The injection water for the Nelson Project is a combination of produced and make-up water, typical of many Eastern Kansas operations. The make-up water is a low-salinity salt water from the ArbucMe Formation and contains dissolved minerals and sulfides. The produced water contains suspended oil, suspended clay and silt particles, along with a combination of other dissolved minerals. The combination of the two waters causes several undesirable reactions. The suspended solids load contained in the combined waters would plug a 75-micron plant bag filter within one day. Wellhead filters of 75-micron size were also being used on the injection wells. The poor water quality resulted in severe loss of injectivity and frequent wellbore cleaning of the injection wells. Various mechanical and graded-bed filtration methods were considered for cleaning the water. These methods were rejected due to the lack of field equipment and service availability. A number of vendors did not even respond to our request. The air flotation process was selected as offering the best hope for a long-term solution. The objective of this work is to: increase the cost effectiveness of the process through optimizing process design factors and operational parameters. A vastly modified air flotation system is the principal tool for accomplishing the project objective. The air flotation unit, as received from manufacturer Separation Specialist, was primarily designed to remove oil from produced water. The additional requirement for solids removal necessitated major physical changes in the unit. Problems encountered with the air flotation unit and specific modifications are detailed in the body of the report. An order of magnitude improvement in water quality has been achieved. Wellhead filters of ten-micron size are now routinely utilized as compared to the previous 75-micron filters. Filter changing frequency is no different. The overall water treating chemical costs have been reduced. The frequency and severity of injection well cleaning jobs has been greatly minimized. Additional detail is being provided regarding the nature of the well cleaning jobs and the frequency with which they occurred during a two-year period. Although all problems are not solved, injectivity has been much easier to maintain as a result of the cleaner water. This is vividly demonstrated by the reduced frequency of injection well cleaning.