IELTSライティング Task 1: バンド8 エッセイサンプル — 環境

The diagram presents the step-by-step process by which rainwater is collected and treated to produce potable drinking water for residents of a town in Australia. Overall, the process follows a clear linear sequence comprising five stages: rooftop collection, filtration, underground storage, chemical treatment, and household distribution. The process begins when rainfall is captured from residential rooftops and channelled through gutters and underground pipes into a water filtration unit. This filtration stage removes physical impurities—such as leaves, sediment, and particulate matter—that accumulate as the water travels from the roof to the filter, thereby completing the first round of purification. The cleaned water then flows into a large underground storage tank, where it is held before being transferred to an adjacent treatment tank. In this critical stage, precisely measured chemical agents are introduced to eliminate any remaining bacteria and contaminants, ensuring the water meets the safety standards required for human consumption. Once the chemical treatment is complete, the fully purified drinking water is pumped through a dedicated pipeline and delivered to each house, ready for use.