The problem of COD (Chemical Oxygen Demand) exceeding the standard in evaporator condensate is a common and complex issue in wastewater treatment, and its causes and solutions can be explored from multiple aspects.

      1、 Reasons for Excessive COD in Evaporator Condensed Water

      1. Raw water composition: The main reason for the COD exceeding the standard in the condensed water of the evaporator is that the raw water contains organic components with low boiling points or similar boiling points to water. These organic components evaporate when heated during the evaporation process, and then condense into the condensate with water vapor, resulting in an increase in COD.

      2. Working principle of evaporator: The evaporator vaporizes wastewater by heating it, but not all organic matter can be completely decomposed or removed at high temperatures. Some low boiling point organic compounds will condense together with water vapor, thereby increasing the COD content in the condensed water.

      3. Operating conditions: The operating conditions of the evaporator, such as temperature, pressure, evaporation rate, etc., can also affect the COD content in the condensate water. Inappropriate operating conditions may lead to incomplete volatilization of organic matter or an increase in organic matter content in condensed water.

      2、 Solution

      To address the issue of COD exceeding the standard in the condensate water of the evaporator, the following solutions can be taken:

1. Optimize the evaporator design:

      Improve the evaporator structure, enhance evaporation efficiency, and reduce organic matter volatilization.

      Adopting multi-stage evaporation or combined evaporation technology to improve the removal rate of organic matter.

2. Preprocessing:

      Pre treatment such as coagulation sedimentation, adsorption, oxidation, etc. should be carried out before the wastewater enters the evaporator to reduce the content of organic matter in the wastewater.

      Select appropriate pretreatment processes based on the characteristics of wastewater from different industries to improve the biodegradability of wastewater.

3. Strengthen operational management:

      Strictly control the operating conditions of the evaporator, such as temperature, pressure, etc., to ensure that it operates under optimal conditions.

      Regularly clean and maintain the evaporator to prevent scaling and blockage, which can affect evaporation efficiency.

4. Deep Processing:

      For situations where COD in condensate water exceeds the standard severely, advanced treatment techniques such as activated carbon adsorption and reverse osmosis membrane separation can be used to further reduce COD content.

      Select appropriate deep treatment processes and equipment based on the composition and characteristics of COD in condensate water.

5. Resource utilization:

      Explore the resource utilization of condensate water, such as reusing treated condensate water for production or as water for other processes, to achieve the recycling of wastewater.

6. Comprehensive governance:

      Based on the actual situation of the enterprise, develop a comprehensive management plan to strengthen wastewater management throughout the entire process from source control, process management to end of pipe treatment.

      Strengthen environmental protection publicity and education, enhance employees' environmental awareness, and jointly promote the development of environmental protection work in enterprises.

      To solve the problem of COD exceeding the standard in evaporator condensate water, it is necessary to comprehensively consider multiple factors and take comprehensive measures for treatment. By optimizing evaporator design, strengthening pretreatment, enhancing operational management, deep treatment, and resource utilization, the COD content in condensed water can be effectively reduced, achieving standard discharge and resource utilization of wastewater.