Removing Heavy Metals in a Ballasted Process
AssigneeEvoqua Water Technologies LLC
InventorsRohan Wikramanayake, Raymond G. Pepln, Thomas Miles
Life of this patent
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Abstract
A system for treating metal-contaminated wastewater includes a primary treatment sub-system, a secondary treatment sub-system, and a tertiary treatment sub-system. The tertiary treatment sub-system includes a reactor tank, a source of ballast material, a source of coagulant, a solids-liquid separator, and a controller configured to recycle ballasted solids from the solids-liquid separator to the reactor tank an amount sufficient to generate metal hydroxide floc in the reactor tank to reduce a concentration of dissolved metal in the reactor tank.
Claims24
A system for treating wastewater, the system comprising:
- a primary treatment sub-system;
- a secondary treatment sub-system in fluid communication downstream of the primary treatment sub-system, the secondary treatment sub-system configured to remove biological contaminants from the wastewater and produce a partially treated wastewater including a dissolved metal;
- and
- a tertiary treatment sub-system in fluid communication downstream of the secondary treatment sub-system, the tertiary treatment sub-system comprising:
- a reactor tank configured and arranged to receive the partially treated wastewater from the secondary treatment sub-system, the reactor tank including at least one inlet and an outlet;
- a source of a ballast material fluidly connected to the reactor tank;
- a source of coagulant fluidly connected to the reactor tank;
- a solids-liquid separator having an inlet fluidly connected to the outlet of the reactor tank and including a solids-lean effluent outlet and a ballasted solids outlet, the solids-liquid separator configured to separate ballasted effluent from the outlet of the reactor tank into a solids-lean effluent and ballasted solids, to discharge the solids-lean effluent from the solids-lean effluent outlet, and to discharge the ballasted solids from the ballasted solids outlet;
- a recycle conduit having an inlet fluidly connected to the ballasted solids outlet, and an outlet fluidly connected to the reactor tank;
- and
- a controller configured to recycle a portion of the ballasted solids from the ballasted solids outlet of the solids-liquid separator to the reactor tank through the recycle conduit in an amount sufficient to generate an amount of metal hydroxide floc in the reactor tank sufficient to reduce a concentration of dissolved metal in the reactor tank.
A method for treating wastewater, the method comprising:
- treating the wastewater in primary treatment sub-system and a secondary treatment sub-system to produce a partially treated wastewater having a reduced concentration of organic contaminants as compared to the wastewater and including a dissolved metal;
- introducing the partially treated wastewater into a reactor tank with a ballast material and a coagulant to form ballasted solids;
- introducing a ballasted effluent from the reactor tank including the ballasted solids into a solids-liquid separator;
- separating the ballasted effluent into ballasted solids and a solids-lean effluent in the solids-liquid separator;
- and
- recycling a portion of the ballasted solids from the solids-liquid separator to the reactor tank in an amount sufficient to generate an amount of metal hydroxide floc in the reactor tank sufficient to reduce a concentration of dissolved metal in the reactor tank.
24-30:
- (canceled)
Dependencies are inferred from the claim text.