Model Based Design of a Novel Process for Nitrogen Removal from Concentrated Flows

TLDR

Large‑scale applications are being built to treat reject water from sludge digestion, highlighting underlying kinetic principles and their pH dependency. The study develops a model for the SHARON process to design full‑scale systems that achieve high‑rate ammonia conversion in concentrated flows. The model incorporates denitrification to control pH within a single aerated reactor operating at high temperature and pH. The SHARON process, a single aerated reactor that stops ammonium oxidation at nitrite, eliminates sludge retention, requires no external heating, and achieves overall processing costs below 50% of alternative methods.

Abstract

Abstract A new process for biological nitrification was developed that is operated in a single aerated reactor at relatively high temperature and pH. This process, termed SHARON, was designed to achieve substantial ammonia conversion at high reaction rates for relatively concentrated flows, rather than to meet strict effluent standards. First large scale applications that are under construction now, aim at treating reject water from a sludge digestion unit. The SHARON process operates without sludge retention, and ammonium oxidation is stopped at nitrite, which saves on aeration costs. Denitrification is used as a cheap means to control the pH. Under typical conditions, no heating is necessary due to the heat production by the reactions. Overall processing costs are less than 50% of other techniques. This contribution focuses on model development for process design calculations at full scale. Underlying kinetic principles, and especially their pH dependency, are highlighted as well.