Methods for effectively treating soap wastewater

Soap Wastewater

Soap wastewater is a type of wastewater with many distinct characteristics. Notable among them are: high pH concentration, containing a lot of detergent chemicals, high color and turbidity.

There are also some surfactants present in wastewater. Without a professional treatment process, it will be very difficult to completely remove these substances from the water source.

Some surfactants present in wastewater include: Ammonia, Cationic, Non-Ionic, zwitterionic, Alkylbenzene sulfonate,... These are all substances that are difficult to decompose under normal conditions, so specific treatment methods are needed.

Methods of treating soap wastewater

2.1 Physical

The physical method, also known as mechanical, uses machinery to treat some of the pollutants in wastewater. Examples include the process of screening with bar screens, sludge pressing machines, activated carbon filters, sand filters, etc.

2.2 Chemical

The main application of the chemical method in treating soap wastewater is the coagulation process, creating flocs with alum, PAC, or Polymer chemicals... Other applications include flocculation, flotation.

The main purpose of chemical methods is to remove suspended solids, surfactants in wastewater. At the same time, it improves the color, turbidity, COD, and BOD of wastewater.

2.3 Chemical

The mechanism of this method is based on chemical reactions to convert pollutants into less or non-polluting substances. Examples include the use of ozone, chlorine to disinfect, oxidize organic and inorganic substances remaining in water after biological treatment.

2.4 Biological

The mechanism of biological treatment of soap wastewater relies on the growth and development of microorganisms to decompose organic matter in water, reduce BOD and COD.

Biological treatment is usually divided into types such as aerobic biological treatment, anaerobic biological treatment. Some specific biological facilities in the water treatment system include Aerotank, SBR biological tank, UASB tank...

Soap wastewater treatment technology process

Soap wastewater treatment technology consists of several different stages. Each stage plays a specific role. Specifically as follows:

3.1 Pretreatment stage

• The main goal of this stage is to remove large solid waste, stabilize flow and wastewater concentration before proceeding to the next processes.
• Soap wastewater will be collected and sent to settling tank one. Bar screens, mesh screens will be installed at the beginning of the water pipes and at the head of the settling tank to block large solid waste, coarse sludge. This reduces the pressure load on downstream facilities, limiting pipe blockages.
• The solid waste trapped at the bar screens will be collected and put into trash cans. Wastewater is then sent to settling tank one and then transferred to the equalization tank. Here, agitators, air diffusers can be installed to provide oxygen, reduce anaerobic decomposition causing foul odors.
• The main function of the equalization tank is to stabilize flow and wastewater concentration. This facility is also used to store wastewater whenever the system stops operating for maintenance.

3.2 Chemical treatment stage

In this stage, wastewater will be treated using specific methods as follows:

• Neutralization: The main purpose is to adjust and control the pH concentration in wastewater according to standards.
• Coagulation - Floc formation: Adding coagulant aids, PAC, Polymer chemicals into wastewater to bind suspended solids in water into large flocs.
• Chemical settling: Large flocs formed earlier will settle down and be pushed into the sludge holding tank. Clearer water is then transferred to the next stage.

3.3 Microbial treatment stage

• Anaerobic biological tank: Here, anaerobic microorganisms will decompose organic matter in water. This process involves circulation and is combined with water treatment in aerobic biological tanks.
• Aerobic biological tank: Microorganisms will decompose, absorb organic and inorganic substances in wastewater for growth and development. It can be combined with MBBR biological membrane to increase efficiency.

3.4 Secondary treatment stage

• In this stage, a second flocculation process will take place to clean up suspended solids in water.
• Next, wastewater will be filtered through a pressure filter tank or rapid filter tank.
• Finally, the wastewater is sent to a disinfection tank, using ozone or chlorine to remove disease-causing bacteria present in the wastewater.

Treating soap wastewater is not a simple task. Therefore, it is necessary to design and build a system scientifically, modernly, suitable for the volume and characteristics of the water source. If you are looking for a unit to design, construct facilities in this treatment system, contact Toan A JSC for assistance.