Water is a crucial topic that cannot be avoided in the development of coal chemical industry. In recent years, the pace of technological upgrading for near-zero discharge treatment of coal chemical wastewater has accelerated, but the transition from near-zero discharge to zero discharge remains a significant hurdle for many companies. How to turn this hurdle into a smooth path?

Tian Xufeng, chairman of Hezhongsi (Beijing) Environmental Protection Engineering Co., Ltd., recently gave an answer during an interview with a reporter from China Chemical News, based on his company's achievements in zero-discharge of industrial wastewater in the Yellow River Basin—advanced evaporation crystallization and high-value resource utilization technology. As a footnote to this answer, the company's invention patent "High-salt wastewater MVR evaporation crystallization treatment technology equipment" was included in the "Catalogue of Major Environmental Protection Technology Equipment Encouraged for Development (2023 Edition)" released by the Ministry of Industry and Information Technology and the Ministry of Ecology and Environment on December 25, 2023.

The coal chemical industry is characterized by high water consumption, high pollution, and high emissions, and it has high and difficult treatment costs. Wastewater treatment accounts for 10% to 20% of the total project investment. Therefore, the development of new coal chemical industries in China faces many challenges from the outset. In particular, many areas in China that are rich in coal resources have fragile ecological environments and water shortages, or even severe water shortages. This is the case in the "golden triangle" of coal chemical industry in the Yellow River Basin, including Ordos, Inner Mongolia; Yulin, Shaanxi; and Ningdong, Ningxia.

Many early coal chemical pilot projects, in order to save costs, injected production wastewater into evaporation ponds for treatment, or even illegally discharged or reinjected it. Some companies spared no expense in treating wastewater, but had to stop due to unstable operation of the treatment system or the need to discharge a large amount of toxic and harmful brine, resulting in environmental pollution. "From today's perspective, the coal chemical industry at that time was like a premature baby with congenital deficiencies." An industry expert described it this way.

In recent years, with the rapid popularization of the concept of high-quality development and increasingly strict environmental regulations, governments, enterprises, and various parks at all levels have formulated strict water conservation and emission reduction policies according to actual conditions. Coal chemical enterprises have also taken active actions to explore how to "squeeze out" production wastewater.

The huge market demand has led many water treatment companies to focus on and enter the field of coal chemical wastewater treatment, and has also promoted the upgrading and replacement of coal chemical wastewater zero-discharge treatment technology. Bio-methods, membrane concentration methods, advanced oxidation methods, and electro-adsorption desalination methods have each shown their capabilities. However, no matter which process is used, the treatment and resource utilization of high-salt wastewater in the later stage of coal chemical wastewater treatment has always been a difficult problem, becoming a technical bottleneck restricting the development of wastewater treatment processes.

How to achieve true zero discharge?

"Water treatment technology has always been upgraded and iterated with the improvement of customer needs." This is Tian Xufeng's experience in the water treatment field for 20 years, leading Hezhongsi.

Tian Xufeng told the reporter that from 1995 to 2005, the demand for desalted water, boiler feed water, electronic pure water, and even pure water in the beverage industry spurred the application of reverse osmosis membranes in the Chinese market; from 2006 to 2010, improving the reuse rate of water became a new demand, and the development of various wastewater reuse technologies further promoted the widespread application of ultrafiltration membranes; after 2010, China's economy developed rapidly, and the insufficient environmental capacity created a new demand for zero discharge of industrial water, which is to reuse nearly 100% of industrial water in the industrial system, and reuse the useful components (such as sodium chloride and sodium sulfate) in water pollutants in the industrial system. However, at that time, the few zero-discharge projects were unable to operate normally.

"Combining years of practical experience in the water treatment industry, we set our sights on the goal of zero discharge and chose to make breakthroughs in the field of evaporation crystallization technology." Tian Xufeng said that based on the introduction of advanced foreign technologies, they combined domestic industrial practices to make improvements, and developed efficient, energy-saving, and economical evaporation crystallization system process packages for coal chemical, mine, and power plant wastewater treatment, forming a zero-discharge solution for high-salt wastewater, and successfully applied it in many benchmark projects.

It is worth mentioning that the evaporation crystallization technology developed by the company has broken the monopoly of key technical equipment in Europe and the United States, reducing the total investment of system engineering by at least 50%, and forming a new technological route suitable for China's industrial and operating environment, filling a domestic gap.

"After achieving zero discharge, we have been striving for a higher goal of wastewater resource utilization in the past five years, turning waste in water into valuable industrial products and reducing the investment and operating pressure of owners." Tian Xufeng said, "Some projects can even become profit points, turning waste into treasure. For example, in a wastewater treatment project for the positive electrode materials of a new energy battery that we participated in, we can earn 10 yuan by treating 1 ton of wastewater, turning an environmental protection project from a "money-eater" into a "money-maker".

Hezhongsi's success in technological innovation is no accident.

As a "specialized, refined, distinctive, and innovative" small giant enterprise in Beijing, Hezhongsi also interprets its innovation path with "specialized, refined, distinctive, and innovative": focusing on the field of zero discharge of industrial wastewater and wastewater resource utilization without distraction, which is "specialized"; continuously optimizing its own processes and striving for excellence to create benchmark projects without seeking quick success, which is "refined"; basing itself in the Yellow River Basin to develop advanced technologies to solve water treatment problems without being greedy for all-encompassing solutions, which is "distinctive"; taking technological innovation as the foundation while introducing and digesting advanced foreign technologies to create new highs without being complacent, which is "innovative".

"In the 20 years since its establishment, the company has always attached importance to technological innovation and equipment research and development, and has invested 60 million yuan to build laboratories, pilot plants, and production bases." Tian Xufeng introduced that they have independently developed high-flow filtration systems, full-series pollution index measuring instruments, evaporation crystallization system-specific reagents, and other products, as well as two industry-leading high-salt wastewater treatment technologies, including the freezing method and the seed crystal method. Relying on the developed concentrated crystallization and differentiated salt extraction and resource utilization technology equipment and coal chemical wastewater deep treatment technology equipment, the company was selected as one of the first batch of "national key environmental protection technology equipment supporting units" encouraged for development by the Ministry of Industry and Information Technology. The industrial high-salt wastewater evaporation crystallization and high-value resource utilization technology developed by the company has been included in the "Beijing Energy-Saving Technology Product Recommendation Catalog (2020 Edition)" and the "National Advanced Pollution Prevention and Control Demonstration Technology List." At the same time, they have participated in the compilation of 7 national and industry standards for industrial water treatment, and applied for nearly 200 patents, including 11 authorized invention patents.

Powerful technology drives the implementation of high-quality projects. For 20 years, they have completed more than 1,000 water treatment projects in more than 50 countries. The projects they have participated in have won 26 awards at or above the ministerial level, including several industry benchmark projects, such as the largest zero-emission project in a coal chemical industrial park in Asia—the National Energy Group Ningdong Mining Area mine water and coal chemical wastewater treatment and utilization project; the first salt separation zero-emission project in the power industry—the Guodidian Hanchuan Power Plant desulfurization wastewater zero-emission project; the first graphene wastewater zero-emission project in China—the Qingdao Laixi City Graphite New Materials Industry Cluster Sewage Treatment Plant construction project evaporation crystallization project; and the Ningxia Baofeng Energy Storage Materials Co., Ltd. battery material industry chain demonstration project, etc.

"Innovation knows no bounds." Tian Xufeng said that after achieving the "transformation of an insurmountable obstacle" in zero-emission of coal chemical wastewater, the company will continue to focus on the field of wastewater resource utilization in the future, making the industry "astonish the world."

Original title of China Chemical News:《Turning the "insurmountable obstacle" of zero-emission of coal chemical wastewater into a "smooth road"》