Since the Japanese government insisted on starting the discharge of nuclear sewage in Japan, there have been waves of opposition from the international community.
At the beginning of considering the issue of dealing with nuclear-contaminated water, an expert group organized by the Ministry of Economy, Trade and Industry of Japan proposed five options. It is understood that in addition to ocean discharge, formation injection, steam discharge, hydrogen discharge and underground burial are all viable options. However, the Japanese side said that the two options of discharging into the sea and evaporating into the atmosphere are the “most practical solutions”, and finally chose the option of discharging into the sea that “requires the shortest time and costs the least” .
Zhang Qiyue, an assistant researcher at the Institute of Global Governance of the Shanghai Institute of International Studies, said that Japan adopts the lowest economic cost treatment method, intending to minimize the damage caused by nuclear sewage discharge to the country, and put the international community at risk of damage to the ecological environment and life and health. Among the security risks, it is an obvious violation of the “duty to the world” to protect the environment.
This can’t help but make people think that in the organic silicon industry, similar to most traditional chemical industries, the production of organic silicon materials, especially organic silicon monomers, will generate a large amount of toxic and harmful wastewater. If discharged without effective treatment, it will not only damage the ecology environment, and endanger the health of the general public. Today, as environmental protection standards are becoming more and more stringent, the wastewater generated during the production of organic silicon monomers has complex components, large discharge volume, and difficult treatment. If it is not handled properly, it will bring serious pollution to the environment.
The main source of organic silicon wastewater
The main pollutants in organic silicon production process wastewater are siloxane and chloride salts . Chloromethane synthesis, monomer synthesis, hydrochloric acid desorption, dimethyl hydrolysis, cracking, slurry hydrolysis and other organic silicon production processes.
Characteristics of organic silicon wastewater
The wastewater contains a large amount of hydrochloric acid , which leads to a low pH value of the wastewater. After the wastewater is fully neutralized, the salinity is at a high level, making it difficult to carry out biochemical treatment in the future.
The types of organic pollutants are complex and the concentrations are high . The production of organic silicon is relatively complicated, and the procedures and required materials are relatively cumbersome, which eventually leads to a variety of pollution in the production wastewater, and the concentration of COD in the wastewater is as high as 4 0~45 g/L .
Production wastewater also contains a large amount of organic halides , which have poor degradation performance, poor biodegradability, inhibit microbial activity, and cause large fluctuations in wastewater quality and water content. B/C concentration is generally lower than 0.2, and the biodegradability of wastewater is poor.
In the process of organic silicon production, because different production workshops in the product have independent reservoirs, it is indirect drainage . Therefore, its water quality not only has strong volatility, but also has no certain regularity. This series of wastewater characteristics makes it difficult to effectively treat production sewage.
Treatment process of organic silicon wastewater
At present, the treatment process of organic silicon production wastewater at home and abroad mainly uses physical and chemical methods to treat sewage. The physical method mainly uses some physical effects in the application process, including precipitation, adsorption, filtration and other methods to effectively reduce production . Suspended solids present in wastewater. The coagulation process can effectively remove the suspending agent and colloid in the raw water, and reduce the pollution of emulsified oil, paraffin, chromium and other heavy metal ions. According to the effect of flocculation, binders and coagulants can be used as flocculants and put into the organic silicon production wastewater. In order to ensure the coagulation effect and precipitation effect, it is necessary to select the appropriate material according to the characteristics of the water quality.
In the chemical treatment, the chemical oxidation method can treat a variety of refractory organics at normal temperature and pressure, overcome the problem that some polymers and long-chain molecules are difficult to degrade, and effectively treat organic silicon wastewater. The most important chemical oxidation method for treating organic silicon wastewater is the Fenton process. In the Fenton oxidation method, under acidic conditions, H2O2 generates OH with strong oxidation ability in the presence of Fe2+. It is a very active and non-selective species, which can cause most organic substances in aqueous solution to undergo oxidation-reduction reactions and degrade, and Promote its cracking and polymerization , etc., thereby effectively reducing the chroma, COD and TOC of wastewater, and significantly improving the biodegradability of wastewater.
Organic silicon production wastewater contains various complex pollutants and has poor biodegradability. Biochemical treatment method is a popular method for high concentration sewage treatment . In the process of specific application of biochemical methods, the organic pollutants in wastewater are effectively reduced mainly by cultivating and acclimating microorganisms, and different microorganisms have completely different oxygen requirements, so at this stage the main The applied biochemical methods include aerobic biochemical treatment and anaerobic biochemical treatment.