A novel method of beer brewery wastewater treatment was developed based on in situ hypochlorous acid generation. The hypochlorous acid was generated in an undivided electrolytic cell that consisted of two sets of graphite as the anode and stainless sheets as the cathode. The generated hypochlorous acid served as an oxidizing agent to destroy the organic present in the brewery wastewater. An influent chemical oxygen demand (COD) concentration of 2470 mg/L at an initial pH 4.5, a current density of 74.5 mA/cm(2), a sodium chloride content of 3%, and an electrolysis period of 50 min resulted in the following values: pH, 6.7; COD, 64 mg/L; biochemical oxygen demand (BOD5), 30 mg/L; total organic carbon (TOC), 40 mg/L; residual total chlorine, 162 mg/L; turbidity, 20 NTU (nephelometric turbidity units); ammonia nitrogen (NH3-N), below the detectable limit; and temperature, 40 degrees C. The energy requirements were determined to be 56 and 39 W/L, while treating 24 L of beer brewery wastewater with sodium chloride concentrations of 2% and 3% and at a current density of 74.5 mA/cm(2). The observed energy difference was due to the improved conductivity at high sodium chloride contents. The cost incurred in treating 1 m(3) of beer brewery wastewater was determined to be RM 8, when the electrolytic reactor was operated at a current density of 74.5 mA/cm(2) and the sodium chloride content was 3%.