In industrial production and daily life, wastewater treatment is a critical step for environmental protection and water resource recycling. Selecting the right chemicals not only improves treatment efficiency but also minimizes operational costs and reduces secondary pollution. So, which chemical agents deliver the best results in wastewater treatment?
1. Coagulants: Rapid Suspended Solids Removal
Coagulants are among the most widely used agents in wastewater treatment, primarily for removing suspended particles and colloidal substances. Common coagulants include:
- Polyaluminum Chloride (PAC): Strong adaptability, fast settling speed, suitable for various water qualities.
- Polyacrylamide (PAM): Available in cationic, anionic, and non-ionic types, allowing selection based on specific wastewater characteristics. Offers excellent flocculation performance.
Application Scenarios: Municipal sewage, industrial wastewater (e.g., papermaking, printing & dyeing, food processing).
2. Oxidants: Effective Organic Matter Degradation
When dosing oxidants, low concentrations should be applied first to ensure uniform mixing. For wastewater containing refractory organic compounds (e.g., chemical and pharmaceutical wastewater), oxidants can effectively break down pollutants. Common oxidants include:
- Sodium Hypochlorite (NaClO): Strong sterilization and disinfection capability, suitable for wastewater treatment in hospitals, swimming pools, and related facilities.
- Hydrogen Peroxide (H₂O₂): When combined with catalysts such as Fenton’s reagent, it effectively degrades toxic organic compounds.
- Ozone (O₃): High oxidation strength, no residual byproducts, ideal for high-concentration organic wastewater.
Application Scenarios: Chemical wastewater, pharmaceutical wastewater, landfill leachate.
3. pH Adjusters: Optimizing the Reaction Environment
The pH of wastewater directly affects treatment efficiency, making acid or alkali adjusters essential:
- Lime (Ca(OH)₂): Raises pH and promotes heavy metal precipitation.
- Sulfuric Acid (H₂SO₄) or Hydrochloric Acid (HCl): Lowers pH, suitable for alkaline wastewater.
Application Scenarios: Wastewater from electroplating, metallurgy, pickling, and related industries.
4. Biological Treatment Agents: Enhancing Microbial Degradation
In the biochemical treatment stage, nutrients or bio-enzymes can be added to boost microbial activity:
- Urea and Phosphates: Supply nitrogen and phosphorus nutrients, promoting activated sludge activity.
- Bio-enzyme Preparations: Accelerate organic matter decomposition and improve treatment efficiency.
Application Scenarios: Domestic sewage, food processing wastewater, aquaculture wastewater.
5. Heavy Metal Capture Agents: Deep Removal of Hazardous Ions
For industrial wastewater containing heavy metals such as lead, cadmium, and mercury, chelating agents can be used:
- DTC Reagents (Dithiocarbamate): Form stable precipitates with heavy metals.
- Sodium Sulfide (Na₂S): Produces metal sulfide precipitates with high removal efficiency.
Application Scenarios: Wastewater from electroplating, mining, and electronics industries.
Post time: Apr-20-2026
