To solve the mine water utilization, lack of highly mineralized mine water discharge standards and the actual problem, recently, the ecological environment, National Development and Reform Commission (NDRC), the National Energy Administration jointly issued by the "on further strengthening the management of the coal resources development and environmental impact assessment notice, the mine water management strategy adjustment, clearly put forward" mine water should be used in project construction and production, and to encourage more ways to use mine water surplus ", make full use of still have surplus is really necessary, the outside has been clear about the outside conditions; At the same time, in order to control the problems of soil salinization caused by the discharge of mine drainage with high salinity, the control standard of total salinity of mine drainage was put forward.
"Mine water is both a water hazard and a precious resource," Liu Hanhu, a professor at the School of Environment and Geomatics at China University of Mining and Technology, told reporters. "Mine water treatment and recycling are imperative in order to ensure sustainable use of mine water and build green mines and ecological mines."
It is necessary to find out the bottom of the house
In recent years, in order to promote the comprehensive utilization of mine water resources, the state has issued a series of related policies.
In 2006, the National Development and Reform Commission issued the Special Plan for Mine Water Utilization, which proposed that the utilization rate of coal mine water should reach 70% by 2010.
In 2013, the National Development and Reform Commission and the National Energy Administration jointly issued the Development Plan for Mine Water Utilization, which proposed that the utilization rate of coal mine water should be increased to 75% by 2015.
In 2015, the Coal Industry "Thirteenth Five-Year" Development Plan "raised the utilization rate of mine water to 80% by 2020; In the same year, the State Council "Water Ten" made it clear that to promote the comprehensive utilization of mine water, the supplementary water in coal mining areas, surrounding areas and ecological water should be given priority to use mine water;
In 2019, technical guidelines for the treatment and reuse of mine water were formulated: Technical Guidelines for the Treatment and reuse of Mine Water with High Mineralization Degree and Technical Guidelines for the Treatment and reuse of Acid Mine Water.
Liu Hanhu told reporters that mine water treatment technology includes coagulation, precipitation, filtration and other conventional treatment technology and ultrafiltration, reverse osmosis and other deep treatment technology.
Before 2015, the "Ten Water Regulations" had not been promulgated, and the coal mine water treatment technology in China was mainly conventional technology with low utilization rate. With article 10 of "water" promulgated, the state of shandong weishan lake ecological scenic area, the Yellow River basin and the xinjiang desert regions such as the water environment quality standard put forward higher requirements, the conventional mine water treatment technology of water salinity, sulfate, chloride cannot meet the emission requirements, the depth of the mine water treatment technology and strong water desalination began a wide range of applications.
"Due to the wide distribution and large number of coal mines in China, and the difficulty in verifying the authenticity of the reported data, and the large changes in the number of coal mines since the implementation of coal supply side structural reform, it is necessary to find out the bottom of mine water resources, which is also conducive to the regulation and policy-making adjustment of the competent authorities." Beijing can research management consulting co., LTD. Technical Director Jiao Jingping pointed out. In this regard, Liu Hanhu expressed agreement, suggested that the relevant departments take the lead, in the nationwide development of mine water treatment and resource investigation.
There is still room for improvement in utilization
Liu Hanhu introduced that at present, the comprehensive utilization of mine water mainly includes underground reuse, such as underground dust suppression, spraying, production, etc. As well as mine ground utilization, such as ground sprinkling, vegetation greening, coal preparation water, landscape water, ecological water, cooling water, domestic water, etc. "The specific approach depends on geographical location, industrial chain, local environmental requirements and other factors."
The reporter further learned that at present, mine water is mainly divided into mine water containing special components, acid mine water, high salinity mine water, mine water containing suspended matter, clean mine water and so on several categories, among which suspended matter treatment technology has been very mature, high salinity water treatment cost is high.
According to statistics from the China Coal Industry Association, the country's comprehensive utilization of mine water reached 75.8% in 2019. However, due to the influence of mine water quantity, surrounding industrial layout, water quality and other factors, the mine water utilization rate is quite different, and some coal mines are still low.
"On the one hand, the implementation of relevant policies and standards that have been issued is not strong enough; On the other hand, due to the influence of economic development and regulation, the economic benefits of coal enterprises are fluctuating, and most of the coal enterprises are located in towns, remote locations, and the mine water utilization way is single. At the same time, the weak awareness of environmental protection and one-sided pursuit of economic benefits also affect the improvement of mine water utilization rate." Liu Hanhu analysis pointed out.
In addition, Jiao Jingping also believes that mine water utilization rate is also affected by the high cost of treatment and the large amount of water that is difficult to reuse and discharge.
Jiao Jingping bluntly, in the implementation of mine water utilization process, also encountered some resistance. "Because of the large amount of water inflow in some coal mines, there is no outlet for mine water after treatment, and some places explicitly require not to let the treated mine water enter the water system. In addition, the cost of comprehensive utilization is too high to reduce the enthusiasm of enterprises. In Liu Hanhu's view, the biggest obstacle lies in the backward ideology and environmental awareness.
From harmless change to resource change treatment
Liu Hanhu told reporters that the adjustment of mine water management ideas, means that the use of mine water will run through the whole cycle of coal production, the whole process, at the same time, the mine construction will gradually realize the transformation to green mine, ecological mine, beautiful mine.
"Mine water treatment should adhere to the principle of 'reduction, harmless and resource recovery'." Liu Hanhu pointed out that, first of all, from the source to reduce the production of mine water, such as the use of water conservation mining technology, underground reservoir purification technology, grouting sealing technology; Secondly, conventional technology and advanced treatment technology are used to effectively remove suspended matter, coal dust, colloid, salt, sulfate, chloride and so on in mine water, so as to realize mine water harmless. In addition, it is necessary to adhere to the principle of "cleaning and diverting, grading treatment and quality utilization", and reuse mine water for underground, ground and surrounding mining areas, so as to realize mine water resources.
At present, mine water treatment has been gradually transformed from harmless to resource utilization, but there are still many problems to be solved. Industry insiders point out that not only is there a lack of regional planning for mine water utilization, but there are also misunderstandings in the implementation of the "zero discharge" policy.
In order to improve the utilization rate of mine water, Liu Hanhu suggested that while improving the guidelines and standards for mine water treatment and resource utilization, the mine water treatment technology suitable for China's national conditions should be developed, and the cost of mine water treatment should be further reduced.
In addition, Gu Dazhao, an academician of the Chinese Academy of Engineering, also pointed out that mine drainage treatment grade is not the better the higher the better, should be appropriately treated according to the actual water demand index, to avoid unnecessary increase in treatment costs and burdens on enterprises.