METHOD TO TREAT PRODUCED WATERS FROM THERMALLY INDUCED HEAVY CRUDE OIL PRODUCTION (TAR SANDS)

摘要

A method for treating oil field produced wastewater containing high organics, silica, boron, hardness, and suspended and dissolved solids by applying three membrane types in series is provided. First, Ultrafiltration (UF) is applied to remove oil and suspended solids. Second, Nanofiltration (NF) is used to reject hardness, soluble iron and organics. Subsequently, the NF permeate is treated by a double pass Reverse Osmosis (RO) process. The first-pass is applied at a high temperature of about 180° F. and low pH to remove the majority of the salts and silica. Then the feed is chilled, stripped of carbon dioxide and finally pH adjusted to 10 to maximize boron removal.