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Discuss in detail, using notes and freehand sketches, three functional requirements of a wastewater treatment system suitable for the on-site treatment of sewage from a single house - Leaving Cert Construction Studies - Question 4 - 2008
Question 4
Discuss in detail, using notes and freehand sketches, three functional requirements of a wastewater treatment system suitable for the on-site treatment of sewage fro... show full transcript
Worked Solution & Example Answer:Discuss in detail, using notes and freehand sketches, three functional requirements of a wastewater treatment system suitable for the on-site treatment of sewage from a single house - Leaving Cert Construction Studies - Question 4 - 2008
Step 1
Discuss in detail, using notes and freehand sketches, three functional requirements of a wastewater treatment system suitable for the on-site treatment of sewage from a single house.
Answer
A suitable wastewater treatment system for a single house must have various functional requirements, including:
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Collection of All Wastewater: The system must efficiently gather all wastewater generated by the house, ensuring a direct connection from all plumbing fixtures.
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Separation of Suspended Solids and Gases: It is crucial that the system prevents suspended solids from entering the drainage system and facilitates the decomposition of organic matter while allowing gases to escape to prevent buildup and potential hazards.
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Adequate Capacity and Access: The treatment system should have sufficient capacity to handle peak flows of wastewater. Additionally, easy access for maintenance and inspection is required to ensure the longevity and functionality of the system.
Sketch: [Freehand sketch showing the layout of the treatment system with labels]
Step 2
Using notes and freehand sketches, show the plan of a typical on-site wastewater treatment system for a single house. Include three main dimensions in your sketch.
Answer
A typical plan for an on-site wastewater treatment system can be illustrated as follows:
- Septic Tank: Dimensions of at least 2.2m x 1m x 1m with two compartments.
- Percolation Area: Minimum size of 3m x 0.3m x 0.4m deep, sloping towards distribution boxes.
- Outlet Pipes: At least 100mm in diameter.
Sketch: [Freehand sketch of the system including tank, percolation area, and outlet pipes with dimensions labeled]
Step 3
Using notes and freehand sketches, describe one test that is carried out to determine if a site is suitable for an on-site treatment system.
Answer
One crucial test to assess site suitability is the Percolation Test. This involves the following steps:
- Dig a Test Hole: Size should be around 30cm x 30cm and approximately 40cm deep.
- Soak the Hole: Fill it with water to a level of 300mm and let it stand for about 24 hours to saturate the soil.
- Measure Drainage Time: After 24 hours, remove the water and measure how long it takes for the water level to drop by 25mm. This time indicates the percolation rate, which is crucial in determining suitability for effluent absorption.
Sketch: [Freehand sketch of test hole with water levels marked]