Method and apparatus for treating natural gas and oil well waste waters for removal of contaminants and dissolved solids

Abstract

A method for treating wastewater is disclosed. The method is useful in particular for treating wastewater that is generated from the process of drilling, hydraulic fracturing and / or cleaning a bore of an oil or natural gas well bore. The method may include performing cold lime softening of the wastewater to form waste salt floes, filtration of waste salt floes, ozonation of the filtrate from the filtration, and reverse osmosis of the filtrate to produce a purified permeate.

Description

[0001]This application claims priority from United States Provisional Application for Patent No. 61 / 759,427, filed Feb. 1, 2013. This application is also related to the inventions disclosed in U.S. patent application Ser. No. 12 / 914,072 filed Oct. 28, 2010, which claims priority from United States Provisional Application for Patent No. 61 / 255,504, filed Oct. 28, 2009; and U.S. patent application Ser. No. 13 / 461,871 filed May 2, 2012, which claims priority from United States Provisional Application for Patent No. 61 / 481,370, filed May 2, 2011. The disclosures of all of these United States patent applications are incorporated herein by reference.TECHNICAL FIELD[0002]This invention relates to the removal of contaminants from waste water discharged at a gas wellhead, and more particularly to the removal of contaminants from water that is used during the process of drilling, hydraulic fracturing and / or cleaning a well bore, and then subsequently discharged from the wellhead.BACKGROUND AR...

AI Technical Summary

Benefits of technology

The patent describes a process and apparatus to treat waste waters by removing organic matter and suspended solids, softening the water, and then reducing the saline content using a reverse osmosis membrane system. The process can be customized to different saline levels and can also include an advanced ozone oxidation process to prevent organic fouling of the membranes. The invention is designed to reduce the risk of blinding the membranes with precipitates of metal salts and can include a bypass for the softening stage when anions like carbonate and hydroxide are not present. Overall, the patent provides a flexible and effective solution for treating high-saline waste waters.

Problems solved by technology

Due to various logistical limitations this water may not be readily and / or cost effectively disposed in injection wells.

In addition, the elevated levels of dissolved salts or total dissolved solids (TDS) in the water produce a potential for contamination of subsurface and surface waters from compromised storage systems.

Therefore certain restrictions through new and proposed regulations in many jurisdictions limit the means and / or increase to cost of storage of the water for reuse or awaiting disposal.

New regulations require secondary containment around the frac tanks and specially lined ponds and impoundments with requirements for routine and expensive integrity testing of the pond and impoundment liners.

This often requires the trucking and disposal of the waste water prior to its reuse; or its repetitive relocation with trucking, which often renders its reuse uneconomical.

The utilization of batteries of frac tanks for storage of this water becomes expensive and logistically difficult in remote regions.

Furthermore, to the best of the Applicants' knowledge, a portable integrated system treating multiple and variable water sources and producing customizable saline levels in the effluent is not available.

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