A method of reducing the odor released by a wastewater treatment system without eliminating the entire aerobic and/or anaerobic bacteria population within the system, the method comprising the steps of:
- continuously or variably adding to a process flow of water a composition in an amount such that it is in excess of the SRP PAA demand but is below the aerobic PAA demand,
- detecting an increase in PAA demand in the process flow of water,
- in response to the detected increase in PAA demand, adding an effective amount of PAA to the flow to reduce the PAA demand to levels which are found to reduce malodor,
- wherein the composition comprises at least one peroxy acid.