Is a proprietary device (ATU) considered "public domain" technology?

A proprietary device, such as an aerobic treatment unit (ATU), is not considered "public domain" technology because it is developed and owned by a private entity or manufacturer that holds exclusive rights to its design and operation. The proprietary nature of these devices means they often involve patented technology or trade secrets, which restrict their use, production, and distribution to those authorized by the owner.

Public domain technology, on the other hand, is freely available for anyone to use, adapt, and share without restrictions. Therefore, since a proprietary device like an ATU does not fall under this definition and typically requires licenses or permissions for use, it is not classified as public domain technology. This distinction is crucial in understanding intellectual property rights and the application of technology in wastewater management.