Flexibility and adaptability: essential elements of the WRRF of the future

All Water Resource Recovery Facilities (WRRFs) must comply with evolving treatment objectives and product water quality requirements, using technologies which also evolve over time. The useful life of the physical structures, especially hydraulic conveyance (pipes and channels) and water holding structures, is significantly longer than that of the specific technologies used. Thus, the WRRF of the future must, first and foremost, be designed with the flexibility to adapt to a wide variety of requirements over its life using a wide variety of technologies, some of which are currently known while others will be invented and/or further developed over time. This might be seen as the true essence of the WRRF of the future, rather than the specific technology implemented at a particular time. While incorporating flexibility and adaptability into facilities may seem daunting, especially since future requirements and technologies are largely unknown, experience indicates that much can be done to prepare for such changes. Proven engineering approaches are presented and discussed in the paper, including the ‘building block approach’ to plant layout and design, and the choice of process tank configurations which can accommodate numerous technologies.