Imhoff

Imhoff is a surname of German origin. Notable bearers include Karl Imhoff, a German sanitary engineer who contributed to the development of wastewater treatment technologies in the early 20th century.

Karl Imhoff (1876–1965) designed various components for primary sewage treatment. The Imhoff tank, a gravity sedimentation system, consists of a settling chamber above a digestion chamber separated by a bottom that helps direct settled solids downward. Settled solids are collected and directed to the digestion chamber, where they are treated anaerobically, while the clarified effluent flows onward for secondary treatment. The design aimed to improve solids removal and reduce sludge handling in small communities.

The Imhoff cone is a 1-liter sedimentation vessel used to determine settleability of suspended solids. A sample is filled into the cone and allowed to sit for a fixed period, typically one hour, after which the volume of settled solids is read against the graduation. It remains a standard reference method in some wastewater and water quality laboratories, though automation and other modern methods have supplemented it.