Indonesia Water Treatment Plant Automation | SENTRADO
A detailed case study of SENTRADO's industrial automation solution delivering measurable results for water treatment operations in Indonesia.
Project Background & Objectives
A regional water utility in Indonesia commissioned SENTRADO to modernize the automation systems at their primary water treatment plant, which supplies potable water to over 500,000 residents across multiple municipalities. The aging infrastructure, originally installed in the early 2000s, relied on manual monitoring and local control loops that required constant on-site operator attention and could not respond quickly to changes in raw water quality or demand patterns.
The treatment process includes raw water intake, pre-chlorination, coagulation and flocculation, sedimentation, rapid sand filtration, activated carbon adsorption, pH correction, disinfection, and high-lift pumping to the distribution network. SENTRADO's challenge was to automate all of these stages while ensuring uninterrupted water supply throughout the modernization period — a mandate that affected public health and fire safety for the entire service area.
The project also needed to provide remote monitoring capability so that utility management could oversee plant operations from their central office, reducing the need for 24-hour on-site staffing at the treatment facility while maintaining rigorous water quality standards.
Problems We Had to Solve
1. Aging Manual Infrastructure
The original plant used analog panel meters, manual valve operation, and local single-loop controllers. Operators physically walked the plant every two hours to read instruments and adjust settings, resulting in delayed responses to water quality fluctuations and inconsistent treatment performance.
2. Continuous Supply Mandate
Water treatment is a 24/7 operation that cannot be interrupted. The modernization had to be completed while maintaining treated water production at design capacity, with no degradation in water quality during the transition period.
3. Variable Raw Water Quality
Surface water from the source river experiences significant seasonal variations in turbidity, pH, and organic content — especially during monsoon season. The existing manual chemical dosing system could not react fast enough, occasionally producing water that barely met regulatory standards.
4. High Energy Costs
The high-lift pumps operated at fixed speed with throttle valve control, wasting significant energy during low-demand periods. The utility wanted VFD control to match pump output to actual distribution demand.
5. Remote Monitoring Gap
Without SCADA, utility management had no real-time visibility into plant status. Operational decisions were based on daily paper reports, delaying response to abnormal conditions and making performance optimization difficult.
Our Approach & System Architecture
SENTRADO implemented a modern PLC-based SCADA system centered on a Siemens S7-1500 controller with ET 200SP distributed I/O stations located throughout the plant. The control network uses PROFINET with managed switches, and all field instruments were upgraded to smart transmitters with HART communication for remote diagnostics and calibration. The system automates chemical dosing based on streaming current detector (SCD) feedback for coagulant dosage, residual chlorine analyzers for disinfection control, and pH analyzers for acid/caustic dosing.
VFD panels were installed on all six high-lift pumps and four backwash pumps, enabling variable-speed operation controlled by the PLC based on distribution system pressure setpoints and clearwell level. This eliminates the energy waste from throttle-valve control and provides soft starting that reduces mechanical stress on pumps and piping. The pump optimization algorithm rotates lead/lag assignments to equalize wear and automatically stages pumps based on demand.
The WinCC SCADA system provides a complete graphical overview of the treatment process with real-time trending, alarm management, and automated regulatory reports. A secure web-based remote access portal allows authorized personnel to view plant status, acknowledge alarms, and adjust setpoints from any location using two-factor authentication. The system includes automated filter backwash sequencing based on headloss and turbidity breakthrough, optimizing wash water consumption while maintaining filter performance.
System Architecture Highlights
- Siemens S7-1500 controller with ET 200SP distributed I/O
- Automated chemical dosing with SCD and residual chlorine feedback
- VFD control on all 10 pumps with pressure-based speed regulation
- Smart HART transmitters for remote diagnostics and calibration
- WinCC SCADA with web-based remote access and 2FA security
- Automated filter backwash sequencing based on headloss/turbidity
- PROFINET control network with managed switches
- Automated regulatory compliance reporting
System Parameters & Configuration
| Control System | Siemens SIMATIC S7-1500 |
| Controller | 1 × CPU 1515-2 PN |
| Total I/O Points | 680+ (AI: 120, AO: 40, DI: 380, DO: 140) |
| Communication Protocol | PROFINET / HART / Modbus TCP |
| HMI / SCADA | WinCC RT Advanced — 2 OS + Web client |
| Control Cabinets | 4 × IP54 with cooling |
| VFD Panels | 10 × ABB ACS580 (7.5kW–132kW) |
| Pump Control | 6 high-lift + 4 backwash with VFD |
| Power Range | 400V 3-phase, 50Hz |
| Remote Access | Secure web portal with 2FA |
| Chemical Dosing | Automated coagulant, chlorine, pH control |
| System Availability | 99.5% |
Key Components & Hardware
Siemens CPU 1515-2 PN
6ES7515-2AM01-0AB0
Main plant controller
ET 200SP I/O
6ES7155-6AU01-0BN0
Distributed I/O stations
WinCC RT Advanced
6AV2104-0DA06-0AA0
SCADA with web navigator
ABB ACS580 VFD
3ABD00036842-D
Variable frequency drive for pumps
SITRANS LUT400
7ML5050-0AA22-1DA0
Ultrasonic level for clearwell
SITRANS P220
7MF0300-1TE01-5AF2
Pressure transmitter for pump control
SCALANCE XC216
6GK5216-0BA00-2AC2
Managed PROFINET switch
HACH CL17 Analyzer
8572100
Online residual chlorine analyzer
Project Phases
Detailed Design
4 weeksI/O list, control philosophy, network design
Panel Manufacturing
4 weeks4 control + 10 VFD panels built and tested
Software Development
6 weeksPLC, SCADA, dosing algorithms, reports
FAT
1 weekFull simulation with utility engineers
Phased Installation
6 weeksInstall alongside old system, area by area
Commissioning
4 weeksWet testing, loop tuning, VFD optimization
Training & Handover
2 weeksOperator training, documentation, SAT
Measurable Outcomes
Performance data verified after system commissioning and sustained operation.
Continuous automated operation
Remote monitoring reduced on-site staffing
VFD pump control optimization
Automated dosing precision
Before vs After: Quantified Comparison
| Metric | Before | After | Change |
|---|---|---|---|
| System uptime | ~95% (manual intervention) | 99.5% automated | +4.5 pts |
| On-site operators | Full shift crew (8+) | 50% reduction via remote monitoring | −50% |
| Energy consumption | Baseline (fixed-speed pumps) | 25% savings via VFD control | −25% |
| Chemical dosing | Manual, imprecise | 30% less chemical via auto-dosing | −30% |
| Response to alarms | 30+ minutes | Instant remote alerts | Real-time |
Data based on project commissioning reports and sustained operational measurements. Client name available under NDA.
Bottom Line Impact
The delivered automation system exceeded all performance targets specified in the contract, achieving higher throughput, lower energy consumption, and improved product quality compared to the baseline operation. The client reported full return on investment within the projected payback period and has since engaged SENTRADO for additional plant expansion phases.
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