Oxygenated Wet Pail for Soiled Laundry
Storing reusable diapers, reusable personal wiping cloths and reusable menstrual cloths in water between use and washing can help prevent stains from setting, but the anaerobic conditions of a pail of stagnant water makes such stinky items even more stinky and can pose health risks. The introduction of oxygen to such a pail by an air pump and air stone (as used in aquariums and hydroponics) could help to control the growth of the anaerobic microorganisms that are the source of these offending odors.
A water pump could also be added along with a mechanical filter to filter out solids and a biofilter to convert compounds such as ammonia to less toxic and stinky ones, such as nitrate. A biofilter would act on water after it is mechanically filtered and would consist of a well-aerated medium with a large surface to harbor beneficial bacteria that break down unwanted compounds (search Google for "biofilter"). Some aquaculture systems have incorporated plants into their biofilters (Growing plants with water that fish live in is called aquaponics). The filters would need to be cleaned regularly. It may be helpful to add certain compounds to the water to adjust its pH or carbon/nitrogen ratio.
If the water was filtered well, it could be connected to a toilet to refill the tank after flushing and draw new water from what would have been the toilet's water connection. If the water was filtered very well, it could just stay in the pail indefinitely.
If a biofilter were used, care would need to be taken to ensure that oxygen delivery is not interrupted, as this could kill the aerobic microorganisms and plants. If a biofilter is not added, a UV sterilizer could be used to kill bacteria. In this case, a motorized agitator could also be included in the pail for it to be used as a mini-washing machine. Alternatively, the pail itself could be agitated. It seems that the portable "Wonder Washer" works this way. A portable spin dryer or manual wringer could be used to extract water from the items before and after rinsing.
Sonic waves could be introduced to break up stains. Sonic waves are used in some jewelry cleaners. I am not sure how microorganisms respond to sonic waves though. Sonic waves might not be usable with a biofilter.
This pail could make it easier for people and families wanting to use disposable hygiene products and help them save water in the process.
Reward: A free one. Don't ask what for.