FR2476629A2 - Denitrification and nitrification reactors for water treatment - with at least one granular bacterial support bed - Google Patents

Abstract

An installation according to claim 2 of the principal patent comprising a denitrification reactor functioning anaerobically and a nitrification reactor functioning aerobically is characterised in that one and/or the other of the reactors consists of a granular filter bed on which microbial cultures are fixed through which the water to be treated is passed. The principal patent relates to the use of heterotrophic bacteria in the 1st and autotrophic bacteria in the 2nd system with recycling of water from the 2nd to the 1st system. The above replaces an active sludge basin and/or a bacterial bed. The installation avoids the need for clarifiers.

Description

 The main patent claims a process for eliminating carbon and nitrogen pollution of wastewater by nitrification - denitrification by means of heterotrophic and autotrophic bacteria, in which the water to be treated is caused to pass successively in two separate systems containing cultures. different bacteria, the first based on heterotrophic bacteria maintained in anoxia achieving elimination of carbon pollution and denitrification, the second, operating aerobically, based on autotrophic bacteria, carrying out the nitrification of nitrogen pollution, the outgoing nitrified water from the second system being recycled to the first denitrification system.

 The process according to the main patent is characterized in that the sludges of each system are separated and run through independent circuits to be, optionally, brought back, those containing heterotrophic organisms, to the first system, operating in anoxia, those containing autotrophic organisms, to the second system, operating aerobically.

 The same patent also describes an installation for the implementation of said method, successively comprising a first reactor operating in anoxia and a second reactor operating in aerobic mode.

 According to one embodiment of the invention, the second reactor consists of an activated sludge tank; according to another embodiment of the invention, the second reactor consists of a bacterial bed.

 In both of these embodiments, each reactor is associated with a clarifier (bearing the references Z and 6 respectively in the drawing appended to the patent) from which the sludge is optionally recycled, under the conditions provided for in the patent and from which the excess sludge is discharged.

 According to the present addition, one and / or the other of the reactors, instead of being constituted by an activated sludge tank and / or a bacterial bed, consist of an immersed filter, made of a granular support material bacteria that the water to be treated is caused to pass from top to bottom or from bottom to top.

 The important advantage determined by the use of such reactors with a bed of granular materials, which act both as a biological support and as a filter for the suspended matter contained in the water to be treated, consists in the elimination of clarifiers which, both in the case of an activated sludge pool and in that of a bacterial bed, are necessarily associated with these reactors to separate the sludge from the treated water. This results in significant savings in the construction of the installation and facilities in its operation and maintenance.

 It suffices simply to proceed, at suitable intervals, to washing the granular materials which the reactors contain according to well known and effective techniques.

 The materials used for the constitution of such filters can be any, such as: diatoms, cellulose, activated carbon, sand or consist of more elaborate materials of the alveolar or macroporous type such as for example those described and claimed in French patent No. 71 41292 and its additions N0 76 00219 and 77 14196 from the Applicant.

 It is the same with regard to the particle size which must be chosen according to the usual parameters of the water to be treated and the treatment to be applied to it.

 It should be noted that both the reactor operating aerobically and that operating anoxically can consist of such filters.

 It is particularly interesting that the aerobically operating reactor in which the bacterial nitrification cells develop is a reactor with a bed of granular materials.

Claims (1)

 CLAIM  Installation according to claim 2 of the patent application  main, comprising a denitrification reactor operating in  anoxia and an aerobic aerosol nitrification reactor, character  laughing at the fact that one and / or the other of these reactors consist of one (or more) submerged filters with a granular bed, support of bacteria, on which (or the  which) the water to be treated is caused to pass, the microbial cultures res  both fixed on the granular support.