Abstract: A process for treating frac flowback that contains barium, naturally occurring radioactive materials (NORM) and hardness for minimizing the amount of sludge produced that contains hazardous levels of NORM by employing a dual stage precipitation process. In the first stage a sulfate source is mixed with the frac flowback and barium sulfate and NORM is precipitated, the frac flowback is subjected to a solids-liquid separation process to produce a first effluent and a first sludge. In the second stage hardness is precipitated from the first effluent by addition of an alkali reagent, said first effluent is also subjected to solids-liquid separation producing a second effluent and a second sludge. The first sludge is recycled and mixed with the frac flowback and the sulfate source in a sufficient amount to maintain the NORM concentration in the second sludge at or below a threshold level.

Abstract: A process for treating frac flowback that contains barium, naturally occurring radioactive materials (NORM) and hardness for minimizing the amount of sludge produced that contains hazardous levels of NORM by employing a dual stage precipitation process. In the first stage a sulfate source is mixed with the frac flowback and barium sulfate and NORM is precipitated, the frac flowback is subjected to a solids-liquid separation process to produce a first effluent and a first sludge. In the second stage hardness is precipitated from the first effluent by addition of an alkali reagent, said first effluent is also subjected to solids-liquid separation producing a second effluent and a second sludge. The first sludge is recycled and mixed with the frac flowback and the sulfate source in a sufficient amount to maintain the NORM concentration in the second sludge at or below a threshold level.

Abstract: A method of treating produced water, such as frac flowback, that includes pre-treating the produced water which is followed by a crystallization process that produces a condensate that typically includes ammonia and benzene. The ammonia and benzene concentration is reduced by biologically nitrifying and denitrifying the condensate. This produces an effluent that is directed to a solids-liquid separation process that removes suspended solids. The solids-liquid separation process produces another effluent that is subjected to a benzene polishing process that further reduces the benzene concentration of the effluent produced by the solids-liquid separation process.

Abstract: A method of treating produced water, such as frac flowback, that includes pre-treating the produced water which is followed by a crystallization process that produces a condensate that typically includes ammonia and benzene. The ammonia and benzene concentration is reduced by biologically nitrifying and denitrifying the condensate. This produces an effluent that is directed to a solids-liquid separation process that removes suspended solids. The solids-liquid separation process produces another effluent that is subjected to a benzene polishing process that further reduces the benzene concentration of the effluent produced by the solids-liquid separation process.