In contemporary water treatment facilities, adding chemical agents is an essential process to ensure that treated water complies with quality standards. Whether using disinfectants for drinking water purification or applying coagulants and flocculants in wastewater treatment, the amount administered must be precisely regulated. Overdosing not only wastes chemicals but can also cause secondary pollution, while underdosing may compromise purification efficiency. To achieve such accuracy, metering pumps play a central role.
Working Principle of a Metering Pump
A metering pump delivers a controlled and consistent flow of liquid within a set time frame. Its operation is based on generating an exact change in the pump chamber's volume through a mechanical mechanism-commonly a plunger or diaphragm-which pushes the liquid forward. In most treatment plants, metering pumps are linked with real-time monitoring systems that automatically adjust the dosage based on parameters like turbidity, pH, or residual chlorine, enabling adaptive and precise chemical dosing.
Why Precision Matters
Different chemicals are introduced at various stages of treatment to remove impurities, neutralize pathogens, or stabilize water properties. Accurate dosing directly influences the treatment outcome and operational expenses:
Flocculant Addition – Flocculants, such as polyaluminum chloride (PAC), cause fine particles to clump and settle. Too much increases sludge generation, while too little weakens sedimentation efficiency. Metering pumps maintain the ideal balance.
Disinfectant Injection – Sodium hypochlorite kills harmful microorganisms, but excessive amounts can form byproducts like chloroform, whereas insufficient levels can compromise water safety. Precise pump control minimizes these risks.
pH Regulation – Acids and bases are used to stabilize pH. Metering pumps ensure steady dosing to prevent abrupt quality fluctuations.
A 2024 International Water Association (IWA) survey found that treatment plants employing high-accuracy metering pumps reduced chemical consumption by 15%, lowered operating costs by 10%, and cut chemical waste emissions significantly.
Technical Advantages
Several features make metering pumps particularly well-suited for demanding water treatment applications:
Exceptional Accuracy – Advanced models combine frequency converters and integrated sensors to dynamically regulate dosage according to real-time water quality or flow rate. For instance, Prominent's Gamma X automatically optimizes dosing through continuous feedback.
Leak-Proof Construction – Multi-layer PTFE diaphragms prevent chemical leakage, safeguarding workers and the environment. Lewa's EcoFlow incorporates leak detection for additional safety.
Durable, Corrosion-Resistant Materials – Wetted components often use 316L stainless steel or PVC, withstanding acidic and alkaline environments and offering service lives of 15+ years.
Smart Control and Remote Access – IoT-enabled systems, such as Xylem's intelligent pump platform, allow remote operation, performance tracking, predictive maintenance, and reduced downtime.
These qualities ensure metering pumps can meet the operational challenges of water treatment plants and maintain stable, long-term performance.
Regulatory Compliance
Metering pumps in water treatment must conform to rigorous standards:
ISO 16301 – Defines testing and performance requirements for accurate dosing.
NSF/ANSI 61 – Certifies that materials are safe for potable water applications.
ATEX – Ensures safe use with flammable chemicals.
EHEDG Guidelines – Maintain hygienic design for drinking water processing.
As water management becomes increasingly data-driven, metering pumps are evolving toward greater automation, connectivity, and self-adjustment capabilities. Integrated with big data analysis, future pumps will enhance operational efficiency, reduce environmental impact, and further improve water treatment effectiveness.