In 2013, Clear Creek was invited to participate in a design build project for improving stormwater quality at a rail facility in south-western Washington. Clear Creek worked with the project engineer to identify and screen candidate treatment technologies. Chitosan Enhanced Sand Filtration (CESF) was selected for this application.

Clear Creek worked with the project team to evaluate infrastructure modifications, treatment system footprint, and equipment orientation. Upon the completion of the system design, Clear Creek custom fabricated an enclosed 400 gpm CESF system and installed it on-site. Since the site consisted of two separate drainage basins, Clear Creek developed a microprocessor controlled system to proportionally split the discharge between the two drainage basins in order to maintain the predevelopment flow conditions as required.