Patent ID: 7824552

Claim:
A method of water treatment for sufficiently treating produced water containing particulate and borate so that the treated water may be utilized in well-treatment operations, the method comprising the steps of: (a) pumping said water as part of a treatment stream; (b) centrifugally removing at least some of the particulate present in the treatment stream; and (c) filtering out at least some of the borate in the treatment stream with a filter media capable of removing a borate from the treatment stream at a pH of 8 or above, wherein at least during the step of filtering of borate, the pH of the treatment stream is or is adjusted to be 8 or above; (d) chemically treating the treatment stream, to precipitate sulfate, calcium, magnesium, or iron ions wherein the step of chemically treating comprises at least one of the following steps: (i) adding a water-soluble calcium, strontium, or barium halide to the treatment stream upstream of the centrifugally removing step, wherein the calcium, strontium, or barium halide is capable of precipitating at least some of the sulfate ions dissolved in the treatment stream as calcium, strontium, or barium sulfate; (ii) adding a water-soluble carbonate to the treatment stream upstream of the centrifugally removing step, wherein the carbonate is capable of precipitating at least some of the calcium ions dissolved in the treatment stream as calcium carbonate; and (iii) adding a water-soluble alkali metal hydroxide to the treatment stream upstream of the centrifugally removing step, wherein the hydroxide is capable of precipitating at least some of the magnesium and iron ions dissolved in the treatment stream as magnesium and iron hydroxide, wherein at least some of the precipitated sulfate, calcium, magnesium, or iron ions is removed with said particulate in step (b); and (e) using the filtered water in a well-treatment operation, wherein the filtered water is not suitable for use as freshwater or potable water.