China Coal Tuoke Large-scale Fertilizer Plant: Achieving zero wastewater discharge

Zero wastewater discharge, like it: D:D

Nowadays, when it comes to wastewater treatment, people talk about zero emissions. But is zero emission really achieved in all cases?

It’s near-zero emissions, right? What’s done with wastewater that has a high salt content? Are you done collecting?

Zero wastewater discharge is achievable, but what is difficult at present is the recovery of salts; there are no reliable recovery technologies available. In plants that achieve zero discharge, the salts that crystallize inside the facility accumulate in large quantities, forming another source of pollution.

Shenhua Overcomes Challenges in Treating Coal Chemical Industry Wastewater, Achieving Zero Waste Discharge Author/Source: Date: 2017-02-20 Clicks: 57 In recent years, with the introduction and implementation of a series of regulations and policies such as the new Environmental Protection Law, the Guidelines issued by the General Office of the State Council on Promoting Third-Party Management of Environmental Pollution, and the Action Plan for Water Pollution Prevention and Control, along with an increasingly competitive market environment in the wastewater treatment sector, reducing waste discharge and reusing resources have become inevitable choices. Precision and specialization have also emerged as necessary trends. Against this backdrop, zero discharge of industrial wastewater has come to the forefront. Shenhua has found a solution to the challenge of treating coal chemical industry wastewater, achieving zero wastewater discharge. Worldwide, existing technologies for zero-discharge treatment of industrial wastewater suffer from significant issues such as complex processes and high treatment costs; moreover, they generate large amounts of crystalline by-products that cannot be disposed of, making this a recognized technical challenge in the industry. In our country, the energy sector, represented by coal-fired power generation and modern coal chemical industry, not only supports the development of the national economy but also consumes large amounts of water resources and generates significant amounts of industrial wastewater. In recent years, as efforts to protect the environment have intensified, particularly after the newly revised Environmental Protection Law and the \"Ten Measures for Water Management\" were introduced, the requirements and challenges associated with addressing water pollution have become increasingly stringent. How to safely and efficiently treat and dispose of these industrial wastewater streams is increasingly becoming a major issue critical to the healthy development of the industry. Especially in regions such as Inner Mongolia, Shaanxi, Ningxia, and Xinjiang, where water resources are scarce and the ecological environment is relatively fragile, zero-discharge treatment of industrial wastewater has become an increasingly urgent requirement. It was against this backdrop that, in 2015, the Beijing Institute of Low-Carbon Clean Energy, located in the Future Science and Technology City in Changping District, Beijing, and affiliated with Shenhua Group, established a specialized water treatment R&D team, making the efficient reuse and safe disposal of industrial wastewater one of its six key focus areas. Xiong Rihua, technical director of the water treatment platform at the Low-Carbon Research Institute, explained that water plays a vital role in industrial processes such as coal mining, power generation, and coal chemical manufacturing. The water treatment team was established in response to Shenhua’s actual needs regarding the treatment of wastewater from coal chemical processes and desulfurization processes in coal-fired power generation, by focusing on the challenges faced in this industry. As one of China’s leading large-scale energy enterprises, Shenhua Group consumes 1 million tons of fresh water per day in areas such as raw coal production, coal-fired power generation, and coal-to-chemicals manufacturing. This results in the generation of nearly 400,000 tons of industrial wastewater; of this amount, around 300,000 tons can be reused after treatment, while 100,000 tons are discharged after meeting environmental standards. The investment in environmental protection measures for wastewater management alone exceeds 1 billion yuan per year. For the most difficult-to-treat desulfurization wastewater and coal chemical industry wastewater, the existing treatment processes consist of three steps: pretreatment, pre-concentration, and evaporation crystallization. “Pre-treatment mainly involves filtering out large particles such as sludge, while pre-concentration is used to produce recycled water, which accounts for 70-80% of the total output. The remaining concentrated water is then subjected to evaporation and crystallization, resulting in some recycled water and crystallized salts. The resulting mixed salt waste cannot be disposed of due to its large volume and high cost; at present, there is no practical method for dealing with it. ”Xiong Rihua said. In the view of Xiong Rihua, the main challenges of existing zero-emission technologies lie in high reagent consumption, high operating costs, complex processes, low concentration limits, large treatment volumes, high investment and energy demands, and the inability to dispose of mixed salt waste. “Based on the current trends in water treatment, we believe that the pinnacle of industrial wastewater treatment technology has evolved from the conventional technologies aimed at ensuring compliance with discharge standards, to zero-liquid discharge technologies today, and will further develop into zero-waste discharge technologies in the future. Therefore, the R&D team set three main goals: high efficiency, low cost, and the recycling of crystalline salts, and embarked on the development of technologies for zero discharge treatment of industrial wastewater from the outset. ”Xiong Rihua explained. In the water treatment laboratory of the Low-Carbon Research Institute, the initial demonstration results of the water treatment R&D team are on display: a bottle of pale yellow coal chemical wastewater, a bottle of clear reclaimed water, and three bags of inorganic salt by-products, calcium sulfate, sodium sulfate, and sodium chloride. “This bottle of reclaimed water is potable; it mainly depends on psychological acceptance. ”Xiong Rihua believes that, thanks to their technical processing, the calcium sulfate, sodium sulfate, and sodium chloride salts obtained from industrial wastewater have extremely high purity, making them fully suitable for use as industrial raw materials. “Calcium sulfate is gypsum, a building material with wide-ranging uses; it is also the liquid used in the process of making tofu from brine. Sodium sulfate, on the other hand, is the ingredient in laundry detergent that we use regularly. Our goal of achieving zero emissions is to recycle solid crystalline salts, which is the biggest difference from existing technologies; pilot tests are currently being conducted in Ningxia, Fujian and other places. ”Xiong Rihua said. Today, the water treatment team, which has been in development for over two years, consists of 21 members and has taken initial shape. In addition to Xiong Rihua, it includes Wei Chang, the director of the Low-Carbon Research Institute and an expert under the Thousand Talents Program, as well as doctors and masters from renowned institutions such as Tsinghua University, Peking University, Tianjin University, the University of Cincinnati in the United States, and the University of Pittsburgh in the United States. In 2009, the Low-Carbon Research Institute was established. In 2011, it moved into the Future Technology City. In 2013, the first technology developed by the institute was successfully commercialized. In 2015, the first company with a mixed ownership structure was founded… As a R&D institution of Shenhua Group, over the past 8 years the Low-Carbon Research Institute has taken on the important task of helping Shenhua achieve a strategic transformation toward clean energy and sustainable development. In response to this, Wei Chang, a globally renowned expert in water treatment, an expert under the Thousand Talents Program, and director of the Low-Carbon Institute, explained that the vision of the institute is to become a testing ground for corporate research and development, a pioneer in institutional reform, a hub for high-caliber talents, and an incubator for innovation and entrepreneurship. Today, Low Carbon employs 15 experts under the Thousand Talents Program and over 350 R&D personnel, having filed more than 600 invention patents in total. Its R&D efforts are focused on six areas: the clean conversion and utilization of coal, catalytic technology, water treatment, distributed energy, coal-based functional materials, as well as hydrogen energy and its applications. “Focusing on global challenges such as economically viable carbon dioxide reduction, true zero discharge of industrial wastewater, affordable solar power generation, hydrogen storage and transportation, refueling, and large-scale application, we are seeking technological breakthroughs. Taking advantage of the favorable opportunities presented by mass entrepreneurship and innovation, we aim to turn Low Carbon into a world-class industrial R&D institution, thereby helping Shenhua Group become a world-leading provider of clean energy. ”Wei Chang spoke frankly.