Smart Secondary Supply Disinfection
Unattended pump-room retrofits: hypochlorite dosing with online residual chlorine/pH and remote alarms.
Challenges
Secondary water supply stores and boosts municipal water for high-rise buildings and residential estates. Long residence time in tanks lets residual chlorine decay, especially in summer, and poorly sealed or rarely cleaned tanks can see microbial growth and rising turbidity at the tap. Drinking-water standards set disinfectant residual requirements at the point of use, so secondary supply facilities are a critical control point.
Pump rooms are numerous, scattered and usually unattended. Manual inspections and periodic lab samples detect problems late, and poorly controlled disinfection either leaves too little residual or creates taste complaints from too much.
Our Approach
We recommend online monitoring, supplementary disinfection and remote management:
1. Online monitoring: residual chlorine and pH (plus turbidity if needed) at the tank outlet or booster discharge. The chlorine sensor uses a constant-flow cell for stable readings, with 4–20 mA or RS485 output.
2. Supplementary disinfection: when residual drops below setpoint, a metering pump adds sodium hypochlorite, or a chlorine dioxide unit is started. Dose follows supply flow with residual feedback to avoid large swings. Small pump rooms can use compact disinfection units combining tank, pump and controller.
3. Materials and safety: wetted parts resist oxidants and pump heads have degassing valves. Chlorine dioxide equipment needs ventilation and chemical storage as specified by the manufacturer, and qualified operators.
4. Remote management: readings and equipment status can be sent to the utility or property platform, with alarms for low residual, low tank level and faults, reducing site visits.
5. Maintenance: chlorine sensors need regular calibration and electrolyte or membrane replacement, and sample lines need cleaning. Online disinfection does not replace scheduled tank cleaning.
Please provide the number of pump rooms, supply flow per room, tank volume and residence time, current disinfection method, and power and communication availability so we can define monitoring points, disinfection method and equipment.
Practical notes: place the injection point at the tank outlet or around the booster pumps where mixing is good. Keep online and manual sampling points the same for easy comparison. Stop dosing during supply shutdowns to avoid local overdosing.