What function does a backwater valve serve in a collection system?

A backwater valve is a critical component in a collection system specifically designed to prevent wastewater from flowing back into a building. This device is usually installed in the main sewer line and helps protect homes and businesses from potential sewer backups, especially during heavy rainfall or when the municipal sewer system is overloaded. By closing off the line during such events, the backwater valve acts as a barrier, ensuring that effluent from the sewer does not re-enter the plumbing system of a property.

The other functions mentioned do not accurately represent the role of a backwater valve. For example, increasing water pressure is not related to the purpose of a backwater valve; instead, it is more associated with pumps and pressure regulators. Promoting faster waste decomposition pertains to biological treatments or aeration systems rather than mechanical valves. Similarly, enhancing sewage treatment effectiveness is more aligned with treatment processes or technologies rather than the mechanical function of backwater valves. Therefore, the primary and essential purpose of a backwater valve is to safeguard buildings by preventing backflow of wastewater, making option B the correct choice.