Odour removal with a trickling filter at a small WWTP strongly influenced by the tourism season

Etaples-Le Touquet's wastewater treatment plant (WWTP) is based on a coasta l area of the Artois-Picardie region. The pollution load can vary from 20,0 00 p.e. to 60,000 p.e. over a weekend or in summer. The Collectivity and th e Water Agency decided to cover and ventilate the main odour source points of the plant. The foul air was directed to a 2,500 m(3)/h inorganic bed bio filter (Alizair (R)) for odour control. An odour monitoring took place duri ng the first year of operation taking into account cold and warm seasons, h igh and low tourism seasons. The Alizair biofilter appeared an appropriate odour control process for sma ll sized wastewater treatment plants, easy to operate and efficient even in areas where tourism seasons have a great impact on the pollution load arri ving at the plant. The neighbourhood did not complain about odours any more and the operator was very confident with such a simple and effective syste m. The local Authorities and the Water Agency agreed to recommend Alizair biof ilters with an autotrophic biomass adapted in the case of an old WWTP that cannot be up graded any more or for large pumping stations and wastewater s torage prior treatment.