Biological Nutrient Removal (BNR) is critical for the preservation of our lakes and streams. Large amounts of waste products are passed through our sewage treatment systems on a continuous basis. Nutrient loads discharged from these systems must be reduced to avoid eutrophication of the receiving waters. Microbes are particularly useful in biodegrading most of the compounds treated by wastewate...

There are several long term water quality issues associated with discharging nutrients, specifically nitrogen and phosphorus into receiving water streams that are very difficult to manage. Due to these concerns many environmental regulatory agencies have either established nutrient discharge criteria or in the process of developing nutrient management plans. If a wastewater treatment plant is r...

Biological nutrient removal (BNR) may be an effective strategy to reduce eutrophication; however, concerns remain about effects on receiving waters of removing both nitrogen (N) and phosphorus (P), rather than P alone. Phytoplankton abundance (as µg chlorophyll a/L) community composition nmol biomarker pigment/L) were quantified over 6 years in two connected eutrophic streams determine how alga...

Most filamentous bacteria in biological nutrient removal (BNR) processes have not been identified beyond their morphotype and simple staining reactions. Furthermore, the majority of sludge filaments observed under the microscope do not hybridize to commonly used phylogenetic probes for well characterized bacterial phyla such as the Proteobacteria, Actinobacteria, Firmicutes and BACTEROIDETES: S...

To understand wastewater quality transformations in the sewer system, a full-scale study focused on the characteristics of the influent wastewater in a middle-sized wastewater-treatment plant receiving only municipal sewage. The objective was to identify conditions in which prefermentation prior to the biological nutrient removal (BNR) process would be useful. Prefermentation aims at increasing...

The operating characteristics of six full-scale wastewater treatment plants using the staged, closed loop bioreactor process known as orbal were evaluated to determine the degree of simultaneous biological nutrient removal (SBNR) occurring. Low effluent total nitrogen concentrations indicate that simultaneous nitrification and denitrification occurs reliably in these facilities. The use of SRT ...

The objective of this research was to advance a fundamental understanding of a unique post-anoxic denitrification process for achieving biological nutrient removal (BNR), with an emphasis on elucidating the impacts of surface oxygen transfer (SOT), variable process loadings, and bioreactor operational conditions on nitrogen and phosphorus removal. Two sequencing batch reactors (SBRs) were opera...

In the external nitrification (EN) biological nutrient removal (BNR) activated sludge (AS) system, the nitrification process is removed from the BNR activated sludge system and performed ‘externally’ on an integrated nitrifying trickling filter (NTF). As such, optimum design and operation of the NTF is essential for reliable performance of the ENBNRAS system. Although information on the design ...

A biological nutrient removal (BNR) activated sludge (AS) scheme incorporating external nitrification in a fixed media system is evaluated. A laboratory scale investigation of the scheme indicates that it holds considerable potential for BNRAS system intensification through major reduction in sludge age and oxygen demand and significant improvement in sludge settleability. Because the BNRAS sys...

An innovative static/oxic/anoxic (SOA) activated sludge process characterized by static phase as a substitute for conventional anaerobic stage was developed to enhance biological nutrient removal (BNR) with influent ammonia of 20 and 40 mg/L in R1 and R2 reactors, respectively. The results demonstrated that static phase could function as conventional anaerobic stage. In R1 lower influent ammoni...