Evaluation of methods to detect and control nitrification inhibition with specific application to incinerator flue-gas scrubber water

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Water Environment Research

DOI:https://doi.org/10.2175/106143098X123606· OSTI ID:318627

Daigger, G T; Sadick, T E

Two procedures for determining the maximum specific growth rate of nitrifying bacteria in the presence of inhibitors were evaluated. One procedure uses a population of nitrifying bacteria and a short-term (6-hour) batch assay to determine the impact of the test wastewater on the maximum specific growth rate of the nitrifiers. The difference in the specific nitrification rate for the subject population between a control and the test wastewater quantifies the effect of the constituents in the test wastewater on the nitrifier maximum specific growth rate. The second procedure uses batch fill-and-draw bioreactors operated under steady-state conditions to determine the minimum mean cell residence time for growth of the nitrifiers. The need to assess nitrification inhibition at two large municipal wastewater treatment plants provided the opportunity to evaluate these two procedures. Incineration of biosolids is practiced at both of these plants, and it was shown that in-plant recycle of the multiple-hearth flue-gas scrubber water can be inhibitory to nitrification. Results from extensive testing indicated that hydrocyanic acid (HCN), present in the scrubber water, is the probable inhibitor. Consistent results were obtained at both plants. They indicated that HCN concentrations on the order of 0.1 to 0.2 mg/L resulted in a reduction in the nitrifier maximum specific growth rate of approximately 50%. Treatment methods were evaluated at each plant and implemented. At one plant, aerobic biological treatment of the incinerator sidestream is being practiced. At the other facility, cyanide is thermally destroyed in afterburners before contact with the wet scrubbing system.

• Sponsoring Organization: USDOE
• OSTI ID: 318627
• Journal Information: Water Environment Research, Journal Name: Water Environment Research Journal Issue: 7 Vol. 70; ISSN WAERED; ISSN 1061-4303
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BACTERIA
BIOASSAY
BIOREACTORS
CYANIDES
FLUE GAS
INCINERATORS
MUNICIPAL WASTES
NITRIFICATION
WASTE WATER
WATER TREATMENT