Aerated Grit Chamber - Perfect Grit Chamber Design For Wastewater Treatment

An aerated grit chamber is an enlarged channel orOne minute (volume of the grit chamber/flow rate) is
long basin in which the cross-section is increased tothe detention time normally employed. Since
reduce the velocity of the flowing sewagesedimentation of granular solids is dependent to a
sufficiently to cause heavy inorganic wastewaterlarge extent upon the surface area of the aerated
matter such as grit, sand and gravel of size 0.2 mm,grit chamber, their width could be kept large. A length
and larger wastewater suspended solids to settle,to width ratio of 8 to 1 may be used limiting the
while the lighter organic matter remains in suspension.effective depth to about 2 m.
This is used to remove solids having specific gravity(iii) Method Of Cleaning
greater than water.Grit chambers are cleaned by hand, mechanically or
This article takes a look at 4 important factors youhydraulically. Hand cleaning is done only in the case of
must consider when you design a grit chamber:smaller plants, is less hygienic and odor-free though
(i) Velocity Of Flowsomewhat easier for disposing off the removed
Velocity of wastewater flow must be 0.3 m/sec. Thismaterial than in the case of mechanical cleaning.
will permit the deposition of the bulk of heavier(iv) Grit Storage
mineral solids in wastewater while most organicStorage space for grit may be provided throughout
matter remains in suspension. A velocity of flow inthe length of the aerated grit chamber or by means
the range 0.15 - 0.3m/sec. is generally recommended.of one or more pits deeper than the remainder of
In order to keep the velocity within the desirablethe basins. Concentration of grit is also useful for
limits, it is usually necessary to provide two or morecleaning purposes. Channel may be provided with a
channels to manage fluctuations in sewage flow.frequency of cleaning of 15 days.
(ii) Period Of Detention