Thousand Island Lake, picturesque scenery, blue waters, and the famous local 'Fish Head Banquet' is also known for its excellent water quality environment. As one of the important water harvesting areas of 'Nongfu Spring', its water is sweet and clear, and it should be The description of one side of the water and soil. However, unlike the lucky Qiandao Lake area, the drinking water environment in most parts of China is unsatisfactory, and there are very few people who can enjoy high-quality direct drinking water. At present, the water environment facing Chinese society is real. What is the situation? With this question, at the 2nd Doctoral Forum on Drinking Water Safety and Health in 2018, China National Grid reporter interviewed Wang Hao, the academician of the Chinese Academy of Engineering and director of the Water Resources Institute of the Chinese Academy of Water Sciences.
Water and life
'How many things in life, but nothing is more important than drinking water safety.' Wang Hao pointed out, 'In the life of a person, it is the process of gradual dehydration. The birth of life begins with amniotic fluid, and the living body exists in 100% water environment.甫 born newborn, water accounts for 90% of the body's weight; in early childhood, 80% of body weight; from juvenile to old age, the water accounts for 70% of the body; and the year of the year, body water content Reduced to 60%; and to death, water accounted for 50%. And the body's tissues and organs, even the least watery bones, water accounted for 22% of its total weight; brain water accounted for about 76%; The water content of blood is about 75%. When a person's body water is reduced by 1%-2%, it will be obviously thirsty; when dehydrated by 5%, the human body will be unconscious and briefly faint; when dehydrated by 15%, the human body will die.
Wang Hao cited the importance of water to the world. 'With China as an example, we can become the world's largest country, and it is inseparable from the boiling water habits developed in ancient times. It kills pathogens and microorganisms by boiling water, ensuring the Chinese population. The natural mortality rate has fallen sharply. For the accumulation of the population base, healthy drinking water has contributed.
'Now, everyone talks about the importance of electricity, energy, and the Internet. But from the 100,000 years of human beings going out of Africa, the 600 years of human beings from the ancestors to the modern people, electricity is only about 150 years, and water is indispensable. If there is no electricity, we can continue to exist; if there is no water, the 7.3 billion people will be collectively extinct within 3-5 days.
This is the magic of water, and it is also our original intention to pay attention to drinking water safety.
China's drinking water environment
However, although the Chinese drinking water environment has improved, it is not optimistic.
Wang Hao pointed out that China's natural water conservation areas, such as natural water circulation, rivers and lakes, have suffered serious pollution and destruction in the past 30 or 40 years. At that time, only Jinshan Yinshan was heavy, causing environmental degradation, water. Resources have been polluted. After nearly 10 years of centralized environmental management, China's water environment has begun to turn to a good point in recent years. The important indicators that can be referenced are 'two rises, two declines'.
'Two rises', one refers to rising GDP, and the other refers to rising water environment. 'In the past few years, our GDP has grown by 7% to 12%, and now it has dropped to about 6.5%, and it may fall to 5% in the future. Generally speaking, in the course of development of various countries, when GDP maintains a growth rate of more than 5%, the environmental deterioration momentum is present. While China's GDP is rising in the range of 6% to 8%, the water environment is also rising, according to the national drinking water concentration. The national monitoring of the first-class water, water, and water standards of the water source shows that the riverbed is rising. This shows that the drinking water quality in our country has not deteriorated due to economic development, but GDP growth and water quality deterioration have occurred. Decoupling trend. '
'Two declines' refers to the decline of COD, negative nutrition, ammonia nitrogen, total phosphorus total nitrogen, pollutants and other indicators in 50,000 large and large rivers across the country. Meanwhile, the number of 'inferior five' water bodies, black odorous rivers On the decline.
Wang Hao said, 'Based on the two statistics of national statistics, the two declines can draw a basic judgment: The overall environment of China's drinking water is gradually improving, and there has been a turning point of hope.
However, he also mentioned that the conservation of water resources and the continuous improvement of water quality are still facing many challenges, and the task of the future is arduous.
'This argument is mainly due to the increase in population and the high growth of urbanization.'
Wang Hao pointed out that China's urbanization rate was 58% in 2017, and it is still in a period of rapid development. 'One basic judgment is that China's urbanization rate will slow down after 70%. 'Intensive urban population will promote more Garbage discharge, generating more building solid waste, kitchen waste, etc., poses a constant threat to environmental pollutants. According to statistics, one person in China produces 0.8-1.5 kg of garbage per day. From the perspective of environmental planning, one person produces one year. 450 kilograms of garbage. 'At present, China has a population of 1.407 billion. Although the country covers an area of 9.6 million square kilometers, the plain area only accounts for 10% to 12%. The top ten plain areas with the most dense population in China are less than 1 million square kilometers. More than 100 million people squeezed about 10% of the space, the pollution is very serious, which also caused the water source of many cities to move up.
Wang Hao cited the example of Shanghai. 'Shanghai used to take water from the Suzhou River. After that, it extended to the Huangpu River to take water. Then it moved up to Dianshan Lake. Finally, there was no way to do the grass and sand water project in the middle reaches of the Yangtze River. The supply of 10,000 tons of far water has solved the problem of pollution and shortage of seawater source. In addition to Shanghai, there are still many cities with this problem.
'In addition, there is another challenge is that our 'historical deposits' are many. China's construction waste stock is more than 8 million tons. It can be seen from the urban photos taken by aerial remote sensing that more than 200 cities in China exist in solid waste formation. The 'small basin' is the so-called 'small basin', which refers to the surrounding mountains and surrounding flat areas. But the 'mountains' around these cities are caused by solid waste landfill, and the solution of stockpiles will become a long-term solution. And a huge challenge. '
' Moreover, China's current physical industry accounts for a large proportion of the national economy, and it relies heavily on heavy chemicals. The problem of wastewater discharge is more prominent. 'Wang Hao pointed out, 'In terms of black odor river management, although we have made great efforts, we still Not quite satisfactory. Now, the country is gradually solving these problems with systematic thinking and multidisciplinary crossover.'
Among them, the most important is the 'Water Ten Articles' promulgated by the Politburo. The drinking water source is governed by the principle of 'one river and one policy' and 'one lake and one policy'. According to Wang Hao, the current surface water quality standards in China are still in use. GB3838-2002 standard, 'The standard faces scientific problems and is out of touch with the national conditions.'
He pointed out that the water quality standard originated from the 1971 pioneering of environmental protection in China. It mainly copied the North American and European standards, and after several upgrades, it is still out of touch with the national conditions. 'Not mentioning the vastness of the population, the environmental capacity is very The big Canada, only the United States, for example, in its 9.18 million square kilometers of land, 65% belong to the plain, with a population of about 320 million. In the 100-kilometer river section of the United States, there are generally only 3-5 factories, if one The factory discharges 1 unit of pollutants into the river, and only 3-5 units of pollutants entering the river in the 100-kilometer section. In the US standard, the pollutant capacity of the 100-kilometer section is 5 units, and the total amount of pollutants does not exceed the river. The water environment capacity of the section ensures the safety of drinking water. However, as a world factory, China has a dense physical industry. Although it is a national performance, it also causes intensive pollution. In China, it does not mention Beijing-Tianjin-Hebei, the Yangtze River Delta. In economically developed areas such as the Pearl River Delta, there are at least 100-200 enterprises distributed in the 100-kilometer section of the general area. According to the national standard, each unit of pollutants entering the river is 100-200 units, and the pollutants in the river section are Capacity is only 5 units, this As a result, the pollution is seriously exceeded, and the water quality is black and odorous. In Dongguan, for example, Dongjiang, which flows through the region, has a length of about 100 kilometers. The two banks are not small factories. There are only 400,000 factories above designated size in the National Bureau of Statistics. According to the national standard across the board, the total amount of pollutants entering the river is 400,000 units, far exceeding the capacity of 5 sections of the river section. Such water sources cannot be basically protected.
'It is precisely the inaccuracy of this one-size-fits-all approach. The country has adopted the 'Water Ten Articles', emphasizing the fact that according to the actual situation, 'one river and one policy, one lake and one policy', to develop more stringent pollutant discharge standards. The thinking of total control in the past was changed to capacity control thinking, taking into account the link between economy and river water quality. The specific operation of 'One River and One Policy' is reflected in the definition of river ecological function, then surveying water quality, and developing water environment. Capacity, then investigate and analyze the pollutants entering the river, use the difference between the pollutant capacity of the river and the water environment capacity as the repair reduction amount, and then distribute the corresponding repair reduction amount to each sewage outlet of the 100-kilometer river section, and finally each The sewage outlets allocate their own total reductions, and the amount of sewage that can be tolerated by each household sharing the sewage outlets is introduced.
In addition, in addition to the river environment, 'Water Ten' also emphasizes the protection of water sources, which are divided into core areas, transition areas, control areas, test areas, etc. The core areas must be clear grass vegetation that conserves water. At the same time, it contains a large number of water-purifying microorganisms; the protected areas are not allowed to form new sources of pollution, and these have been issued with corresponding national standards for protection.
Drinking end safety
In addition to the water quality of the water source, Wang Hao also mentioned the safety of drinking water terminals.
He pointed out that 'currently, the development of membrane technology is triggering a revolutionary revolution in drinking water worldwide. The application of membrane technology not only greatly promotes pollution control, but also accelerates the popularization of healthy drinking water in life.
It is reported that traditional sewage treatment generally relies on biochemical methods, that is, the use of activated sludge containing microorganisms to purify water quality, and its standards are also unreasonable and unsuitable for national conditions. 'Taking the super-large cities such as the North, Guangzhou and Shenzhen, for example, the sewage treatment plant The water quality needs to meet the standards of four types of water or quasi-four types of water, in order to basically maintain the urban water environment. The water treated by the traditional technology can never reach the level A and the first level B standard specified by the national standard. However, the use of the membrane process, the actual It is able to reach the first-class standard, and the cost increase is less. At present, some areas use the double-purity membrane method to achieve three types of water after sewage treatment.
He also mentioned the use of membrane technology in waterworks. 'At present, most of our waterworks use traditional purification technology. The steps are basically coarse grid, fine grid, sedimentation, precipitation, sand filtration, carbon filtration, dosing, etc. The area is up, the manpower is used more, but the water quality is unstable, it is difficult to reach the national 106 drinking water standards. But through the membrane technology, with three workers, two and a half days of construction time, the membrane technology construction can be completed, providing rural and large The city supplies more than 150,000 tons of drinking water, and the cost is only one water and one hair.
'In recent years, a large number of membrane innovation technologies have emerged in China. For example, the membrane technology company Lixin Company produces PVC membranes at a cost of only 1/7 of the foreign PVBF membranes, but the effect is basically the same. They will film holes. Improved to the knife-edge type, that is, energy saving is more conducive to the retention of microorganisms and pollutants. After improvement, the distance of water flow through the membrane hole is equivalent to improving the purity of the effluent through a 3-6 km tunnel.
Wang Hao believes that in the next 10 years, the face of China's waterworks and sewage plants will undergo subversive changes.
'At the same time, membrane innovation technology will also change with each passing day. Now, the PVC film of the water plant can not completely block the salt, heavy metal ions and emerging soluble chemicals. In the family, only the water purifier can be used to achieve direct drinking water, but the drawbacks of the water purifier It removes harmful substances and removes beneficial minerals and other elements. Now researchers are studying the use of nanomaterials to remove heavy metal ions from water flowing through the membrane; in addition, tap water is generally disinfected with hydroxyl radicals for a long time. In the transportation and terminal, it is easy to form secondary pollution. In the future, our official website may no longer be a large network, but a decentralized pipeline. In addition, some new discoveries, such as water rich in hydrogen ions, are better for the human body. Effectively delays the body's oxidative aging rate, 40 times stronger than the known effective anti-aging drugs, and the cost of creating one ton of hydrogenated tap water is only 3-4 cents, which is good for the health and longevity of residents; The water contains traces of strontium and other elements, and cockroaches have a great impact on the aging of human organs. Researchers are also studying the technology of tap water removal. Now, the Chinese market has imported hydrogen-rich low-lying water. The price of a cola-sized product is around 50 yuan. With the advancement of domestic drinking water technology, we hope that one day, the majority of the people can enjoy this healthy drinking water. . '
Finally, Wang Hao pointed out that drinking water safety is more important than Mount Tai, and hopes that the new drinking water technology formed by more disciplines will bring Chinese people a safe and healthy drinking water world!