Augmenting wastewater treatment processes with cultures of nitrifying bacteria can increase microbial abundance and, correspondingly, improve nitrification efficiency. Additionally, introducing organic matter-degrading microorganisms into a system can increase the time available for nitrifying bacteria to oxidize ammonia.¹
The following case study describes the effectiveness of BioLynceus® bioaugmentation in improving nitrification in an activated sludge system with fixed-media trickling filters.
Figure 1. Combined activated sludge and trickling filter system with
direct feeding of the trickling filter with activated sludge mixed
liquor to conduct better ammonia removal. Inoculation point of
case study bioaugmentation is indicated (Modified from Soriano
et al. 2014).1
1 Soriano, A. G., Audic, J. M., McCarley, S., Ekama, G., & Wentzel, M. (2014).
Options for the Upgrading of WWTP’s by Means of Trickling Filters.
Retrieved at https://www.researchgate.net/publication/228598263_
OPTIONS_FOR_THE_UPGRADING_OF_WWTP%27s_BY_MEANS_
A 0.2 MGD municipal activated sludge plant in Oregon was experiencing high ammonia concentrations in its treated wastewater. Nitrifying bacteria in the trickling filters were inhibited by undesirable wastewater conditions during the summer months.
Influent flows were low and varied in temperature and pH. These fluctuations in wastewater conditions impaired nitrification, resulting in high effluent ammonia concentrations.
Facility management was concerned about violating the plant’s ammonia permit limits.
1 Kirchman, D. L. (2012). Processes in Microbial Ecology. New York:
Oxford University Press Inc. Pp. 228, 229.
In need of a solution to promote ammonia removal, the plant supervisor contacted BioLynceus®. A specialized bioaugmentation plan was designed for the facility. ProBiotic Scrubber® N (PBN), a live-culture product abundant in nitrifying bacteria and organic substrate-degrading microbes, was implemented just ahead of the plant’s trickling filters.
After a few days of treatment, the biology in the system was nitrifying properly. Ammonia concentrations in the effluent decreased. Additionally, BioLynceus® bioaugmentation helped the plant remain in compliance with its ammonia permit. The activated sludge facility continued to use PBN from May to October to promote efficient nitrification in its trickling filters.
Establishing an effective community of nitrifying bacteria in wastewater treatment systems can be challenging. This process is most efficient under suitable environmental conditions and can be inhibited by extreme temperatures and pH levels.
Beyond the physical factors affecting nitrification in wastewater processes, maintaining a high abundance of nitrifying and organic matter-degrading organisms is essential for optimal ammonia conversion. Nitrification is often the rate-limiting reaction in wastewater treatment.² This process has a low energy yield for nitrifying bacteria, which affects their growth rates and abundance.
Because of this, these bacteria require a sufficiently long residence time in the aerobic process to properly oxidize ammonia. Bioaugmentation, like the treatment used in the case study above, can be a helpful solution for improving nitrification in activated sludge processes.
2 Gerardi, M. (2016). Wastewater Bioaugmentation and Biostimulation.
Lancaster, Pennsylvania: DEStech Publications, Inc. Pp. 20, 64.
BioLynceus® ProBiotic Scrubber® N promotes nitrification in activated sludge processes.