AE2S developed a Master Plan for the City of Williston that analyzed population projections, water demands, regulations, capacity, water quality, water supply, and performed an evaluation of the existing surface water treatment plant. The Master Plan included interim conclusions and recommendations, developed costs for alternative solutions, and recommended improvements to resolve numerous challenges that had not been addressed since the original plant was designed and constructed in 1959. The final section of the Master Plan included an improvement prioritization plan that has become a living document used by the City as they work with funding and regulatory agencies to complete needed improvements.
The City’s need to comply with the Interim Enhanced Surface Water Treatment Rule by January 2002 made it necessary for the existing gravity filters to be rehabilitated with new underdrains, media, and controls. Upon completion of the project, AE2S won an ACEC Engineering Excellence award for the Williston Phase I project. It was the first treatment plant in North Dakota to install dual parallel lateral underdrains. It was such a success that many plants in Minnesota and North Dakota have since followed suit with this type of filter underdrain. The Phase I project also included a new electrical room and plant-wide SCADA system that was designed and programmed by AE2S. Phase I also included a new traveling water screen, raw water pump replacements, and transfer pumps improvements. AE2S assisted the City staff in securing a $5,000,000 grant for the Phase II Improvements. The Phase II project was completed in late 2006 at a total cost of $20,000,000. It is the first plant in North Dakota and Minnesota to install ActiFLO pretreatment basins (manufactured by Kruger), and the first plant in the upper Midwest to install large-scale ultraviolet light disinfection reactors. Other Phase II project components included a new solids contact basins, new sludge handling system, an 18,000 square foot addition, rehabilitation of the 1959 plant, a new control room and lab, and new chemical feed systems.
Lastly, AE2S designed and bid a project to add approximately 43-acres of ponds to store water treatment residuals. This project was bid in February 2006 and included more than 130,000 cy of excavation to create the various ponds that store the residuals. The Residual Ponds project was completed in late 2006.