Method and apparatus for recovery of water containing silica

Abstract

Disclosed are embodiments of a method and apparatus for the treatment of water containing silica in order to recover as much treated water from a water source as possible while minimizing the generation of waste products. Other embodiments include removing specific elements from the water source and utilizing those elements. Embodiments of the method and apparatus uses in-line physical and physio-chemical treatment methods to remove potential biological, colloidal and hardness foulants continually so that there is minimal loss of water from the water source stream and minimal addition of chemicals to accomplish removal or reduction of these potential recovery-limiting foulants.

1 . A method to remove elements from water, said method comprising the steps of:
 receiving a feed water from a water source, the feed water containing at least silica and hardness ions;   ensuring the feed water has a Silt Density Index (SDI) of no more than 3 and polyvalent cations less than 5 mg/L as CaCO 3 ;   introducing the feed water to a high pressure side of a high pressure Reverse Osmosis (RO) membrane system; and   pressurizing the feed water on the high pressure side of the high pressure RO membrane system to produce a permeate stream and a reject stream, the reject stream having a silica concentration of at least 140 mg/L.   
   
   
       2 . The method of  claim 1  wherein the high pressure RO membrane system is operated at a pressure of at least 400 psi. 
   
   
       3 . The method of  claim 1  wherein the ensuring step further includes:
 receiving a water source stream from the water source as a process stream; and   pretreating the process stream with an ion exchange (IX) softener to produce the feed water.   
   
   
       4 . The method of  claim 3  wherein the IX softener is a weak acid cation (WAC) ion exchange resin system operated at least partially in the sodium form. 
   
   
       5 . The method of  claim 3  wherein the wherein the IX softener is a WAC ion exchange resin system operated at least partially in the hydrogen form. 
   
   
       6 . The method of  claim 3  wherein the IX softener is a strong acid cation (SAC) ion exchange resin system. 
   
   
       7 . The method of  claim 1  further including:
 the ensuing step further includes receiving a water source stream from the water source as a process stream and pretreating the process stream with an ion exchange (IX) softener to create a first feed water;   introducing the first feed water into a high pressure side of a low pressure RO membrane system;   pressurizing the first feed water on the high pressure side of the low pressure RO membrane system to produce a first reject stream and a first permeate stream; and   introducing the first reject stream as the feed water to the high pressure side of the high pressure RO membrane system.   
   
   
       8 . The method of  claim 7  wherein the low pressure RO membrane system is operated at a pressure less than 400 psi. 
   
   
       9 . The method of  claim 7  wherein the ensuring step further includes removing micro-colloidal material from the process stream with at least one micron filtration unit. 
   
   
       10 . The method of  claim 9  wherein the at least one micron filtration unit removes micro-colloidal material in the range of 0.01 to 5 microns in size. 
   
   
       11 . The method of  claim 9  wherein the ensuring step further includes exposing the process stream to Ultra-Violet (UV) lights. 
   
   
       12 . The method of  claim 11  further comprising adding at least one of the steps selected from the group consisting of:
 adding an antiscalant to the process stream; and   adding an antiscalant to the first reject stream.   
   
   
       13 . An apparatus to remove elements from a water, said apparatus comprising:
 at least one high pressure RO membrane;   a water source stream from a water source containing at least silica and hardness ions;   a means to ensure a feed water from the water source stream has a Silt Density Index (SDI) of no more than 3 and polyvalent cations less than 5 mg/L as CaCO 3 ; and   a means to introduce the feed water to the high pressure side of the high pressure RO membrane whereby the RO membrane produces a permeate stream and a reject stream, the reject stream having a silica concentration of at least 140 mg/L.   
   
   
       14 . The apparatus of  claim 13  wherein the high pressure RO membrane system is capable of being operated at a pressure of at least 400 psi. 
   
   
       15 . The apparatus of  claim 13  wherein the means to ensure the feed water further includes an IX softener capable of pretreating the water source stream from the water source to create the feed water. 
   
   
       16 . The apparatus of  claim 15  wherein the IX softener is a weak acid cation (WAC) ion exchange resin system capable of being operated at least partially in the sodium form. 
   
   
       17 . The apparatus of  claim 15  wherein the IX softener is a WAC ion exchange resin system capable of being operated at least partially in the hydrogen form. 
   
   
       18 . The apparatus of  claim 15  wherein the IX softener is a strong acid cation (SAC) ion exchange resin system. 
   
   
       19 . The apparatus of  claim 13  further including:
 the means to ensure the feed water further includes an IX softener capable of pretreating the water source stream to create a process stream; and   a low pressure RO membrane system capable of receiving the process stream from the ensuring means as a first feed water and producing a first permeate stream and a first reject stream whereby the first reject stream is the feed water introduced to the high pressure side of the high pressure RO membrane system.   
   
   
       20 . The apparatus of  claim 19  wherein the low pressure RO membrane system is capable of being operated at a pressure less than 400 psi. 
   
   
       21 . The apparatus of  claim 19  wherein the means to ensure the feed water further includes at least one micron filtration unit capable of removing micro-colloidal material from the process stream. 
   
   
       22 . The apparatus of  claim 21  wherein the at least one micron filtration unit removes micro-colloidal material in the range of 0.01 to 5 microns in size. 
   
   
       23 . The apparatus of  claim 21  wherein the means to ensure the feed water further includes at least one Ultra-Violet (UV) light capable of disinfecting the process stream. 
   
   
       24 . The apparatus of  claim 21  further comprising a means to add an antiscalant to at least one of the streams selected from the group consisting of:
 the process stream; and   the first reject stream.