What's the COD wastewater treatment and what are the methods to remove COD

COD (Chemical Oxygen Demand) wastewater treatment is a measure of the concentration of organic matter in a body of water. The purpose of removing COD is to protect water quality, prevent water pollution, and protect ecosystems and human health. Typically, the following types of wastewater require COD removal:

Industrial wastewater:

Industrial production may produce wastewater with large amounts of organic compounds. These wastewaters usually contain high COD. For example, chemical factories, pharmaceutical factories, textile factories, etc.

Urban domestic sewage:

Domestic sewage from urban residents and commercial areas, including domestic water, wastewater from commercial and office areas, usually also contains certain organic matter, and COD needs to be removed to comply with emission standards.

Agricultural wastewater:

Agricultural activities, especially in the process of breeding and farmland irrigation, will produce wastewater containing organic matter, such as animal and plant residues, pesticides, chemical fertilizers, etc.

Food processing wastewater:

Wastewater generated during the production process of food processing plants, including wastewater generated during food production, processing and cleaning, usually contains large amounts of organic matter.

Brewing wastewater:

The wastewater generated during the brewing process contains a large amount of organic matter and needs to be treated to reduce the COD concentration.

Tannery wastewater:

In the tannery industry, wastewater contains organic matter such as degreasing agents, dyes, and tanning agents.

Textile printing and dyeing wastewater:

Dyes, auxiliaries and other chemicals used in the textile and printing and dyeing industries often contain large amounts of organic matter in wastewater.

So what method can be used to effectively remove COD from sewage? Biochemical treatment method is a common and effective method to remove COD from water bodies. The following are several commonly used biochemical treatment methods:

Activated sludge method:

This is a common biochemical treatment method that mixes wastewater with a contact tank with activated sludge. The microorganisms in the activated sludge will decompose organic matter in the wastewater, thereby reducing the COD concentration. The treated water passes through the sedimentation tank to separate the waste sludge to achieve the purpose of purifying water quality.

Biological filter method:

Pass the wastewater through the filler layer, and the microorganisms in the biofilm attached to the filler will degrade organic matter and reduce the COD concentration. Biological filters usually include fillers such as sand, stone, and biological filter materials. The fillers provide a large surface area for microbial growth and accelerate the degradation of organic matter in wastewater.

Aeration method:

Oxygen is added to the aeration tank mechanically or naturally to promote the microorganisms in the wastewater to metabolize organic matter, thereby reducing the COD concentration. The aeration method is usually used in conjunction with the activated sludge method or the biological filter method.

Biofilm Reactor (MBR):

MBR combines biological treatment and membrane separation technology to degrade organic matter through microorganisms, and then uses a membrane filtration system to separate the biological volume and pollutants, thereby improving the removal efficiency of COD.

Biological contact oxidation method: Fully contact the wastewater with the biological system. Under oxidation conditions, microorganisms degrade the organic matter in the wastewater and reduce the COD concentration.