What are the conventional process technologies for high salt wastewater treatment?

The difficulty of high-concentration brine treatment technology is basically concentrated in the pretreatment unit, that is, the commissioning of the clarifier, the debugging of the clarifier, the determination of the dosage, is a dynamic control process, the so-called dynamic refers to the changeable quality and quantity of the incoming water, and the control refers to the control range of P alkali and M alkali must be in a certain range, only according to the change of the incoming water, timely adjust the dosage and control 2P-M in a fixed range, in order to ensure the stability and continuous operation of the follow-up section. Of course, the stable water quality and quantity of the biochemical treatment and reuse water unit are also an important factor to ensure the stable operation of the evaporation and crystallization unit.

Characteristics of high-salt wastewater.

High-saline wastewater is defined as wastewater with a total salt content of at least 1%. It mainly comes from chemical plants and oil and gas gathering and processing. This wastewater contains a variety of substances (including salts, oils, organic heavy metals, and radioactive materials).

Saline wastewater is generated in a wide range of ways, and the amount of water is increasing year by year. Removing the environmental impact of organic contaminants in saline effluents is crucial. The biological method is used for treatment, and the high concentration of salt substances has an inhibitory effect on microorganisms, and the physicochemical treatment is large, the operating cost is high, and it is difficult to achieve the expected purification effect.

The use of biological methods to treat such wastewater is still the focus of research at home and abroad.

High salt wastewater treatment method.

Biological treatment is one of the most commonly used methods for wastewater treatment, which has the characteristics of wide application range and strong adaptability. Chemical wastewater such as dyes, pesticides, pharmaceutical intermediates and other wastewater with high salt content brings certain difficulties to biological treatment. This type of wastewater is highly salty and polluting, and must be treated before it can be discharged.

In addition, this type of wastewater is complex in composition, does not have the best value, and other treatment methods are more expensive, so biological treatment is still the preferred method.

Inorganic salts play an important role in promoting enzymatic reactions, maintaining membrane homeostasis and regulating osmotic pressure during microbial growth. However, if the salt concentration is too high, it will have an inhibitory effect on the growth of microorganisms. The main reasons for inhibition are:

1) When the salt concentration is too high, the osmotic pressure is high, which causes the dehydration of microbial cells and causes the separation of cell protoplasm;

2) In the case of high salt content, the dehydrogenase activity is reduced due to salting out;

3) high chloride concentration has a toxic effect on bacteria;

4) Due to the increase in the density of water, activated sludge is easy to float and lose.

What about the treatment of salty and high-salt wastewater? Kang Jinghui solves the problem of wastewater treatment for you!

The treatment method of high-salt wastewater is very simple, it is enough to add a Sonny electrocatalytic oxidation system and an ozone catalytic oxidation system before evaporation, the two systems can remove organic matter, and the crystalline salt after evaporation can even meet the industrial product standard.

1. Acclimation:

Under the condition of salinity less than 2 g l, saline sewage may be treated by acclimation. However, the acclimation salinity concentration must be gradually increased, and the system must be domesticated to the required salinity level in stages. Sudden high-salt environments can cause domestication failures and delays in initiation.

2. Dilute the salinity of the inlet water

Since high salt becomes an inhibitor and poisoning agent for microorganisms, the incoming water is diluted so that the salinity is below the toxicity value, and the biological treatment is not inhibited. This method is simple, easy to operate and manage; The disadvantages are that it increases the scale of treatment, increases infrastructure investment, increases operating costs, and wastes water resources.

3. Evaporation, concentration and desalination

When the salinity is greater than 2g l, evaporation concentration and desalination are the most economical and effective feasible methods. Other methods, such as the cultivation of salt-containing bacteria, have problems with the difficulty of industrial practice.

4. Biological methods:

Many studies have shown that biological methods can treat highly saline wastewater. But from low to high salt, microorganisms have an adaptation period. From freshwater environment to high salt environment, because the change of salt may cause changes in microbial metabolic pathways, the result of strain selection makes fewer strains suitable for high salt, and only when microorganisms are cultured and domesticated, can they produce strains adapted to high salt to tolerate a certain salt concentration.

There are two treatment methods for high-salt wastewater, one is distillation and desalination, in which the brine is heated to boil and evaporate, and then the steam is condensed into fresh water. The distillation method is the earliest desalination method used, and its advantages are simple structure, easy operation, and good quality of freshwater obtained. There are many kinds of distillation methods, such as multi-effect evaporation, multi-stage flash evaporation, pressure gas distillation, membrane distillation, etc.

The second is the Shenpei membrane method to treat high-salt wastewater, for the high-salinity wastewater treatment method, the membrane treatment method can achieve a high desalination rate, usually more than 95%. Among them, the desalination rate of nanofiltration membrane is 95% 98% for bivalent salts and 90%-95% for monovalent salts.

There are two treatment methods for high-salt wastewater, one is distillation and desalination, in which the brine is heated to boil and evaporate, and then the steam is condensed into fresh water. The distillation method is the earliest desalination method, which has the advantages of simple structure, easy operation and good quality of fresh water. There are many kinds of distillation methods, such as multi-effect evaporation, multi-stage flash evaporation, pressure gas distillation, membrane distillation, etc.

The second is the membrane method to treat high-salt wastewater, for the high-salinity wastewater treatment method, the membrane treatment method can achieve a higher desalination rate than Butan, usually more than 95%. Among them, the desalination rate of nanofiltration membrane is 95% 98% for bivalent salts and 90%-95% for monovalent salts.

High-salt wastewater can be treated by evaporation, and the organic matter can be removed by catalytic oxidation and ozone catalytic oxidation technology of electric power generation.

The treatment methods of high-salt wastewater mainly include evaporation method, ion exchange method, reverse osmosis method and crystallization method. Here's a quick rundown of these methods:

Evaporation method: The water in the wastewater is evaporated through the evaporation process, so as to realize the separation and concentration of dissolved salts in the wastewater. It is suitable for the treatment of high-salt wastewater, which can effectively reduce the volume of wastewater, but consumes a large amount of energy.

Ion exchange method: Ion exchange resin is used to adsorb ions in wastewater to achieve the removal of salts. This method can effectively reduce the concentration of salts in wastewater, but it will produce a waste liquid containing high concentrations of salts, which requires further treatment.

Reverse osmosis method: The selective permeability of the reverse osmosis membrane is used to separate the water from the wastewater to achieve the purpose of removing salts. Reverse osmosis is highly effective at removing salts, but it requires a lot of energy and is expensive to maintain.

Crystallization method: By controlling the concentration of solutes in the wastewater to exceed the saturation, the salts can crystallize and precipitate. The crystallization method can realize the separation and development of salts, but the treatment process of wastewater is more demanding.

Regarding the question of how to avoid evaporator fouling in the evaporation method, the following measures can be considered:

Water pre-treatment: Before the wastewater is sent to the evaporator, the necessary water pre-treatment, such as the removal of suspended solids, particulate matter and organic matter, is carried out to reduce the formation of dirt in the evaporator.

Control the evaporation temperature: Properly control the operating temperature of the evaporator to avoid exceeding the fouling temperature. Excessively high temperatures can cause solute crystallization and deposition, exacerbating the fouling problem.

Cleaning and maintenance: Regularly clean and maintain the evaporator to remove the scale that has formed. It can be cleaned according to the instructions for use of the evaporator using the appropriate cleaning agent and tools.

Control of water quality and chemical additives: Monitor the composition and water quality in the wastewater and add appropriate chemical additives such as corrosion inhibitors and scale inhibitors as needed to reduce the occurrence of fouling.

Optimize operating parameters: Reasonably control the operating parameters of the evaporator, such as flow, concentration, cycle rate, etc., to avoid the formation of fouling.

In summary, when the evaporation method is closed to treat high-salt wastewater, the water quality pretreatment, temperature control, cleaning and maintenance, water quality and chemical additives control, and optimization of operating parameters can effectively reduce the problem of evaporator scaling, improve the wastewater treatment effect and the operation stability of the equipment.

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The introduction of high-salt wastewater treatment equipment is as follows:

The equipment adopts the flotation technology in the treatment of physical and chemical principles, and its basic principle is to introduce air into the water to produce a large number of microbubbles in the water, and make them adhere to the impurity particles, forming a floating body with a specific gravity less than the water, and floating to the water surface, so as to separate the technology of impurity particles. The high-efficiency air flotation host includes: pool body, scum collection device, stationary ring, and isolation ring.

Overflow adjustment device, walking frame, rotating water inlet pipe, rotating water distribution mechanism, etc. The advantages are good effect, quick effect, low investment, and a large amount of oxygenation can be added to the water at the same time to improve the self-cleaning function of water extraction; The processing system is fully automatic operation control, easy to operate, and the daily maintenance workload is small; The equipment has stable operation and long service life, and can be effectively used for more than ten years.

Wastewater with high salt content

High-salt wastewater refers to wastewater containing organic matter and at least total dissolved solids (TDS) with a mass fraction greater than or equal to it, including high-salt domestic wastewater and high-salt industrial wastewater. It is mainly used in industrial production, domestic water and food processing plants, chemical plants, and oil and gas collection and processing that directly use seawater.

In addition to organic pollutants, these wastewater also contain a large amount of inorganic salts, these high-salt, high-organic wastewater, if directly discharged without treatment, is bound to be extremely harmful to water organisms, drinking water and industrial and agricultural production water production. However, the brine concentration in the conventional treatment method should not be too high, and it is urgent to develop the process technology to treat higher concentration of high-salt wastewater.