Pickling is a metal surface treatment used by stainless steel manufacturers to remove impurities from steel and obtain optimal surfaces. The process uses mixtures of nitric and hydrofluoric acid however, this results in large amounts of waste acid. After pickling these acids need to be disposed or regenerated. Disposal of spent acid causes environmental problems and very high operation costs. Also regeneration of the acid causes high operation costs, burdens the environment and remains a problem not being solved satisfactorily until today. Sustec has developed the REGMAX system to overcome these issues by regenerating the waste acid and improving the efficiency of both the pickling line and resources used. The patented process enables impressive recovery rates for both nitric and hydrofluoric acids and metals. The process is applicable to all metal and acid concentrations and gives freedom of choosing the optimum pickling conditions for best pickling performance. The objectives of the feasibility study were to evaluate the system engineering required and address the necessary customisations for the pilot plant user. Sustec also aimed at securing a commercial partner for the pilot plant and sequential scale-up. The overall objectives for the innovation project are to carry out the engineering activities, commission the pilot plant and demonstrate its validity in continuous industrial conditions.