What is COD?
Chemical Oxygen Demand (COD) is the amount of the amount of oxygen that is needed to oxidize soluble and particulate organic matter in water.
COD is an extremely important element of water quality. It helps to assess the effect that wastewater will have on the environment that it’s being released into. When the COD levels are higher, there is a greater demand for oxygen. This means that there is likely more oxidizable organic material in water with high COD levels. This also means that there are reduced Dissolved Oxygen (DO) concentrations in wastewater with high COD levels. A Low concentration of Dissolved Oxygen is harmful life forms which oxygen to live. Therefore it’s best to reduce COD levels, thus increasing DO concentrations, in wastewater before releasing it.
How to Reduce COD in Wastewater
Luckily, there are several ways to reduce COD. One way to reduce COD in water is to use coagulants and flocculants to bind sludge together. Once they are bound into big enough masses that they can be easily filtered out and deposited into a sedimentation tank for removal. This method does however rely on the use of chemicals, and requires high reoccurring cost.
It is also possible to use biology to reduce COD and thus promote BO levels. More specifically, utilizing certain types of bacteria can reduce COD. To do this you must first aerate the wastewater in order to provide an environment in which the bacteria can live. Aeration provides oxygen to the bacteria. The bacteria can treat and stabilize the wastewater without the use of chemicals. Moving Bed Bio Reactors utilize this bacteria process in order to clean wastewater. If you are wondering if this process is right for treating your wastewater please reach out to us and we will provide complimentary consultation.
COD can be found in the wastewater of landfills, the food and beverage industry, the diary industry and more. Visit our Case Studies page if you are interested in industry specific solutions.
Here is a sneak peek of what you will find:
- Vineyard Reduced COD <90% for water reuse & vine irrigation.
- Centralized Industrial Treatment installed a bioFAS MBBR biological treatment process designed for COD reduction to meet compliance and continue to allow discharging to the local municipality.