Bioaugmentation with Nitrifying Granules in Low‐SRT Flocculent Activated Sludge at Low Temperature

Abstract

Nitrifying granules were grown in a sidestream reactor fed municipal anaerobic digestion centrate and added in an initial slug dose and subsequent smaller daily doses to a non-nitrifying mainstream activated sludge system at 12 °C and 2.5-day aerobic solids retention time (SRT) to increase its nitrification capacity. Effluent NH3-N concentrations less than 1 mg/L were achieved with bioaugmentation, and nitrification was immediately lost when granules were removed after 30 days of bioaugmentation. Molecular microbial analyses indicated that nitrifying organisms remained attached to granules in the mainstream system with little loss to the flocculent sludge. Maximum specific nitrification activity of the bioaugmented granules decreased in mainstream treatment but the nitrification capacity remained due to new granule growth in the mainstream. This study demonstrated that bioaugmentation with sidestream nitrifying granules can intensify nitrification capacity in low-SRT, low-temperature flocculent activated sludge systems to achieve low effluent NH3-N concentrations and nitrogen removal.

Preparation, Performances, and Mechanisms of Microbial Flocculants for Wastewater Treatment

“…Colloidal particles are adsorbed on the molecule by the adsorption of the active site [71,146]. At the same time, multiple microbial flocculant large chainlike molecules through hydrogen bond intermolecular van der Waals forces the particle bypass to be formed by a three-dimensional network structure and set down [147]. The length of the flocculant should be long enough to extend from the surface of the particle to the other in order to effectively build bridges [148].…”

Modeling, instrumentation, automation, and optimization of water resource recovery facilities (Review of 2018 Literature) DIRECT

“…Using bench‐scale bioreactors, Figdore, Winkler, and Stensel (2018) developed nitrifying granules grown on anaerobic digester dewatering centrate for bioaugmentation of a low SRT, low‐temperature flocculant activated sludge process. The granules were shown to be responsible for the bulk of the nitrification and the loss of nitrifiers from the granules to the flocs and the waste activated sludge was minimal.…”