NOVELTY - Production of biodiesel from natural oils involves providing waste natural oil having a relatively high free fatty acid content; providing virgin natural oil having a relatively low, or zero, free fatty acid content; blending the waste oil and virgin oil in proportions to produce an oil blend having a target reduced free fatty acid content; stripping the oil blend to produce distilled fatty acids and separating the fatty acids from the oil blend; feeding the oil blend to a transesterification stage to form biodiesel end product.    USE - For production of biodiesel from natural oils (claimed) useful as fuel for diesel compression ignition internal combustion engines.    ADVANTAGE - The method avoids the use of a complex and expensive preliminary acid esterification process and associated plant machinery to remove unwanted free fatty acids (FFA). This provides significant economic benefits, both in terms of process simplification and reduced use of machinery and materials. The process is more efficient than the prior art preliminary esterification phase, eliminating the use of highly corrosive concentrated sulfuric acid involved in preliminary esterification, thus reducing both capital costs and revenue costs in the production of biodiesel. The oil stripping step serves a dual purpose in removing fatty acids from both the virgin oil feed and the waste oil feed. The stripping step also provides a significant secondary product stream of graded fatty acids, which can be exploited as commercial grade raw material in many chemical processes. The removal of FFA's during steam stripping provides an additional income stream for the biodiesel plant operator. In the prior art UCO (used cooking oil) biodiesel processes, the use of concentrated sulfuric acid as an esterification catalyst requires substantial safety precautions and the use of specially specified materials of construction. The use of corrosive materials inevitably increases maintenance costs over the life of the plant, as well as requiring additional revenue for the purchase of the sulfuric acid. The process eliminates the aforementioned problems and provides more economically viable biodiesel manufacture process.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an apparatus for conducting the process for the production of biodiesel from natural oils comprising: a feedstock of waste natural oil having a relatively high free fatty acid content; a feedstock of virgin natural oil having a relatively low, or zero, free fatty acid content; unit for blending the waste oil and virgin oil in proportions to produce an oil blend having a target reduced free fatty acid content; a stripping stage for stripping the oil blend to produce distilled fatty acids and separating the fatty acids from the oil blend; and unit for feeding the stripped oil blend to a transesterification stage in which biodiesel end product is formed.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a process and apparatus for the removal of high levels of free fatty acids from a used cooking oil stream prior to biodiesel production.