The "indoor dry toilet" developed by me was approved on 1988, and was installed and used in a farmer's house in the suburb of Acheng on 1989. In the past two years, it has completely met the design requirements of indoor toilets, without flushing, odor, groundwater pollution, cold prevention and low cost. 1990 passed the expert appraisal and reached the domestic advanced level. 19 1 won the second prize of scientific and technological progress in urban and rural construction. And has declared a patent.
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In the research of waterless toilet flushing, some countries with more developed science and technology in the world have long been ahead of us. Either from the perspective of water saving, or used in villas without water pipes. Among them, there is an inclined compost bin integrating kitchen and toilet, and there is a treatment device combining domestic garbage decomposition and feces decomposition. It does not need any chemical reagents and any auxiliary equipment. Using the aerobic principle, the volume of garbage is reduced by 90% in the process of moving from top to bottom under the action of gravity, making garbage and feces harmless. There is also a dry toilet, in which a base material capable of decomposing excrement is arranged in a collection container, and the excrement and the base material are lifted and mixed by shaking the handle by hand to achieve the purpose of decomposition. Some dry toilets decompose feces and urine in different ways after they fall into the container, and some have built-in heating devices to ensure the temperature and accelerate the decomposition. No matter what form they take, what these toilets have in common is that they don't need to be flushed, they are odorless, and there is no pollution to the environment after the feces are decomposed. This not only saves a lot of valuable water resources, but also makes it possible to set up indoor toilets in areas without water supply and drainage facilities. A large number of waterless indoor aqua privies are used in Hokkaido, Japan. According to science and technology reports, Japan has specially developed and produced disposable plastic gaskets for toilets and toilet supporting equipment with different functions such as automatic flushing, heating and drying, and emitting fragrance, which can keep the toilet at a constant temperature in winter. Computer technology has also been applied to toilets, analyzing urine and measuring people's temperature, blood pressure and pulse.
Compared with developed countries, there is a big gap in the research of dry toilets. Of course, there are many economic reasons. However, in recent years, due to the improvement of people's awareness and the urgent need to improve the environment, some provinces and cities have successively developed or are studying dry toilets suitable for China's national conditions and different regions under the condition of insufficient funds and late start. In the south, such as Yibin, Sichuan, there is a toilet with biogas purification device, which can live on the top of the public toilet. The treated manure is not only harmless, but also has a biogas digester. The biogas produced by a public toilet is enough for people to live on the top of the public toilet all year round, and the environment is transformed. There are also waterless and odorless plastic dry toilets produced by a research institute of the Corps of Engineers and Beijing Haidian Acoustic Equipment Factory, which fundamentally solve the problem of odorless and flushing. In the Yellow River Basin, Le Song Credit, a doctor from Yucheng County Health and Epidemic Prevention Station in Henan Province, developed a "double-urn funnel" dry toilet in 10. Toilets are located in the outdoor courtyard, which is odorless and has no loss of feces, but they are located outdoors.
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The indoor aqua privy I developed is different from the luxury in foreign countries and the style adopted in the Yellow River Valley of China. However, it has the characteristics of economy, practicality, cold and antifreeze.
The dry toilet I developed consists of a toilet (special equipment for dry toilets), a defecation pipe, a ventilation pipe and a toilet trough.
The toilet is ceramic, which is a double-layer partition toilet (there are also single-layer partitions). When in use, the top cover is opened by hand, and the opened toilet is tightly blocked by the body. Then, the second partition is opened by hand, and the excreta first enters the fermentation broth with sufficient capacity through smooth defecation, and when the excreta is too much, it flows into the storage room.
The toilet will be built together with the newly-built house, and its volume will be calculated according to the excretion of the family population, and it will be cleaned once a year, with an air layer about 40 cm high. Considering anti-freezing, it should be buried at the freezing depth of about 1 m. Considering that the excavation should be carried out outdoors, the toilet is buried under the foundation of the house and has an indoor part and an outdoor part. Leave a cleaning hole in the outdoor part, and consider two possibilities: manual cleaning and dung suction car collection. Pay attention to keep warm when not in use, and consider it as the air inlet of the toilet.
The biggest problem of indoor dry toilets is that there is no odor in the room and feces digestion.
1, indoor odor problem
The deodorization of flushing the toilet with water is cut off by setting a trap under the toilet to prevent the odor in the pipeline from spreading indoors. The odor removal measures taken by dry toilets are based on the principle that an air duct is arranged on the toilet trough, which extends out of the roof and is exposed to the atmosphere, and is actually a chimney. Moreover, the amount of fermentation products is large and the amount of primary excreta is limited. The excrement enters the toilet bowl and decomposes quickly, and the generated gas is quickly discharged through the deodorizing tube.
Through our actual measurement and calculation, we can see that the toilet and ventilation system we adopted are successful.
When the outdoor temperature is lower than the temperature in the tank, the hot pressing is positive and the air flows outward. On the contrary, when the outdoor temperature is higher than the temperature in the tank, the exhaust in the tank is not smooth. However, because the feces in the tank continuously produce gas during fermentation, when the gas in the tank accumulates to a certain amount, the pressure is greater than the outdoor pressure, and the gas is discharged into the atmosphere from the ventilation pipe. Natural ventilation is a complicated process. When the temperature difference between the inside and outside of the tank is large, it is mainly hot-pressing exhaust, and when the temperature difference is small, it will be compensated by air pressure exhaust. Moreover, hot pressing and negative pressure often act at the same time, and they are inseparable, ensuring the natural ventilation effect. Not only that, the urinal in the dry toilet is a sitting toilet, and there is a double-layer sealed partition, so the gas in the water tank has no way out indoors, which ensures that the odor will not spread indoors.
In addition, it is also important to brush the toilet once or twice a week with a small amount of water (such as face washing water).
2. Digestion of feces
Before using the dry toilet, about 5 kg of soybeans are fermented with about 100 kg of water, and then put into the toilet tank once before use. When the aqua privy is used, excrement enters the excrement tank, and the excrement in the tank is basically anaerobic. Especially, after the feces are piled up to a certain height, they naturally ferment under anaerobic conditions like septic tanks because there are no measures such as heating, blowing and stirring. After one year's use, we sampled the toilet tank in early June+February, 5438, and analyzed the degradation of organic matter and the killing rate of bacteria. The results are as follows:
The chemical oxygen demand (COD) decreased from 30,000 mg/L to 32,000 mg/L in fresh manure to18,790 mg/L, and the biochemical oxygen demand (BOD) decreased from 20,000 mg/L in fresh manure to 7,474 mg/L in five days, and the digestibility was about 50%.
The total number of bacteria decreased from1.1×101before digestion to 1× 105 after digestion.
Escherichia coli was destroyed from 9.0× 109 before digestion to 9.0× 106 after digestion (the water content of digested sludge was about 80%). It can be seen that the total number of bacteria and fecal Escherichia coli were killed about 100 times.
From the laboratory analysis, it can be seen that the natural digestion of feces in anaerobic condition in the pool is satisfactory, and its digestion effect is almost the same as that of sludge in large sewage treatment plants at medium temperature (33℃), without any auxiliary facilities. Its digestive effect is basically similar to that of a toilet. Dry toilets that do not need to be flushed with water save a lot of resources and energy. It is advanced to some extent. Feces will not be lost.
The partially digested manure is directly applied to the farmland, but we suggest to use compost for further decomposition before application, because the internal temperature of compost can reach about 70℃, and almost all eggs and germs can be killed at 25℃ for about 40 days, without too much economic investment, and the fertilizer content can be improved after composting.
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After years of practice, indoor dry toilets have good social, environmental and economic benefits. To sum up, there are the following points:
1, improve the environment and reduce pollution.
A considerable number of rural toilets in the northern region are "pigs and dogs have fun" toilets. First, the incidence of cysticercosis increased after pigs ate human feces, reaching as high as 12-20% in our province, and the economic loss was equivalent; Second, flies breed in summer, which increases the incidence of people; Third, groundwater has been polluted, and the penetration rate of tap water in rural areas of our province is about 30%. A considerable number of farmers drink shallow groundwater that does not meet the drinking water standards; Fourth, the environment is not beautiful. Indoor dry toilets completely solve the above problems.
2, the use of feces, turning waste into treasure
According to the data, the feces excreted by an adult in one year contain the following contents.
Fat content in feces and urine excreted by an adult in one year (kg)
The excretion of nitrogen (N) is equivalent to ammonium sulfate and phosphorus (P2O5), calcium superphosphate (K2O) and potassium sulfate.
Human1801.009.000.904.50.671.40
Human urine1400 7.00 35.01.82 9.5438+0 2.67 5.55
* * * m1580 8.80 44.0 2.7213.6 3.34 6.95
More than 900 million people in China live in suburbs, counties, towns and villages, and about 65438+ 1 100 million adults in Heilongjiang Province alone live in such areas. If the manure is well treated and turned into treasure, it can be converted into 220,000 tons of ammonium sulfate, 30,000 tons of potassium sulfate and 70,000 tons of calcium superphosphate every year. What a big economic figure.
3, saving water and energy, with remarkable effect.
At present, the penetration rate of water supply in counties, townships and villages is not high, and drainage facilities are not available, so it is impossible to build indoor flush toilets. Indoor aqua privies can be set in all areas without flush toilets, and their functions can be comparable to those of flush toilets, saving a lot of water. According to statistics, about 40% of the domestic water consumption standard is used for flushing toilets, so compared with two toilets with the same function, dry toilets save a lot of water. There are 4 million farmers in our province. If 5% of them use aqua privies, there will be 200,000 households. Compared with flushing toilets with water, if each household saves 50 liters of water every day, it will be 360,000 tons per year, which is equivalent to a medium-sized water purification plant. Its effect is remarkable and its benefit is amazing.
4, the living environment, comprehensive improvement.
If a house is equipped with an indoor toilet, it will greatly improve the living conditions and improve the comfort of people's lives. In the vast areas without sewage facilities in the north, especially in winter, the temperature difference between indoor and outdoor is large, and indoor dry toilets are equipped, which is convenient to use and reduces diseases. It is also an important part of the construction of two civilizations.
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Regarding the requirement of building "sanitary toilets" in rural areas by the end of this century, the National Patriotic Health Association clearly put forward: "According to the strategic deployment of the CPC Central Committee on China's economic development, referring to the global indicators of the World Health Organization, starting from the current actual level, it is proposed that the minimum level of achieving the goal of' health care for all in 2000' in rural areas in China, that is, the penetration rate of sanitary toilets in different economic areas of rural four levels reaches 35%, 45%, 70% and 80% respectively. We believe that the dry toilet developed by our research institute will make due contributions to the realization of the above goals.