Which of the following represents primary wastewater treatment technologies used by industry?

The correct answer effectively represents the various primary wastewater treatment technologies employed by industry. Primary treatment generally refers to the initial stage of wastewater treatment that aims to remove solid materials from sewage. This can involve several methods:

• Biological processes utilize microorganisms to break down organic matter.

• Chemical techniques may involve adding chemicals to precipitate solids or neutralize harmful contaminants.

• Land treatment methods, also known as land application, involve spreading wastewater over land to enhance its natural treatment through soil filtration and microbial activity.

• Physical processes can include screening and sedimentation, where larger particles are removed through physical separation.

These combined methods ensure that the bulk of suspended solids and organic materials are significantly reduced before the wastewater proceeds to secondary treatments, where biological methods are typically further utilized.

The other options do not accurately encompass the primary wastewater treatment technologies. Some mention advanced processes or specific technologies that are typically associated with secondary or tertiary treatment stages, which focus more on further purification and removal of dissolved contaminants rather than the initial solid removal typical of primary treatment.