Wu Yan, Professor, School of Chemical Engineering and Materials, Tianjin University of Science and Technology, pays attention to the utilization of dredged sediment as a resource and protects "green water and green hills" with all efforts
The report of the 19th National Congress of the Communist Party of China pointed out that building a beautiful China, creating a good environment for people's production and living, and contributing to global ecological security, and stressed that "we must establish and practice the concept that green mountains and green waters are golden mountains and silver mountains." In response to the Party's call and the profound implementation of the concept of green development, China's first "harmony with nature" International Conference on water environment and ecological construction technology was held in Wuhan on October 18. The annual summit of dredging industry attracted the participation of many top experts and scholars. A series of professional and authoritative special reports on the innovation of comprehensive river basin management, coastal restoration, River and lake ecology and materials, etc. provide guidance for the development of the industry.
At this meeting, the sponsors of the conference invited Professor Wu Yan of Tianjin University of Science and Technology to make a special report entitled "Current Situation and Prospects of Research on the Utilization of Dredged Soil in Building Materials Industry". This paper introduced the new methods of comprehensive utilization of sediment and provided new ideas. During the meeting, the reporter interviewed Professor Wu and asked her to talk about her views on the promotion and implementation of the concept and principles of ecological and green industries in the dredging industry.
Professor Wu Yan, Tianjin University of Science and Technology
Professor Wu Yan has been engaged in the research and development of deep dewatering and resource utilization technology for environmental dredging sediment for a long time. He has cooperated with dredging enterprises for many times and paid close attention to the dredging industry in China. The reporter first consulted Professor Wu about the resource utilization of sediment in the environmental dredging business.
Professor Wu said that the resource utilization of dredged sediment is one of the hot issues in the dredging industry. In practical engineering, if the pollution of heavy metals in sediment does not exceed the standard, but there is eutrophication problem, because of its rich nutrients and high organic matter content, it is highly recommended to use the planting soil, especially the greening soil as a resource. To "." In addition, some of the sediments only have higher organic matter content, and the middle and lower layers are mainly sediment particles. In view of this kind of sediment with high sediment content and less than 10% organic matter content, the research group has developed a technology for preparing unburned aggregate from dredged soil. The performance of unburned aggregate has reached the national standard and can replace natural sandstone for preparing unburned bricks, artificial pebbles and concrete blocks. With the rapid development of urbanization in China, the annual consumption of gravel has reached more than 18 billion tons, but the recycling of solid waste in China's construction industry is less than 100 million tons. This is a very big contradiction: first, the dredging industry produces a lot of sediment resources nowhere to use; second, the construction industry needs a lot of gravel, constantly mining.
"The technology of dredged soil and unburned aggregate developed by our research group can not only effectively solve the difficult problem of dredged sediment treatment, but also protect China's non-renewable mineral resources and effectively protect China's green mountains." The third is to fill, solidify, stabilize, and make the foundation, high-efficiency sludge solidifying agent is also one of the hot issues of current research. There is a problem of heavy metal pollution in sediment, which is generally concerned by the outside world. In general, it can be treated by solidification and stabilization, soil leaching, electrodialysis and so on.
It is understood that Professor Wu led a team to develop environmental dredging "filter drying integration" technology, the reporter asked Professor Wu for the specific content of this innovative technology.
Large dredging project (data sheet)
Professor Wu said that dredging projects are characterized by large quantity, short construction period, less land occupation and high environmental protection requirements. Aiming at the problems that water quality is not up to the standard and the utilization efficiency of plate and frame filter press is low in the integrated mechanical dewatering process of environmental protection dredging, the research group has developed the integrated technology of filter aid and drying, which combines chemical conditioning with mechanical pressure filter dewatering, and greatly reduces the volume by selective dosing and successive reduction. The water content of the sediment can be reduced to about 45% after drying, which can be used for resource disposal. The process features are two step dosing and innovative introduction of filter aids. In the first step, the volume reduction of slurry is 70-85%, and the solid content of slurry is 20-30%. In the second step, a grid water conveyance channel can be constructed between the slurry and soil particles, which can significantly improve the pressure filtration property of the slurry, achieve rapid and efficient separation of slurry and greatly improve the plate and frame. Dewatering efficiency. The introduction of filter aid does not change the chemical structure of soil, does not affect its utilization of resources (planting soil, building materials, etc.), does not change the pH value of raw water, the effluent quality is better.
The dredging industry is in a critical period of transformation and upgrading. Professor Wu has been immersed in the study of dredging for many years. Professor Wu expressed her views to reporters on the development of the dredging industry.
She said that after years of innovation and practice, China's dredging industry has made great breakthroughs. In the face of changes in the market situation, China Dredging Association is always looking for long-term development for the industry. For example, the industry summit sponsored by the association has focused on the theme of "harmony with nature". It has brought together authoritative experts from all walks of life and drawn on their strong points to guide the dredging industry forward. Wu's impressive achievements have also impressed Professor Wu. "I have been studying the technology of deep dewatering and resource utilization of dredged sediment for more than ten years. From the classic operation of chemical industry, the desiccation and drying of dredged sediment is a solid liquid separation.