TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In producing biodiesel using acid esterification, pumping the partially reacted PFAD, catalyst, and solvent mixture through a nano reactor including a cavitation chamber comprises forcing the partially reacted PFAD, catalyst, and solvent mixture through a nano orifice where, by a phenomenon of hydro cavitation, collapsing nano liquid molecules to generate instantaneous temperatures of approximately 1000 degrees C resulting in quick reaction taking place at the surface of collapsing nano molecules to continue the reaction of the partially reacted PFAD, catalyst, and solvent mixture. Alternatively, producing biodiesel using acid esterification comprises: mixing a feed oil, acid catalyst, and solvent mixture in a nano reactor feed tank; heating the feed oil, acid catalyst, and solvent mixture to produce a partially reacted feed oil, acid catalyst, and solvent mixture; forcing the feed oil, acid catalyst, and solvent mixture through a cavitation chamber comprising a nano orifice where, by a phenomenon of hydro cavitation, collapsing nano liquid molecules to generate instantaneous temperatures of approximately 1000 degrees C resulting in quick reaction taking place at the surface of collapsing nano molecules to continue the reaction of the feed oil, acid catalyst, and solvent mixture; cycling the partially reacted feed oil, acid catalyst, and solvent mixture through the cavitation chamber more than one time to continue the reaction to produce raw biodiesel; and distilling the raw biodiesel to produce finished biodiesel. Preferred System: In the system, the feed oil consists essentially of PFAD. The feed oil is approximately 30 percent by weight of the feed oil and acid catalyst mixture. The acid catalyst consists essentially of PTSA. The PTSA is approximately 30 percent by weight of the feed oil and acid catalyst mixture. The feed oil and acid catalyst mixture further includes methanol as a solvent. The cavitation chamber includes a nano orifice where, by a phenomenon of hydro cavitation, collapsing nano liquid molecules generate instantaneous temperatures of up to 1000 degrees C resulting in quick reaction taking place at the surface of the collapsing nano liquid molecules to produce the reacted mixture. The feed oil and acid catalyst mixture in the nano reactor feed tank is heated to approximately 80 degrees C reaction temperature to start a reaction between the feed oil and catalyst to generate biodiesel. The feed oil and acid catalyst mixture cycles through the cavitation chamber for a period of time between three and five minutes to complete the reaction into biodiesel. The feed oil and acid catalyst mixture is cycles through the cavitation chamber for a period of time of approximately three to compete the reaction into biodiesel. The feed oil and acid catalyst mixture is cycled through the cavitation chamber approximately six times to compete the reaction into biodiesel. It further comprises a demethylation section for recovering methanol solvent for reuse. It further comprises biodiesel distillation for processing the reacted mixture to strip off impurities. The waste biodiesel comprising a remaining approximately ten percent by weight of the total biodiesel in a distillation column is drawn at the bottom of the distillation column and stored for boiler fuel for generating steam for use in heat exchanger elements of the biodiesel production system. EXAMPLE - No example given.