How to Choose the Right Water Treatment Chemicals for High-COD Wastewater?

Chemical Oxygen Demand (COD) is a key indicator of organic pollution in wastewater. The higher the COD, the more organic pollutants are present — and the more challenging the treatment becomes.

Industries like printing and dyeing, pharmaceuticals, paper making, food processing, electroplating, and chemicals all face high-COD discharge issues. Relying on physical or biological methods alone is often not enough — chemical agents are essential for efficiency and compliance.

Let’s explore how to select the right chemicals for different types of high-COD wastewater.

Where Does COD Come From?

Each industry generates different types of organic pollutants:

-Food wastewater: sugars, proteins, fats

-Chemical wastewater: aromatic hydrocarbons, phenols, aldehydes

-Dyeing wastewater: dyes, surfactants, additives

-Pharmaceutical wastewater: antibiotics, solvents, high-toxicity organics

Understanding your COD sources is key to selecting the right treatment agents.

Recommended Chemicals for COD Reduction

-COD Degraders: Fast-acting for medium/high COD; ideal for pre-treatment and emergency cases

-Advanced Oxidants: Sodium hypochlorite, hydrogen peroxide, ozone — suitable for hard-to-degrade organics

-Coagulants/Flocculants: PAC, PAM, polyferric sulfate — assist in removing suspended organic matter

-Decolorizing Agents: Great for dyeing and paper wastewater with both color and COD

-Biological Nutrients/Enzymes: Enhance bio-system for long-term COD digestion

Key Selection Tips

✅ Identify your wastewater source and COD composition

✅ Consider pH, toxicity, color, and biodegradability

✅ Always conduct a lab test before bulk use

✅ Balance between chemical efficiency and operational cost

What Works in Real Projects?

From our experience:

       -A single coagulant is not enough for high-COD wastewater

      -COD degraders can cut 80% COD in some chemical industries

      -For complex-color wastewater, combining Decolorizing Agent + PFS + PAM gives excellent results

Final Advice

There is no one-size-fits-all chemical, but with proper testing and combinations, high-COD wastewater can be effectively managed at lower cost and higher reliability.

Contact us today for a free consultation or water test — we’ll tailor the best solution for your industry and wastewater profile.