Biological nitrogen removal from septic tank effluents

1996 1996

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Abstract (summary)

On-site wastewater treatment and disposal systems are used by approximately 25% of all housing units in the United States, with septic tank systems being most common. One of the environmental concerns associated with the use of septic tank systems is the potential for local and regional groundwater contamination. Nitrogen, which is typically not removed in conventional septic tank systems, is one of the most important contaminants associated with septic tank systems. Studies have directly linked nitrate-nitrogen with methemoglobinemia, a disease of concern to infants, and it may also be a carcinogen.

This project examined a laboratory scale modified septic tank design which utilized an attached growth column for nitrification and an anoxic reactor for denitrification. A synthetic septic tank effluent was developed specifically for this project using respirometric methods. The septic tank design used in this research represents a relatively simple and potentially economic modification to traditional septic tank designs, yet has the potential to reduce nitrogen discharge to acceptable levels.

The analysis of the experimental design results indicated that it was possible to remove significant amounts of nitrogen prior to discharge from the modified septic tank system. It was also determined that a hydraulic residence time of two days in the anoxic reactor and an operating mixer within the anoxic reactor produced the optimal result. A subsequent linear regression analysis of the nitrification efficiency determined that the initial BOD$\sb5$, initial NH$\sb3$-N, column depth, and an interaction variable of the column depth and the initial NH$\sb3$-N were the significant variables. Based on this model, three contour plots of the expected nitrification efficiency were developed for concentrations, volumetric loading rates, and surface loading rates. These contour plots can be used to further optimize the modified septic tank system used in this research. In addition, the contour plots can also be applied to other applications of biological nitrogen removal.

Indexing (details)

Environmental engineering;
Chemical engineering;
0775: Environmental engineering
0542: Chemical engineering
0554: Sanitation
Identifier / keyword
Applied sciences; anoxic reactor
Biological nitrogen removal from septic tank effluents
Katers, John Francis
Number of pages
Publication year
Degree date
School code
DAI-B 58/01, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
9780591273762, 0591273764
Zanoni, Alphonse
Marquette University
University location
United States -- Wisconsin
Source type
Dissertations & Theses
Document type
Dissertation/thesis number
ProQuest document ID
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
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