Final answer:
Chlorine is used in aircraft lavatories to neutralize urine and waste products. This disinfection method kills harmful bacteria and pathogens, but excessive chlorine must be neutralized to prevent harm.
Step-by-step explanation:
The lavatories of aircrafts use a chemical called chlorine to neutralize urine and waste products. This is a common method of disinfection used to kill harmful bacteria and pathogens in wastewater. However, excessive chlorine can be harmful, so it may need to be neutralized with other chemicals after it has killed the bacteria.