Abstract: The present invention concerns a process for treating waters containing at least two different dissolved inorganic salts which do not precipitate and/or crystallize in the same conditions by precipitation and ballasted flocculation, in which the ballast is produced in situ.

Abstract: A method for removing sulfate from a wastewater stream includes mixing gibbsite and a calcium source to precipitate Ettringite from the wastewater stream and produce an effluent with a reduced sulfate concentration. The gibbsite in the precipitated Ettringite is regenerated by mixing an acid with the Ettringite and precipitating gibbsite particles, after which the gibbsite particles are subjected to a crystallization process to increase the size of the gibbsite particles which are recycled back to the main stream.

Abstract: The present invention concerns a process for treating waters containing at least two different dissolved inorganic salts which do not precipitate and/or crystallize in the same conditions by precipitation and ballasted flocculation, in which the ballast is produced in situ.

Abstract: A method of removing barium, calcium, strontium, and magnesium from frac flowback. A sulfate reagent and carbonate reagent are mixed with the frac flowback, causing barium, calcium, strontium, and magnesium to precipitate. The precipitants are crystallized and the resulting frac flowback and crystals are separated into relatively heavy solids and a stream of relatively light solids. The stream of relatively light solids is subjected to a further separation process that produces sludge that is recycled to aid in the crystallization process and a treated effluent which is recycled to the fracking operation or collected and used in another fracking operation.

Abstract: A method for removing sulfate from a wastewater stream includes mixing gibbsite and a calcium source to precipitate Ettringite from the wastewater stream and produce an effluent with a reduced sulfate concentration. The gibbsite in the precipitated Ettringite is regenerated by mixing an acid with the Ettringite and precipitating gibbsite particles, after which the gibbsite particles are subjected to a crystallization process to increase the size of the gibbsite particles which are recycled back to the main stream.

Abstract: A method for removing sulfate from a wastewater stream includes mixing gibbsite and a calcium source to precipitate Ettringite from the wastewater stream and produce an effluent with a reduced sulfate concentration. The gibbsite in the precipitated Ettringite is regenerated by mixing an acid with the Ettringite and precipitating gibbsite particles, after which the gibbsite particles are subjected to a crystallization process to increase the size of the gibbsite particles which are recycled back to the main stream.

Abstract: A ballasted flocculation system that chemically softens water and causes hardness particles to precipitate from the water and crystallize. In the course of crystallizing, the hardness particles grow and form ballasted floc that are separated from the water in the form of sludge by a clarification unit, producing a clarified effluent. The separated sludge including the hardness crystals is directed to a separator where the sludge is separated into two streams with each stream having hardness crystals contained therein. In one process design, one stream includes relatively small hardness crystals and the other stream includes relatively large hardness crystals. The stream having the relatively small hardness crystals is directed to a first reactor and mixed with the incoming water and a softening reagent. The stream having the relatively large crystals is directed to a second downstream reactor and mixed with water and a flocculant which facilitates the growth of the hardness crystals.

Abstract: A method or process for removing perchlorate ions from water includes mixing water containing perchlorate ions with a reducing agent such that the perchlorate ions and the reducing agent undergo an oxidation-reduction reaction. During the oxidation-reduction reaction, perchlorate ions are reduced to chloride ions and the reducing agent is oxidized. The oxidized reducing agent is separated from the water containing chloride ions and the oxidized reducing agent is regenerated and reused in the reduction of the perchlorate ions.

Abstract: A method of reducing a sulfate concentration in wastewater comprises directing the wastewater stream to a precipitation reactor and mixing the wastewater stream with a calcium source and a calcium salt seed material to precipitate calcium sulfate. The precipitated calcium sulfate is then separated from a treated effluent and directed to a settling tank where the precipitated calcium sulfate is separated into heavier calcium sulfate precipitants and lighter calcium sulfate precipitants. The heavier calcium sulfate precipitants and the lighter calcium sulfate precipitants are separately recirculated to the precipitation reactor. A predetermined mass ratio of solids is maintained in the precipitation reactor.

Abstract: A method for removing sulfate from a wastewater stream includes mixing gibbsite and a calcium source to precipitate Ettringite from the wastewater stream and produce an effluent with a reduced sulfate concentration. The gibbsite in the precipitated Ettringite is regenerated by mixing an acid with the Ettringite and precipitating gibbsite particles, after which the gibbsite particles are subjected to a crystallization process to increase the size of the gibbsite particles which are recycled back to the main stream.

Abstract: A ballasted flocculation system that chemically softens water and causes hardness particles to precipitate from the water and crystallize. In the course of crystallizing, the hardness particles grow and form ballasted floc that are separated from the water in the form of sludge by a clarification unit, producing a clarified effluent. The separated sludge including the hardness crystals is directed to a separator where the sludge is separated into two streams with each stream having hardness crystals contained therein. In one process design, one stream includes relatively small hardness crystals and the other stream includes relatively large hardness crystals. The stream having the relatively small hardness crystals is directed to a first reactor and mixed with the incoming water and a softening reagent. The stream having the relatively large crystals is directed to a second downstream reactor and mixed with water and a flocculant which facilitates the growth of the hardness crystals.

Abstract: A method of removing barium, calcium, strontium, and magnesium from frac flowback. A sulfate reagent and carbonate reagent are mixed with the frac flowback, causing barium, calcium, strontium, and magnesium to precipitate. The precipitants are crystallized and the resulting frac flowback and crystals are separated into relatively heavy solids and a stream of relatively light solids. The stream of relatively light solids is subjected to a further separation process that produces sludge that is recycled to aid in the crystallization process and a treated effluent which is recycled to the fracking operation or collected and used in another fracking operation.

Abstract: A method for treating wastewater comprises biologically treating the wastewater in a fixed-biomass biological reactor and then treating the wastewater in a ballasted flocculation system. The ballasted flocculation system produces a clarified effluent and sludge containing inert granular material having biomass accumulated thereon and suspended solids. The inert granular material having biomass accumulated thereon is separated from the suspended solids and then cleaned with a cleaning solution. After separating the biomass from the cleaned inert granular material, the cleaned inert granular material is recycled for use in the ballasted flocculation system.

Abstract: A method or process for removing perchlorate ions from water includes mixing water containing perchlorate ions with a reducing agent such that the perchlorate ions and the reducing agent undergo an oxidation-reduction reaction. During the oxidation-reduction reaction, perchlorate ions are reduced to chloride ions and the reducing agent is oxidized. The oxidized reducing agent is separated from the water containing chloride ions and the oxidized reducing agent is regenerated and reused in the reduction of the perchlorate ions.

Abstract: A method of reducing a sulfate concentration in wastewater comprises directing the wastewater stream to a precipitation reactor and mixing the wastewater stream with a calcium source and a calcium salt seed material to precipitate calcium sulfate. The precipitated calcium sulfate is then separated from a treated effluent and directed to a settling tank where the precipitated calcium sulfate is separated into heavier calcium sulfate precipitants and lighter calcium sulfate precipitants. The heavier calcium sulfate precipitants and the lighter calcium sulfate precipitants are separately recirculated to the precipitation reactor. A predetermined mass ratio of solids is maintained in the precipitation reactor.

Abstract: A process for removing phosphorus from wastewater wherein an iron or aluminum salt is added to the wastewater. The iron or aluminum salt results in the precipitation of certain iron or aluminum species that include phosphorus adsorption sites. These iron or phosphorus species are settled and become a part of sludge produced in the course of the wastewater treatment process. By recycling substantial portions of the sludge, the concentration of these iron or aluminum species in the wastewater is increased. This increased concentration results in the presence of large quantities of unused phosphorus adsorption sites that attract and adsorb phosphorus, resulting in phosphorus being removed from the wastewater.

Abstract: A method for treating wastewater comprises biologically treating the wastewater in a fixed-biomass biological reactor and then treating the wastewater in a ballasted flocculation system. The ballasted flocculation system produces a clarified effluent and sludge containing inert granular material having biomass accumulated thereon and suspended solids. The inert granular material having biomass accumulated thereon is separated from the suspended solids and then cleaned with a cleaning solution. After separating the biomass from the cleaned inert granular material, the cleaned inert granular material is recycled for use in the ballasted flocculation system.

Abstract: A process for removing phosphorus from wastewater wherein an iron or aluminum salt is added to the wastewater. The iron or aluminum salt results in the precipitation of certain iron or aluminum species that include phosphorus adsorption sites. These iron or phosphorus species are settled and become a part of sludge produced in the course of the wastewater treatment process. By recycling substantial portions of the sludge, the concentration of these iron or aluminum species in the wastewater is increased. This increased concentration results in the presence of large quantities of unused phosphorus adsorption sites that attract and adsorb phosphorus, resulting in phosphorus being removed from the wastewater.

Abstract: A process for removing phosphorus from wastewater wherein an iron or aluminum salt is added to the wastewater. The iron or aluminum salt results in the precipitation of certain iron or aluminum species that include phosphorus adsorption sites. These iron or phosphorus species are settled and become a part of sludge produced in the course of the wastewater treatment process. By recycling substantial portions of the sludge, the concentration of these iron or aluminum species in the wastewater is increased. This increased concentration results in the presence of large quantities of unused phosphorus adsorption sites that attract and adsorb phosphorus, resulting in phosphorus being removed from the wastewater.

Abstract: A method for reducing barium concentration in waste streams. Hydrous manganese oxide (HMO) is formed in solution/slurry and mixed with water containing barium such that the hydrous manganese oxide exhibits a negative charge at a desired pH. Barium from the water is adsorbed onto the negatively charged HMO surface. The HMO with adsorbed barium is separated from the water, producing treated effluent having a reduced barium concentration.