What water quality characteristic enables direct filtration to produce good quality water at a lower cost?

Low turbidity is a key characteristic that allows direct filtration to effectively produce good quality water at a lower cost. Turbidity refers to the cloudiness or haziness of water caused by suspended particles, which can include sediments, algae, and microorganisms. When the turbidity levels in water are low, it implies that there are fewer suspended particles that can obstruct or impair the filtration process.

Direct filtration relies on physical barriers, such as filters, to remove particles from water. With low turbidity, the filters can work more efficiently, requiring less frequent cleaning and maintenance. This not only reduces operational costs but also minimizes the amount of chemical coagulants needed, further lowering overall treatment expenses.

In contrast, high turbidity would necessitate more extensive pretreatment and could result in higher costs associated with additional chemicals and equipment to manage the increased particle load. Similarly, high color content and high levels of coliform bacteria can complicate treatment processes, demanding more rigorous treatment methods and monitoring to ensure water safety and quality. Hence, maintaining low turbidity is crucial for economical and effective water treatment using direct filtration technologies.