The term "stack" carries a familiar image in our minds – a towering structure of materials, often associated with industrial production. However, in the field of environmental and water treatment, "stack" takes on a broader meaning, signifying different approaches to tackling pollution and purifying water. Two distinct interpretations of this term deserve our attention:
1. Stack as a Vertical Conveyance Method:
This usage of "stack" refers to a vertical system designed to elevate and disperse pollutants into the atmosphere. It's commonly seen in industrial settings where airborne emissions are generated during manufacturing processes. Imagine a tall chimney, for instance, where smoke or gases from a factory are directed upwards and released into the air.
Key features:
Examples:
2. Stack as the Core of Electrodialysis:
In the realm of water treatment, "stack" takes on a different form. Here, it represents the key element of an electrodialysis unit. Electrodialysis is a membrane-based process used for desalination and purification of water, where salt ions are selectively removed. The "stack" in this context refers to a series of membrane cells arranged between two electrodes.
Key features:
Examples:
Conclusion:
The term "stack" in environmental and water treatment encompasses a variety of applications, highlighting the diverse and innovative methods used to address pollution and purify water. Whether it's a towering structure dispersing pollutants into the atmosphere or a layered assembly of membranes separating salts from water, the concept of "stack" stands as a testament to human ingenuity in tackling environmental challenges.
Instructions: Choose the best answer for each question.
1. Which of the following is NOT a key feature of a stack used as a vertical conveyance method?
a) Vertical structure
b) Horizontal dispersion
c) Emission control
d) Dilution of pollutants
2. What is the primary function of a stack in an industrial setting?
a) To collect and store industrial waste
b) To elevate and disperse pollutants into the atmosphere
c) To purify water for industrial use
d) To generate electricity from waste materials
3. Which of the following is NOT an example of an industrial application of a vertical conveyance stack?
a) Factory chimneys
b) Power plant stacks
c) Electrodialysis stacks
d) Incinerator stacks
4. What is the core element of an electrodialysis stack?
a) A series of filters
b) A vertical chimney
c) A collection of membrane cells
d) A large storage tank
5. Which of the following is NOT a potential application of electrodialysis stacks?
a) Desalination of seawater
b) Purification of industrial water
c) Removal of pollutants from the atmosphere
d) Demineralization of fruit juices
Scenario: You are tasked with designing a water treatment system for a small town. The town's water source is a nearby river, which is contaminated with a high concentration of dissolved salts.
Task:
**1. Electrodialysis would be appropriate because:**
**2. Key components of an electrodialysis stack:**
**3. Advantages and Disadvantages:**
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