Abstract: A battery manufacturing operation employs a first NaOH solution for washing an intermediate product generating a waste caustic, and a second NaOH solution for impregnation. In addition, quasi-periodically a fixed quantity of waste wash water is available. The invention includes a process, and an apparatus for carrying out the process, for using the waste wash water as one component of the second NaOH solution, to which is automatically added fresh NaOH until a specific NaOH solution (25% NaOH), by weight is obtained. Thereafter, the waste caustic is added resulting in the second solution. The process is effected typically automatically notwithstanding variations in the components of the waste water, and normal variations in the flow rates, etc.