Lesson Notes By Weeks and Term v4 - SHS 3
Safety, Quality and the Environment
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Safety, Quality and the Environment
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Subject: Manufacturing Engineering
Class: SHS 3
Term: 2nd Term
Week: 6
Grade code: 2.3.3.LI.2
Strand code: 3
Sub-strand code: 3
Content standard code: 2.3.3.CS.1
Indicator code: 2.3.3.LI.2
Theme: Manufacturing Tools, Equipment and Processes
Subtheme: Safety, Quality and the Environment
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This lesson explores the critical relationship between manufacturing and our environment. In Ghana, manufacturing gives us essential products like processed foods (e.g., FanYogo, Ideal Milk), building materials (cement, roofing sheets), and clothing, while also creating jobs for many people. However, these activities can have serious consequences for our land, water, and air. From the smoke we see rising from factories in Tema to the plastic waste that chokes our gutters in Accra and Kumasi, the impact is all around us.
The core idea is that every manufacturing process is a system of inputs, processes, and outputs. Inputs: Raw materials, energy (electricity), water. Process: The transformation of inputs into products. Outputs: The desired product AND undesirable by-products (waste).
The environmental impact comes from how we get the inputs and what we do with the undesirable outputs. We will analyse this through three main areas mentioned in the indicator. A. Effect 1: Waste Generation and Disposal
Manufacturing processes are never 100% efficient. There will always be leftover materials or by-products. This is called industrial waste. We can classify it into three main types: Solid Waste: What it is: Any solid material discarded during manufacturing. This includes metal scraps, plastic off-cuts, wood shavings, fabric remnants, and packaging materials. Ghanaian Example: A furniture workshop in Accra produces large amounts of sawdust and wood off-cuts. A factory producing plastic bowls and chairs in the Free Zones enclave will have plastic trimmings and rejected products. Environmental Effect: Improper disposal leads to land pollution. These wastes are often dumped in landfills (like the Kpone Landfill Site) or burned in the open. Burning plastics releases toxic fumes (like dioxins) into the air, causing respiratory problems. Landfills can contaminate the soil and groundwater if not properly managed. Liquid Waste (Effluents): What it is: Wastewater from manufacturing processes, often containing harmful chemicals, dyes, oils, and heavy metals. Ghanaian Example: A textile factory in Akosombo might release wastewater containing chemical dyes directly into the Volta River. A fruit juice company like Blue Skies might release water used for washing fruits, which contains organic matter. Environmental Effect: This is a major cause of water pollution. Chemicals can kill fish and other aquatic life. They can make the water unsafe for drinking, farming, and recreation. The contamination of rivers like the Densu or the Odaw by industrial and domestic waste is a clear example of this danger. Gaseous Waste (Emissions): What it is: Gases, smoke, and fine particles released into the atmosphere from burning fuels or from chemical reactions in the factory. Ghanaian Example: The Tema Oil Refinery (TOR) releases smoke and gases like sulphur dioxide during its refining process. A steel manufacturing plant melts scrap metal, releasing thick smoke containing particulate matter. Environmental Effect: This causes air pollution. It can lead to acid rain, which damages crops and buildings. It contributes to climate change through the release of greenhouse gases like carbon dioxide (CO₂). For people living near these factories, it can cause asthma and other serious breathing problems. B. Effect 2: Power and Energy Consumption
All factories need energy to run machines, light the premises, and power processes. In Ghana, our electricity comes mainly from two sources: Hydroelectric Power: (e.g., Akosombo and Kpong Dams). Thermal Power: (e.g., plants in Takoradi and Tema that burn natural gas or crude oil).