How to Reduce COD in Wastewater
By: WebFx
Post Date: August 26th 2024
How to Reduce COD in Wastewater
Chemical oxygen demand is one indicator of wastewater quality. It’s an essential measurement for anyone working in industrial wastewater processing — without knowing COD levels, you could harm the environment or the public with improperly treated water. Understanding wastewater’s COD and how to treat it will reduce pollutants in wastewater. The right treatments ensure you correctly dispose of wastewater while protecting the environment.
What Is Chemical Oxygen Demand?
COD measures the amount of oxygen needed to break down organic matter in wastewater. The higher the COD value, the higher the water’s concentration of pollutants, since there needs to be more oxygen to oxidize everything. Facilities can measure the water’s COD level by adding an oxidizing agent to water samples under acidic conditions. The resulting reaction lets teams measure the oxygen amount consumed to get the COD.
Why Test for High Levels of COD?
Testing COD levels is essential for ensuring a facility’s wastewater has limited pollutant levels. Higher COD levels mean more pollution, which can drain oxygen from water bodies. Water with minimal oxygen cannot support aquatic organisms. Sending wastewater into these ecosystems can lead to ecosystem disruption and organism death. Testing for high COD levels protects the environment from wastewater pollutants.
Regular COD testing lets operations identify pollution levels and sources, like sewage leaks or industrial discharge. Once they know pollutant concentrations, they can intervene early, before high COD wastewater damages ecosystems. Additionally, monitoring COD levels ensures wastewater treatment processes are effective. Facilities stay compliant with regulatory standards while protecting public health and the environment.
Chemical Oxygen Demand vs. Biochemical Oxygen Demand
Biochemical oxygen demand is also a measure of oxygen consumption potential in wastewater. However, it measures differently and covers a slightly different area than COD. COD measures the total oxygen needed to chemically oxidize material in water. On the other hand, BOD measures the dissolved oxygen consumed by microorganisms in a set period. Like COD, high BOD means water has its oxygen depleted too quickly, suffocating the organisms that depend on it to survive.
BOD tests take several days to complete since they measure microorganism activity. COD tests take less time and can capture a broader range of pollutants. BOD testing provides insight into the biodegradable portion of wastewater. Use COD and BOD testing together to get a complete picture of water quality and pollution levels.
How to Reduce COD Through Wastewater Treatment
Sewage treatment plants and other industries that produce wastewater should invest in COD reduction to stay compliant and protect environmental health. With the right methods, it’s easier to control COD levels in wastewater. With a range of products and methods on the market, it’s essential to get expert advice tailored to your needs. Understanding COD and wastewater treatment options allows each operation to customize their approach to the pollutants in their wastewater. Here are some of the most common techniques for COD removal through wastewater treatment:
1. Wastewater Separation
Separation methods like coagulation and flocculation are popular and highly effective wastewater treatment methods. These techniques reduce COD and remove suspended solids from wastewater.
- Coagulation involves adding things like ferric chloride or aluminum sulfate to wastewater. These materials make small particles clump up into larger formations.
- Flocculation follows coagulation. This process involves stirring these larger clumps into bigger groupings, which then get filtered out.
Coagulation and flocculation effectively remove a wide range of pollutants. Combining these methods with other treatments improves wastewater’s COD levels. However, this method requires careful control of the chemical dosing for success and proper disposal of any sludge produced.
2. Chemical Oxidation
Chemical oxidation uses strong oxidizing agents to reduce wastewater’s COD levels. Adding hydrogen peroxide, chlorine or ozone to water creates a reaction with inorganic and organic pollutants. These oxidizing agents break down pollutants into less harmful substances, protecting oxygen levels in the wastewater. This method is effective at rapidly reducing COD levels even in high pollutant loads. However, it’s more costly than other treatments and can produce hazardous byproducts that need additional treatment.
3. Activated Sludge
The activated sludge process is a biological treatment process instead of a chemical one. It uses microorganisms to decompose any organic matter in wastewater. With less organic material, you lower the COD levels. During this process, wastewater gets aerated in large tanks. Aeration grows aerobic bacteria, which eat organic pollutants. Once they’ve eaten the treated water, they produce activated sludge, which gets thrown out or recycled.
The activated sludge process is relatively affordable compared to chemical treatments. Additionally, it’s a highly efficient and sustainable option since it uses microorganisms to achieve its results. However, this method needs significant space, maintenance and condition control to ensure microbial activity and success.
4. Membrane Filtration
Membrane filtration techniques such as nanofiltration, ultrafiltration and reverse osmosis use semi-permeable membranes to separate wastewater from pollutants like suspended solids, organic molecules and other contaminants. However, membranes are often expensive and need regular cleaning or replacement to ensure filtration success.
5. Real-Time Monitoring
Real-time monitoring systems can help facilities stay on top of their COD levels. This technology uses sensors to constantly monitor COD for simple process adjustment as needed. While regular treatments are essential for controlling COD levels, real-time monitoring shows how effective they are. The earlier you can catch and correct high COD levels, the more time, money and resources you’ll save during the treatment process.
Expert Wastewater Treatment From SSI Aeration, Inc.
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Additionally, our expert field services team is ready to travel globally to inspect wastewater systems. Technicians check installation and performance, ensuring everything works optimally. From new aeration systems to retrofitting existing ones, field services teams make service quick, easy and accurate. With extensive checklists and a highly trained team, trust SSI Aeration to get wastewater treatment back in shape.
Choose SSI Aeration for unmatched technical capabilities and a 24/7 global service network. Let us help you achieve long-term, reliable performance for better wastewater treatment. Contact us for your custom quote online today!
