Applied Science Unit 25: Water Quality

Unit 25: Water Quality Delivery guidance Water is essential for all life on the planet, whether plant, animal or human. Learners will be aware that access to water depends on the hydrological (water) cycle, in which water is constantly coming into contact with the air and the earth. As a consequence, the water we use in our everyday life is never pure: biological, chemical and physical materials are dissolved in it and/or carried by the flow. Issues with water quality can cause serious problems, so it is essential to monitor and control this quality. Conservation officers, environmental research technicians, environmental protection officers and others will apply many of the principles covered in this unit as part of their everyday role. Learners will study what is in our rivers, seas and drinking water, and how it has come to be there, either through the natural hydrological cycle or as a consequence of human activity. They will learn about the water footprint as a marker to gauge the water requirement for different activities and processes. They will consider the influences of factors such as pollution, eutrophication, acidification etc. on water quality and the aquatic habitat. They will have opportunities to participate in practical activities, involving water analysis in the field and in industry, recording results, interpreting data and suggesting improvements to an area of water. Learners will explore the measures that can be taken to reduce the impact of human activity on water quality and make efficient use of water through effective conservation and control. Use online and other resources to investigate policies and strategies in different areas which seek to conserve and control water usage and improve water quality. Make use of any contacts who are involved in areas such as environmental science, water analysis, water purification and waste water control. Where possible, give learners the opportunity to visit appropriate establishments (for example, those involved in water conservation and control, water analysis, water treatment and waste water management). Approaching the unit From other units, learners may have some appreciation of the importance of water to all living things on the planet, and the impact of shortages of water and/or water of poor quality. In Unit 2, they will have learned that the properties of water are very unusual for a molecule of its size. In this unit, learners will further explore the structure and bonding of water and the reasons for its anomalous behaviour. They will also investigate the distribution of water around our planet by the hydrological cycle (better known as the water cycle) and consider the effects of different factors on different processes within the cycle. They should understand how biological, chemical and physical factors influence water quality and aquatic species and realise that water can contain chemical substances, physical matter and biological material such as microorganisms. Learners will understand the need to monitor water quality to ensure effective water conservation and consumption control. Learning aim A is primarily concerned with three main areas: the structure, properties and uses of water; the hydrological cycle; and the water footprint. Learners will revisit some ideas from Unit 2 in relation to bonding in the water molecule, its structure and its ability to form hydrogen bonds. They will understand that the latter property gives rise to many of the anomalous properties of water, such as its high boiling point, high specific heat capacity and ability to dissolve numerous substances. Learners will further explore how these properties lead to a wide range of uses and applications. BTEC INTERNATIONAL APPLIED SCIENCE UNIT 25: WATER QUALITY Pearson BTEC International Level 3 Qualifications in Applied Science – Delivery Guide Issue 1 – May 2020 © Pearson Education Limited 2020 2 Learners will look at the water cycle, the processes involved and how these processes vary according to different climatic conditions and terrain. They will then consider the impact on the water cycle of human activity, such as the burning of fossil fuels and deforestation. Learners will also explore the concept of the water footprint and assess its effectiveness as a measure of the use of water in a range of activities and processes. Learning aim B looks at the factors – physical, chemical and biological – which can influence water quality and affect aquatic species. From other units and learning aim A, learners will understand that water can contain soluble substances, particulate matter and biological material such as microorganisms. From their knowledge of the water cycle, they will realise that this is due to various factors such as soil composition, plant/animal life and human activity. There are opportunities for practical activities involving water quality analysis, using a variety of biological, chemical and physical tests. These activities could form part of the learner’s investigation into the composition of naturally-occurring substances and what constitutes good water quality, in terms of potability and acceptability for marine and freshwater habitats. This can extend to investigation of potential pollutants and the impact of biological organisms, organic and inorganic chemicals and physical effects on water supplies and on aquatic and marine environments. Learners will understand the effects of acidity caused by increased levels of carbonic acid (e.g. on coral reefs) and the impact of eutrophication (due to intensive farming methods) on different ecosystems. Learning aim C is concerned with monitoring and reporting on water quality. There is a focus on practical activity, as learners must carry out sampling and testing in the field, over a period of time, as well as laboratory analysis of samples. They should be able to explain the principles behind and significance of biological tests (e.g. for populations of species), chemical tests (e.g. dissolved oxygen and pH) and physical tests (e.g. temperature and turbidity). They should also demonstrate the use of quantitative wet techniques (e.g. titration) and instrumentation techniques (e.g. spectroscopy or gas chromatography) to investigate water quality. A visit to an industrial or university laboratory may be beneficial. Learners must comply fully with health and safety requirements for sampling, testing and laboratory analysis. They must report their findings in a scientific format including: title, abstract, introduction, method, results, accuracy, discussion, conclusions, evaluation, references and bibliography. Learning aim D focuses on methods of water treatment and strategies to control and conserve. Learners will understand from the previous learning aims (and perhaps from other units) that water can contain biological, chemical and physical matter. To render it potable and safe for human consumption and use, water must go through treatment processes such as screening, filtration, pH correction and sanitisation. Learners should understand that there will be variations according to the terrain (e.g. hard or soft water areas), climatic conditions, water source (e.g. marine or freshwater) and local policies that seek to enhance health (e.g. addition of fluorine). They should appreciate that, once the water has been used, it is likely to contain more biological, chemical and physical matter than before, presenting a greater risk to the environment. Before it can be discharged into the water cycle (via waterways etc.), it must be treated again. Learners should understand why sewage discharged from households, businesses and industrial premises needs treatment that involves removal of debris and sediment, oxidation to facilitate microbial decomposition of organic matter, and removal of toxic chemicals e.g. nitrates and phosphates. Finally, learners should have opportunities to explore a range of measures designed to control and minimise the use of water. If possible, invite a visiting speaker from the local authority or relevant government department who is involved in promoting water conservation and can provide information and details about policy and regulations. BTEC INTERNATIONAL APPLIED SCIENCE UNIT 25: WATER QUALITY Pearson BTEC International Level 3 Qualifications in Applied Science – Delivery Guide Issue 1 – May 2020 © Pearson Education Limited 2020 3 Assessment model Learning aim Key content areas Recommended assessment approach A Understand the properties and uses of water A1 Structure, properties and use of water A2 The hydrological cycle A3 The water footprint A report that reviews a wide range of uses and applications of water, with explanation of its unique properties. The report should include an explanation of the hydrological cycle for the global distribution and recycling of water, with an assessment of the different factors that affect the balance of the processes involved. The report should also cover the use and evaluation of the water footprint concept for a range of products and users. B Understand how biological, chemical and physical factors influence water quality and aquatic species B1 Factors affecting water quality B2 Water content B3 Pollutants B4 Acidification B5 Eutrophication A report on the presence and impact of substances and microorganisms in water sources, with a comparison of typical water content from different sources. The report should include a discussion of how water quality of a river changes as it travels from source to mouth, and the impact of significant processes of acidification and eutrophication. The report should also evaluate the impact of a range of factors on two different species of aquatic life. C Investigate basic water quality of an aquatic habitat C1 Measuring and reporting on water quality A report explaining biological, chemical and physical tests, and indicators of water quality. Learners’ diaries, risk assessments, photographs and results of practical work carried out for the investigation of water quality for an aquatic habitat over a specified period of time. A report on the investigation, following a scientific format, giving conclusions and suggestions for improvements to the water quality of the aquatic habitat. An evaluation of the methods and techniques used, considering alternative approaches and other similar studies. D Understand the principles of water treatment and conservation D1 Water treatment D2 Sewage treatment D3 Water conservation and consumption control A report explaining different methods of treatment, conservation, consumption and management of water resources, and their evaluation for different purposes. BTEC INTERNATIONAL APPLIED SCIENCE UNIT 25: WATER QUALITY Pearson BTEC International Level 3 Qualifications in Applied Science – Delivery Guide Issue 1 – May 2020 © Pearson Education Limited 2020 4 Assessment guidance This unit is internally assessed via a number of independent tasks. Learners must produ