Aside from microorganisms and carbon dioxide, what is another benefit of biological treatment in secondary treatment?

The correct answer emphasizes the increased particle size as a benefit of biological treatment in secondary treatment. In the context of wastewater treatment, biological processes, such as aeration and the use of microorganisms, can promote the aggregation of smaller particles into larger flocs. This increase in particle size is advantageous because larger flocs can settle more effectively during the clarification stage of treatment. Better settling enhances the efficiency of the subsequent separation processes, allowing for improved removal of solids from the treated water.

Larger particle sizes also aid in the filtration processes that may follow secondary treatment, resulting in clearer effluent that is less likely to contain suspended solids. Moreover, the formation of larger, more stable flocs during biological treatment can reduce the overall energy needed for mixing and aeration, contributing to a more efficient operation in wastewater facilities.

Other options provided do have their benefits in the context of biological treatment. However, they do not directly highlight the specific benefits linked with particle size enhancement through biological processes.