How to Treat Feces in Mobile Toilets
The treatment of feces in mobile toilets mainly relies on technologies such as anaerobic fermentation, microbial decomposition, chemical treatment, recirculating water flushing, dry packing, and vacuum suction, achieving harmless treatment through physical, biological, or chemical means.
1. Anaerobic Fermentation and Physical Sedimentation
The septic tank is the most common treatment method for mobile toilets, with its core being the use of a layered structure for natural decomposition. Fresh feces enter the first tank and, due to density differences, form three layers: a糊状 (paste-like) fecal crust on the top, clarified fecal liquid in the middle, and块状 (lumpy) fecal residue at the bottom. The middle fecal liquid overflows through a fecal pipe to the second tank for secondary fermentation, further decomposing organic matter and killing parasite eggs and intestinal pathogens; it eventually flows into the third tank for storage, where the fecal volume significantly decreases, meeting harmless standards. The entire process requires more than 30 days, and the septic tank volume must be designed according to the foot traffic to avoid incomplete treatment due to insufficient capacity.
2. Microbial Decomposition Technology
By adding efficient bacterial strains such as Bacillus, fecal degradation is accelerated. After feces enter the fermentation tank and mix with wood chips and biological strains, under the action of microorganisms, the degradation rate can exceed 90% within 24 hours, ultimately decomposing into carbon dioxide and water, with a degradation rate of ≥99%. This technology is suitable for high-frequency usage scenarios but requires regular supplementation of bacterial strains to maintain activity and has certain temperature requirements for the environment (usually needs to be kept above 10°C).
3. Chemical Treatment Method
Using strong oxidants such as sodium hypochlorite to rapidly decompose feces, treatment can be completed within 10 minutes. However, chemical agents may produce harmful gases such as chlorine, posing a risk of secondary pollution, and long-term use can corrode the tank. Therefore, this method is mostly used as an emergency or supplementary measure, requiring strict control of agent dosage and enhanced ventilation.
4. Recirculating Water Flushing Technology
Combining biofilm technology with anaerobic treatment devices, organic matter in fecal sewage is degraded by microorganisms, while anaerobic reactions produce biogas to reduce odors. The treated water can be recirculated for toilet flushing, significantly reducing suction frequency and water consumption. This technology requires professional equipment, with high initial costs but lower long-term operating costs.
5. Dry Packing and Foam Sealing
The dry packing type uses biodegradable plastic bags to directly receive excreta without flushing, suitable for water-scarce or sewer-less areas; the foam sealing type covers the toilet surface with foaming liquid, forming a seal to reduce odor diffusion while reducing flushing water volume. Both methods require regular replacement of packing bags or supplementation of foaming liquid, and feces need to be transported to a professional treatment plant for centralized processing.
6. Vacuum Suction and Packing Technology
Vacuum technology uses negative pressure to suck feces into a sealed storage tank, reducing odor leakage; the packing technology individually wraps excreta with biodegradable film for easy transportation. These two methods have high treatment efficiency but high equipment costs and maintenance requirements, mostly used for large-scale events or high-end mobile toilets.
Treatment Precautions: Septic tanks should be made of corrosion-resistant materials such as fiberglass or high-density polyethylene; regularly add biological agents or chemical deodorizers to maintain treatment efficiency; adjust the cleaning cycle according to usage frequency to avoid fecal overflow.
