Wastewater treatment system
AssigneesThe United States of America as represented by the Secretary of Agriculture, North Carolina State University
InventorsMatias B. Vanotti, Ariel A. Szogi, Patrick G. Hunt
Life of this patent
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Abstract
Wastewater treatment systems and processes for: removal of solids, pathogens, nitrogen, and phosphorus from municipal and agricultural wastewater include nitrification of wastewater and increasing the pH of the nitrified wastewater by adding a metallic-containing salt and hydroxide to precipitate phosphorus to form a useable effluent having a specified nitrogen:phosphorus ratio that is useful as a fertilizer or spray for remediation of contaminated soils. The presence of infectious microorganism such as enteropathogenic bacteria and picarnoviruses will be reduced in the useable effluent. The precipitated phosphorus is recovered and used to form useable phosphorus products.
Claims25
A process comprising:
- (a) providing wastewater having at least reduced levels of carbonate and ammonium buffers, and at least reduced levels of suspended solids to a reactor vessel, and
- (b) adding an alkaline earth base to said wastewater to precipitate soluble phosphate.
A process comprising:
- (a) providing a nitrified wastewater having at least reduced levels of suspended solids to a reactor vessel,
- (b) adding an alkali to said nitrified wastewater to increase pH of said nitrified wastewater to at least about pH 9, and
- (c) adding a metallic-containing salt or hydroxide to said wastewater having a pH of at least about pH 9 to precipitate phosphate.
A process comprising:
- (a) providing nitrified wastewater to a reactor vessel,
- (b) adding an alkali to said nitrified wastewater to increase pH of said nitrified wastewater to at least about pH 9, and
- (c) adding a metallic-containing salt or hydroxide which is an alkaline earth metal-containing salt or hydroxide selected from the group consisting of calcium, magnesium, and mixtures thereof.
A process comprising:
- (a) providing nitrified wastewater to a reactor vessel,
- (b) adding an alkali to said nitrified wastewater to increase pH of said nitrified wastewater to at least about pH 9, and
- (c) adding a metallic containing salt or hydroxide selected from the group consisting of sodium, potassium, and mixtures thereof to said wastewater having a pH of at least about 9 to precipitate phosphate.
A process for removing soluble phosphorus from animal wastewater comprising:
- (a) providing wastewater to a nitrification reactor vessel to produce a clarified nitrified wastewater,
- (b) flowing said nitrified wastewater to a separate reactor vessel and adding alkali to said nitrified wastewater to increase the pH of said nitrified wastewater to at least pH 9, and
- (c) adding calcium or magnesium salts or hydroxide to precipitate soluble phosphorus to produce an effluent with a predefined nitrogen:phosphorus ratio.
A process for removing soluble phosphorus from animal wastewater comprising:
- (a) providing wastewater to a nitrification reactor vessel to produce nitrified wastewater,
- (b) flowing said nitrified wastewater to a separate reactor vessel and adding alkali to said nitrified wastewater to increase the pH of said nitrified wastewater to at least about pH 9,
- (c) adding calcium or magnesium salts to precipitate soluble phosphorus to produce an effluent with a predefined nitrogen:phosphorus ratio, and
- (d) using said effluent in a constructed wetland to facilitate denitrification of said effluent.
A process for at least reducing the presence of infectious microorganisms in wastewater comprising:
- (a) providing wastewater to a nitrification reactor vessel to produce clarified, nitrified wastewater, and
- (b) flowing said nitrified wastewater to a separate reactor vessel and adding alkali to said nitrified wastewater to increase the pH of said nitrified wastewater to at least pH 9 and at least reducing the presence of infectious microorganisms.
A process for at least reducing the presence of infectious microorganisms in wastewater comprising:
- (a) providing wastewater to a nitrification reactor vessel to produce nitrified wastewater,
- (b) flowing said nitrified wastewater to a separate reactor vessel and adding alkali to said nitrified wastewater to increase the pH of said nitrified wastewater to at least pH 9 and at least reducing the presence of infectious microorganisms,
- (c) adding calcium or magnesium salts or hydroxide to precipitate soluble phosphorus to produce an effluent with a predefined nitrogen:phosphorus ratio and at least reduce levels of infectious microorganisms, and
- (d) flowing said effluent into a constructed wetland.
A process for at least reducing the presence of infectious microorganisms in wastewater comprising:
- (a) providing wastewater to a nitrification reactor vessel to produce clarified, nitrified wastewater, and
- (b) flowing said nitrified wastewater to a separate reactor vessel and adding alkali to said nitrified wastewater to increase the pH of said nitrified wastewater to at least pH 9 and at least reducing the presence of infectious microorganisms selected from the group consisting of enteropathogenic bacteria, picarnovirus, and mixtures thereof.
A system for wastewater treatment comprising:
- (a) a primary settling unit,
- (b) an aeration unit in fluid communication with said primary settling unit,
- (c) a nitrification bioreactor unit in fluid communication with said aeration unit, and
- (d) a phosphorus separation unit in fluid communication with said nitrification bioreactor unit.
A system for wastewater treatment comprising:
- (a) a solid separation unit,
- (b) an aeration unit in direct fluid communication with a clarified effluent of said solid separation unit,
- (c) a nitrification bioreactor in direct fluid communication with said aeration unit, and
- (d) a phosphorus separation reactor unit in fluid communication with a liquid effluent from said nitrification bioreactor.
A system for wastewater treatment comprising:
- (a) a solid separation unit,
- (b) a denitrification unit in direct fluid communication with a clarified effluent from said solid separation unit,
- (c) a nitrification unit in fluid communication with said denitrification unit, and
- (d) a phosphorus separation reactor unit in fluid communication with a liquid effluent from said nitrification unit.
Dependencies are inferred from the claim text.