PROCEDE DE COMPOSTAGE D'UNE BOUE LIQUIDE COMPORTANT UNE FILTRATION SEQUENTIELLE SUR SUBSTRAT CARBONE ET INSTALLATION DE MISE EN OEUVRE DU PROCEDE

• Main Authors: IN JEAN LOUIS, PAYET CECILE, RENAT JEAN CHRISTOPHE
• Format: Patent
• Language: French
• Published: 06.06.2003
• Edition: 7
• Subjects: CHEMISTRY; FERTILISERS; MANUFACTURE THEREOF; METALLURGY; ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

L'invention concerne un procédé pour la transformation de boues liquides de siccité < à 8 % sortant d'un silo de stockage de stations d'épuration comportant un ensemble d'étapes (3) de compostage, caractérisé en ce qu'il comporte avant l'ensemble (3) d'étapes de compostage une étape de filtration séquentielle constituée par une alternance (A1 , F1 ,... An, Fn) de (1 à n) étapes d'alimentation (A1 ... An) en boues en provenance du silo et de (1 à n) étapes de filtration gravitaire (F1 ... Fn) à travers un substrat carboné (4). L'invention concerne également une installation de mise en oeuvre du procédé. Application : compostage des boues liquides. The procedure for treating liquid sludge from a purification plant consists of taking the sludge with a dry content of over 8 percent from a storage silo, injecting polymers and passing it first through a sequential filtering stage comprising feed stages alternating with gravitational filtration stages through a carbonaceous substrate made e.g. from bark, straw, sawdust, maize waste or a mixture of these. The procedure for treating liquid sludge from a purification plant, and including composting stages, consists of taking the sludge with a dry content of over 8 per cent from a storage silo (9), injecting polymers and passing it first through a sequential filtering stage (2) comprising feed stages (A1, A2...An) alternating with gravitational filtration stages (F1, F2...Fn) through a carbonaceous substrate made e.g. from bark, straw, sawdust, maize waste or a mixture of these. The filtering stage is carried out without aeration, and the liquid sludge is sprayed over the surface, producing a solid phase of filtered sludge and carbonaceous substrate, and a liquid phase containing 0.2 - 8 per cent of dry material. The filtrate is collected in channels and returned to the beginning of the process, and the solids go on to a composting stage where they are mixed (14) with green waste, fermented (15), matured (16) and riddled (17) before converting into compost.