Wastewater Treatment MCQ with answer and solution

Concept

Function of a trickling filter

Step-by-step solution

1. A trickling filter is a fixed-film biological reactor. 2. Settled sewage is sprayed over a bed of stones or plastic media. 3. A slime of micro-organisms on the media oxidises the organic matter.

Explanation

The trickling filter is a secondary treatment unit. Aerobic bacteria growing as a biofilm on the media break down the dissolved and colloidal organic matter in the sewage (biological oxidation).

Shortcut

Trickling filter and activated sludge = biological oxidation (secondary treatment).

Common mistake

Choosing suspended solids removal because it is called a filter.