Abstract: Electrodialysis stacks comprising a series of electrodialysis cells and anaerobic digestion systems incorporating the electrodialysis stacks are provided. Also provided are methods of using the electrodialysis stacks and systems to recover nitrogen, in the form of ammonia, from separated anaerobic digestate. The electrodialysis stacks use monovalent-selective cation exchange membranes to concentrate ammonium ions and other monovalent ions in a concentrate stream, while discriminating against multivalent cations, which, as a result, are retained in a diluate stream. The electrodialysis stacks may use monovalent-selective anion exchange membranes to discriminate against multivalent anions, which, as a result, are selectively retained in a diluate stream.

Abstract: Provided are methods for recovering phosphate from wastewater by treating the wastewater with calcium containing compounds to raise its pH to near neutral values in order to precipitate calcium phosphate compounds, such as brushite, from the wastewater.

Abstract: Electrodialysis stacks comprising a series of electrodialysis cells and anaerobic digestion systems incorporating the electrodialysis stacks are provided. Also provided are methods of using the electrodialysis stacks and systems to recover nitrogen, in the form of ammonia, from separated anaerobic digestate. The electrodialysis stacks use monovalent-selective cation exchange membranes to concentrate ammonium ions and other monovalent ions in a concentrate stream, while discriminating against multivalent cations, which, as a result, are retained in a diluate stream. The electrodialysis stacks may use monovalent-selective anion exchange membranes to discriminate against multivalent anions, which, as a result, are selectively retained in a diluate stream.

Abstract: Provided are methods for recovering phosphate from wastewater by treating the wastewater with calcium containing compounds to raise its pH to near neutral values in order to precipitate calcium phosphate compounds, such as brushite, from the wastewater.

Abstract: A method for recovering phosphate from sewage treatment plants using multi-stage anaerobic digestion includes the treatment of organic acid digest with calcium hydroxide, calcium oxide, and similar compounds to raise pH to near neutral values and precipitate calcium phosphate compounds such as brushite and similar amorphous compounds. The method includes the formation of calcium phosphates on weak-acid ion exchange columns and membranes in contact with organic acid digest. The system includes removal of the calcium phosphate compounds formed by sedimentation, either static or against an upwelling flow, centrifugation, or filtration.

Abstract: A method for recovering phosphate from sewage treatment plants using multi-stage anaerobic digestion includes the treatment of organic acid digest with calcium hydroxide, calcium oxide, and similar compounds to raise pH to near neutral values and precipitate calcium phosphate compounds such as brushite and similar amorphous compounds. The method includes the formation of calcium phosphates on weak-acid ion exchange columns and membranes in contact with organic acid digest. The system includes removal of the calcium phosphate compounds formed by sedimentation, either static or against an upwelling flow, centrifugation, or filtration.

Abstract: A method for recovering phosphate from sewage treatment plants using multi-stage anaerobic digestion includes the treatment of organic acid digest with calcium hydroxide, calcium oxide, and similar compounds to raise pH to near neutral values and precipitate calcium phosphate compounds such as brushite and similar amorphous compounds. The method includes the formation of calcium phosphates on weak-acid ion exchange columns and membranes in contact with organic acid digest. The system includes removal of the calcium phosphate compounds formed by sedimentation, either static or against an upwelling flow, centrifugation, or filtration.

Abstract: A method for recovering phosphate from sewage treatment plants using multi-stage anaerobic digestion includes the treatment of organic acid digest with calcium hydroxide, calcium oxide, and similar compounds to raise pH to near neutral values and precipitate calcium phosphate compounds such as brushite and similar amorphous compounds. The method includes the formation of calcium phosphates on weak-acid ion exchange columns and membranes in contact with organic acid digest. The system includes removal of the calcium phosphate compounds formed by sedimentation, either static or against an upwelling flow, centrifugation, or filtration.

Abstract: The present invention provides a method and apparatus for removing phosphorus from phosphorus containing waste. In one embodiment, the method is preferably carried out by contacting the phosphorus containing waste with a non-cellular membrane and precipitating phosphorus from the waste as struvite. Another aspect of the invention includes a method of removing phosphorus from phosphorus containing sewage comprising filtrates and biosolids. The removal of phosphorus as struvite occurs in two stages as primary and secondary removal. In the primary removal process, the sewage from a dewatering unit is contacted with a first polymeric membrane reactor and the phosphorus is removed as primary struvite. Subsequently Mg is added so as promote struvite formation and the secondary removal process of struvite. In the secondary removal process, the sewage from GBT Filtrate well or Centrifuge Liquor well is contacted with a second monomolecular membrane and the phosphorus is removed as secondary struvite.