How can biological contamination in water be controlled?

Biological contamination in water is effectively controlled through a combination of methods that work to eliminate or deactivate microorganisms, which could include bacteria, viruses, and algae. Chlorination involves adding chlorine or chlorine compounds to the water, which acts as a disinfectant, killing or inactivating harmful pathogens. UV light treatment uses ultraviolet radiation to disrupt the DNA of microbes, rendering them unable to reproduce and effectively neutralizing their threat. Filtration removes particles and microorganisms from the water physically, providing an additional layer of protection against biological contaminants.

The effectiveness of this multi-barrier approach ensures that each method complements the others, leading to a more comprehensive reduction in microbial presence in water supplies. This is crucial for ensuring safe drinking water and maintaining public health.

While introducing antibiotics could theoretically target specific bacteria, it is not a practical or effective approach for broad water treatment due to potential environmental impacts and the risk of promoting antibiotic-resistant strains of bacteria. Ozone treatment is effective but is mentioned as being "only," which limits its comprehensive nature compared to the combination of methods in the correct answer. Sedimentation is a process that can help reduce some types of contaminants, but it does not address the need for immediate and effective disinfection against biological agents.