Refinery Wastewater Treatment
The wastewater produced in the refinery production process has been a concern. These wastewater contains complex organic matter, oil, sulfur, phenol and other pollutants, which is very harmful to the environment and organisms. Therefore, oil refining wastewater treatment is not only an important environmental protection task, but also a key link to achieve sustainable development.
As an important part of the petrochemical industry, refineries have always received much attention for the wastewater produced during their production processes. These wastewaters contain complex organic matter, oil, sulfur, phenol and other pollutants, which are very harmful to the environment and organisms. Therefore, refinery wastewater treatment is not only an important environmental protection task, but also a key link in achieving sustainable development. This article explores the challenges and solutions for refinery wastewater treatment.
Characteristics of refinery wastewater Large amount of sewage and complex wastewater components:
Refinery wastewater mainly consists of a large amount of oily sewage discharged from petroleum refining and wastewater generated from mechanical processing and metal cleaning. The wastewater has a large amount and complex components.
High organic matter content: Wastewater contains a large amount of organic matter, especially hydrocarbons and their derivatives, which are difficult to degrade and have high COD (chemical oxygen demand) content.
Contains a variety of pollutants: In addition to organic matter, refinery wastewater also contains oil, sulfur, phenol, acetone, aromatic hydrocarbons, naphthenate, unsaturated hydrocarbons, alkali, acid, salt and other pollutants. These pollutants are very harmful to the environment and living organisms.
Large changes in pH value: Refinery wastewater is affected by alkali residue wastewater and pickling water, and its pH value changes greatly, which brings certain difficulties to wastewater treatment.
Stable suspension of tiny oil droplets: Refinery wastewater contains tiny oil droplets with a particle size between 100 and 1000 nm. These oil droplets are easily surrounded by surfactants and hydrophobic solids, forming emulsified oil, which is stably suspended in the water. Oil in this state cannot be separated from wastewater by standing method.
Harm to the water environment: Oil pollutants will form a molecular film after being discharged into the water body, polluting the water quality, reducing the dissolved oxygen (DO) content in the water, and generating CO2 to form H2CO3, which will reduce the pH value and turbidity. Increase. This not only affects the ecological balance of the water body, but may also cause harm to aquatic life.
Challenges of Refinery Wastewater Treatment
1 The composition of wastewater is complex:
Refinery wastewater contains a variety of organic matter, oil, sulfur, phenol and other pollutants. These pollutants are difficult to degrade and difficult to treat.
2 High treatment technology requirements:
Based on the characteristics of refinery wastewater, it is necessary to adopt efficient, stable and economical wastewater treatment technology to meet environmental protection requirements and economic benefits.
3 Large investment in treatment equipment:
Wastewater treatment equipment requires a large investment. For small refineries, investment pressure is high. CTCP plate treatment of refinery wastewater is a common and effective wastewater treatment technology. Activated carbon plays an important role in refinery wastewater treatment due to its unique physical and chemical properties.
Activated carbon is made from carbonaceous materials such as wood, coal, and fruit shells that are activated under high temperature and anoxic conditions. It has a lot of micropores and a huge specific surface area. Usually, the surface area of 1 gram of activated carbon can reach 500 to 1500 m², so it has strong physical adsorption capacity. This powerful adsorption capacity enables activated carbon to effectively adsorb organic pollutants, heavy metal ions and other harmful substances in wastewater.
In refinery wastewater treatment, activated carbon can play a role in the following ways:
Adsorption: The microporous structure of activated carbon can absorb organic matter, oil, solvents, pigments, etc. in wastewater, effectively reducing COD (chemical oxygen demand) and BOD (biological oxygen demand) in wastewater.
Decolorization and deodorization: The physical adsorption and chemical adsorption characteristics of activated carbon can remove the color and odor in wastewater and improve water quality.
Removal of heavy metal ions: During the activation process, some oxygen-containing functional groups, such as carboxyl groups (-COOH), hydroxyl groups (-OH), carbonyl groups, etc., will be formed on the amorphous parts of the activated carbon surface. These groups enable activated carbon to have chemical adsorption and catalytic oxidation and reduction properties, and can effectively remove metal ions in wastewater.
The method of treating refinery wastewater with activated carbon usually includes the following steps:
Pretreatment: Before introducing wastewater into the activated carbon treatment system, appropriate pretreatment is required, such as removing large suspended solids, grease, etc. in the wastewater to reduce clogging and wear of the activated carbon.
Activated carbon adsorption: The pretreated wastewater is passed through the activated carbon bed, and the organic pollutants and heavy metal ions in the wastewater are adsorbed by the activated carbon.
Activated carbon regeneration: As the number of pollutants adsorbed by activated carbon gradually increases, its adsorption capacity will decrease. At this time, the activated carbon needs to be regenerated to restore its adsorption capacity. Common activated carbon regeneration methods include thermal regeneration, chemical regeneration, etc.
Wastewater discharge: After activated carbon treatment, the concentration of pollutants in wastewater has been greatly reduced, and it can be discharged up to standard or further processed.
Activated carbon treatment of refinery wastewater has the advantages of good treatment effect, easy operation and strong adaptability.
Refinery wastewater treatment is a complex and important task. In response to the challenges of complex wastewater composition, high treatment technology requirements, and large investment in treatment equipment, it is necessary to adopt a combination of multiple physical, chemical, biological and other treatment technologies to achieve efficient treatment and resource utilization of wastewater. At the same time, strengthening comprehensive management measures such as source control, wastewater reuse and environmental supervision is also the key to achieving sustainable development of refinery wastewater treatment.