Apparatus, systems and methods for subjecting biological contaminated liquid fuels and/or liquids to an oscillating electric field for an extended duration within a treatment vessel that has a defined cavity having an insulating fill material encasing a number of insulating flow tubes each having at least one conductive body therein. The defined cavity also has one or more reservoirs in communication with the insulating flow tubes. An oscillating electric field is generated within the insulating flow tubes and reservoirs, whereby a biologically contaminated liquid fuel and/or lubricant is subjected to this oscillating electric field for an extended time to inhibit proliferation of these biological contaminants within the liquid fuels and/or lubricants.