On-board Digester for Human Waste Using Segmented Anaerobic and Chlorination Chambers
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Solution Overview
Problem
There is a lack of effective systems for on-site treatment and safe disposal of human waste in public transport vehicles, leading to environmental pollution, health risks, and high operational costs due to the need for manual collection and transportation of waste, which is aesthetically and environmentally undesirable.
Innovation Solution
A digester system comprising a stainless steel tank with two chambers for anaerobic biological treatment and chemical chlorination, utilizing PVC sheets as an immobilization matrix for bacteria to prevent washout and enhance biodegradation, and an automated chlorine dispensing system for pathogen inactivation, designed to be energy-independent and easily maintainable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If human waste is transported to remote disposal sites, then disposal capacity is improved, but operational cost and time increase
Solution Approach 1:
The waste treatment system is divided into two functional chambers: an anaerobic digestion chamber for biological treatment and a chlorination chamber for chemical disinfection. This segmentation allows different treatment processes to occur simultaneously in separate zones, enabling comprehensive waste treatment without requiring external transportation infrastructure.
Solution Approach 2:
The digester is designed as a self-contained unit that performs both anaerobic digestion and chlorination functions internally. The system treats and disinfects waste on-board the public carrier without requiring external treatment facilities, making the system self-sufficient and eliminating the need for waste transportation to remote sites.
2Object-affected harmful factors
If chemicals are added to collection containers to prevent foul smell, then aesthetic nuisance is reduced, but biodegradation process is delayed
Solution Approach 1:
The system separates odor control from the biodegradation process by implementing chlorination in a dedicated second chamber after anaerobic digestion is complete. This segmentation allows the biodegradation process to proceed uninterrupted in the first chamber while odor control is applied in the second chamber, eliminating the conflict between smell prevention and degradation rate.
Solution Approach 2:
The anaerobic digestion process is allowed to complete first in the first chamber, converting organic matter into biogas and stabilized sludge. Only after this preliminary biodegradation action is complete does the chlorination process begin in the second chamber, ensuring that chemical disinfection does not interfere with the biological breakdown of organic material.
3Productivity
If aerobic bacteria are used for biodegradation, then degradation rate increases, but sludge production and energy consumption increase
Solution Approach 1:
The system changes the oxygen parameter from present (aerobic) to absent (anaerobic) in the digestion chamber. By creating an oxygen-free environment, the system shifts bacterial metabolism from aerobic to anaerobic pathways, which produces significantly less sludge and biomass while still achieving effective waste degradation through methanogenic bacteria.
Solution Approach 2:
The system converts the traditionally harmful anaerobic conditions (which were considered to produce foul odors and slow degradation) into a beneficial process. By controlling anaerobic digestion, the system achieves both effective waste breakdown and minimal sludge production, while the biogas produced can be utilized as an energy source, turning a potential harm into a benefit.
4Loss of substance
If incineration is used for waste disposal, then waste volume is reduced, but environmental pollution and cost increase
Solution Approach 1:
The system converts the potentially harmful anaerobic decomposition process (which can produce methane and hydrogen sulfide) into a beneficial energy source. The biogas generated from anaerobic digestion is captured and can be burned for energy, while the remaining sludge is disinfected through chlorination. This approach achieves waste volume reduction without the harmful emissions associated with direct incineration.
Solution Approach 2:
The system changes the temperature parameter from high-temperature incineration to ambient-temperature anaerobic digestion followed by chemical chlorination. This parameter change achieves waste stabilization and pathogen destruction without the energy-intensive combustion process that generates noxious gases, providing a more environmentally friendly alternative.
5Reliability
If conventional septic tank systems are used, then waste treatment is achieved, but they cannot be used in mobile public carriers
Solution Approach 1:
The system merges two previously separate waste treatment functions into a single integrated unit: anaerobic digestion and chlorination disinfection. By combining these functions in one compact digester unit, the system achieves comprehensive waste treatment suitable for mobile public carriers while maintaining the reliability of conventional treatment methods.
Solution Approach 2:
The digester is designed as a multi-functional unit that can be installed in various mobile public carriers (buses, trains, boats, airplanes). The system performs multiple functions including anaerobic digestion, biogas production, sludge stabilization, and chemical disinfection, making it universally applicable to different mobile platforms while maintaining effective waste treatment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The digester enables efficient, odorless, and pathogen-free biogas production from human waste, reducing aesthetic and health hazards, and eliminating the need for off-site transportation, while being cost-effective and resistant to environmental stresses.
Implementation Method 1
anaerobic process employs bacteria, which grow strictly in the absence of air/oxygen... The main products of anaerobic degradation include methane, carbon dioxide and hydrogen sulphide
Implementation Method 2
Biodegradation is considered to be the most preferable way of treating the waste... anaerobically
Implementation Method 3
anaerobic processes are known to inactivate the pathogens present in the human waste... chemical treatment compartment (3) to discharge treated waste
Data Source
AI summary
A digester for degradation of human waste comprising a main tank having biochemical treatment compartment and chemical treatment compartment connected by connecting pipe as a passage for bio-chemically treated waste to chemical treatment compartment; the biochemical treatment compartment has at least one loosely fitted partitioned wall and at least one inlet to receive waste, at least one gas outlet and at least one waste drain pipe to remove sludge; the chemical treatment compartment has discharge means to discharge treated waste and excess of liquid, and float ball assembly to release chemical for chemical treatment.