Robots do the dirty work to keep drainage network clear

Guernsey Water encourages islanders to help avoid blockages, backing the UK’s ‘Unblocktober’ campaign.

Only the three Ps – poo, pee and paper – should be put into the drainage network to avoid sewage backing into properties, damage and pollution.

‘Unblocktober started last year, which we [backed] as part of our ongoing campaigning to encourage the island to only flush the three Ps,’ said Jon Holt, operations manager.

‘Our biggest problem is fats, which bind other things together, and wet wipes.’

Jerbourg’s La Route des Blanches sewer was cleaned on Thursday.

‘It’s part of our scheduled preventative maintenance. There’s a combination of using a CCTV camera and jetting. This cleans sewers and checks the level of accumulated debris, helping us to judge the frequency of preventative cleaning needed.’

Maintenance frequency depends on location.

‘Some we clean more regularly because they are in busier network areas of catchment. We have to monitor it to prevent build ups.’

Robots help to show what cannot normally be seen.

‘We use two pieces of equipment – a CCTV survey robotic unit with a camera, and on another end of the network States Works jetters clear blockages.’

Engineering technician Sean Connolley and CCTV operator George de Carteret worked together to assess the sewage network 5.5 metres below ground.

‘Blockages tend to be managed pro-actively because of our cleaning programme, so we are ahead of most problems. It is far cheaper and more efficient to deal with blockages pro-actively rather than reactively.’

Heavy rainfall and wind, coupled with trees shedding leaves, creates build-ups.

‘We get lots of debris on the road which finds its way into the sewers, combined with the usual amount.’

Traffic governs scheduled work, especially in key areas and main roads which must be maintained on Sundays.

Approximately 35km of sewage networks are maintained annually, as well as additional unblocking of sewers and pumps.