polyacrylamides , guar gum , xanthan gum , carboxymethylcellulose , hydroxyethylcellulose , and other water - soluble polymers are dissolved and hydrated in salt solutions , including especially recycled drilling , fracturing , and other oilfield fluids having significant salt contents , by passing the water - soluble polymer to an eductor for mixing with the salt - containing solution and then to a cavitation device including an integrated disc pump . the ability to use water - soluble polymers with the salty recycled oilfield fluids has significant environmental benefits , namely fresh water is not needed , disposal of the environmentally undesirable returned fluids is not needed , difficultly degradable synthetic polymers may not be needed , and , in particular , the enhanced ability to use guar , which , being a natural product , is biodegradable , is environmentally favored .