Principles of Mobile Public Toilets
The principles of mobile public toilets vary depending on their types, mainly including various technical paths such as water flushing, foam sealing, and microbial degradation.
Water-flushing mobile toilets need to be connected to municipal water supply and drainage networks. Their core principle is similar to that of traditional fixed toilets: flushing excrement into the sewer system through gravity or pressurized water flow. This type relies on a continuous water supply and is suitable for places with municipal network conditions, such as city squares and commercial streets. However, it has limitations such as high water consumption and dependence on infrastructure.
Foam-sealing types adopt physical sealing and water-saving technologies. They generate high-density lubricating foam through a foaming device to cover the surface of the toilet. When excrement falls, it is wrapped by the foam, which not only reduces water consumption (only 50-100 ml of water is needed for a single flush) but also blocks the spread of odors through the sealing property of the foam. This technology is particularly suitable for water-scarce areas or temporary event scenarios.
Microbial degradation types utilize bioengineering technology. A strain culture box is set at the bottom of the toilet. Specific microorganisms (such as aerobic bacteria and anaerobic bacteria) decompose excrement into carbon dioxide, water, and organic matter through enzymatic hydrolysis, with a conversion rate of over 90%. The treated residues can be used as organic fertilizers. The entire process does not require an external sewage discharge pipeline, making it suitable for remote scenic spots without network coverage or post-disaster emergency scenarios.
Packing and dry-packing types both adopt the principle of physical isolation. They seal excrement in biodegradable plastic bags through mechanical devices or gravity. The former achieves automatic bag replacement through rotating buckles, while the latter relies on gravity to make feces fall into the bag. Both types of toilets do not require a water-flushing system but need to regularly replace the collection bags. They are suitable for short-term high-traffic scenarios such as construction sites and open-air music festivals[3]^.
Circulating filtration and chemical treatment types achieve water resource recycling through multi-stage purification. Urine is filtered through a membrane to meet the flushing standard, and solid feces are disinfected with chemical agents and stored separately. The circulating water-flushing type combines biological treatment technology and is equipped with an intermittent aerobic-anaerobic reaction device. It accelerates the decomposition of organic matter through a biofilm, and the treated reclaimed water can be recycled for flushing, with a water resource utilization rate of over 80%[3]^.
