2. Clarifier Operation
Primary clarification is the physical treatment process of removing solids before biological
treatment. It is the most cost effective way to remove these solids after basic screening.
Process water enters the clarifier tank and floatable solids (scum) are removed from the
surface by skimmers while settleable solids (sludge) are collected on the bottom by a rake and
removed via a sludge removal system. Effluent destined for biological treatment leaves the
clarifier over a weir. The expected range for percent removal in a primary clarifier is 90%-95%
settleable solids, 40%-60% suspended solids, and 25%-50% total BOD.
Skimming and Scum Removal
Our Environmental can provide a traditional skimming arm with scum beach and sludge box
at the tank periphery, a full-radius scum trough, or a ducking skimmer to remove floating
material.
Clarifier Effluent
Our custom designed scum baffles and V-notch weirs will assure a high quality effluent
preventing floating material from reaching the effluent launder and providing laminar flow
throughout the clarifier.
Weirs, baffles, and launders can be furnished in a variety of materials including stainless
steel, FRP, aluminum, and galvanized steel.
Clarifiers
3. Centrally Driven:--
The mechanism would be of centrally
driven type with fixed full bridge
spanning the tank diameter. Bridge is
to be trust type or I-beam type.
This is used for the small diameter
clarifier. This called Primary or
Secondary clarifier.
In that water entry are from top.
Scrapper is directly connected to drive
mechanism through heavy duty
Centre shaft.
Centre Cage Driven:-
The mechanism would be of
centrally driven type with fixed
half bridge spanning the tank
radius. One end over the tank
wall and other over a Centre
mechanism cum turn table in
the Centre pier.
In the Centre cage driven type
water entry is form bottom.
Around that structure cage one
end is connected with the drive
mechanism & other end
connected with the scrappers.
Centre cage drive the scrappers.
Clarifiers
4. Peripherally Driven:
The mechanism would be of
peripherally driven type having half
bridge spanning the tank radius.
Bridge one end would be connected
to the Centre support and the other
to the traction trolleys. Centre
support shall rest over the Slewing
type Turntable over base plate will
be anchored to the Central civil
RCC pier. Traction trolleys will be
positioned on the tangential line of
the RCC tank to enable smooth
running.
A Slip ring assembly (Four ring
collectors) will be provided for
power supply.
Clarifiers
5. Thickener
Centrally driven
The mechanism would be of
centrally driven type with fixed full
bridge spanning the tank diameter.
Bridge is to be trust type or I-beam
type.
This is used for the small diameter
clarifier. In that water entry are
from top. Scrapper is directly
connected to drive mechanism
through heavy duty Centre shaft.
Centre Cage Driven:-
The mechanism would be of
centrally driven type with fixed
half bridge spanning the tank
radius. One end over the tank
wall and other over a Centre
mechanism cum turn table in
the Centre pier.
In the Centre cage driven type
water entry is form bottom.
Around that structure cage one
end is connected with the drive
mechanism & other end
connected with the scrappers.
Centre cage drive the scrappers.
6. High Rate Solid Contact Clarifier
This Clarifier is a high rate, solid contact, sludge recirculation in minimum space and
using a minimum amount of chemicals, produces an effluent of the highest quality.
Used for clarification, lime softening, Silica reduction or organics reduction of water &
waste waters containing suspended solids, colors and organic impurities. It provides
means for chemical addition and mixing, flocculation and up flow clarification in a
single unit.
The mechanism would be of centrally driven type with fixed full bridge (Lattice type)
spanning the tank diameter with necessary walkway and handrails to access drive unit
at the centre. Two more truss fabricated structures shall be placed at 90º to the bridge
spanning the tank diameter to help suspend and hold the drat tube and detention
hood.
An intermediate Scraper arm shaft made out of Heavy duty pipe suspended from the
vertical shaft.
Recirculation system will be placed between the top and bottom portions of the bridge.
Suitable diameter of Draft tube for dozing and mixing suspended from the bridge
bottom and properly reinforced. Inlet nozzle with flange at the bottom tangentially
placed for Feed entry.
Suitable diameter of Detention hood made out of FRP fixed for flocculation.
7. Peripherally driven Clarifier / Centrally driven Flocculator
A RCC civil pier construction with feed inflow arrangement and suitable RCC
flocculation tank. Main driving half bridge spanning the tank radius of necessary
walkway with handrails to access drives units at the centre.
Centre mechanisms have a basic Turn table and a Bevel gear/Pinion arrangements
resting RCC centre pier.
Centre support with hinge pin arrangements rests over the Center mechanism.
Bridge one end would be connected to the Centre support through hinge pin
arrangements and the other to the traction trolleys.
A truss type Scraper arm for outer tank is hung in Bridge bottom with suspended and
cross braced vertical structures to sweep the tank floor with Scraper blades, Neoprene
Rubber squeezes and Strips to hold Squeezes.
Two truss type Scraper arms, rigidly fabricated for inner Flocculation tank would be
fixed to the Turn table of the Centre mechanism to sweep the tank floor with Scraper
blades, Neoprene Rubber squeezes and Strips to hold Squeezes.
Rotor flocculation paddles would be fixed to a centre cage which in turn would be
bolted to the bevel gear of the centre mechanism.
Paddle will be rotate in opposite direction.
Clariflocculator
8. Centre Cage Driven
The mechanism would be of centrally driven type with fixed half bridge spanning the
tank radius. One end over the tank wall and other over a Centre mechanism cum turn
table in the Centre pier.
Bridge consists of necessary walkway with handrails to access drive unit at the centre.
Centre mechanism – Internal gear worm drive type turn table resting over a base frame
on the RCC centre pier.
Drive unit consisting of Centre mechanism with internal gears through which the
Scraper Cage is hung. This internal gears in turns is run by worm Drive head (Worm
shaft & worm gear) connected Gear Box by Chain & sprockets and the Gear box
connected to Motor by Love joy Coupling.
Suitable diameter of Influent well made out of MS or FRP bolted to the Center Scraper
Cage.
Feed inlet to the Clarifier is through the hollowed civil Centre pier bottom.
Two Scraper arms, truss type fabricated fixed to Centre Scraper Cage suspended from
the Centre mechanism to sweep the tank floor with Scraper blades, Neoprene Rubber
squeezes and Strips to hold Squeezes.
Clariflocculator
9. Peripherally driven Clarifier / Independent Flocculator
The mechanism would be of peripherally driven type having half bridge spanning the
tank radius and having two or four independent flocculators within the flocculation
tank. Bridge one end would be connected to the Centre support and the other to the
traction trolleys.Bridge centre support shall rest over the Slewing type Turntable over
base plate will be anchored to the Central civil RCC pier.
Traction trolleys will be positioned on the tangential line of the RCC tank to enable
smooth running.
A truss type Scraper arm for outer tank is hung in Bridge bottom with suspended and
cross braced vertical structures to sweep the tank floor with Scraper blades, Neoprene
Rubber squeezes and Strips to hold Squeezes.
A Slipring assembly (Ten ring collectors) will be provided for power supply.
Two or Four independent flocculators placed at 90º or 180º on the bridge on the
flocculation tank. Each flocculator drive consists of helical or worm geared motor with
output shaft coupling.
Clariflocculator
10. Circular tanks require careful design of the inlet stilling well (inlet buffer) to achieve a stable
radial flow pattern without causing excessive turbulence in the vicinity of the central sludge
hopper.
The removal efficiency of the chain and flight type collector mechanism is much higher than that of
bridge type mechanisms. This is due to the large number of flights. Moreover, the power
consumption and maintenance cost of these devices are minimal.
These mechanisms can be assembled with non-metallic components including Collector Chains,
Head and Idler Shaft Sprockets and Scrappers, which not only ensure easier erection due to their
light weight but also contribute to making the product, have a longer life. These Scrappers are
driven through the collector chains on both ends of the tank and in-turn are carried on the
sprocket mounted on the solid stainless steel shafts running across the tank width, which are
supported on the tank walls.
Horizontal Scrapper:-
There are four different type of arrangement are available as per below..
1) Four Shaft scrapper arrangements: This type of arrangement is available when need
to remove the sludge form bottom and floated scum from the top. Floated scum collected
on the top scum box and sludge are collected in the sludge box at bottom.
11. 2) Three Shaft scrapper arrangements: This type of arrangement is available when need
to remove the sludge form bottom which is collected at bottom in the sludge box.
Horizontal Scrapper:-
3) Two Shaft scrapper arrangements: This type of arrangement is available when need to
remove the scum form top of the clarifier. This type of arrangement available in DAF
system.
4) Two Shaft scrapper arrangements: This type of arrangement is available when need to
remove the sludge form bottom which is collected at bottom in the sludge box. This type
of arraignment available when need to use the tube settler or lamella plate for remove
the sludge particles.
