Les virus des eaux usées et leur élimination au cours des traitements des effluents pollués

Abstract

Viruses are a biological pollution in wastewaters. Their elimination results from treatment processes of polluted effluents in the sewage treatment plant or in the lagooning pilot plant. Bacteriophages are regarded as viruses models and as indicators of faecal contamination. In an expiremental study, two pilot plants laboratories have been used (natural lagooning and activated sludge pilot) to follow and evaluate the elimination rate of somatic coliphage X-174 or the ARN F-specific one MS2. The two phages removal, ranging to 99 % in the two systems, are related with previous values on enteric viruses. The main factors of viral removal and inactivation (adsorption to solid matters, microbial activities, solar radiations, dissolved matters) have been studied too. Adsorption of infectious particles to solid matters is a very significant process. This was obtained in the pilot plant laboratory experiment and in in vitro study ( X-174 or MS2 in the presence of the kaolinite or the montmorillonite). Otherwise, 12 hours of solar rays exposition were efficient ro inactivate nearly the whole phagic suspension. The ciliate protozoan Tetrahymena pyriformis does not seem to have an important role for elimination of phages ( X-174 and MS2.