Water purification at water works involves a combination of physical, biological, and chemical processes to make water safe for consumption. These methods work together to remove impurities and contaminants.
Water Purification Methods
Here's a breakdown of the key methods used in water treatment plants, based on the provided reference:
1. Physical Processes
These methods focus on the removal of particulate matter and other physical contaminants.
- Filtration: Water is passed through layers of materials such as sand, gravel, and charcoal to trap larger particles and sediments.
- Sedimentation: Water is held in large basins, allowing heavier particles to settle to the bottom.
- Distillation: Though less common in large waterworks due to cost, this process boils water and collects the steam, leaving impurities behind. Distillation is more common for niche applications.
2. Biological Processes
These methods use biological agents to remove organic matter.
- Sand Filters: Layers of sand and gravel allow microorganisms to consume organic pollutants as water slowly filters through.
- Active Carbon: This porous material adsorbs organic compounds and chlorine by-products, improving water taste and odor.
3. Chemical Processes
These methods use chemicals to disinfect water and remove dissolved substances.
- Flocculation: Chemicals like alum are added to the water, causing small particles to clump together into larger, heavier particles called "floc," making them easier to remove by settling or filtration.
- Chlorination: Chlorine is added to water to kill remaining bacteria, viruses, and other harmful microorganisms.
- Use of Ultraviolet Light: UV light is used as a final disinfection step, inactivating any remaining microorganisms by damaging their DNA.
Summary Table
| Process Type | Specific Methods | Purpose |
|---|---|---|
| Physical | Filtration, Sedimentation, Distillation | Removal of particulate matter and larger contaminants |
| Biological | Sand filters, Active carbon | Removal of organic pollutants and improving taste and odor |
| Chemical | Flocculation, Chlorination, UV Light | Disinfection and removal of dissolved substances and harmful microorganisms |
By combining these physical, biological, and chemical processes, water treatment plants ensure that water is safe, clean, and palatable for public use.
