The Removal Rate of COD in Evaporation Process

The COD (Chemical Oxygen Demand) level in wastewater is mainly determined by the concentration and characteristics of organic compounds present in the wastewater. During the evaporation process, organic substances may behave differently depending on their volatility and boiling characteristics.

• For high-boiling-point organic compounds

They tend to remain in the concentrated solution and are discharged together with salts through the solid waste or liquid waste stream. As a result, the COD concentration in the evaporated condensate can be significantly reduced.

• For low-boiling-point organic compounds

They may evaporate together with water vapor and enter the condensate system. In this case, the COD removal efficiency of the evaporation process may be limited, and the COD level in the condensate may not decrease significantly.

Therefore, the COD removal rate during evaporation is highly dependent on the specific composition, concentration, and properties of the organic compounds contained in the wastewater. If detailed information regarding the type and content of organic matter is available, a preliminary assessment of COD removal performance can be conducted. However, the most reliable method is to perform an evaporation test to evaluate the actual COD removal efficiency under simulated operating conditions.

At Enchem Technology, an evaporation test is always conducted to simulate the actual wastewater evaporation process before the design and manufacture of an evaporator system. This ensures that the final system design is technically reliable, economically optimized, and tailored to the specific wastewater characteristics.

The evaporation test typically includes the following evaluations:

1. pH value of wastewater

The wastewater pH is evaluated, and neutralization is recommended when necessary to improve compatibility with construction materials and reduce corrosion risks.

2. Specific gravity of wastewater

The wastewater density is measured, which is an important parameter for selecting suitable pumps and determining the hydraulic design of the evaporator system.

3. Boiling point evaluation under atmospheric and vacuum conditions

The boiling characteristics of wastewater are tested under different pressure conditions to determine suitable evaporation operating parameters.

4. Concentration behavior observation

The physical characteristics of wastewater at different concentration levels are observed, including viscosity changes, crystallization behavior, and potential scaling risks.

5. Condensate quality analysis

The quality of the evaporated condensate is analyzed to determine the appropriate material selection and design requirements for the condensate recovery system.

Based on the experimental results, Enchem Technology can design and manufacture a customized evaporator system with optimized performance, reliable operation, and maximum treatment efficiency for each specific wastewater application.