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US 2024/0116792 A1Published application
Method for the combined recycling of phosphate and nitrogen from sewage sludge and optionally biological waste
AssigneeRemondis Aqua GmbH & Co. KG
InventorMartin Lebek
Life of this patent
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Abstract
The invention relates to a process for the combined recycling of phosphate and nitrogen from sewage sludge. The core task of the invention consists of the recycling of phosphorous from sewage sludge ash and the reaction of phosphorous with nitrogen from the vapors of the sewage sludge drying and the manure to form NP fertilizer diammonium phosphate.
Claims10
Process (1) for the combined recovery of phosphate and nitrogen from sewage sludge, comprising the following process stages:
- Stage (1A1):
- Optional disintegration of the sewage sludge;
- Stage (1A2):
- Drying of the sewage sludge, resulting in vapors rich in NH3 and dried sewage sludge;
- Stage (1B1):
- Optional condensing of the NH3-rich vapors from Stage (1A2);
- Stage (1B2):
- Optional alkalizing of the condensed NH3-rich vapors from stage (1B1) with release of ammonia [NH3], and driving out of the ammonia [NH3] with heating and/or by applying a reduced pressure and/or with the aid of an air or steam flow (ammonia stripping 1);
- Stage (1D2):
- Incinerating the dried sewage sludge from stage (1A2) into sewage sludge ash;
- Stage (1D3):
- Treating the sewage sludge ash from stage (1D2) with phosphoric acid;
- Stage (1D4):
- Separating the acid-insoluble portion of the treated sewage sludge ash from stage (1D3) to produce an acid-insoluble portion and a filtrate or supernatant in the form of a phosphoric acid-containing liquid;
- Stage (1D5):
- Optional recycling of at least a part of the phosphoric acid-containing liquid from stage (1D4) for use in stage (1D3);
- Stage (1D6):
- Purifying the phosphoric acid-containing liquid from stage (1D4) by adding sulfuric acid to the phosphoric acid-containing liquid from stage (1D4) so that a calcium sulfate precipitate is recovered and separated, and/or by applying ion exchange or Liquid-liquid extraction, resulting in a purified phosphoric acid-containing liquid;
- Stage (1D7):
- Optional concentrating of at least a part of the purified phosphoric acid-containing liquid from stage (1D6) so that phosphoric acid is recovered and separated;
- and
- Stage (1 E):
- Reacting the condensed NH3-rich vapors from stage (1B1) and/or the ammonia [NH3] obtained in stage (1B2) with phosphoric acid [H3PO4] in the form of the phosphoric acid-containing liquid from stage (1D4), the purified phosphoric acid-containing liquid from stage (1D6) and/or the phosphoric acid from stage (1D7) to obtain ammonium phosphate compound and optional separating off of the ammonium phosphate compound obtained.
20 more elements
Combination process (2) for the combined recovery of phosphate and nitrogen from sewage sludge and biological waste, the biological waste comprising an aqueous liquid phase in which at least urea and ammonium compounds and inorganically and organically bound phosphates are dissolved and/or contained in particulate form, comprising the following process stages:
- Stage (2A1):
- Optional disintegration of the sewage sludge;
- Stage (2A2):
- Drying of the sewage sludge, resulting in vapors rich in NH3 and dried sewage sludge;
- Stage (2B1):
- Optional condensing of the NH3-rich vapors from Stage (2A2);
- Stage (2B2):
- Optional alkalizing of the condensed NH3-rich vapors from stage (2B1) with release of ammonia [NH3], and driving out the ammonia [NH3] with heating and/or by applying a reduced pressure and/or with the aid of an air or steam flow (ammonia stripping 2);
- Stage (2C1):
- Optionally separating the solids of the biological waste from the liquid phase;
- Stage (2C2):
- Introducing carbon dioxide gas [CO2] under increased pressure or supercritical carbon dioxide into the liquid phase of the biological waste in order to solubilize particulate-bound phosphates;
- Stage (2C3):
- Reducing the CO2 content in the liquid phase from stage (2C2) by acidifying the liquid phase and driving off dissolved CO2 and/or CO2 bound as carbonate;
- Stage (2C4):
- Alkalizing the liquid phase from stage (2C3) with release of ammonia [NH3] and driving out the ammonia [NH3] with heating and/or by applying a reduced pressure and/or with the aid of an air or steam stream (ammonia stripping 3);
- Stage (2C5):
- Precipitation and separation of calcium phosphate from the liquid phase from stage (2C4);
- Stage (2D1):
- Admixing the precipitated and separated calcium phosphate from stage (2C5) to the dried sewage sludge from stage (2A);
- Stage (2D2):
- Incinerating the mixture of precipitated and separated calcium phosphate from stage (2C4) and dried sewage sludge from stage (2A) to sewage sludge ash;
- Stage (2D3):
- Treating the sewage sludge ash from stage (2D2) with phosphoric acid;
- Stage (2D4):
- Separating the acid-insoluble portion of the treated sewage sludge ash from stage (2D3) to produce an acid-insoluble portion and a filtrate or supernatant in the form of a phosphoric acid-containing liquid;
- Stage (2D5):
- Optional recycling of at least a part of the phosphoric acid-containing liquid from stage (2D4) for use in stage (2D3);
- Stage (2D6):
- Purifying the phosphoric acid-containing liquid from stage (2D4) by adding sulfuric acid to the phosphoric acid-containing liquid from stage (2D4) so that a calcium sulfate precipitate is recovered and separated, and/or by applying ion exchange or Liquid-liquid extraction, resulting in a purified phosphoric acid-containing liquid;
- Stage (2D7):
- Optional concentrating of at least a part of the purified phosphoric acid-containing liquid from stage (2D6) so that phosphoric acid is recovered and separated;
- Stage (2E):
- Reacting the condensed NH3-rich vapors from stage (2B1) and/or the ammonia [NH3] obtained in stage (2B2) and the ammonia [NH3] obtained in stage (2C4) with phosphoric acid [H3PO4] in the form of the phosphoric acid-containing liquid from stage (2D4), the purified phosphoric acid-containing liquid from stage (2D6) and/or the phosphoric acid from stage (2D7) to obtain ammonium phosphate compound, and optionally separating the ammonium phosphate compound obtained.
31 more elements
Dependencies are inferred from the claim text.