Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Influent:Raw groundwater
Denitrification system:Closed-system hydrogen-based hollow fiber MBfR
Denitrifying reactor:Membrane biofilm reactor (MBfr)
Medium:H2-based membrane biofilm
Culture taken from:Raw groundwater
Organism (s) cultured:nan
Respiration:nan
Electron donor:Hydrogen
Electron acceptor:Nitrate
Input NO3-N (mg/l):13
Nitrate removal rate (mg NO3-N/l/h):nan
Denitrification rate (gNO3-N removed/m3/day):7200
Microorganisms identified:nan
Molecular tools:nan
Major findings:Developed a pH control model that can be used in both heterotrophic and hydrogen-based denitrification systems to measure or predict the pH, alkalinity, and Langelier Saturation Index.
Authors:Tang et al., 2011
Title:A pH-control model for heterotrophic and hydrogen-based autotrophic denitrification
Pubmed link:Link
Full research link:Link
Abstract:This work presents a model to predict the alkalinity, pH, and Langelier Saturation Index (LSI) in heterotrophic and H2-based autotrophic denitrification systems. The model can also be used to estimate the amount of acid, e.g. HCl, added to the influent (method 1) or the pH set point in the reactor (method 2: pH can be maintained stable by CO2-sparge using a pH-control loop) to prevent the pH from exceeding the optimal range for denitrification and to prevent precipitation from occurring. The model was tested with two pilot plants carrying out denitrification of groundwater with high hardness: a heterotrophic system using ethanol as the electron donor and an H2-based autotrophic system. The measured alkalinity, pH, and LSI were consistent with the model for both systems. This work also quantifies: (1) how the alkalinity and pH in Stage-1 significantly differ from those in Stage-2; (2) how the pH and LSI differ significantly in the two denitrification systems while the alkalinity increase is about the same; and (3) why CO2 addition is the preferred method for autotrophic system, while HCl addition is the preferred method for the heterotrophic system.