Mobile Toilet Feces Recycling

Mobile toilet feces recycling is mainly achieved through technologies such as biodegradation, packaging, suction and drainage, resource utilization, recirculating water flushing, and foam sealing. Different methods are suitable for different scenarios, with the core goals being resource utilization and harmless treatment.

1. Biodegradation Type
Probiotics or microorganisms are used to decompose the organic matter in feces, converting it into water, carbon dioxide, and a small amount of solid residue within 24 hours to 15 days. The water can be used for toilet flushing or watering plants after multi-layer filtration (such as activated carbon and quartz sand), and the solid residue can be used as organic fertilizer. For example, some mobile toilets in Inner Mongolia completely degrade feces into methane gas and liquid by enhancing the activity of beneficial microorganisms. The liquid is recycled for flushing after ultraviolet disinfection, achieving 'zero emissions'. This technology is suitable for remote areas or long-term use scenarios, but it requires regular replenishment of bacterial strains and control of environmental temperature and humidity.

2. Packaging Type
Biodegradable plastic bags or drawer-type containers are used to collect feces, which are automatically sealed by foot pedals or mechanical devices to prevent leakage and odor diffusion. This design is common in construction sites and temporary event venues. The containers are regularly replaced and transported to treatment plants for composting or incineration. Its advantages are simple operation and low cost, but it requires frequent replacement of containers, and the degradation cycle of plastic bags is relatively long, which may cause secondary pollution.

3. Suction and Drainage Type
Vacuum fecal suction trucks are used to transport feces to sewage treatment plants for centralized treatment. The single suction volume is about 2-3 cubic meters, suitable for large-scale events or fixed mobile toilets in densely populated areas. This method has high treatment efficiency but relies on transportation vehicles and treatment facilities, resulting in high costs. It may also increase carbon emissions due to transportation distances.

4. Resource Utilization Technologies

• Dehydration and Drying: The moisture content of feces is reduced from 90% to below 30% through centrifugation or heating, forming solid fuel or fertilizer. This technology can reduce volume but has high energy consumption and requires supporting drying equipment.
• Biogas Fermentation: Feces are mixed with organic waste for fermentation to produce biogas (with a methane content of 60%-70%), which can be used for power generation or heating. A single toilet can produce about 500 cubic meters of biogas per year, but it requires the construction of fermentation tanks and control of parameters such as temperature and pH, making it suitable for large-scale applications.

5. Recirculating Water Flushing Type
Intermittent aerobic and anaerobic treatment devices are configured, and biological strains are added to accelerate fermentation and decomposition. The filtered water is recycled for toilet flushing, reducing the frequency of suction. This technology can reduce water consumption but requires regular maintenance of the treatment system to prevent strain inactivation or pipe blockage.

6. Foam Sealing Type
Foam generated by a foaming liquid mixture covers the inside of the toilet bowl, isolating odors and reducing the amount of flushing water. The collected hand-washing water can meet the water demand for foam generation. This technology has significant water-saving effects, but the foaming liquid needs to be replenished regularly, and the stability of the foam is greatly affected by temperature.

Scenario Selection Suggestions: For short-term events, suction and transportation are preferred. For remote areas, biodegradation or solar drying technologies are suitable. In resource-intensive areas, a combination of biogas fermentation and dehydration and drying can be used to achieve dual outputs of energy and fertilizer.