Oil-water separator pond, utilizing the specific gravity difference between oil, water, and suspended matter, separates through natural floating separation method under the action of gravity, distinguishing the oil layer 23, water layer, and vegetable residue 22. Natural separation requires no chemical treatment, thus preventing secondary pollution. In practical applications, the separator pond is typically cascaded, usually 2 to 4 stages, for enhanced effectiveness.

The shortcomings of the above plan include: (1) The liquid level of oil layer 23 cannot be ascertained, requiring manual opening of the lid for observation each time; failure to promptly clean out oil layer 23 can lead to overflow through outlet 31, further polluting the water body; (2) Frequent lid openings waste human resources, and the heavy covers are not convenient to open. Moreover, it is difficult for administrators to supervise and notify maintenance personnel.