RFP-3185-10-SDH - Persigo WWTP UV Disenfection Design Services

Summary of Specifications:
The City of Grand Junction Waste Water Department operates the Persigo Wash Waste Water Treatment Plant (WWTP). The WWTP is jointly owned by the City of Grand Junction and Mesa County. This is a 27 year old, activated sludge treatment plant. The plant is currently treating 30-day avg. peak flows 8.4 MGD with a current capacity of 12.5 MGD permitted through the Colorado Department of Public Health and Environment (CDPHE). Design hydraulic capacity of the WWTP at build out is 25 MGD. There is the possibility of further expansion to 37.5 MGD capacity that would likely be the ultimate capacity of this WWTP. The City plans to retrofit the Aeration Basins to allow for nitrification/denitrification that will allow us to meet impending ammonia standards. We anticipate that this modification to the plant process will necessitate high chlorine usage at times. We also anticipate that federal restrictions regarding the use of chlorine disinfection will impose additional costs to operation of the plant that could be avoided if UV disinfection were provided.