A method for treating produced water in a system for treating wastewater is disclosed. The system includes a reverse osmosis unit for removing dissolved solids. The reverse osmosis unit produces a permeate and concentrate. To reduce the fouling potential of the membranes associated with the reverse osmosis unit and/or to increase membrane lifetime and/or to increase system recovery, at least a portion of the concentrate is recycled and mixed with the wastewater stream at a point upstream of the reverse osmosis unit.

A method for treating produced water in a system for treating wastewater is disclosed. The system includes a reverse osmosis unit for removing dissolved solids. The reverse osmosis unit produces a permeate and concentrate. To reduce the fouling potential of the membranes associated with the reverse osmosis unit and/or to increase membrane lifetime and/or to increase system recovery, at least a portion of the concentrate is recycled and mixed with the wastewater stream at a point upstream of the reverse osmosis unit.

An energy recovery system for use in a reverse osmosis system is provided. The energy recovery system has a pair of double headed pistons that reciprocate to pressurize unfiltered water into a reverse osmosis filtration unit. High pressure wastewater from the reverse osmosis filtration unit is used in conjunction with a pump to pressurize the unfiltered water that is pumped to the reverse osmosis filtration unit.

An energy recovery system for use in a reverse osmosis system is provided. The energy recovery system has a pair of double headed pistons that reciprocate to pressurize unfiltered water into a reverse osmosis filtration unit. High pressure wastewater from the reverse osmosis filtration unit is used in conjunction with a pump to pressurize the unfiltered water that is pumped to the reverse osmosis filtration unit.

A method for separation and enrichment of lithium includes the following steps: pretreatment: diluting and filtering salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, and the electrodialysis concentrate is solution enriching lithium ions. The present application couples several different membrane separation technologies by utilizing the advantages of different membrane separation technologies, thereby achieving the purposes of improving the separation efficiency of magnesium and lithium and improving the enrichment efficiency of lithium.

A method for separation and enrichment of lithium includes the following steps: pretreatment: diluting and filtering salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, and the electrodialysis concentrate is solution enriching lithium ions. The present application couples several different membrane separation technologies by utilizing the advantages of different membrane separation technologies, thereby achieving the purposes of improving the separation efficiency of magnesium and lithium and improving the enrichment efficiency of lithium.

A method for separation and enrichment of lithium includes the following steps: pretreatment: carrying out at least two dilutions and at least two filtrations on salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, and the electrodialysis concentrate is solution enriching lithium ions. The present application couples several different membrane separation technologies and dilutes the salina aged brine for many times, thereby realizing the purposes of improving separation efficiency of magnesium and lithium and improving the enrichment efficiency of lithium.

A method for separation and enrichment of lithium includes the following steps: pretreatment: carrying out at least two dilutions and at least two filtrations on salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, and the electrodialysis concentrate is solution enriching lithium ions. The present application couples several different membrane separation technologies and dilutes the salina aged brine for many times, thereby realizing the purposes of improving separation efficiency of magnesium and lithium and improving the enrichment efficiency of lithium.

A method for efficient separation and enrichment of lithium includes the following steps: pretreatment: diluting and filtering salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate, wherein the operation pressure of the nanofiltration separation system is 1.0 MPa˜5.0 MPa; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; and second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, wherein the electrodialysis concentrate is a solution enriching lithium ions. The present application couples several different membrane separation technologies and adopts the monovalent ion selective nanofiltration membrane having good separation performance in the process of nanofiltration.

A method for efficient separation and enrichment of lithium includes the following steps: pretreatment: diluting and filtering salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate, wherein the operation pressure of the nanofiltration separation system is 1.0 MPa˜5.0 MPa; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; and second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, wherein the electrodialysis concentrate is a solution enriching lithium ions. The present application couples several different membrane separation technologies and adopts the monovalent ion selective nanofiltration membrane having good separation performance in the process of nanofiltration.