RTW Engineering - Teton Village Project Highlight

RTW >Consulting Services > Teton Village Wastewater Treatment Plant

Teton Village Wastewater Treatment Plant Denitrification Facility Upgrade

RTW performed a CPE of the plant because of alleged discharge permit violations related to nitrates and phenols. The plant's inability to meet permit requirements for nitrates was based on the fact that the original design approached overall nitrogen control by breakpoint chlorination for a portion of the ammonia in the plant effluent. However, the operators were not operating the breakpoint process because of economic and environmental concerns. Our Teton Village Wasterwater Plant analysis revealed that the plant could easily nitrify all of the influent ammonia up to design capacity. We concluded that the reasonable alternative for assuring compliance with nitrogen control aspects of the discharge permit would be to remove nitrogen to produce effluent levels of total inorganic nitrogen to less than 10 mg/L.

The District's engineer retained RTW to design process, electrical, and control facilities necessary to nitrify and denitrify the wastewater. RTW's approach employed an anoxic basin at the head of the plant, just downstream from the barscreen and grit basin. The wastewater in this basin is mixed with large propeller-type mixers; however, aeration is not provided in the basin. The existing aeration basins were retained for operating in a nitrifying, extended-aeration mode. The process also included a mixed-liquor recycle flow from the aeration basins to the anoxic basin. The process performed well under wide variations in influent flow, influent organic loads, and influent nitrogen loads.