The Imhoff tank, named for German engineer

Karl Imhoff Karl Imhoff (7 April 1876 in Mannheim – 28 September 1965) was a German civil engineer, author, and a pioneer of wastewater treatment used throughout the world. Action Karl Imhoff was the driving force in the development and invention of the ...

(1876–1965), is a chamber suitable for the reception and processing of

sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from reside ...

. It may be used for the clarification of sewage by simple

settling Settling is the process by which particulates move towards the bottom of a liquid and form a sediment. Particles that experience a force, either due to gravity or due to centrifugal motion will tend to move in a uniform manner in the direction ...

and

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

, along with

anaerobic digestion Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the ferm ...

of the extracted

sludge Sludge is a semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on-site sanitation systems. For example, it can be produced as a settled suspension obtained from conventional ...

. It consists of an upper chamber in which sedimentation takes place, from which collected solids slide down inclined bottom slopes to an entrance into a lower chamber in which the sludge is collected and digested. The two chambers are otherwise unconnected, with the more liquid sewage flowing only through the upper sedimentation chamber and only a slow flow of sludge in the lower digestion chamber. The lower chamber requires separate

biogas Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a ...

vents and pipes for the removal of digested sludge, typically after 6–9 months of digestion. The Imhoff tank is in effect a two-story

septic tank A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater ( sewage) flows for basic sewage treatment. Settling and anaerobic digestion processes reduce solids and organics, but the treatm ...

and retains the septic tank's simplicity while eliminating many of its drawbacks, which largely result from the mixing of fresh sewage and septic sludge in the same chamber. Imhoff tanks are being superseded in

sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding en ...

by plain

sedimentation tank Sedimentation is a physical water treatment process using gravity to remove suspended solids from water. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans. ...

s using mechanical methods for continuously collecting the sludge, which is moved to separate digestion tanks. This arrangement permits both improved sedimentation results and better temperature control in the digestion process, leading to a more rapid and complete digestion of the sludge. Imhoff tank (5547295318)

A test for settleable solids in water, wastewater and stormwater uses an Imhoff cone, with or without

stopcock A stopcock is a form of valve used to control the flow of a liquid or gas. The term is not precise and is applied to many different types of valve. The only consistent attribute is that the valve is designed to completely stop the flow when cl ...

. The volume of solids is measured after a specified time period at the bottom of a one-liter cone using graduated markings. Imhoff Cone
Retrieved 2012-05-29.

References

External links

Water/Wastewater Distance Learning at Mountain Empire Community College {{Wastewater Anaerobic digester types Sewerage infrastructure

See also

References

External links