Lanes tests technology to the limit to empty septic tank

Lanes for Drains engineers in South Wales have tested drainage technology to its limits to help the Royal National Lifeboat Institution empty a septic tank on the seashore below a cliff.

The maritime search and rescue charity called the Lanes for Drains Cardiff Depot to find a way to clean out the tank at its Angle Lifeboat Station in the mouth of Milford Haven in Pembrokeshire.

Damian Tranter, Area Development Manager in South Wales for Lanes for Drains, the UK’s largest independent drainage specialists, visited the lifeboat station and realised straight away it would not be a run-of-the-mill septic tank cleaning job.

He said: “Angle RNLI Lifeboat Station can only be reached by driving along a beach and then a very narrow winding track that leads to a small headland.

“The septic tank was unusually large for the facility it serves, about 10,000 gallons, and was situated on a rocky platform behind the lifeboat station, under a low cliff which becomes washed with sea water at high tide.

“We’re very experienced at clearing blocked drains, repairing drainage pipes and emptying septic tanks, but this was an unusual challenge, even for us.”

However, the team at the Lanes for Drains Cardiff Depot, in Pontyclun, Mid Glamorgan, did have the sophisticated equipment they needed.

They deployed a Kaiser Whale tanker, which has a KWP high-performance liquid ring vacuum pump, plus a CCTV survey unit, along with its fully-trained confined space engineers.

Damian said: “The difficult access meant the vacuum pump needed nearly a nine metre lift. This was very close to the maximum achievable by any device that sucks fluid, as this does, rather than mechanically pumping it.

“So, to achieve the lift, we needed a recycling unit with a vacuumation pump that was powerful enough to reduce suction pressure to almost zero.

“We were helped by the tank being almost exactly at sea level, where atmospheric pressure was at its highest, helping to force the waste fluid up the suction pipe.

“On higher ground, atmospheric pressure would have been lower, reducing the vacuum pump’s capabilities. Success, in this case, depended on these critical factors.

“This job reflects the technical know-how Lanes for Drains can bring to bear. It is essential we understand the science behind our equipment to devise practical solutions for our customers that are safe and do a good job.

It took a day for the Lanes Cardiff team to empty the tank, carry out a confined space inspection by sending an engineer into the tank and using HD quality video cameras to survey its structural condition.

Martin Brough, RNLI’s Shoreworks Deputy Divisional Manager, said: “Lanes for Drains solved a real problem for us. The job presented a practical challenge, with the difficult location, and a technical one, with the need to have the right equipment and expertise, and Lanes for Drains met it admirably.”

Angle Lifeboat Station has been operating since 1868. It has two full time staff and a volunteer crew who, in 2012, responded to 35 emergency ‘shouts’.