Traveling bridges

The first step in wastewater treatment is coarse screening to remove largematerials (rags, logs and other large objects) from the wastewater that couldinterfere with the treatment process. The next step is to remove smaller objects(such as sand, broken glass, silt and pebbles). If these objects are notremoved, they can damage pumps and other mechanical devices. These objects alsohave a tendency to settle in corners and bends, thus reducing flow capacity andeventually clogging pipes and channels. Grit chambers are concrete-linedrectangular ponds, where the wastewater enters one end and leaves at theopposite end. These chambers are typically sized so that the speed of thewastewater flowing through the chamber is kept slow enough to allow sandparticles to settle out of the wastewater.

There are three principal types of grit removal systems: gravity channel,Aerated grit channels and vortex grit traps. Gravity Channels are sized toproduce a certain optimum maximum flow velocity through the channel. Up to thisvelocity the majority of grits will fall out of solution and be collected in abottom dump pit in the channel. These channels are long, narrow, relatively deepand aerated with coarse bubble diffusers. Aerated channels are usually used inlarger sewage works and may be equipped with a mechanized grit removal deviceand a conveyor system to a bagging bin.
Vortex grit traps such as the Pista or Jetta types remove the grit from sewageinflow in a mechanized vortex flow container.


Components and materials:

Mojan traveling bridges mainly consist of: Bridge body,geared motor, bogie, bottom sand scrapper, surface scum skimmer and controlpanel.

The bridge body itself is a trussed or steel plate construction manufacturedfrom coated pipes or properly shaped steel plates.

Mojan traveling bridges are driven by a bridge-mounted motor and gearassembly. A separate geared motor is also installed on the bridge that controlsthe sand scraper movements. 

The bogie is equipped with adjustable wheels, shafts and a plate cover thatencloses the shafts and wheels. The necessary power for moving the bridge istransmitted to the wheels through a chain-wheel mechanism and a longitudinalshaft that connects the two moving wheels together.

Bottom sand scraper, which transports the sand to the sand hoper, ismanufactured from stainless steel. The complete unit is assembled by means ofbolts and this allows an easy assembly.

Surface scum skimmers are manufactured from stainless steel and fixed in tothe bridge body by means of steel members in such a way that enables theadjustment of the skimmers according to water level during operation.  

Mojan traveling bridges are equipped with control panels. The control panelcabinet is manufactured from steel and is designed for outdoor use. Achequerplate walkway and tubular hand railing is supplied with traveling bridgesas well.



- Some of Mojan Co. traveling bridges features is as follows:

- Efficient separation of liquid and solid phases

- Low energy consumption

- Economic design

- Low maintenance costs

- Easy to installation

- Long life



Mojan traveling bridges are widely utilized in sand and scum (grease) removalunits in both municipal and industrial wastewater treatment plants.