1. “Package plant for sewage treatment” means any plant which:
(a) Consists of units or modules designed for construction, assembly, connection and installation at the site for treatment of sewage; and
(b) Is privately owned and will be operated to treat wastewater and sewage for a limited area.
2. The term does not include:
(a) A plant for the treatment of domestic sewage whose capacity is less than 5,000 gallons per day;
(b) Septic systems comprised of single or multiple septic tanks and leach fields; or
(c) Systems operated for the pretreatment of industrial wastewater before disposal to a publicly owned treatment plant.