Engler

Engler Degrees: A Legacy of Viscosity Measurement in Environmental and Water Treatment

The term "Engler" in environmental and water treatment refers to a unit of measurement for viscosity, a crucial property in characterizing the flow behavior of fluids. It represents the Engler degree (°E), a unit named after the German chemist Carl Otto Engler, who devised the Engler viscometer in 1884.

What is Viscosity?

Viscosity describes a fluid's resistance to flow. Think of honey versus water. Honey has a high viscosity, meaning it flows slowly and resists movement, while water has a low viscosity, flowing easily. This property is vital in understanding how fluids behave in various processes, especially in environmental and water treatment applications.

The Engler Viscometer: A Historical Tool

The Engler viscometer utilizes a simple principle: it measures the time it takes for a specific volume of liquid to flow through a calibrated orifice under a specified pressure. The viscosity is then determined by comparing this time to the time it takes for the same volume of water to flow under the same conditions.

Engler Degrees: A Simple, Yet Limiting Measurement

Engler degrees are based on a relative scale, where water at 20°C has a viscosity of 1°E. Higher Engler degrees indicate higher viscosities. While the Engler viscometer was widely used historically, it has limitations. It is an empirical method that doesn't directly correlate to other viscosity units like centipoise (cP) or Pascal-second (Pa·s).

Modern Alternatives

Today, more accurate and standardized methods are used for viscosity measurements. The Saybolt Universal Seconds (SUS) and Kinematic Viscosity (cSt) units are prevalent in industry. These methods offer better precision and are more widely accepted internationally.

Engler Degrees in Practice

Despite the availability of more sophisticated methods, Engler degrees continue to be used in some specific applications, particularly in older industries and for historical reference.

Why is Viscosity Important in Environmental and Water Treatment?

Viscosity plays a critical role in various environmental and water treatment processes:

• Sludge handling: Viscosity influences the pumping and dewatering of sludge, affecting efficiency and cost.
• Filtration: High viscosity can hinder filtration processes, impacting the removal of impurities.
• Chemical mixing: Viscosity influences the mixing and distribution of chemicals used in water treatment.
• Biological processes: The viscosity of water can impact the growth and activity of microorganisms used in wastewater treatment.

Conclusion

The Engler degree, though a historical unit, still holds relevance in some niche applications within environmental and water treatment. Understanding its limitations and recognizing the advancements in viscosity measurement technology are crucial for ensuring accurate and efficient process control in this critical field.