As water becomes more scarce, engineers are turning to composting toilets for installation in a variety of commercial applications.
The composting toilet system at Mule Creek Junction was designed to fit the rest area's high use projections. It includes six new composters along with five of the original units, which were refurbished by the manufacturer. Toilet waste falls from the toilet fixture through a 14" plastic chute, to the composting tank directly below the toilet fixture. Although the toilet fixture is just a large opening, there is no odor, thanks to a fan that pulls air continuously down the toilet. Urine and feces are separated by gravity in the sloped chamber of the composter, and both are treated by the system. The urine becomes a stable, high nitrogen solution. Although in some instances this liquid is used as fertilizer, at Mule Creek Junction, it is put into a leachfield, along with water generated by sinks. Wood chips are added to the system to help create the proper conditions for composting. After more than a year within the system, the volume of feces is reduced by over 90%. The composted end product biologically and chemically resembles topsoil and can be used as a soil conditioner. It's not expected that it will be necessary to remove the composted end product at Mule Creek for several years.