Method for the pretreatment of a biofuel feedstock

A method comprising

• contacting a composition with an aqueous solution to yield a mixture, wherein
• the composition comprises
• one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil,
• about 5 wt. % or more of free fatty acids,
• about 10 wppm or more of total metals,
• about 8 wppm or more phosphorus,
• about 20 wppm or more of nitrogen, and
• the aqueous solution comprises diammonium dihydrogen ethylenediaminetetraacetate (“(NH4)2H2EDTA”), tetraammonium ethylenediaminetetraacetate (“(NH4)4EDTA”), a monoammonium salt of diethylenetriaminepentaacetic acid, a diammonium salt of diethylenetriaminepentaacetic acid, a triammonium salt of diethylenetriaminepentaacetic acid, a tetraammonium salt of diethylenetriaminepentaacetic acid, pentaammonium diethylenetriaminepentaacetate (“(NH4)5DTPA”), a combination of citric acid and tetrasodium ethylenediaminetetraacetate (“Na4EDTA”), a combination of citric acid and disodium ethylenediaminetetraacetate (“Na2H2EDTA”), a combination of citric acid and a monosodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a disodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a trisodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a tetrasodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and pentasodium diethylenetriaminepentaacetate (“Na5DTPA”), or a combination of any two or more thereof;
• and
• centrifuging the mixture to yield a first treated composition, wherein the first treated composition has less total metals and less phosphorus than the composition.