Sewerage pumping stations in the east of the Islabd

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WRITTEN QUESTION TO THE PRESIDENT OF THE ENVIRONMENT AND PUBLIC SERVICES COMMITTEE BY DEPUTY G.C.L. BAUDAINS OF ST. CLEMENT

ANSWER TO BE TABLED ON TUESDAY 13th SEPTEMBER 2005

Question

"Would the President –

( a ) inform members whether the Committee monitors sewerage pumping stations on the east of the Island

and, if so, would he advise if any of stations located between Fauvic and Le Marais, in particular, have had any high odour levels recorded?

( b ) advise what action, if any, the Committee intends to take to resolve any identified problems with these

particular stations, given the close proximity of, for example, the Jambart and Le Hocq pumping stations to nearby hotels and restaurants? and,

( c ) give an assurance that development in the Jambart area, including the new estate, will not exacerbate any

identified problems?"

Answer

"(a) All of the public pumping stations administered by the Committee are monitored using telemetry 24 hours a

day, 365 days a year. This monitoring enables any problems at the pumping stations, such as a pump failure or high level alarm, to be identified and corrected quickly. In addition, the pumping stations are routinely visited twice a week by the Department's pumping station operatives, who check and record the operating performance of the facility. Any odour problems would be identified during the twice weekly routine visits, as such problems cannot be detected automatically by the telemetry system.

O  dour problems have been identified at certain times of the year in the vicinity of the major east coast

pumping stations at Le Bourg, Pontac and Le Hocq. These odour problems tend to occur during long dry periods in the summer months, when ambient temperatures are high and flows in the sewers are low.

2. The Departmentis undertaking trials using various typesofbacteriological dosing systems at Le Bourg pumping station inanattempt to prevent the formation of the odours at source. These systems use bacteria to prevent odours normally produced if the sewagebecomes septic, a problem most likely tooccur during hot dry periods during the summer.The results of the trials, the latest ofwhich uses a bacteriologicaldosing system successfully employedinGuernsey,shouldbeknownby the Autumn.

I n addition to these trials, the existing odour control systems at Le Bourg and Le Hocq pumping stations,

which are reaching the end of their effective life, are to be replaced with Biofilter odour control systems, similar to the units already installed at Pontac pumping station and the sludge holding tanks at the sewage treatment works. The Biofilter system has been proven to operate very effectively, and is far more efficient than the older type of odour control systems currently in use at the stations.

I t has also been identified that, despite regular attention, the seals on the multiple covers over the main

working sumps at Le Bourg, Pontac and Le Hocq stations are failing to consistently provide an air tight seal as originally intended, and hence allowing odours to emanate from the pumping station building itself from time to time. In order to resolve this problem, the covers at these three stations are to be replaced with purpose made air tight units.

I t is anticipated that the replacement odour control systems and new covers will all be delivered and installed

by late November this year.

3. I can confirm that Pontacpumping station, which is located in Jambart Lane, can deal with the additional flows from the new developmentin the JambartLane area, and that this development will not exacerbate the odour problem at this station. If anything, the additional flow will tend toreduce the potential for odour problems,which traditionally occurduring the summermonths,by increasing the flow through this pumping station during times of dry weather."