The government is exploring the feasibility of extending trenchless technology using horizontal directional drilling (HDD) to lay sewerage lines. This is expected to prevent digging of roads and disruption of traffic.
Using the technology, a high-density polyethylene pipe (HDPE) was successfully laid for the first time in the State on a 540-metre stretch near Chakka, close to the entrance of the international airport. The line was part of the 37-km sewerage network to Muttathara.
(Directional boring, commonly called horizontal directional drilling, is a method of laying underground pipes, conduits, and cables along a prescribed bore path using a surface-launched drilling rig. The impact on the surrounding areas will be minimal).
The HDPE pipes had been laid at a depth of two to seven metres in Chakka as part of work to prevent recurrent flooding.
Another 500-metre HDPE pipe would be laid to work out the cost if the technology was to be used in Kollam, Kochi, and Kozhikode.
The HDD method does not need tar-cutting, scaffolding, and restoration. Traffic would not be affected. The cost of operation varied from Rs.3,000 to Rs.25,000, depending on the depth to which the earth was dug. The cost would be on par with conventional technology if the depth was maintained at 3.5 metre, sources said.
Officials of a Mumbai-based firm which came forward for the pilot project said 100 metres of pipe could be laid using HDD technology in as much time taken to lay 30 metres of pipes using conventional technology. The maintenance was less as the number of joints were less. Chances of drinking water and waste water getting mixed could be better avoided, they said.
On Tuesday, Minister for Urban Affairs Manjalamkuzhi Ali reviewed the work done at Chakka. He said the government intended to extend it to other areas after taking up a comparative cost study.
The government wanted to use the technology for the time-bound completion of sewerage treatment plants, Mr. Ali said.