I. Introduction.
Wastewater treatment With the rapid development of the chemical industry, the problem of wastewater generated is becoming more and more serious. Chemical wastewater contains a variety of harmful substances, such as organic matter, heavy metals, acids and alkalis, etc., which are potentially harmful to the environment and human health. Therefore, the treatment of chemical wastewater is one of the important tasks in the field of environmental protection. This article will share the technical experience of chemical wastewater treatment, in order to provide some reference for those in the environmental protection and water control industry.
Second, the major difficulties of chemical sewage treatment.
1. The composition is complex.
The composition of chemical wastewater is complex and changeable, including a variety of organic matter, heavy metals, acids and alkalis, etc. The handling of these substances is difficult and requires different treatment methods for different substances.
2. High toxicity.
Many substances in chemical wastewater are toxic, highly toxic to the environment and biological systems, and potentially harmful to human health.
3. Water quality fluctuates greatly.
The discharge and water quality of chemical wastewater fluctuate greatly, which brings great difficulties to wastewater treatment. At the same time, different types of chemical wastewater have different requirements for the treatment process, so customized treatment solutions are required for different chemical wastewaters.
3. The harm of chemical wastewater to people and the environment.
1. Harm to people.
Long-term exposure or ingestion of toxic substances such as organic matter and heavy metals in chemical wastewater will have a serious impact on human health, such as nervous system damage, immune system disorders, reproductive system hazards, etc.
2. Harm to the environment.
The discharge of chemical wastewater into the water body will damage the ecological environment of aquatic organisms and affect the growth and reproduction of aquatic organisms. In addition, toxic substances in wastewater can be passed through the food chain, which can adversely affect the entire ecosystem. At the same time, the discharge of chemical wastewater will also lead to problems such as soil pollution and groundwater pollution.
Fourth, the experience sharing of chemical sewage treatment technology.
In view of the above major and difficult problems, the following is a set of accurate and coherent experience in chemical wastewater treatment technology:
1. Pretreatment.
Pretreatment is the first step in the treatment of chemical wastewater, mainly to remove suspended solids and solid particles in wastewater. Commonly used methods include filtration, sedimentation, and air flotation. The purpose of pre-treatment is to reduce the burden on the subsequent processing units.
2. Chemical oxidation.
Chemical oxidation is the use of oxidants to oxidize and decompose refractory organic matter in chemical wastewater into small molecule organic matter or inorganic substances. Commonly used oxidants include ozone, hydrogen peroxide, etc. Chemical oxidation can effectively remove organic matter and toxic substances from wastewater.
3. Biochemical treatment.
Biochemical treatment is the use of microorganisms to convert organic matter in chemical wastewater into inorganic substances. Commonly used biochemical treatment methods include activated sludge method, biofilm reactor, etc. The purpose of biochemical treatment is to further remove organic matter and toxic substances from wastewater.
4. Physical and chemical treatment.
For organic matter and other pollutants that cannot be completely removed after biochemical treatment, physical and chemical methods can be used for advanced treatment. Commonly used physical and chemical methods include adsorption method, membrane separation method, chemical precipitation method, etc. These methods can further remove organic matter from wastewater and improve water quality.
5. Sludge treatment.
The sludge produced during biochemical and physicochemical treatment is rich in organic matter and other contaminants. This sludge needs to be stabilized and solidified before being recycled or safely disposed of. The purpose of stabilization treatment is to reduce the content of organic matter in the sludge so that it is not easy to decompose;The purpose of solidification treatment is to convert the harmful substances in the sludge into insoluble substances or immobilized forms to reduce the harm to the environment and human health. The ways of resource utilization include agricultural utilization, industrial utilization, etc.;Approaches to safe disposal include landfills, incineration, etc.
5. Summary and outlook.
This paper shares the technical experience of chemical wastewater treatment, including pretreatment, chemical oxidation, biochemical treatment, physicochemical treatment and sludge treatment. These technical experiences can provide some references for people in the environmental protection and water control industry. However, with the continuous improvement of environmental protection requirements and the continuous development of technology, we need to continuously explore new treatment technologies and methods to improve the treatment efficiency and quality of chemical wastewater. At the same time, enterprises also need to strengthen environmental awareness and management efforts to reduce the discharge of chemical wastewater and environmental pollution. Only in this way can we achieve harmonious coexistence and sustainable development between man and nature.