Petroleum and petrochemicals

Home » Applications » Petroleum and petrochemicals

Applications-Petroleum and petrochemicals Wastewater Treatment

Our goal is to work closely with partners to help customers achieve greater success in multiple fields.

Surface Treatment

Municipal sewage

Petroleum resources are a vital resource for human beings. They have brought colossal development impetus to human society. They are also a resource that is widely used and has a direct relationship with people's daily production and life.

However, in the petroleum processing stage, there will inevitably be a lot of wastewater and other pollutants, and wastewater will also be produced during the mining process. Data statistics show that the water content of current oil field extraction has exceeded 80%. With the development of society, the environmental situation is becoming increasingly severe, especially the water pollution problem. It has become a major problem for people, and timely measures must be taken to solve it.

Table of contents（Click to go to where you want to see）

6.1. Physical treatment process ( Our company’s main products and cases)

6.1.1 Flotation method

6.1.2Electrolytic magnetization method
6.1.3 Biochemical treatment
6.1.4.Aerobic biological treatment process

6.2 Chemical method

6.2.1 Flocculation method

6.2.2 photooxidation

6.2.3 sonochemical oxygen method

6.2.4 Oxidation method

6.3 Biological methods
6.4 physical and chemical methods

What is petroleum and petrochemical wastewater?

Petrochemical wastewater is generated during production and usually contains various organic compounds, inorganic salts, heavy metal ions, suspended solids, dissolved gases, and other chemical substances.

The components of these wastewaters are complex and diverse. They may originate from crude oil refining, petroleum processing, oil refining, cracking, ammonia, methanol, ethylene, etc. These production processes involve many chemical reactions and material transformations, resulting in wastewater containing various harmful substances, such as benzene series, polycyclic aromatic hydrocarbons, cyanide, heavy metal ions (such as lead, mercury, cadmium, chromium, etc.), volatile organic compounds, etc.

What is the source of petrochemical wastewater? How to classify?

The primary sources of wastewater from petrochemical enterprises include the following categories:

The wastewater discharged after water comes into contact with materials during the production process is called process wastewater;
Drainage of auxiliary equipment of public works, such as circulating cooling water drainage, steam generator drainage, waste heat boiler drainage, etc., the water quality is relatively simple and mainly contains inorganic salts;
Wastewater discharged from corporate laboratories;
Wastewater generated in accidents, such as accident material leakage, firefighting wastewater, rainwater contaminated during the accident, etc.;
Rainwater in the early stages of rainfall in contaminated areas or contaminated rainwater caused by material leakage during rainfall;
Domestic sewage is discharged from corporate living facilities such as offices, canteens, etc.

In summary, wastewater from general petrochemical enterprises can be divided into process wastewater, salty wastewater, experimental wastewater, accident wastewater, polluted rainwater, and domestic sewage according to water quality.

What are the characteristics of petrochemical wastewater?

Complex ingredients

Petrochemical wastewater is a complex wastewater whose components include various organic matter, inorganic matter, heavy metals, and other pollutants.

Regarding organic matter, there are various organic compounds in wastewater, such as petroleum hydrocarbons, benzene, phenols, and alcohol. These organic compounds are usually toxic and refractory to degradation, seriously threatening water bodies and the ecological environment.

In terms of inorganic substances, there are acidic, alkaline, and salt substances in wastewater. Inorganic substances discharged at high concentrations will change water bodies' acid-base balance and salinity, negatively affecting aquatic life and ecosystems.

In addition, wastewater also contains a variety of heavy metal ions, such as lead, mercury, cadmium, chromium, etc. These heavy metals are cumulative and toxic in water bodies, posing potential threats to the ecological environment and human health.
High concentrations and large emissions

Wastewater generated during petrochemical production processes is usually characterized by high concentration and large amounts of discharge. The concentration of pollutants in sewage is often high and requires effective treatment measures to meet discharge standards. This is because much water and wastewater is generated during petrochemical production. Large-scale production results in relatively large amounts of wastewater discharge, and corresponding control and management measures must be taken to reduce the impact on the water environment.
Factors affecting water quality changes

The discharge of petrochemical wastewater has an essential impact on the water quality. The organic and inorganic substances in the wastewater will cause eutrophication and deterioration of water quality, destroying the living environment and ecological chain structure of aquatic organisms.

High-concentration discharge of organic matter will cause eutrophication of water bodies, reducing dissolved oxygen in the water and affecting the respiration and survival of aquatic organisms.

The discharge of inorganic substances will change the acid-base balance and salinity of the water body, negatively impacting the growth and reproduction of aquatic organisms. The heavy metal ions in the wastewater will also have toxic effects on the water body, posing potential threats to the ecological environment and human health.
Refractory to degradation and difficult to handle

Most organic matter in petrochemical wastewater is refractory, so it cannot be quickly degraded and removed through conventional treatment methods. This is because the organic matter in sewage has a complex structure and high chemical stability and is not easily degraded naturally or by microorganisms.

Therefore, treating petrochemical wastewater is relatively tricky and requires appropriate treatment technologies and processes. Physical treatment methods such as precipitation, filtration, and adsorption can remove suspended solids and particulate matter in wastewater. In contrast, chemical treatment methods promote the precipitation, dissolution, or oxidation of organic matter and heavy metals by adding appropriate chemical reagents, thereby achieving their removal and transformation.

Biological treatment methods use the metabolic ability of microorganisms to convert organic matter and heavy metals into harmless substances to achieve biodegradation and purification of wastewater. Standard biological treatment technologies include activated sludge, biofilm, and biological filter methods.

What is the significance of petroleum and petrochemical wastewater treatment ?

Measures should be taken to treat petroleum wastewater to reduce the impact of petrochemical wastewater on biological toxicity. At the same time, it can also conduct an overall evaluation of various severe toxicities and make the initial identification of pollution to facilitate the subsequent determination of pollutants. And provide a basis for formulating reasonable and practical handling measures.
The evaluation of petroleum wastewater and the determination of conventional pollutant concentration parameters can better reflect the pollution situation of petrochemical wastewater, thus explaining the effect of optimized treatment.
Conduct in-depth research on the currently widely used petroleum wastewater treatment methods and comprehensively analyze the advantages and disadvantages of various treatment methods to improve and upgrade process technology, further enhance the efficiency of petroleum wastewater treatment, and increase resource utilization.
To better achieve energy conservation, achieve the ultimate goal of sustainable development, protect the global environment, and benefit future generations while ensuring the lives of modern people, this requires continuous research and development of new technologies to treat petroleum wastewater scientifically and rationally.

Have a water or wastewater challenge? Get a free consultation

Ask an Engineer

Why is petroleum wastewater so difficult to treat?

As a significant global energy source, petroleum is exploited in large quantities worldwide. The petrochemical industry is scattered and not highly concentrated in many developing countries. Many companies are small in scale, have backward technology and equipment, have significant environmental risks, and are more toxic and harmful. Chemical substances enter the relevant environment, producing various comprehensive pollution phenomena and biological toxicity.

The so-called biological toxicity refers to the nature and ability of chemical substances to cause damage to living organisms. According to the action characteristics, it can be divided into general and extraordinary toxicity.

General toxicity includes acute toxicity, subchronic toxicity, and chronic toxicity;

Extraordinary toxicity usually refers to the so-called "three effects" of teratogenesis, carcinogenesis, and mutagenesis. From a mechanism point of view, teratogenesis, carcinogenesis, and mutagenesis are all related to damage to genetic material, which is the damage to genetic material that causes germ cells or Changes in somatic cells.

In addition, some chemicals with hormone-like functions in the environment have attracted more attention in recent years. Researchers believe that they all work by interfering with the endocrine system of organisms. Therefore, the endocrine-disrupting activity of environmental pollutants is also a factor. A specific toxicity that requires further study.

The environmental pollution caused by petrochemical wastewater has attracted more attention recently. Still, most research has focused on the improvement of treatment technology and the control of pollutant concentration.

There are relatively few research materials on the biological toxicity of petrochemical wastewater, mainly focusing on two categories. One category is toxicological studies on some characteristic pollutants, such as PAHs, listed as priority pollutants for control by the USEPA and EU.

PAHs in petrochemical wastewater have been studied for their concentration and toxic effects and are thought to exhibit genotoxicity.

In addition, the ecological effects of soil and water contaminated by petrochemical wastewater have also attracted attention. The mutagenicity of chemicals in soil contaminated by petrochemical wastewater has been studied. Domestic and foreign scholars have used the Ames experiment, prophage induction test, and Daphnia magna chronic Toxicity experiments to analyze the ecotoxicological characteristics of river beds contaminated by petrochemical wastewater and found that it has damaging effects on rat testicular cells, spermatogenic cells, interstitial cells, etc. From this point of view, petroleum wastewater pollution and its impact are severe.

What are the treatment technologies for petrochemical wastewater?

Physical treatment process(Our company’s main products and cases)

Flotation method

Dissolved Air flotation, also known as flotation, produces many fine bubbles in the water to form a three-phase heterogeneous system of water, gas, removed materials, and interfacial tension. Under the action of bubbles, the bubbles and removed materials The combination floats on the water to achieve separation from the water.

Currently, there are three types of suspension methods: electrolytic, compressed air, and airlift. The main difference between them is the manufacturing principle of flotation bags.

A blower blows air into the petrochemical wastewater using the air flotation method. Compressed air suspension uses an air compressor to pressurize air to dissolve in petrochemical wastewater.

Electrolysis flotation refers to the electrolysis of water to produce oxygen, which pushes substances suspended in the water to separate oil and water from petrochemical wastewater.

Application case(Preprocessing-physical method)

Case Studies-Environmental Protection Technology City Industrial Wastewater Treatment Plant Project

This case study introduces how Environmental Protection Technology City Industrial Wastewater Treatment Plant Project uses our factory's high-efficiency dissolved air flotation to treat oily wastewater, such as machining and cutting fluids. After treatment, the effluent quality was significantly improved, the effluent indexes of animal and vegetable oils and petroleum reached about 1 mg/L, and the total phosphorus removal rate was over 98%.

Petrochemical wastewater

Petrochemical wastewater treatment project in Dalian,Liaoning

Case Studies-Tarim Ethane To Ethylene Project

This case study introduces the Tarim Ethylene Ethane Project of Dushanzi Petrochemical. The treatment of ethylene waste alkali liquid used the high-efficiency dissolved air flotation produced by our factory as a pretreatment to remove the oil substances entrained in the waste alkali liquid, and good results were achieved.

Have technical questions about your wastewater application ?

Ask an Engineer

Electrolytic magnetization method

This method is to add electrolytes to petrochemical wastewater, mainly using the principle of electrolysis to increase the conductivity of wastewater, forming magnetic fluid under the magnetoelectric device, destroying the oil in petrochemical wastewater, and combining oil droplets to achieve oil-water separation. Recent research progress is encouraging.

However, this approach is still in the research and testing stage and requires more in-depth research and experimentation.

Gravity separation method

Gravity separation mainly uses the difference between the density of water and oil and the gravity received to separate water and oil.

Gravity separation is mainly used to remove dispersed oil films in grease traps, and this method has good results.

The gravity separation method using oil retaining rings has the characteristics of a simple structure, less auxiliary equipment, low operating cost, etc. There are many factors, such as advection, wave swing disk type, parallel disk type, etc.

However, the grease trap has shortcomings, such as requiring too much area and being unable to effectively remove emulsified and dissolved oil, which limits its development.

Chemical method

Flocculation method

This method mainly involves adding certain substances to the wastewater of the petrochemical industry. Substances that are difficult to filter and precipitate in the wastewater will form large particles to achieve the ultimate goal of separation.

This substance is polymerized and usually used in petrochemical wastewater treatment with sediment during the flocculation process so that petrochemical wastewater can be treated thoroughly.

According to the flocculation method, the best effect is to use composite flocculants. Composite flocculants are two or more single-component flocculants that undergo specific chemical reactions to form a large molecular weight copolymer complex, which overcomes the shortcomings of a single flocculant. , and also give full play to the complementary effects of various flocculants to produce significant flocculation, which can improve the impact of wastewater treatment.

In addition, the microbial aggregation method has broad application value. This method has good stability and ease of use and is mainly a biotechnology that uses microorganisms and secretions to treat petrochemical wastewater. Compared with complex flocculation methods, it has more significant advantages in use and development.

photooxidation

Generally speaking, this method can only be used when petrochemical wastewater contains catalysts or oxidants; oxidants or catalysts will decompose free radicals and reactive oxygen species. Light energy can decompose organic matter in petrochemical wastewater. This method has the advantages of fast response and sound effects.

The current photooxidation process mainly includes photocatalytic oxidation and photochemical oxidation. Among them, photochemical oxidation requires adding an appropriate amount of oxidant to the wastewater and using ultraviolet light to generate highly oxidizing OH.

UV and H₂O₂ alone have little effect. Photocatalytic oxidation is mainly used for aromatic compounds. Petrochemical wastewater containing chemical compounds and unsaturated organic matter does not cause secondary pollution, the reaction conditions will not be severe, and the application space will be significant.

sonochemical oxygen method

In recent years, ultrasonic technology has become a widely used new form of energy in various industrial fields. In addition to transmitting data information, ultrasound can achieve energy transfer efficiency.

Sonochemical oxidation wastewater is mainly obtained through ultrasonic treatment. This operation can effectively remove many pollutants from wastewater, primarily when used in advanced treatment of high concentrations of refractory organic pollutants.

Oxidation method

In petroleum production, the composition of petrochemical wastewater is very complex, and the chemical oxidation method should be selected according to the type of wastewater composition.

Photocatalytic oxidation is a new oxidation technology. The advantage of this technology is that it does not cause secondary pollution, and the treatment effect is pronounced. Its advantage is that it is unsuitable for companies that use a lot of wastewater due to the high equipment cost and relatively high treatment cost.

A standard wastewater treatment method in petrochemical companies combines ozone oxidation and adsorption technology. This combination method is advanced and has sound wastewater treatment effects. It can effectively oxidize organic pollutants and has apparent decomposition effects.

Other oxidation methods include wet air oxidation, catalytic wet oxidation, and wet oxidation, which have sound treatment effects on toxic wastewater or high concentrations of pollutants and decomposition.

Biological methods

The biological process of treating chemical wastewater refers to the decomposition of organic matter under the action of microbial metabolism.

With the continuous development of the chemical industry, the composition of pollutants is constantly changing. In chemical wastewater, many organic pollutants are treated only through chemical or physical means, and it is difficult to achieve the goal of complete removal. Biological methods using microorganisms can convert organic substances in wastewater into non-toxic and harmless substances through the metabolism of microorganisms, thereby achieving the purpose of purifying water.

Biological methods are mainly divided into two types: aerobic and anaerobic. The biofilm and wastewater are combined to absorb the organic matter in the wastewater through adsorption of the biofilm.

Anaerobic wastewater treatment refers to the metabolic decomposition of organic matter in wastewater by anaerobic microorganisms under anaerobic conditions, converting the organic matter into methane and carbon dioxide to purify water. The anaerobic biological process produces more complex biochemical processes. When using biological wastewater treatment methods, some microorganisms may be affected by several factors, such as the acidity and alkalinity of the wastewater, temperature, composition, etc.

Physical and chemical methods

First, in the ion exchange process, the ion exchanger exchanges ions with the ions in the wastewater to remove harmful ions and achieve water purification.

Ion exchange membranes are widely used in water softening and organic wastewater treatment processes. For the extraction process, the principle is to achieve the final effect of extracting the solubility difference of the substance in the substance and extracting the insoluble substances in the water and the impurities dissolved in the water. Good contact with the effluent can be used. Different extraction solvent solubilities and impurities in the water are used to extract impurities and remove contaminants from it, thereby purifying the water.

Wastewater treatment based on electrodialysis refers to the effect of direct current through anion exchange and cation exchange, which is selected to achieve a permeable solution of cations and anions. The separation of water can be a physical and chemical reaction process.

Membrane separation technology uses a semipermeable membrane for molecular filtration to treat wastewater. The membrane separation process is also called reverse osmosis. Reverse osmosis is a reverse migration movement of osmosis. It is mainly driven by pressure and uses a semipermeable membrane. The interception effect forces the solvent and solute in the solution to separate, thereby purifying water by blocking some dissolved organic substances.

Leave a Message