Estimation of Ammonia Removal Capacity at the San Jose Creek East Water Reclamation Plant

Bleed through of NH3-N into the nitrified/denitrified secondary effluent produced at the San Jose Creek East Water Reclamation Plant has the potential to disrupt the plant's production of California Title 22 compliant reclaimed water for unrestricted, non-potable reuse. To minimize the potential for NH3-N bleed through, the Sanitation Districts of Los Angeles County conducted an assessment to determine the plant's NH3-N removal capacity and the maximum NH3-N load that could be applied to the biological system without causing secondary effluent NH3-N excursions above specific target concentrations. A spreadsheet model to simulate ammonia removal in a treatment unit was developed to support this effort. Batch experiments were conducted to estimate the value of the critical model kinetic parameter. The model was used to examine the effect of wastewater temperature, mixed-liquor suspended solids and DO concentrations on NH3-N removal and maximum NH3-N loading capacity. The model application identified the need to improve aeration system performance.