Slater Wastewater Treatment Plant Improvements

Story Construction served as the general contractor for an innovative wastewater treatment upgrade for the City of Slater, IA, incorporating a cutting‑edge Revolving Algal Biofilm (RAB) system into the city’s existing facility. Work on the project began in 2021, and the system became fully operational in March 2023.

Located within a new greenhouse structure on the treatment site, the patented RAB process from Gross‑Wen Technologies uses specialized polyester belts that grow algae to naturally remove nutrients – including nitrogen and phosphorus – from wastewater. As the algae develop on the belt surfaces, they biologically consume these nutrients, enabling the City of Slater to consistently meet more stringent municipal discharge permit requirements.

In addition to enhanced nutrient removal, the RAB system provides operational advantages over traditional mechanical treatment options. The city selected this technology in part due to its lower labor and long‑term operating costs. An added benefit of the design is the ability to harvest the algae biomass, which can be dewatered and pelletized for use in value‑added products.

To construct the facility, Story crews prepared the site by draining and desludging the primary lagoon to accommodate the new greenhouse and associated settling basin. Structural fill material was placed, and Story personnel performed concrete foundations, basin construction, and installation of piping and utilities tied to the new process.

This project demonstrates Story Construction’s ability to deliver complex, sustainable water infrastructure solutions that incorporate emerging technologies. The upgrade positions Slater as a regional leader in innovative wastewater treatment and supports long‑term compliance and environmental stewardship.