Min Yang: Safeguarding China's Drinking Water Safety with Technological Power

Source: China Network

Editor’s Note: The “Discussion” interview program is jointly produced by the Journal of the Chinese Academy of Sciences and the China Internet News Center. Through interviews with academicians and expert scholars from the two academies, it delves into the development prospects of various fields of Chinese society as it enters the “14th Five-Year Plan” period. With objective and precise interpretation, scientific and forward-thinking analysis, it aims to unravel the mysteries of China’s development at the intersection of the “Two Centenary Goals” and contribute intellectual strength to achieving the second centenary goal.

Discuss and deliberate, seek strategies and explore solutions.

China Network / China Development Portal News: Drinking water safety directly affects human health and has always been a major issue of public concern. It is of great significance to build a scientific and technological innovation system for ensuring the safety of drinking water in China. How does the power of technology help address the prominent issues of rural drinking water safety in China? What achievements have Chinese scientists and technologists made to support the “Three Waters Governance”? How does China’s technology for ensuring drinking water safety help countries along the “Belt and Road” initiative? In response to these questions, “Discussion” interviewed Researcher Min Yang, Deputy Director of the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences.

China Network: Last year, 79.6% of the problem clues transferred and verified by the Ministry of Water Resources’ 12314 Supervision and Reporting Platform were related to rural drinking water safety. Does the construction of a scientific and technological innovation system for ensuring drinking water safety help address the deficiencies and gaps in this area?

Min Yang: The issue of rural drinking water has always been a concern of our team. Relatively speaking, our country did not invest much in technology in this area in the past few years. Of course, the country has attached great importance to it in recent years and has done a lot of work. The main work of our team is to break through the two world problems of arsenic and fluoride removal from groundwater. High levels of arsenic and fluoride in groundwater can affect human health. In the areas where groundwater is used as a water source in our country, these two substances have been a long-term health hazard. In recent years, we have focused on these two challenges and made breakthroughs. After years of effort, our team has made breakthroughs in arsenic and fluoride removal, applied them in water improvement projects in dozens of villages, and played a good role in poverty alleviation efforts in Inner Mongolia and other places. At the same time, these technologies are also being promoted to countries along the “Belt and Road” initiative.

Rural drinking water systems are small in scale, and disinfection effects are often unstable. There is a lack of a very suitable disinfection technology for application in small-scale water supply systems. Currently, our team is also working on developing disinfection technologies suitable for small-scale water supply systems, including ultraviolet disinfection technology, to provide better protection for biological risk control in rural water supply.

In addition, besides technical issues, there are also problems with the supply mode of rural drinking water. We are also cooperating with the government and enterprises to address these issues. For example, through third parties or through some large-scale, market-oriented mechanisms, we aim to improve the capability to ensure the safety of rural drinking water from the perspective of water supply scope and scale.

China Network: Each link of the “Three Waters Governance” - water pollution control, water ecosystem restoration, and water resource protection - relies on monitoring. What role does the proposal of this systematic solution play in improving monitoring technology and quality?

Min Yang: In fact, the source of drinking water is the water in our environment, from rivers, lakes, to groundwater. “Three Waters Governance” aims to prevent water pollution and ensure water resources. It is essential to protect the water source, which includes preventing water pollution. Over the years, we have conducted long-term monitoring and investigation of drinking water. From the “Eleventh Five-Year Plan” to the “Thirteenth Five-Year Plan”, we have been conducting surveys of key urban water sources nationwide. What sets these surveys apart from routine monitoring is that we do not limit ourselves to monitoring the indicators specified in the drinking water standards. Instead, we expand the scope to include more indicators, such as more than 700 in total, covering various potential pollutants. Through these investigations, we have discovered some new pollutants, such as perchlorate, sulfides, perfluorinated compounds, etc. Through extensive national surveys, we found that these pollutants have a relatively large pollution surface in China and have a significant impact on water quality. We have included them in the revision of the “Hygienic Standard for Drinking Water”. Some are included in mandatory standards, and some are included in reference indicators. Therefore, through the research of our team, the level of risk control for drinking water in our country has also been improved.

China Network: What are the biggest challenges in achieving breakthroughs in core key technologies during the research process?

Min Yang: Drinking water is a system directly related to thousands of households, and water plants are very large in scale. The technology used must be safe and cannot use various chemical agents indiscriminately. At the same time, it requires low cost, which greatly limits the choice of technologies. When developing drinking water technology, our first consideration must be green, using as few chemical agents as possible, and using natural or physical methods to purify water. For example, in terms of water source restoration, we do not use chemical agents like copper sulfate, which is used abroad to control algae, because this method is harmful to the ecosystem. So we use some natural methods to solve the problem of algae causing odors.

In water plants, we try to make the technology as simple as possible and not too complicated. It should be implementable at an acceptable cost. We think the challenge is relatively large in this aspect, but it also brings us a lot of joy. By meeting these challenges, we can find many new ideas and technologies.

China Network: You mentioned earlier that some of the developed technologies for ensuring drinking water safety are also being promoted to countries along the “Belt and Road” initiative. Could you provide some specific examples?

Min Yang: It can be said that the issue of drinking water safety is a major challenge for countries along the “Belt and Road” initiative. Many countries are greatly restricted in terms of water sources, and at the same time, they are economically underdeveloped, making it difficult to develop good water treatment and safety technologies to improve the level of drinking water safety. Therefore, we focus on developing some technologies for the challenges faced by developing countries in water supply and apply them. For example, in Sri Lanka, in some dry areas in the north, mainly rely on groundwater as a source of drinking water. Later, it was found that there was a prevalence of kidney disease in areas using groundwater for drinking. A team of experts from the World Health Organization conducted a two-year investigation, but ultimately did not find the real cause. The Sri Lankan government invited a team of experts from the Chinese Academy of Sciences to participate in some of their investigations and research. Because the environmental causes of disease are certainly complex, we organized a multidisciplinary team, including experts in public health and medicine from Peking University Hospital, Beijing CDC (Beijing Municipal Centers for Disease Control and Prevention), as well as Peking University and Fudan University, to discuss the causes. It was found that there are likely some factors in groundwater, such as hardness, fluoride ions, and sodium ions. Although a single factor at high concentrations may not be a problem, when these ions are all high, it may cause kidney damage. We confirmed this phenomenon through animal experiments. The local government also recognized the results of our experiments and invited us to improve the local drinking water system. We proposed a technology called electrodialysis, which can selectively remove harmful ions, and applied it locally. This technology is relatively low-cost and has good results, so the local government also recognizes it. Now they are proposing whether this electrodialysis technology can benefit the local people through cooperation and promote this technology together.

Of course, there are other technologies as well, such as ecological protection technologies for drinking water sources. With the support of the Chinese Embassy in Myanmar, we have promoted it to some villages in Myanmar. The engineering implementation plan has been completed, and construction is about to begin on-site this year.

China Network: The research results of this issue won the Outstanding Scientific and Technological Achievement Award of the Chinese Academy of Sciences in 2021. What positive impacts will it have on the development of disciplines?

Min Yang: Our research is quite different from traditional drinking water research. Traditionally, it is called water supply engineering, mainly focusing on water plants and pipeline distribution. We have expanded the research field to extend to the water source, including the protection and restoration of the water source. At the same time, we also regard management as an important content for research. Conducting research on drinking water in China to see what risks our drinking water has, and then formulating drinking water standards for China to ensure drinking water safety. Therefore, we cover the entire process from the water source to the water plant to the pipeline. At the same time, we also cover a wide range from engineering technology to management technology, which should be our contribution to the discipline of drinking water.

China Network: As a leading scientific and technological worker in the field of drinking water quality risk assessment and control, what research directions will you and your team focus on next?

Min Yang: Drinking water safety is not just a technical issue. Drinking water safety mainly depends on the safety of the water source. Any human activity in the environment will affect drinking water safety. Our country now has the most complete industrial chain in the world, and from another perspective, various chemical production and usage activities in our country are the strongest. As a result, the production, circulation, and consumption of these chemicals will ultimately affect (drinking water safety), as they will be discharged into the water source to some extent. Therefore, we need to build a barrier against chemical pollution caused by human activities on the water source. Firstly, we need to know what substances are in the water source. Currently, there are more than 100 indicators in the “Hygienic Standard for Drinking Water”, but in reality, there are thousands of chemicals used by humans. Next, we are also undertaking a key research and development project, mainly focusing on the two major river basins of the Yangtze River and the Yellow River, which are also the two most important water sources in our country, with a large number of industries along the coast. What harmful substances are discharged into the water, how to identify these substances, and what preventive measures to propose after identifying them, these are the major tasks we will focus on in the next step.

Of course, there are many other aspects, such as how to effectively remove chemical pollutants that enter these waters, and we also need to develop some new technologies for removing pollutants. Currently, water enters every household through a huge underground pipeline network after leaving the water plant. It is difficult to control the water quality during the underground distribution. What is the relationship between the changes in water quality and the conditions of external water sources and water plant processes? By studying these relationships, proposing control measures to prevent deterioration of drinking water after entering the pipeline network, these are the directions we will focus on in the next step.

(Planning of this issue: Yang Liuchun, Wang Zhenhong; editing: Yang Liuchun, Wang Zhenhong, Wang Qian; editing: Wang Qian, Wu Yinan; camera/post-production: Zhu Fashuai. Produced by: Journal of the Chinese Academy of Sciences, China Internet News Center; Production: China Network, China Development Portal)

Min Yang
Min Yang
Professor of Environmental Engneering