An apparatus for disinfecting a fluid has a fluid -containing structure； aninward-facing first electricallyconduc-tive cylindrical body contained vvithin said fluid-containingstructure； an outward-facing electrically conductive-second cylindricalbody disposed within said first cylindrical body, in mutually facing paralleland coaxial relation thereto, and spaced apart therefromto define a fluid-occupiable cavity； a power supply electrically coupledbetween said first cylindrical body and said secondcylin-drical body, said power supply producing therebetween an electric field,said field comprising a waveform approximating a seriesof alternating square wave pulses of opposite polarity, said pulses having amaximum absolute value of approximately 60 volts percentimeter, a complete cycle of said waveform, comprising a first pulse and asucceeding pulse of opposite polarity, recurring witha frequency of between about 2 kHz: and about 5 kHz and providing about 2 ampsto about 4 amps.
