SGER: Enhanced Wastewater Nitrification Using Selective Detachment, Recovery, and Recycling of Nitrifying Bacteria

Purdue University, West Lafayette IN

Investigators

Abstract

0137330 Alleman Wastewater nitrification is considered to be a highly sensitive biological process given the metabolic nature of the involved bacteria (e.g., low growth rate, etc.) and correspondingly low cell population. Furthermore, the daily loss of these nitrifiers within a reactor's necessary waste sludge stream creates a pragmatic limitation on the permissible amount of nitrifiers that can be maintained. This proposed research focuses on an innovative means to beneficially increase the population of nitrifiers beyond that of conventional systems by selectively detaching and recovering these valuable nitrifiers from the waste sludge such that they can then be recycled back into use. As compared to heterotrophic cells whose chemical-based attachment (via an adhesive exocellular polymer) and flocculation behavior does not afford this flexibility, we believe that attached nitrifying cells can be prompted to detach and deflocculate within a suitably motivating environment. The underlying mechanism would subsequently be that of a controlled chemical, physical, and/or electrical effect which induces attached nitrifying cells contained within the waste sludge to detach and deflocculate, at which point these discrete nitrifiers can then be separated from the remaining waste sludge for subsequent reuse. As such, this capability would then facilitate a means of controlling (and beneficially raising) the nitrifier solids retention time (SRT) in a fashion that is independent from that of the remaining mixed-culture SRT. ***