Résumé :
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The problem of deterioration in sewerage systems include all normal types of problems associated with the deterioration of metals, mortars, concrete and timbers, but involde in addition problems arising from the special nature of water-borne wastes flowing in sewers. these include problems caused by the activities of biological organisms. this manual deals in particular with one of the most destructive of these, the corrosion and deterioration wich results from sulphides in the wastes, the evolution of gaseous sulphide environment on the surfaces above the sewage. the manual describes this sequence setting out first the main factors controlling sulphide concentration levels, then those wich operate in connexion with sulphide evolution and oxidation, and finally propounding ways in wich these factors may be controlled. inclued also is a discussion of related aspects of sewerage ventilation, both respecting odours and the possible development of irrespirable or toxic conditions.
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