A method of treating produced water recovered from an oil well comprising: recovering an oil-water mixture from the oil well; separating oil from the oil-water mixture to produce an oil product and produced water having hardness and suspended solids; subjecting the produced water to an enhanced softening process for removing hardness from the produced water, including reacting a softening reagent with the produced water and precipitating hardness particles in a first reactor; transferring the produced water and hardness particles from the first reactor to a second downstream reactor wherein softening reactions continue in the second reactor; mixing a flocculant with the produced water and hardness particles in the second reactor; crystallizing the hardness particles in the first and second reactors and causing the hardness particles to grow and form hardness crystals; clarifying the produced water having the hardness crystals therein to produce a clarified effluent and a sludge having the hardness crystals therein; directing the sludge to a separator and separating the sludge into two streams, a first stream having hardness crystals therein and a second stream having hardness crystals therein; wherein a majority of hardness crystals of the second stream are larger than a majority of the hardness crystals in the first stream; mixing the first stream having the hardness crystals therein with the produced water and softening reagent in the first reactor and mixing the second stream with hardness crystals therein with the produced water in the second reactor; in the second reactor, continuing to grow the hardness crystals and wherein the addition of the hardness crystals in the second stream facilitates and encourages the further growth of the hardness crystals in the second reactor and as the hardness crystals grow larger in the second reactor, the hardness crystals form hardness ballast; agglomerating suspended solids in the produced water around the hardness ballast; wasting a portion of the sludge; directing the clarified effluent produced in the enhanced softening process to a membrane separation unit; and filtering the clarified effluent with the membrane separation unit to produce a permeate stream and a reject stream. recovering an oil-water mixture from the oil well; separating oil from the oil-water mixture to produce an oil product and produced water having hardness and suspended solids; subjecting the produced water to an enhanced softening process for removing hardness from the produced water, including reacting a softening reagent with the produced water and precipitating hardness particles in a first reactor; transferring the produced water and hardness particles from the first reactor to a second downstream reactor wherein softening reactions continue in the second reactor; mixing a flocculant with the produced water and hardness particles in the second reactor; crystallizing the hardness particles in the first and second reactors and causing the hardness particles to grow and form hardness crystals; clarifying the produced water having the hardness crystals therein to produce a clarified effluent and a sludge having the hardness crystals therein; directing the sludge to a separator and separating the sludge into two streams, a first stream having hardness crystals therein and a second stream having hardness crystals therein; wherein a majority of hardness crystals of the second stream are larger than a majority of the hardness crystals in the first stream; mixing the first stream having the hardness crystals therein with the produced water and softening reagent in the first reactor and mixing the second stream with hardness crystals therein with the produced water in the second reactor; in the second reactor, continuing to grow the hardness crystals and wherein the addition of the hardness crystals in the second stream facilitates and encourages the further growth of the hardness crystals in the second reactor and as the hardness crystals grow larger in the second reactor, the hardness crystals form hardness ballast; agglomerating suspended solids in the produced water around the hardness ballast; wasting a portion of the sludge; directing the clarified effluent produced in the enhanced softening process to a membrane separation unit; and filtering the clarified effluent with the membrane separation unit to produce a permeate stream and a reject stream.