How Remote Monitoring Can Improve Water Treatment Management

Key monitoring points and sensors for water treatment and wastewater processing systems include:

• Disinfectant (alkalinity sensor, pH sensor, turbidity sensor);
• Clarifier (sludge-level sensor, chlorine sensor, oxidation-reduction potential sensor);
• Pumps (vibration sensor, pressure sensor, current amperage, run times); and
• Motor/generators (voltage sensor, flow rate sensor, vibration sensor).

3. Evaluate Relevant Types of Condition Monitoring

Let’s take a closer look at a few examples of condition monitoring important for water treatment systems.

Vibration. Every rotating machine has its own vibration characteristics, and when a part starts going bad, those characteristics change. For example, if the seals or bearings on a pump begin to fail or if an impeller breaks, vibrating increases. Although this change would not be noticeable to the human eye or ear, it is easily detected by a vibration sensor installed on the pump. The sensor reads the pump’s acoustics to detect imbalances, providing early warning of issues arising within the pump.

Each vibration sensor communicates its frequency readings in real time to the remote monitoring system, which sends an alert when an out-of-limit value is detected. This gives operators time to take the action required to prevent catastrophic failure, secondary damage, and operational downtime.

When vibration sensors are integrated into the monitoring system, they capture vibration readings at set time intervals, which users can view in real time and/or analyze over a longer period to identify trends that indicate a failure is imminent.

Pressure. Monitoring pressure is a way to understand the characteristics of the pump and increase its life cycle. The greater the flow, the less pressure there will be on the discharge. Low flow will show a higher pressure on the discharge. Pressure sensors help to identify key problems that can prevent the pump from running within its best efficiency point. Ideally, a pump should not operate at flows plus or minus 10% of its efficiency point.

When a pump is not running at its best efficiency point, the motor temperature rises, placing stress on bearings, seals, and impellers, which reduces their service life. All this can lead to premature failure of the pumping system. A pressure sensor on the suction side, where the difference in pressure is proportional to the total head, as well as pressure sensors on both sides of the pump, are recommended.

In addition, pressure sensors monitor pump discharge, so they can alert if a pump shuts down for a long period of time or pressure drops from lack of suction. Pressure alarms let personnel take action to prevent the pumps from running dry if they lose suction for any reason.

In wastewater applications, submersible pumps are typically placed at the bottom of lift station storage tanks to pump suspended solids, sewage, and refuse. Pressure sensors can identify blockages and flooding so that operators can turn on additional pumps during flooding, equalize wear on pumps, and turn pumps off when tanks are low.

Current amperage and voltage. Remote monitoring systems can easily monitor for power failures, which obviously stop pumps and other equipment from running altogether. Taking this a step further by continually monitoring the pump’s motor current can help to determine if there is a hidden problem. A pump running at overcurrent for a long period of time, even by small amounts of 5% to 10% of its rating, will ultimately overheat, damaging internal components and causing the pump to prematurely fail. Bad or failing bearings, clogged lines, or material jammed within the pump can also cause an overcurrent problem.

Reduced flow caused by a blockage can cause an undercurrent situation. In an overvoltage situation, the current can increase and cause motor temperatures to run higher when the load decreases, causing a surge in voltage to the pump’s motor. Similarly, if the voltage sags under heavier loads, the motor can suffer from a low-voltage state, which will increase the motor’s current.