Projects Executed




Machinery & Infrastructure




The desilting operation of sewers proceeds from manhole to manhole. The process starts from the sewer line located most down stream. The lower end of the sewer line is blocked with the help of sand bags. The blocking of sewer with sand bags requires entry of a sewer man into the manhole. Prior to the entry of sewer man into the manhole, manhole covers from both ends of the sewer line to be cleaned are removed. The sewer line is then flushed with air by compressors. The flushing of air removes the harmful gases from sewer line and makes it safe for human entry. However, in order to confirm that sewer line and manholes are free from all harmful gases multi gas detector is lowered in the manhole. The multi gas detector measures the concentration of harmful gases i.e., H2S and CO2, CO as well the concentration of oxygen in the manhole and sewer line. The instrument transmits concentration of harmful gases and oxygen out side the manhole through a cable, which can be seen on the screen held by supervisor of the operation.

After the supervisor of the de silting operation has made sure that manhole is safe for human entry, sewer man wearing gloves, breathing apparatus, helmet with light and water proof shoes with oxygen cylinder on his back and rope tied to his belt enters the manhole. The other end of the rope is attached to a man winch. This arrangement is made to lift the sewer man out of the manhole in case of occurrence of any untoward incident. The sewer man fixes sand bags on the lower end of the sewer line and makes sure it has become leak proof and comes out of the manhole. The sewer man then enters the upstream manhole to fix the pipe of the jetting machine to the sewer line and comes out. Supervisor of the de silting operation then orders to start the jetting machine. The jet of water erodes the solidified silt with its thrust. Water requirement of the jetting machine is fulfilled by the water tanker, which brings water from the nearest tube well. Jetting of the solidified silt and its removal proceed simultaneously. Sludge suckers are used to withdraw silt from the sewer line and manholes. In the sludge sucker silt being heavier than water readily settles at the bottom and supernatant water is collected at the top. After the sludge sucker is filled, the supernatant water, which is free from silt is drained in the nearby drainage channel and sludge sucker is dispatched to the landfill site for silt disposal.The de silting operation usually proceeds at night. This time is selected for two reasons:

- Flow of water in the sewers is almost zero

- Traffic flow on the roads is at its lowest

De silting of drainage channels

In the drainage channels the mechanism of de silting is simpler than in sewers. The reason being, the channels offer an open environment whereas in sewers environment is closed. The probability of accidents and health and safety requirements are lesser. Instead of using jetting machines and sludge suckers the process involves the use of excavators, clam shells and dumper trucks.

The process starts by setting up the excavator/clam shell at site. The choice of machinery is made on the basis of site requirement, channel width and the volume of the silt to be removed. The silt is removed from the channel with the help of bucket attached to the machine. The silt collected in the bucket is unloaded in the dump trucks, which takes the silt for final disposal to the solid waste landfill site. In order to ensure that silt with least water contents is thrown into the dump trucks, the silt filled bucket hangs over the drainage channel for few minutes so that maximum water contents drop back into the channel. This step is necessary to avoid the splashing of water on the roads from the dump trucks that makes the road slippery causing inconvenience to the passer bays.

Health and safety requirements are gloves, safety shoes and helmets. First aid boxes are available on site.








- High pressure jetting (1500 to 10,000) PSI
- Ultra high pressure jetting (30,000 to 40,000) PSI

Capable of removing compact silt, sludge and all other forms of solid and liquid debris

- Blasts away years of accumulated silt, sand and grease build-up on the inside walls
   of the sewers
- The jet has the power to burst open the most adamant of blockages and at the same
   time scours the full diameter of the sewer, flushing debris towards the mouth of the
- This is immediately sucked up by suction machines mounted on trucks very efficiently
   keeping the sewer line clean for CCTV operation.

- Used for coating removal, surface preparation, and hydrodemolition
- Production rates up to 1,000 sq ft/hr (90 sq m/hr) can be achieved with this type of
- Only a single operator is required to operate the system
- At least one model is easily operated by a joystick-type controller that can be as far
  as 250 ft (76 m) from the system
- The high productivity of this tool has led to the use of UHP water jetting on very large
   area removal projects that were not feasible with handheld tools
- Technological developments in water jetting equipment have allowed the process to

   become feasible for large scale projects where productivity demands are high




Copyright KAVERI INFRASTRUCTURE PVT. LTD. All Rights Reserved.

Design by: PGPS Web Solutions