IELTS Writing Task 1: Band 8 Essay Sample on the Environment

The diagram illustrates the process by which rainwater is collected from residential rooftops and systematically purified to produce safe drinking water for an Australian town. Overall, the treatment process follows five clearly defined sequential stages, commencing with the surface collection of rainwater and concluding with the distribution of fully treated water back to individual households. Initially, rainfall is captured from sloped rooftops and channelled into gutters, which direct the water into an underground drainage network connecting all houses in the area. This water is then passed through a multi-layer water filter, which effectively removes larger impurities such as dust, sediment, and particulate matter, completing the primary purification phase. The filtered water is subsequently held in a large underground storage tank, where it accumulates before being transferred to an adjacent water treatment tank. Within this tank, chemical agents are carefully introduced to eliminate residual contaminants and harmful microorganisms, ensuring the water meets the standard required for safe human consumption. Once fully treated, the potable water is distributed to each household through a dedicated underground pipeline, completing the purification process.