Abstract: Methods and systems based on membrane separation processes for removal of field chemicals are provided. In certain embodiments, methods and systems for water impurity removal include introducing contaminated water into membrane separation devices, which comprise ultrafiltration, nanofiltration, or a reverse osmosis membranes. In some embodiments, the reverse osmosis system comprises a semi-permeable membrane capable of rejecting substantially all of the monovalent ions, divalent ions, and organic molecules. Examples of impurities which may be removed by this system include kinetic hydrate inhibitor and/or corrosion inhibitor. In certain embodiments, the impurity removal system may comprise one or more impurity removal stages. Some embodiments of the present invention feature a high field chemical removal rate of from about 84 percent to about 99.9 percent, depending on the choice of membranes.