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SIMPLIFIED NOD DETERMINATION Joseph L. Slayton, Chemist E. Ramona Trovato, Chemist U.S. Environmental Protection Agency Region III, Annapolis Field Office Annapolis, Maryland 21401 INTRODUCTION Biochemical oxygen demand (BOD) is a bioassay procedure concerned with the utilization of oxygen in the biochemical oxidation (respiration) of organic material. This test is one of the most widely used measures of organic pollution and is applied both to surface and wastewaters. The standard method of BOD measurements adopted by APHA [ 1 ] is a five-day test in which a water sample is maintained at 20 C in the dark and oxygen depletion is monitored. The five-day incubation period was selected to maximize the oxygen demand associated with the oxidation of carbon compounds while minimizing the oxygen demand of autotrophic organisms. That portion of the BOD due to the respiration of organic matter by heterotrophic organisms is termed the carbonaceous oxygen demand (CBOD) and that portion involved with nitrification is termed nitrogenous oxygen demand (NOD). The desire to separate NOD and CBOD results not only from the fact that the organisms responsible for these components have different nutrient requirements, but also because they differ in reaction rates A02/Atime, temperature coefficients and tolerance to toxic materials. Nitrifying bacteria are in general slower growing [2], more drasticaUy affected by temperature [3], and are more sensitive to materials like [4] phenols, cresol, halogenated solvents, heavy metals and cyanide. The organisms involved in the CBOD and NOD processes would therefore be expected to react differently to the same aquatic environment. The determination of the BOD components would better define the BOD test results and aid in extrapolating these results to the prediction of dissolved oxygen profiles in a body of water. The purpose of this paper is to demonstrate that a simple procedure involving an inhibitor to nitrification, N-serve, could provide an accurate and precise measurement of nitrification occurring in the BOD test whde not affecting the carbonaceous oxygen demand. NITRIFICATION Nitrification is the conversion of ammonia to nitrate by biological respiration. This type of respiration is employed by seven genera of autotrophic nitrifyers [5]. It should be noted that heterotrophic nitrification can also produce N02" and N03" by reactions that do not involve oxidation [6]. However, only Nitrosomonas spp. and Nitrobacter spp. are regularly reported by in situ nitrification studies [2]. Therefore, the treatment of nitrifying river samples with inhibitors specific to Nitrosomonas and Nitrobacter can be expected to stop all appreciable nitrification [7]. The reactions involved in nitrification are as follows: NH4+ + 1.5 02 NitrOSOm°na.S 2H+ ♦ NO," ♦ H20 (1) Nitrobacter N02 + 0.5 02 +- N03 (2) The stoichiometrics of the nitrification reactions dictate that the conversion of 1 gram of nitrogen from ammonium to nitrite utilizes 3.43 grams of oxygen, and the conversion of 868
Object Description
Purdue Identification Number | ETRIWC197986 |
Title | Simplified NOD determination |
Author |
Slayton, Joseph L. Trovato, E. Ramona |
Date of Original | 1979 |
Conference Title | Proceedings of the 34th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,30453 |
Extent of Original | p. 868-886 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-06-24 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page0868 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | SIMPLIFIED NOD DETERMINATION Joseph L. Slayton, Chemist E. Ramona Trovato, Chemist U.S. Environmental Protection Agency Region III, Annapolis Field Office Annapolis, Maryland 21401 INTRODUCTION Biochemical oxygen demand (BOD) is a bioassay procedure concerned with the utilization of oxygen in the biochemical oxidation (respiration) of organic material. This test is one of the most widely used measures of organic pollution and is applied both to surface and wastewaters. The standard method of BOD measurements adopted by APHA [ 1 ] is a five-day test in which a water sample is maintained at 20 C in the dark and oxygen depletion is monitored. The five-day incubation period was selected to maximize the oxygen demand associated with the oxidation of carbon compounds while minimizing the oxygen demand of autotrophic organisms. That portion of the BOD due to the respiration of organic matter by heterotrophic organisms is termed the carbonaceous oxygen demand (CBOD) and that portion involved with nitrification is termed nitrogenous oxygen demand (NOD). The desire to separate NOD and CBOD results not only from the fact that the organisms responsible for these components have different nutrient requirements, but also because they differ in reaction rates A02/Atime, temperature coefficients and tolerance to toxic materials. Nitrifying bacteria are in general slower growing [2], more drasticaUy affected by temperature [3], and are more sensitive to materials like [4] phenols, cresol, halogenated solvents, heavy metals and cyanide. The organisms involved in the CBOD and NOD processes would therefore be expected to react differently to the same aquatic environment. The determination of the BOD components would better define the BOD test results and aid in extrapolating these results to the prediction of dissolved oxygen profiles in a body of water. The purpose of this paper is to demonstrate that a simple procedure involving an inhibitor to nitrification, N-serve, could provide an accurate and precise measurement of nitrification occurring in the BOD test whde not affecting the carbonaceous oxygen demand. NITRIFICATION Nitrification is the conversion of ammonia to nitrate by biological respiration. This type of respiration is employed by seven genera of autotrophic nitrifyers [5]. It should be noted that heterotrophic nitrification can also produce N02" and N03" by reactions that do not involve oxidation [6]. However, only Nitrosomonas spp. and Nitrobacter spp. are regularly reported by in situ nitrification studies [2]. Therefore, the treatment of nitrifying river samples with inhibitors specific to Nitrosomonas and Nitrobacter can be expected to stop all appreciable nitrification [7]. The reactions involved in nitrification are as follows: NH4+ + 1.5 02 NitrOSOm°na.S 2H+ ♦ NO," ♦ H20 (1) Nitrobacter N02 + 0.5 02 +- N03 (2) The stoichiometrics of the nitrification reactions dictate that the conversion of 1 gram of nitrogen from ammonium to nitrite utilizes 3.43 grams of oxygen, and the conversion of 868 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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