PROCÉDÉ DE TRAITEMENT ET/OU DE PRÉTRAITEMENT DE PURIN OU DE REJET D'INSTALLATION DE BIOGAZ EN VUE D'ÉLIMINER LES SUBSTANCES NOCIVES, EN PARTICULIER L'AZOTE, LE PHOSPHORE ET LES MOLÉCULES D'ODEUR
The invention relates to a method and an apparatus for treating and/or pre-treating liquid manure or biogas plant reject for eliminating harmful substances, particularly nitrogen, phosphorus, and odor molecules. Process tanks (5), which include inlet means (4) for supplying a process tank (5) with a substance to be treated, outlet means for passing a post-treatment matter out of the tank, and air inlet means (2) for supplying the process tank with air required by a biological process, are used for conducting a biological treatment on the matter to be treated. The process tanks (5) are first provided with a microbe population adapted for treating the matter to be treated. The matter to be treated is supplied gradually into the first process tank and then further into a subsequent process tank, such that the microbe population initially provided in the process tanks displaces in a step-by-step manner the original microbe population present in the matter to be treated. The matter, which is substantially free of the original microbes and has been expelled from the final process tank, is returned into the first process tank for diluting the matter to be treated. Downstream of the process tanks is conducted a nitrogen removal treatment by feeding the matter to be treated from the process tank (5) of a stripping tower (22A), in which the pH of a matter to be treated has been raised by means of a biological treatment to a level sufficient from the standpoint of nitrogen removal.