Analysis of Malodorous Volatile Substances of Human Waste: Feces and Urine.

Abstract

The amounts of volatile substances responsible for the malodor of human waste (feces and urine) obtained from the storage tank of a community waste-water treatment plant were determined. Thus far, there has been little systematic research on malodor-causing substances of human waste. These substances were collected using Tenax-TA, and their concentrations were determined by the usual thermal-desorption coldtrap injector/gas chromatography/mass spectrometry (TCT/GC/MS). About 90% of the malodor-causing substances were fatty acids: acetic acid, propionic acid and butyric acid. The proportion of ammonia was 6.5%. Other malodor-causing and minor substances detected were indole, skatole, pyridine, pyrrole, hydrogen sulfide, and methyl mercaptan. In addition, a small amount of paradichlorobenzene used as a deodorizer in household toilets was also recognized.

Innate olfactory preferences in dung beetles

“…These two last compounds, together with pinane-cis and -trans, are partially hydrogenated compounds that correspond to the first steps of reduction reactions but whether they contribute to the typically faecal odour is unknown. Surprisingly, some other compounds that are commonly believed to be responsible for faecal odour, such as methyl sulphides, volatile fatty acids, skatole or indole (Monroe, 1985;Suarez et al, 1998;Sato et al, 2001), were either not found in our study or only present in low levels in some dung extracts (indole, skatole, dimethyltrisulphide and methylthioanisole). However, these compounds are known to produce a very strong odor, even at very low concentration.…”

Analysis of Malodorous Substances of Human Feces.

“…Methyl mercaptan was detected at 2-15 ppb in only three of the seven subjects. The concentrations of both substances were lower than those in the malodorous gas from human waste reported previously, 10) probably because feces immediately after defecation is less decomposed by microorganisms than human sewage waste. However, as the thresholds of olfactory sensitivity 15,16) for methyl mercaptan and hydrogen sulfide are low, their odor intensities, which represent the human olfactory sensitivity to them, are high, and they are considered to contribute significantly to the odor of feces.…”

“…Mass spectral identifications and quantitative measurements were performed by methods similar to those used in our previous study. 10) Determination of Fatty Acids, and Aliphatic and Aromatic Compounds ---After 10 l of the malodorous components in the sampling bag were adsorbed at room temperature onto the trapping agent (Tenax-TA) by the method shown in Fig. 2(A), the volatile compounds on the trapping agent were analyzed using TCT/GC/MS under the conditions shown in Table 1.…”

“…The breakthrough volume was measured to determine the optimum volume of the gas samples that can be captured by the adsorbent Tenax-TA. We evaluated the breakthrough volume of a series of two Tenax-TA tubes for each sample as reported previously 10) to determine the trapping capacity of Tenax-TA that we used in this study to trap the odor of excretion. Specified amounts (1 ppm, 1 µl) of the standard solution of fatty acid, pyridine, and pyrrole were added to Tenax-TA1 and then helium gas was passed through two Tenax-TA trapping tubes connected in series.…”

Color Sensors for Indole Vapors Based on Ehrlich-type Reactions

“…Indole derivatives, occurring widely in plants and animals, play important roles in biological and clinical aspects, 9-13 whereas indole vapors are typical malodorants. [14][15][16][17][18] Neither real-time monitors nor gas detector tubes for indole vapors has been available so far, 5 though highly sensitive instrumental analyses such as chromatographic [19][20][21][22][23] and electrochemical [24][25][26][27] methods have long been employed. While detection of indoles in solution has been extensively used for qualitative (spot-test) [28][29][30][31] as well as quantitative analyses, [32][33][34] no solid sensor for indole vapors based on the Ehrlich-type reactions has been reported so far.…”