Innovative Approach to Centrate Nitrification Accomplishes Multiple Goals – Nitrogen Removal and Odor Control
91st Avenue Wastewater Treatment PlantPhoenix, Arizona
The implementation of centrate nitrification as part of the 91st Avenue WWTP’s conversion from Class B to Class A biosolids has achieved the dual benefits of nitrogen removal and odor control. A significant expansion in biological reactor capacity and/or methanol addition has been avoided and preliminary results indicate that the City may be able to avoid a $40 million (US) capital expenditure to cover the twelve existing 43 m diameter primary sedimentation basins and treat the foul air in wet chemical scrubber systems.
• Nitrogen Removal- The centrate nitrification facility is achieving 50 percent ammonia oxidation to nitrite-nitrate without the addition of supplemental alkalinity, resulting in a 9% reduction in the primary effluent nitrogen concentration to the main activated sludge facilities. A return of approximately 1,300 kg/d of nitrite-nitrate to the headworks is resulting in 2.5 mg/L as N of oxidized nitrogen at the current WWTP influent flow rate of 5.9 m3/s.
• Odor Control- A 70 percent reduction in measured gaseous H2S concentrations in the plant headworks odor control scrubber influent from 17 to 5 ppm has resulted in a 67 percent reduction in odor control wet scrubber chemical (sodium hydroxide and sodium hypochlorite) costs, from $460 to $150 (US) per day. A reduction in the H2S emissions from an uncovered primary sedimentation basin were demonstrated in the center well (11 ppm to 1 ppm) and effluent weir (12 ppm to 6 ppm) with the discharge of oxidized nitrogen to the headworks from the centrate nitrification facility. Source: WEFTEC 2009 Proceedings
Metric Used:
Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Environmental Impact, Odor Control, Optimize Digestion Capacity | No Comments »