Working Principle of Mobile Toilet Fermentation
The working principle of mobile toilet fermentation mainly includes four modes: biodegradation, low-temperature pyrolysis and anaerobic digestion, microbial decomposition, and traditional anaerobic fermentation and sediment separation, as detailed below:
Biodegradation Environmental Protection Mode
This mode utilizes the synergistic effect of microorganisms and biological fiber materials (such as sawdust and straw powder) to achieve harmless treatment of fecal waste. Excreta enters the fermentation tank through an automatically opening toilet bowl, and a screw propeller mixes the initial ingredients (wood shavings) with feces. Under automatic temperature control, microorganisms initiate the fermentation process, decomposing solid components into carbon dioxide (CO₂), water (H₂O), and a small amount of gas. This process achieves a degradation rate of up to 99%, with the capacity to degrade the excreta of 100 people within 4-8 hours. The key points lie in the rapid decomposition ability of microorganisms and the adsorption effect of biological fiber materials, ensuring odor-free and resource-utilized treatment.
Low-Temperature Pyrolysis and Anaerobic Digestion Mode
Taking some mobile restrooms in Beijing as an example, solid excreta is first sent to a dehydration bin equipped with a heating device. Through low-temperature pyrolysis at 120℃, moisture evaporates, and the residue is converted into dry particles with a moisture content of less than 30%. Subsequently, the particles enter a closed anaerobic digestion tank, where, under mesophilic (35-38℃) anaerobic conditions, methanogenic bacteria decompose cellulose and proteins, generating biogas with a methane content of approximately 55%. This mode reduces volume through pyrolysis and then utilizes anaerobic digestion for energy recovery, forming a closed loop of 'volume reduction - gas production'.
Microbial Decomposition Mode
High-efficiency composite microbial communities are added to the septic tank. These communities secrete enzymes such as proteases and lipases, accelerating the decomposition of organic macromolecules in feces, including proteins, fats, and carbohydrates, into carbon dioxide, water, and inorganic salts. This process is usually accompanied by a ventilation system to provide oxygen, promoting the activity of aerobic bacteria, and belongs to aerobic or facultative anaerobic biological treatment. The advantages include high treatment efficiency, no secondary pollution, and the ability of the microbial community to maintain long-term activity, reducing maintenance costs.
Traditional Anaerobic Fermentation and Sediment Separation Mode
After entering the septic tank, feces are stratified by gravity: solid particles settle to the bottom to form a sludge layer, grease floats to form a scum layer, and the middle layer is clarified sewage. Under anaerobic conditions, anaerobic bacteria slowly decompose organic matter in the sludge, producing biogas and stabilizing the material. This mode is simple in structure and low in cost but has a long treatment cycle and requires regular sludge removal, making it suitable for low-flow scenarios.
Summary: Mobile toilet fermentation technology converts excreta into harmless substances or energy through biological, physical, or chemical means, with the core lying in microbial action, temperature control, and stratified treatment. Different modes are suitable for different scenarios, collectively promoting environmental protection and resource recycling.
