Wastewater Treatment Operator Certification Practice Test

Which of the following is typically treated by biological processes?

1. Roots and rags

2. Sand and eggshells

3. Cinders

4. Dissolved and non settable organic material

The correct answer is: Dissolved and non settable organic material

Biological processes in wastewater treatment primarily target organic materials that can be broken down by microorganisms. The correct answer, which refers to dissolved and non-settleable organic material, highlights a key aspect of wastewater treatment. This type of material consists of organic compounds that are often present in higher concentrations in wastewater and can contribute significantly to pollutant loads. Microorganisms such as bacteria and protozoa are employed in biological treatment methods, such as activated sludge systems and trickling filters, to metabolize these organic substances, effectively reducing their concentration and converting them into biomass. This process not only helps to clarify the effluent but also minimizes the environmental impact of the wastewater discharged. Other options, such as roots and rags, sand and eggshells, or cinders, are typically considered inert or non-biodegradable materials and do not undergo biological treatment processes. These substances may require different removal methods, such as screening or physical separation, before the wastewater can be effectively treated biologically. Therefore, focusing on the specific ability of biological processes to treat dissolved and non-settable organic material underscores the efficiency and relevance of this method in wastewater management.