US 8,092,656 B2  17  18  5.  The process as set forth in claim  1,  wherein said feed  water stream contains more alkalinity than multi-valent metal  cations, and further comprising, before feeding said feed  water stream to said cation ion exchange system, the step of  addition of acid to said feed water stream, so as to remove the  excess alkalinity in said feed water stream.  6.  The process as set forth in claim  1,  wherein the step of  multi-valent metal cation removal is accomplished by passing  said feed water stream through a sodium form strong acid  cation ion exchange system.  7.  The process as set forth in claim  1,  wherein after remov› ing substantially all non-hydroxide alkalinity from said feed  water stream dissolved gas is removed from said feed water  stream.  8.  The process according to claim  1,  wherein said evapo› rator is falling thin film evaporation equipment operating as a  single unit or in series or parallel, or forced circulation evapo› ration equipment which operates as a single unit or in parallel,  or natural circulation evaporation equipment which operates  as a single unit or in parallel, to generate said distillate stream  and said high solids blowdown stream.  9.  The process as set forth in claim  8,  wherein said evapo› rator is operated in a steam driven multiple effect mode, or a  mechanical vapor recompression mode, or a thermal com› pression mode, or as a multiple stage flash evaporator.  10.  The process as set forth in claim  1,  further comprising 25  heating said feed water stream to enhance gas removal in a  degasifier prior to entering said evaporator.  15.  The process as set forth in claim  1,  wherein after step ( c)  (II) and prior to step ( d), the process further comprises the step  of removing dissolved gas in a degasifier.  14.  The process as set forth in claim  1,  further comprising,  during the step of removing alkalinity, the additional step of  removing substantially all non-hydroxide alkalinity not asso› ciated with hardness.  13.  The process according to claim  1,  wherein said feed  water stream is cooling tower blowdown, scrubber blow› down, water utilized in ash transport in a coal fired steam› electric power plant, ash pond water, ash-sluicing water,  effluent from sewage treatment, effluent from a food process› ing treatment, boiler blowdown, a concentrated stream from  membrane separation equipment, effluent from oil refining  operations, or effluents from hydrocarbon recovery opera› tions.  12.  The process according to claim  1,  wherein the step of  raising the pH is accomplished by addition of an aqueous  organic base.  11.  The process according to claim  1,  wherein the step of  raising the pH is accomplished by addition of a base in aque› ous solution, said base selected from the group consisting of  sodium hydroxide, sodium carbonate, potassium hydroxide,  and potassium carbonate.  *  *  *  *  * 