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

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.