Method and equipment for processing waste water containing sulphides and ammonium

Abstract

The invention relates to a method for treating waste water containing sulphides and ammonium, in particular waste water from an urban or industrial origin or digestion feedbacks, condensates and lixiviates. The waste water is first subjected to an anoxic processing (1) in a free-culture biological manner, wherein, in a first step (1a), the organic carbon is essentially removed by heterotrophic bacteria and, during a second step (1b) separate from the first, the sulphides are oxidised in a biological manner by autotrophic bacteria with nitrites or nitrates reduction. The effluent from the second step (1b) is submitted to a free-culture aerobic biological treatment (2) for converting the ammonium into nitrates. The conjunction with a sequential aerobic biological reactor (9) compensates a potential nitrate deficit.

Description

technical field [0001] The present invention relates to a method for the treatment of waste water containing sulphide and ammonium, especially waste water or retours de digestions, condensates, leachates of municipal or industrial origin. Background technique [0002] Wastewater, especially wastewater containing carbon, nitrogen and sulfur in the form of various compounds, can be chemically treated by various methods. All physicochemical treatments consist in separating the compounds of these elements from a liquid phase in order to concentrate them in another phase. This relates in particular to methods of stripping (removal of gas from water using entrained gas), reverse osmosis, distillation, chemical precipitation or catalytic oxidation, which are costly to implement and operate. Removal of these compounds via biological pathways is an optional treatment option. [0003] Biological treatment of nitrogen and carbon [0004] Carbon-containing pollutants and nitrogen-con...

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Problems solved by technology

[0027] This method is limited in terms of investment cost as it requires large quantities of expensive carrier materials

[0028] The limitation of this treatment scheme is based on the amount of sulfide oxidized by autotrophic denitrification (which consumes alkalinity)

Since the proposed operating mode consumes alkalinity (autotrophic nitrification in the aeration tank + autotrophic denitrification in the anoxic tank), anoxic media at alkalinity or even There will be restrictions on nitrates

Oxidation of sulfides is therefore not complete

[0029] In addition, the production of volatile fatty acids in the first anaerobic reactor also consumes alkalinity, which is more unfavorable for the sulfide oxidation reaction in the anoxic second reactor

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