Optimized design of a stable, long term and robust attached growth mainstream partial nitritation system

Abstract

A sustainable and cost-effective control system to achieve stable mainstream partial nitritation (PN) is essential to transition the anammox process for mainstream municipal wastewater treatment. This study identifies the optimal distinct elevated surface area loading rates (SALR), hydraulic retention times (HRTs), and airflow rates that achieve stable PN performance (i.e., optimum total ammonia nitrogen (TAN) removal kinetics and percent NO_x as nitrite) in a mainstream elevated loaded PN MBBR system. The study shows that TAN SALR, HRT, and airflow rate significantly affect TAN surface area removal rates (SARR) and percent NO_x as nitrite and, as such, identifies the optimal design parameters (TAN SALR, HRT and airflow rate) of a mainstream elevated loaded PN MBBR system. A TAN SALR of 5 g TAN/m^2.d, HRT of 2h and airflow rate of 1.5 L/min are identified to provide stable PN performance with a TAN SARR of 2.30 ± 0.34 g TAN/m^2.d and a percent of NO_x as nitrite of 84.8 ± 1.2%.