In the blink of an eye, 3 astronauts have been full of 1 month on the space station, astronauts have adapted to life on the space station, we can also see the astronauts' warm space life on the space station from various videos, such as cleaning up "kitchen waste" together after meals, Ye Guangfu 'wiping the air' with paper towels after spilling drinks, Zhai Zhigang took time to play Tai Chi, Wang Yaping and Zhai Zhigang incarnated as "Tony Teacher" for Ye Guangfu's haircut, Zhai Zhigang wore a "flush-free water artifact" to rub and wash his hair, Wang Yaping showed space "no rinse" brushing teeth...
At this time, netizens will have questions, how to solve the problem of water use on the space station? We need to know that in general, normal adults should supplement about 2000 ml per day, which includes drinking water and the amount of water ingested in the diet. According to the appropriate intake of drinking water for Chinese residents released by the Chinese Nutrition Society: the human body needs to consume 1500 ml of water - 1700 ml of water per day.
Even in the case of 1500 milliliters, three astronauts need at least 4500 milliliters of water per day, which does not include sanitary water and water for equipment provided for life support systems, in the case of the International Space Station, the ration of about 4 liters of water per person per day. So how can this water be solved?
The simplest and most rude way, of course, is to send water, and Tianzhou-3 has brought multiple sets of water tanks for astronauts to drink and use this time. These water tanks are made of lightweight, soft materials made of "water bladder" packaging, not only to ensure the safety of drinking water, but also to better store after drinking water is exhausted, manned spacecraft in order to meet the drinking water needs of astronauts, equipped with directly drinkable storage tanks and bagged water, equivalent to "bottled water" and "bottled water". The bagged water is connected to the water bag with a straw and a water stop clip.
In addition, the space station can also generate water through fuel cells, and hydrogen-oxygen fuel cells react under reduced sentence conditions to generate electrical energy, while generating water.
The final is to rely on the station's environmental control and life support technology to recover and reclaim water, space environmental control and life support technology includes oxygen regeneration system, wastewater regeneration system, atmospheric pressure and composition control, cabin temperature and humidity control, sanitation and waste management five parts.
The wastewater regeneration system includes three subsystems: condensate collection, urine treatment, and water treatment. Relying on these three subsystems, the Tiangong space station has achieved 100% regeneration of the water resources in the station.
The condensate produced by cooling and dehumidification will be recovered through condensation, and the wastewater of carbon dioxide reduction will also be returned, and the reclaimed water is mainly the recycling of urine, which is very difficult to technology.
The treatment and recovery of urine is a very important part of the life support system of manned spaceflight, and it is also a more complex and important link in the wastewater treatment process.
China, the United States and Russia and other space powers have invested a lot of manpower and material resources to carry out systematic research, overcome many scientific and technological problems, and successfully developed a urine treatment system.
Astronaut urine wastewater contains up to 95% water, 3.5% organic matter (including urea, creatinine and uric acid, etc.) and 1.5% inorganic salts (sodium, potassium, chlorine, magnesium, calcium, ammonium, sulfates and phosphates, etc.).
The treatment of urine on a space station typically includes pretreatment, material recovery, and post-treatment. Pretreatment is mainly to complete the collection of urine, the addition of pretreatment agents and the separation of gas-liquid phases; the addition of pretreatment agents is mainly to avoid urea water in the urine to explain the ammonia emitted by the air pollution, so before the space station processes and recovers urine, chemical agents are added to pretreat urine to prevent urea hydrolysis, such as the International Space Station IN the UNITED C. module uses strong acids and chromium oxides as urine pretreatment agents, and the "Mir" space station uses preservatives as pretreatment agents. The reprocessing is mainly used to further purify the water recovered from the urine so that it meets drinking water standards.
Russia mainly uses osmotic membrane evaporation technology for astronauts to regenerate urine, and its urine regeneration system has been launched on January 15, 1990 on the Kvant-2 module of the "Mir" space station, the processing capacity of the device is 5 kg of water per day, and the water recovery rate in urine is about 80%. By 1999, the unit had recovered 6,000 kg of recycled water from urine, and the quality of the recycled water was up to drinking water standards. At present, in the Russian module of the International Space Station, the improved osmotic evaporation membrane treatment technology is still used.
The International Space Station and the Chinese space station both use the most advanced steam compression distillation technology, steam compression distillation technology mainly uses phase change latent heat to reduce the operating energy consumption of the whole machine, and the energy consumed by the whole process is mainly used for the work of the Roots compressor and the compensation system for thermal and mechanical losses. The condensed effluent of the urine enters the water treatment together with the air condensate and sanitary wastewater and listens carefully, and then passes through the multi-stage filter bed, the catalytic reactor and the ion exchange bed to achieve drinking water standards.
The water purified by the water treatment subsystem in the Chinese space station can not only meet the drinking water standards, but even exceed the requirements of the domestic drinking water sanitation standards and the astronaut drinking water sanitation standards, and can be used for the cleaning and oxygen production needs of astronauts.
At present, according to the actual data, the urine treatment subsystem can extract 5 liters of distilled water from 6 liters of urine, the maximum water production rate is 2.5 liters per hour, and the distilled water is purified by the water treatment subsystem.
Astronauts take samples of water every month and perform microbiological tests to see if the water drunk in space is clean. Scientists generally believe that living microorganisms must be in contact with aqueous solutions in time and space to be metabolized, and in turn, microbial contamination cannot be completely eliminated from the earth's water, but can only be controlled and weakened in the long run. Because astronauts need to stay on the space station for 6 months, analyzing aquatic microorganisms is crucial.
In order to avoid polluting water samples, Wang Yaping and Ye Guangfu specially wore masks and gloves. The two filtered the water sample and the culture medium, left the microorganisms and nutrients on the filter membrane, and then observed the collected microbial samples to test whether the water could be drunk.
In the future, in order to provide astronauts with a more comfortable and safe living environment, scientists are also developing an artificial ecosystem composed of plants, animals and microorganisms, and the urine treatment system will be further upgraded, and the nutrients in the urine can be recycled for the preparation of nutrients required for plant growth, which can not only ensure the normal growth of plants, but also help to achieve the recycling of substances in the system, thereby greatly reducing the ground replenishment required for long-term space activities.