Laboratory practice in wastewater analysis: Which apparatus is used for evaporation and measurement of settlable solids in sewage?
Civil Engineering
Waste Water Engineering
Difficulty: Easy
Choose an option
-
Aa jar
-
Ba breaker
-
Ca test tube
-
Dan Imhoff cone
-
Ea graduated cylinder only
Answer
Correct Answer: an Imhoff cone
Explanation
Introduction / Context:
Settlable solids testing helps assess grit and heavier particulate fractions in wastewater primary treatment. The Imhoff cone is a standardized device for measuring the volume of settleable solids after a defined settling period.
Given Data / Assumptions:
- Objective: identify the correct apparatus for settlable solids measurement.
- Standard settling interval (typically 60 minutes) applies to Imhoff cone tests.
Concept / Approach:
The Imhoff cone is a clear, conical vessel graduated at the tip to read settled solids volume directly (e.g., mL/L). It is specifically designed for wastewater settleability tests.
Step-by-Step Solution:
Recognize the specific test—sewage settlable solids.Recall the conical, graduated apparatus used is the Imhoff cone.Select “an Imhoff cone.”Verification / Alternative check:
Wastewater lab manuals list the Imhoff cone method for primary settling performance checks.
Why Other Options Are Wrong:
- Jar / test tube / generic beaker (breaker): Not standardized for direct volume reading of settled solids in mL/L.
- Graduated cylinder only: Lacks the conical tip and standardized graduation for this test.
Common Pitfalls:
- Confusing jar tests for coagulation with settlable solids measurement.
Final Answer:
an Imhoff cone