Wastewater treatment of detergent industries|Investigating the treatment method of detergent effluent
Wastewater treatment of detergent industries is a complex process because the wastewater produced by these factories is among the industrial wastewaters with high pollution load. Detergent wastewater contains detergents that are soluble in water, and if they are not separated before disposal in the environment, they can cause many environmental problems. In addition to detergents and surfactants, wastewater from detergent industries often contains polyphosphates that are added to complex calcium. Detergent wastewater is known to be a major source of phosphate entering water sources, which is considered one of the nutrients and causes the phenomenon of eutrification, therefore, detergent wastewater must be treated before disposal. In the following, the characteristics of the wastewater of these industries will be described along with the wastewater treatment method of detergent manufacturing factories.
Definition of synthetic detergents
The term detergents refers to many types of detergents and cleaning materials that are used to remove dirt and pollution from the surface of cloth, carpet, dishes and other objects. The main components of detergents are organic substances that have the property of surface absorption in aqueous solutions and they are called surface absorption agents or surfactants. Surfactans are large polar molecules, one end of which is soluble in water and the other end is easily soluble in fats.
The importance of wastewater treatment in detergent factories
:The discharge of wastewater containing detergents, either through detergent manufacturing factories or through domestic use of detergents, causes major environmental problems. These problems are divided into three main categories
- Environmental problems caused by surfactants
- Environmental problems caused by the introduction of phosphorus
- Environmental problems caused by detergents
Quantitative and qualitative characteristics of wastewater from detergent industries
- The maximum flow rate entering the wastewater collection network of the detergent factory belongs to unknown sources, which constitutes 60% of the total wastewater flow
50% of the total BOD and COD of detergent wastewater belong to the two fat output parts and the soap cooking unit
- COD/BOD ratio for sulfonation units, powder production, dishwashing liquid and industrial products is around 50%
- Since detergent wastewater has a high pH, the design of the treatment process should be made for these conditions
- The temperature of the wastewater is at an optimal level and temperature adjustment is not necessary for the treatment steps
:In the table below, the wastewater characteristics of detergent industries are estimated
| characteristic | unit | amount |
|---|---|---|
| PH | --- | 9.5-11 |
| COD | mg⁄l | 3500-5000 |
| BOD5 | mg⁄l | 1800-3000 |
| animosity | NTU | 250-350 |
| Surface active ingredients | mg⁄l | 350-500 |
| TS | mg⁄l | 9000-11000 |
Detergent industry wastewater treatment method
کFactories producing detergents have different production units depending on their products. In general, factories producing detergents have units for baking soap, sulfonation, powder production, dishwashing and washing liquid production, shampoo production, toothpaste production, and washing machine powder production. Both sulfonation and powder production units are usually present in very large factories. In the following, the wastewater treatment method of one of the factories producing detergents is described
Equalizer
.When the wastewater enters these ponds, sulfuric acid and lime water are injected to adjust the pH. Chemicals are injected into the chemical treatment ponds according to the wastewater flow rate
Chemical treatment of detergent wastewater
After the pH adjusting chemicals are added to the detergent wastewater, the resulting effluent will spend a suitable residence time in a settling pond for the chemical sludge to be directed to the filter press sludge collection pool. After that, in the coagulation and flocculation ponds, we inject coagulants and coagulants so that unstable colloidal particles settle down. Then the flocculation process is completed and at the end, the sludge resulting from chemical treatment is directed by the pump to the filter press sludge collection pool to prepare chemical cake.
Biological treatment of wastewater from detergent industries
The overflow from the chemical treatment process enters the biological aeration ponds. In the biological treatment of detergent wastewater, treatment is done with the help of activated sludge. In this method, we enter the wastewater into ponds to aerate and dissolve oxygen in the water. This oxygen causes the reproduction and life of microorganisms in the wastewater, which reduces the BOD of the wastewater. After that, they enter the sedimentation ponds and activated sludge (biomass) settles there and then it is directed to the sludge concentration ponds. For biological purification with the help of activated sludge and appropriate microbial growth, a rotating biological filter (RBC) can be used
Filtration process
The effluent from the above steps is pumped and directed to the sand filter tank with the aim of removing the formed sediments and clots and reducing suspended particles such as iron and aluminum clots from chemical treatment
Surface adsorption process
The waste water coming out of the sand filter enters the activated carbon tank for color removal. In the surface adsorption method, dissolved substances are trapped at the interface between solid and liquid. The most commonly used adsorbent is activated carbon. Activated carbon is economically viable due to its high absorbency and regeneration capability.
Disinfection process
In the last step, we use chlorination to kill or neutralize pathogenic microorganisms
Design and manufacture of wastewater treatment package for detergent industries
With more than 20 years of successful experience in treating industrial and sanitary wastewaters, Pasenco Company has the ability to design and implement all types of wastewater treatment plants for detergent industries. Also, this company has been able to offer metal and polyethylene packages for wastewater treatment at a reasonable price by using modern wastewater treatment technologies. Wastewater treatment of detergent production factories is in accordance with the standards of the Environmental Organization.
