Realizing Recycling Utilization of Waste Water by Relying on MVR Evaporation Technique——An Interview of Wang Shuhua, President of Kemai Chemical Co., Ltd.
In recent years, as new Environmental Protection Law and “ten-measure action plan to tackle water pollution” are implemented, and the nation constantly enhances its supervision on environmental protection, rubber chemicals enterprises face huge environmental protection pressure. “After several decades of development, the category, scale and industry concentration of Chinese rubber chemicals products are largely improved, however, the environmental protection problems during production, especially the waste water treatment problem, has not been solved thoroughly yet, and becomes the bottleneck restraining the industry development and many chemicals enterprises face the awkward situation of shutdown and rectification.” On the Rubber Industry Cutting-edge Technology Forum held in Tongling recently, Wang Shuhua, president of Kemai Chemical Co., Ltd., expressed when being interviewed by the journalist. Kemai always took waste water treatment as the Ramp;D focus and successfully developed rubber chemicals waste water recycling technology in 2015 to thoroughly solve the waste water pollution problem of rubber chemicals and realize resource application of waste water and green production of rubber chemicals.
Waste water is hard to be treated—— Existing technology can not solve
The journalist learned that the waste water generated by production of rubber chemicals generally had the characteristics of high COD, high salt content and difficult degradation and belonged to the category which was difficult to be treated in waste water treatment industry. Its features were: high salt content, which meant that the salt concentration was more than 3% on average, and the salt concentration of the waste water of some products could even reach over 10%; high COD, which meant that the raw materials, intermediate products and finished products during production had certain solubility in water and the COD was mostly about 20,000mg/L; and difficult degradation, which meant that the waste water generally contained organic amine such as aniline, tert-butylamine, and cyclohexylamine and its derivatives as well as thiazole organics and ammonia nitrogen such as benzothiazole and MBT, which had strong toxicity to microorganisms and poor biodegradability.
Wang Shuhua told the journalist that due to the above reasons, waste water treatment of rubber chemicals process had been the hot spot in the industry, domestic chemicals enterprises carried out extensive attempts for waste water treatment, and the common treatment methods were mainly physical method, chemical method, physical-chemical method and biochemical method. The known reported methods included various combined processes such as “multiple-effect evaporation biochemistry”, “evaporation oxidation”, “deep oxidation flocculation resin absorption” and “electrolysis absorption”. Kemai also tried multiple technologies and combinations for waste water treatment over the years, including multiple-effect evaporation, Fenton oxidation, catalytic oxidation, microelectrolysis, biochemistry, resin absorption, etc., but still had four large problems.
Firstly, waste salt processing problem. A part of processes do not remove the salt from the waste water and can not realize recycling; a part of processes adopt multiple-effect evaporation desalting technology, but can not completely separate the organics and salt; with a large area, high energy consumption and large operation cost. Secondly, organics processing problem. Adoption of oxidation technology generally will destroy the structure of the organics and cause change of the structure of the organics, thus the organics can not be recycled, easily forming solid waste, and the pollution source still exists. Thirdly, large waste water discharge. Generally, the industry will generate over 10 tons of waste water by producing 10,000 ton of rubber chemicals, which has a high operation cost and bad operation stability after being deeply treated. Fourthly, the processing unit covers a large area and has high operation and maintenance cost, which largely squeezes and even totally occupies the living space of the enterprise.
Find a new path——Developing waste water recycling process