Table 1.

Selected Odorous Compounds from Wastewater Treatment Plant and their Corresponding Odor Threshold values.

Compound	Odor Threshold (ppm)	Characteristic Odor
Hydrogen sulfide (H2S)	0.0005a	Rotten eggs
Methyl mercaptan (CH3SH)	0.0016b	Decayed cabbage
Dimethyl sulfide ((CH3)2S)	0.001a	Decayed vegetables
Dimethyl disulfide ((CH3)2S2)	0.003c	Vegetable sulfide
Ammonia (NH3)	5.2b	Pungent, irritating
Triemethylamine ((CH3)3N)	0.0004a	Ammonical, fishy

^aWEF Manual of Practice No. 22 ASCE Manuals and Reports on Engineering Practice No. 82 [15].

^bGuide to Field Storage of Biosolids – Odor Characterization, Assessment and Sampling [16].

^cAnnual Reports of 1990 – Japan Environment Sanitation Center [17].