METHOD FOR RECOVERING GAS FROM SHALE RESERVOIRS AND PURIFYING RESULTING PRODUCED WATER TO ALLOW THE PRODUCED WATER TO BE USED AS DRILLING OR FRAC WATER, OR DISCHARGED TO THE ENVIRONMENT

摘要

A system and method for removing gas from a gas producing subterranean formation and removing contaminants from the produced water is provided. The method includes providing a mixture of gas and water gathered from a gas producing well. Thereafter the method entails separating the gas from the mixture to produce a gas product and the produced water which includes organics, suspended solids and dissolved solids including silica. Thereafter, suspended solids are removed from the produced water. After removing some of the suspended solids, the produced water is directed to a micro porous polymer extraction (MPPE) unit. In the MPPE unit aromatic organic compounds are removed from the produced water. Thereafter the produced water is treated in a membrane bioreactor to remove additional organics. Thereafter the produced water is directed to at least one RO unit that produces a high dissolved solids containing reject stream and a low dissolved solids permeate stream. The method or process described reduces the concentration of certain contaminants in the produced water such that the output or permeate stream from at least one RO unit can be used for frac fluid, drilling mud, or discharged to the environment.