Lesson Notes By Weeks and Term v4 - SHS 3
≈SUBSTRUCTURE AND SUPERSTRUCTURE
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≈SUBSTRUCTURE AND SUPERSTRUCTURE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Applied Technology
Class: SHS 3
Term: 1st Term
Week: 16
Grade code: 3.3.2.LI.5
Strand code: 3
Sub-strand code: 3
Content standard code: 3.3.2.CS.1
Indicator code: 3.3.2.LI.5
Theme: BUILDING CONSTRUCTION TECHNOLOGY
Subtheme: ≈SUBSTRUCTURE AND SUPERSTRUCTURE
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Welcome, future technicians and engineers! Today, we are looking at a critical part of every building that is often hidden but essential for our health and comfort: waste disposal systems. In Ghana, from the bustling streets of Accra to our quiet villages, managing waste properly is a major challenge. Improperly installed systems can lead to choked gutters, the spread of diseases like cholera and malaria, and an unpleasant environment for everyone. As building technologists, understanding the *correct order* or schedule of works for installing these systems is not just about passing an exam; it's about building safe, healthy, and durable homes and communities for our families and clients.
This topic focuses on the practical, step-by-step process of installation. Let's break down the core ideas first. A. Types of Waste: A Clear Distinction
In any building, we generate two main types of waste. It is crucial to handle them differently. Liquid Waste (Wastewater or Sewage): This is any waste in liquid form. In a house, it is further divided into: Blackwater: Water from the Water Closet (WC) that contains human excreta (faecal matter and urine). It is highly infectious. Greywater: Wastewater from kitchens, bathrooms (showers, wash-hand basins), and laundry. It is less contaminated than blackwater but still contains soap, detergents, grease, and food particles. Ghanaian Examples: Water from washing dishes after eating banku; soapy water from bathing; water used to flush a WC. Solid Waste (Refuse or Rubbish): This includes all non-liquid waste materials generated from a household or commercial building. Ghanaian Examples: Empty Voltic bottles and water sachets; leftover kenkey and fish wrappings; yam peels; old newspapers; broken plastic chairs. B. Components of a Liquid Waste Disposal System
Before we discuss the installation sequence, let's understand the parts we are installing. Sanitary Appliances: These are the fixtures you use. Examples: Water Closet (WC), sink, shower tray, wash-hand basin. Pipes: Soil Pipe: A large diameter pipe (usually 100mm or 4 inches) that carries blackwater from the WC. Waste Pipe: A smaller diameter pipe (usually 32mm-50mm) that carries greywater from sinks, showers, etc. Drain Pipes: The underground horizontal pipes that collect waste from all soil and waste pipes and carry it to the disposal point. They are typically made of PVC (Polyvinyl Chloride). Traps: A U-shaped or S-shaped bend in a pipe located just after the drain outlet of an appliance (e.g., under your sink). Purpose: It holds a small amount of water, creating a "water seal" that prevents foul-smelling and dangerous sewer gases from entering the building. Manhole / Inspection Chamber: A covered chamber built underground, providing access to the drain line. Purpose: Allows for inspection, cleaning, and removing blockages. It is also built wherever a drain changes direction, gradient, or joins another drain line. Septic Tank: A large, underground, watertight chamber where solid waste settles and is broken down by anaerobic bacteria (bacteria that don't need oxygen). The liquid part (effluent) then flows out for further treatment. Soakaway (or Soak Pit): A pit filled with hardcore (broken rocks and stones) into which the liquid effluent from the septic tank is discharged. The water then gradually "soaks away" into the surrounding soil, which filters it naturally. C. The Schedule of Works for a Liquid Waste System (Drainage)
This is the most critical part of our lesson. The work must be done in a specific order for the system to function correctly and avoid costly repairs later.