“End-of-pipe” versus “process-integrated” water conservation solutions: A comparison of planning, implementation and operating phases

The technical and economic advantages and disadvantages of numerous approaches for fulfilling environmental protection aims are discussed in the literature. This article compares water conservation solutions that are applied to the wastewater from the production processes (end-of-pipe solutions) and solutions that intervene in the production processes (process-integrated solutions). Three arguments that are commonly used in the literature to compare the technical and economic advantage of “end-of-pipe” versus “process-integrated” solutions are unilateral decoupling, technological maturity and legal security. A unilateral decoupling exists when the production system influences the operating status of the end-of-pipe solution but not vice versa. This prevents the end-of-pipe solution having an unwanted effect on the production system. As markets have developed for end-of-pipe solutions, specialized companies have continuously developed them. The same is not true for process-integrated solutions. Therefore, compared to process-integrated solutions, end-of-pipe solutions can be regarded as old, mature technologies. The authorities being aware of the state-of-the art of water conservation technology favor end-of-pipe solutions. Using end-of-pipe solutions therefore, brings a certain level of legal security. These arguments and their economic importance were used as the basis for a survey on water conservation in Austrian industry. The survey compared the estimated risks of planned water conservation solutions and problems, which actually occurred with end-of-pipe and process-integrated solutions. The main result of the survey is that, for the most part, the expected economic advantages of end-of-pipe solutions as compared to integrated solutions could not be proven. Explanations are given for these deviations between the literature and the survey results.