Name one physical method used in primary treatment of wastewater.

Screening is a crucial physical method utilized in the primary treatment of wastewater. This process involves passing wastewater through a series of screens to remove large solids and debris, such as sticks, leaves, plastic, and other materials that can obstruct pipes and equipment further along in the treatment process. Screening serves to protect the integrity of the treatment facility and improve the efficiency of subsequent treatment stages by ensuring that larger particles do not interfere with the processes designed to treat the water more thoroughly.

Filtration, while also a physical method, typically occurs in later stages of treatment rather than being a primary treatment process. Biological treatment refers to processes that rely on microorganisms to break down organic matter, which is not a physical method. Membrane separation is a more advanced method that can be used in secondary or tertiary treatment settings rather than in primary treatment. Therefore, screening is distinctly aligned with the initial physical processes involved in preparing wastewater for further treatment.