Abstract: A method and apparatus are provided for treating produced water to lower the total dissolved solids of the water for safe discharge to the environment. The produced water is passed through a weak acid cation resin in H+ form to remove cations in the produced water and then preferably through a decarbonator to remove formed CO2 and to provide a first discharge stream. The cation loaded resin is then regenerated using a dilute acid, preferably diluted with produced water, to regenerate the resin to the H+ form. The resultant acid regenerated waste stream is discharged to a reject deep well. The acid regenerated resin is then rinsed, preferably with produced water, to remove residual salts to form a residual salt containing rinse stream. This salt stream is passed into a reverse osmosis unit to form a high salt containing reject stream which is discharged to a waste deep well and a low salt containing product discharge stream which may be safely discharged to the environment.

Abstract: A method and apparatus are provided for treating produced water to lower the total dissolved solids of the water for safe discharge to the environment. The produced water is passed through a weak acid cation resin in H+ form to remove cations in the produced water and then preferably through a decarbonator to remove formed CO2 and to provide a first discharge stream. The cation loaded resin is then regenerated using a dilute acid, preferably diluted with produced water, to regenerate the resin to the H+ form. The resultant acid regenerated waste stream is discharged to a reject deep well. The acid regenerated resin is then rinsed, preferably with produced water, to remove residual salts to form a residual salt containing rinse stream. This salt stream is passed into a reverse osmosis unit to form a high salt containing reject stream which is discharged to a waste deep well and a low salt containing product discharge stream which may be safely discharged to the environment.

Abstract: A biotreatment cell for removing nitrate from water is provided comprising a closed tank having an inlet port and an outlet port, and containing therein particulate matter which forms a fixed porous bed on which microorganisms form a biofilm. Water travels from the inlet to the outlet thereby passing through the bed. The particulate matter has a density and size sufficient to form a fixed bed during the nitrate removal process and provides a bed having a porosity of about 0.25 to 0.95, preferably about 0.45. The bed material is preferably geochemically stable natural rock crushed to promote a specific size distribution. A method and additive system to maintain the nutrient phosphate level at a controlled effluent concentration are also provided for efficiently removing nitrate from water using the biotreatment cell of the invention.

Abstract: A method is disclosed for remediating ponds and other water sites containing sludge and other waste materials by a dredging and dewatering process which is economical and efficient, uses relatively low cost equipment and provides for high remediation rates. The preferred process dredges the site to produce a sludge which is screened to remove oversize material. The screened sludge is then thickened and the thickened sludge dredged and fed as a uniform thickened sludge mixture to a filter press to dewater the sludge producing a final sludge product having a high solids content. A coagulant is preferably added to the sludge and a polymer and/or coagulant added to the thickened sludge filter press feed.