Extraction of carboxylic acids, C-2-C-6, was carried out with tributylphosphate (TBP) from an aqueous waste stream at pH = 2, 2.5, and at as such pH taken from an environmental process engineering point of view. The effect of the presence of H2SO4 and HCl on the distribution coefficients for C-2-C-6 carboxylic acids was investigated. The measurements were also carried out in the presence of inorganic salts such as Na2SO4 and NaCl.