Drinking Water Purification

As a crucial material in the field of water treatment, activated carbon boasts a well-developed pore structure and an enormous specific surface area. Due to its excellent adsorption performance, it plays an irreplaceable role in water treatment processes.

The main function of activated carbon in municipal water plant is adsorption, primarily removing organic pollutants, odor-causing substances, precursors of disinfection by-products, micropollutants (Such as pesticides and endocrine disruptors), and certain heavy metals from the water. Different types of activated carbon, due to variations in their physical form and characteristics, differ in their application locations, methods, and functionalities.

Activated carbon for water purification and treatment in water plants:

1. Powdered Activated Carbon： HNWPC Series, HNCPC Series
2. Granular Activated Carbon: HNCGC Series, HNWC Series, HNCGC-AW Series
3. Pellet Activated Carbon: HNC Series

1. Powdered Activated Carbon (PAC)

Composed of extremely fine carbon particles, PAC typically has a particle size of 10-100 µm, an exceptionally large specific surface area, and extremely rapid adsorption capacity.

- Application point & mode

- Dosing location: Used as an emergency or seasonal pre-treatment step. PAC is injected at the raw-water intake, before coagulation, or in the flocculation tank.

- Dosing method: PAC is slurried and metered continuously into the flow by dosing pumps. After thorough mixing it settles together with the floc in the sedimentation/clarification tank and is finally removed with the sludge.

- Principal uses & features

- Acute pollution incidents: When sudden taste-and-odor events occur (e.g., geosmin, algal blooms) or organic chemicals are spilled, PAC can be deployed within minutes as a "fire-brigade" measure.

- Taste-and-odor control: Highly efficient at removing earthy/musty or fishy odors caused by algal metabolites such as geosmin and 2-methylisoborneol.

- DBP precursor removal: Adsorbs natural organic matter that would otherwise react with chlorine to form trihalomethanes and other disinfection by-products.

2. Granular Activated Carbon (GAC)

Shape: Irregular, coal-like black granules with sieve sizes commonly ranging from 4-8, 8-16, 10-20, 8-30 mesh etc.

- Application point & mode

- Configuration: Used as a filter-adsorber medium packed in carbon canisters or GAC filters.

- Position: Installed after conventional treatment (coagulation, sedimentation, sand filtration) as a dedicated tertiary step, or it can replace sand in a dual-purpose GAC-sand filter.

- Principal uses & features

- Polishing removal: Provides continuous, stable removal of organics, color, and taste/odor compounds.

- Long-term adsorption: The fixed GAC bed supplies a permanent adsorption interface; pollutants are removed while water percolates, giving sustained performance.

- Bioregeneration: After some months the carbon surface becomes colonized by microorganisms, forming biological activated carbon (BAC). These microbes mineralize portions of the adsorbed organics, partially restoring adsorption capacity and extending GAC service life.

3. Extruded (Pelletized) Activated Carbon

Shape: Cylindrical pellets 1-4 mm in diameter produced by extruding powdered carbon with a binder.

- Application point & mode

- The usage method is the same as the GAC filled in the fixed bed adsorber or pressure filters.

- Their regular geometry and high mechanical strength make them especially suited to pressurized steel vessels.

- Principal uses & advantages

- Identical to GAC: Deep removal of organics, color, and odor.

- Specific benefits

- Low head loss: The uniform cylindrical shape creates a homogeneous bed with lower pressure drop and reduced pumping energy.

- High crush strength: Resists attrition during backwashing, generates minimal carbon fines, and has a longer operational life.

- Uniform packing: Easy to load evenly, eliminating channeling or short-circuiting often seen with irregular GAC.