The Importance of Understanding BOD and COD in Wastewater

Knowing BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) in wastewater is crucial as they are key parameters for assessing the level of organic pollution and the efficiency of wastewater treatment processes. Below are the reasons why BOD and COD are essential:

1. Measuring Organic Pollution Load

• BOD is the amount of oxygen required by microorganisms to biologically degrade organic matter in wastewater. Higher BOD and COD levels indicate a greater amount of organic matter needing decomposition, signifying higher pollution levels.

• COD is the total oxygen demand to chemically oxidize organic matter (both biodegradable and non-biodegradable) in wastewater. It provides an overall picture of the organic content.

2. Evaluating Wastewater Treatment Efficiency

• BOD and COD measurements before and after treatment help determine the effectiveness of wastewater treatment processes in reducing organic content.

• The BOD/COD ratio indicates the biodegradability of organic matter in wastewater. A high ratio (e.g., >0.4) suggests that the organic matter is more easily biodegradable.

3. Environmental Impact

• Wastewater with high BOD and COD levels discharged into water bodies can lead to reduced dissolved oxygen levels, disrupting aquatic life and triggering eutrophication (water pollution caused by excess nutrients and minerals).

• Measuring these parameters ensures wastewater complies with environmental standards before being discharged.

4. Regulatory Compliance

• In Indonesia, BOD and COD limits for domestic wastewater are regulated under Minister of Environment and Forestry Regulation No. 68 of 2016, industrial wastewater under Minister of Environment and Forestry Regulation No. 5 of 2014, and recycling under Government Regulation No. 22 of 2021. Adhering to these standards is mandatory to ensure effluent meets environmental quality benchmarks.

5. Planning and Optimizing Treatment Systems

• BOD and COD data are used to design wastewater treatment systems, such as selecting the most appropriate process (biological or chemical).

Conclusion

BOD and COD are key indicators of wastewater quality that help monitor, control, and mitigate pollution's impact on the environment. Measuring these parameters is an essential step in managing liquid waste, particularly for industries producing wastewater with high organic loads.