Water Treatment Plant Electrical Control Model

Industrial water treatment plants move raw water through a chain of stages — coagulation, flocculation, sedimentation, filtration and disinfection — and every stage depends on its electrical control: pumps must start and stop in the right order, tanks must not overflow or run dry, and chemical dosing must follow a schedule. Manual operation invites dry running, overflows and inconsistent dosing, which is why real plants are run from PLC-based control panels with motor protection, level interlocks and alarms. Electrical engineering students study these panels in theory but rarely wire and commission one. This project closes that gap with a tabletop working model: transparent stage tanks with real pumps, float switches and a wired control panel demonstrating sequencing, level control, timed dosing and protection.

1. The raw-water pump fills the flocculation tank; its float switch stops the pump at high level and restarts it at low level.
2. The dosing pump injects a measured dose on a timer cycle while the agitator motor mixes the tank for a preset time.
3. Settled water overflows by gravity into the sedimentation tank model; the transfer pump moves it to the filter bed on level demand.
4. The filtered-water pump delivers clear water to the storage tank only when the filter-bed level is healthy, with interlocks preventing dry running.
5. A backwash timer periodically reverses the flow path through the filter bed to flush trapped sediment, demonstrating maintenance cycles.
6. Any overload trip or overflow condition latches an alarm: the stage lamp turns red and the hooter sounds until the fault is acknowledged and reset.

Tech stack:

• PLC / relay logic: ladder-programmed PLC (Siemens S7-1200 class) or timer-relay panel
• Single-phase pumps for each transfer stage
• Float switches for level sensing
• Contactors, MCB, thermal overload relays
• Push buttons, selector switches, indicator lamps, hooter
• Peristaltic dosing pump with timer
• Transparent acrylic tanks and PVC piping (model hydraulics)

• [Automatic pump sequencing] PLC/timer-relay logic starts the raw-water, transfer and filtered-water pumps in the correct order with interlocks, so a downstream pump cannot start against a dry suction.
• [Float-switch level control] Float switches in each tank hold levels automatically — pumps start on low level and stop on high level without manual intervention.
• [Dosing pump timer control] A peristaltic dosing pump runs on an adjustable timer cycle to demonstrate timed chemical dosing into the flocculation tank.
• [Motor protection wiring] Each pump circuit is wired through an MCB and a thermal overload relay, demonstrating standard industrial motor protection practice.
• [Panel indication and alarms] Indicator lamps show running/stopped/tripped status per stage; a hooter sounds on overload trip or tank overflow.
• [Manual / auto selector] A selector switch per stage lets the operator run the model in manual mode for demonstration or automatic mode for unattended sequencing.
• [Backwash cycle demonstration] A timed valve-and-pump sequence reverses flow through the filter bed model to demonstrate filter backwashing.

• Working tabletop treatment-plant control model with wired panel
• PLC ladder program (or relay wiring schedule) source files
• Panel wiring diagram and component layout drawing
• Complete component list with ratings
• Project report PDF (background, control logic, protection, testing procedure)
• PPT presentation for final review
• Viva Q&A preparation document (PLC logic, motor protection, level control)
• Setup and demonstration guide

• Demonstration model at tabletop scale — piping, flows and timings are illustrative, not sized to a real plant.
• Water is recirculated for demonstration; the model does not produce potable water and is not a certified treatment device.
• Pump duty is light; running the model dry or continuously for long hours can overheat the pumps.
• Float-switch positions need careful setting during commissioning — the setup guide covers this.
• Timer-based dosing approximates chemical dosing; real plants use flow-paced dosing with analyzers.