Practical Example
Drinking Water Treatment Plant for a Town of 20,000 Inhabitants
Initial Situation
A town of around 20,000 people uses a nearby river as its drinking water source. Although the river provides sufficient water quantity year-round, water quality varies significantly due to rainfall events, agricultural activities, and seasonal changes.
Laboratory analyses identify three main challenges:
- elevated turbidity from suspended solids
- microbiological contamination from surface runoff
- seasonal pesticide pollution from agriculture
A treatment system must therefore ensure safe, stable, and economically sustainable drinking water production.
Step 1: Raw Water Assessment
A long-term monitoring program is established to understand seasonal variations and define treatment requirements.
Parameters include:
- turbidity
- microbiological indicators
- pesticide screening
- organic matter
- pH and conductivity
Result
The data confirms the need for a multi-stage treatment process:
- filtration for particles
- activated carbon for dissolved organics
- disinfection for microbiological safety
Step 2: Filtration
Rapid sand filtration is selected as the main particle removal step due to its reliability and suitability for fluctuating raw water quality.
The system is designed to:
- remove suspended solids
- reduce turbidity
- stabilize downstream processes
- operate reliably during peak loads
Backwashing is included for long-term performance stability.
Result
Most particulate matter is removed, producing stable and clear water for subsequent treatment stages.
Step 3: Activated Carbon
Granular activated carbon (GAC) is installed to treat dissolved organic contaminants that remain after filtration.
The system targets:
- pesticides and herbicides
- taste and odor compounds
- selected micropollutants
Result
Pesticide concentrations are significantly reduced, and water aesthetics (taste and odor) improve noticeably.
Step 4: Disinfection Concept
A multi-barrier disinfection strategy is implemented.
- UV disinfection ensures immediate inactivation of bacteria, viruses, and protozoa
- Low-dose chlorination provides residual protection in the distribution network
This combination ensures both plant-level safety and network-level protection.
Result
High microbiological safety is achieved throughout the entire supply system, from treatment plant to consumer.
Step 5: Monitoring and Operation
A continuous monitoring program is established to ensure stable long-term performance.
It includes:
- turbidity and microbiological control
- chlorine residual monitoring
- pesticide tracking
- filter and carbon performance checks
- operational inspections and maintenance
Result
The system operates reliably with consistent water quality and full regulatory compliance.
Final Outcome
The treatment plant delivers a robust multi-barrier system that ensures safe and reliable drinking water production.
Key results:
- effective particle removal
- strong reduction of pesticides and organics
- high microbiological safety
- improved taste and odor
- stable distribution system protection
- economically sustainable operation
- flexibility for future water quality changes
Key Takeaway
A successful drinking water treatment plant is not based on maximum technology, but on appropriate technology selection.
By combining filtration, activated carbon, and disinfection in a targeted way, the system efficiently addresses real water quality problems while maintaining operational and economic sustainability.