Performance evaluation of a low-cost odour trap installed in waterless urinals

Waterless urinals save precious fresh water normally used for flushing and reduce odour levels in restrooms. However, existing models of waterless urinals available on the market are expensive and maintenance costs of the odour traps of these urinals are also quite high. Experiments conducted using a low cost membrane-based waterless-urinal odour prevention trap available in India revealed a reduction of over 90.5% in ammonia gas concentration in the urinals. The ammonia levels observed, in the range of 0.22 to 0.30 ppm in waterless urinals fitted with the odour trap evaluated in this study, is comparable to values reported for the widely used sealant liquid based waterless urinals in the past. No sign of clogging was observed in the clogging tests conducted. Passage of particles up to 4 mm in size in the particle flow analysis tests conducted is somewhat higher than the 2 mm reported for sealant liquid and membrane odour traps in previous studies, and it reveals that the odour trap can perform in adverse conditions without getting clogged. Economics of installation and maintenance aspects of waterless urinals carried out here show that the odour trap evaluated in this study can really be a cost effective alternative.