A dry urinal apparatus, comprising a receptacle configured to store urine, the urine having a layer of oil on its surface and a siphon assembly disposed within the receptacle and coupled to a reservoir. The siphon assembly includes a siphon tube and drain tube, the siphon tube operable to force urine down the drain tube, wherein the reservoir is configured to cease operation of the siphon assembly prior to the siphon tube pulling up the layer of oil with the urine. The reservoir is configured to cease operation of the siphon assembly in response to a distance required to pull air bubbles up the reservoir and into the drain tube being less than a distance required to raise urine into the drain tube.

A dry urinal apparatus, comprising a receptacle configured to store urine, the urine having a layer of oil on its surface and a siphon assembly disposed within the receptacle and coupled to a reservoir. The siphon assembly includes a siphon tube and drain tube, the siphon tube operable to force urine down the drain tube, wherein the reservoir is configured to cease operation of the siphon assembly prior to the siphon tube pulling up the layer of oil with the urine. The reservoir is configured to cease operation of the siphon assembly in response to a distance required to pull air bubbles up the reservoir and into the drain tube being less than a distance required to raise urine into the drain tube.

A siphon assembly includes an ascent conduit having a conduit inlet, a descent conduit having a conduit outlet, and a flow passage through the ascent conduit and the descent conduit. The flow passage connects the conduit inlet and the conduit outlet via a siphon crest. The siphon assembly also includes a filter arranged to filter a siphonic flow towards the siphon crest.