, copper, nickel, cobalt, and metal alloys; and an anode; a cathode comprising a catalytic material for electrochemical generation of persulfate free radicals, wherein the cathode catalytic material comprises a metal selected from the group consisting of iron, copper, nickel, cobalt, and metal alloys; and an anode; a source of a persulfate positioned upstream of the electrochemical cell and fluidly connectable to the source of water; a first contaminant concentration sensor positioned upstream of the electrochemical cell and fluidly connectable to the source of water; and a controller operatively coupled to receive one or more input signals from at least the first contaminant concentration sensor, the controller operable to generate a control signal that regulates at least a rate of introduction of water from the source of water, a rate of persulfate introduction to the source of water, and a potential applied to the electrochemical cell based on the one or more input signals, characterised in that there further comprises a second water flow rate sensor positioned downstream of the electrochemical cell, and wherein the controller is further operable to receive at least one input signal from the second water flow rate sensor to generate a control signal that regulates at least the rate of introduction of water from the source of water, the rate of persulfate introduction to the source of water, and the potential applied to the electrochemical cell.