Why is filtration necessary for removing suspended solids from water?

Filtration is necessary for removing suspended solids from water primarily because bacteria can attach to these solids, leading to the presence of pathogens in the water. When these suspended solids are not removed, they can provide a conducive environment for bacteria to thrive, thus increasing the potential for waterborne diseases. By filtering out these particles, the water treatment process can significantly reduce the number of bacteria and pathogens, ultimately improving water quality and making it safer for consumption and other uses.

Other options, while they may relate to water quality or conditions, do not directly address the role of filtration in removing harmful suspended solids. For example, increasing water acidity and enhancing oxygen levels do not pertain to the physical removal of solids, and preventing water from freezing is unrelated to the filtration process. Hence, option C stands out as the correct rationale for the necessity of filtration in wastewater treatment.