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Ozonation of wastewaters with high ammonia loads

ammoniumBromineESTECHindustrial wastewaterNitrateOzone

Introduction

The patent is aimed at treating industrial wastewaters, containing high concentrations of ammonia, by using a bromide enhanced ozonation process that avoids the generation of nitrate. The treatment is based on the optimization of an already-know process that uses the reaction between ozone and bromide to generate hypobromous acid (HOBr) and, through this, gaseous nitrogen.

Technical features

The process uses the reaction product between ozone and bromide (HOBr) to oxidize ammonia into gaseous nitrogen, thus avoiding the generation of nitrate. The nitrate generation is inhibited by using a careful regulation of the process that needs (1) that all the ozone supplied to the system reacts with bromide and (2) that the ammonia removal process is carried out close to neutrality (pH 6-7). At the end of the reaction that generates gaseous nitrogen, the added bromide is ready for a new treatment cycle. The pH is kept into the correct interval through the dosage of buffering species, such as bicarbonate or acid phosphate. Alkali rich waters do not need the addition of buffers. The process can also be used for municipal and industrial wastewaters purification (i.e. final treatment) and for the sanification of wastewaters from aquaculture ponds, if natural bromide is present (marine–coastal environments).

Possible Applications

  • Treatment of wastewaters originated from the adsorption of ammonia;
  • Purification of wastewater of municipal and industrial origin if natural bromide is present;
  • Purification and sanification of waters from aquaculture ponds in marine environments.

Advantages

  • Rapid process for the ammonia removal;
  • No generation of sludge;
  • No need of buffering species for wastewaters with high alkali content;
  • Control of the nitrate generation;
  • Low environmental impact.