What is defined as a facility receiving domestic sewage from less than 15 people or having no ground surface discharge?

The correct choice identifies a facility that handles domestic sewage from fewer than 15 individuals or has no discharge onto the ground surface as a private sewage disposal system. This definition is essential in understanding the regulatory framework governing sewage systems in Illinois.

Private sewage disposal systems are typically used for single-family homes or small groups of people where the volume of sewage is manageable and does not warrant connection to a larger public sewer system. These systems often include septic tanks or alternative sewage treatment methods that provide on-site treatment without discharging directly into the environment. They are crucial in areas where public sewage infrastructure is lacking or impractical, ensuring that sewage is properly treated and does not pose health risks or environmental damage.

In contrast, public sewage systems serve a larger population and are designed to handle greater volumes of sewage, hence they do not meet the criteria for a private sewage disposal system. Community sewage treatment plants and industrial sewage treatment plants also manage larger volumes of waste compared to private systems, making them inapplicable to this context. Understanding these distinctions is vital for anyone involved in private sewage management or regulatory compliance.