A variety of challenging chemicals are often needed to meet treatment goals for drinking or wastewater operations. Polymers with high viscosities are used for coagulation and flocculation. Similarly, caustic and abrasive chemicals such as sodium hydroxide or sulfuric acid may be added to adjust the pH of water. Even chlorine and other disinfectants can be caustic and dangerous to people and equipment.
Such chemicals can be difficult to meter accurately. Peristaltic metering pumps are most often used for caustic, abrasive, and viscous liquids. These pumps work by using a set of rollers to compress and release a flexible tube or hose, creating a peristaltic motion that moves the fluid through the tube. As a result, the chemical being metered never comes into contact with the mechanical components of the pump. Even with this advantage, many metering pumps can struggle with challenging liquids. Thankfully, there are technologies and techniques that can make metering such chemicals more manageable.