Methods and compositions for dispersing a biofilm in an aqueous stream using fatty acids are disclosed. The fatty acids may have the formula: R1-R5—CH3 wherein R1 is an aryl or arylalkyl, —COR2, —COOR2, or —CONR3R4, —PO3(R2)3; R2 is H, an alkyl, an aryl or arylalkyl, or a halide; R3 and R4 may be the same or different and are H, a hydroxyl, an alkyl, an aryl or arylalkyl, a halide, or a sulfo (sulfonic acid group); R5 is an aliphatic chain having 2-30 carbon atoms and at least one double bond; and wherein when R1 is —COOH and R5 has eight carbon atoms and the FA has only one double bond, such double bond is not on the number 2 carbon.