Membrane filtration apparatus and process for reuse of industrial wastewater

Abstract

Laundry, industrial or food processing wastewater is purified to the degree that it can be reused. Water quality is ensured through the final process of reverse osmosis (“RO”) which removes dissolved contaminants such as mineral hardness, soils and residual detergents. The process combines a ceramic tubular cross-flow membrane filter to remove the suspended solids, oils and greases ahead of the RO. The RO process employs high temperature, low fouling membranes. This enables the RO process to operate sustainably, i.e. without fouling, plugging or membrane degradation.

1 - 21 . (canceled) 
     
     
         22 . A water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system, comprising:
 said ceramic membrane filter system includes:   a source of water to be filtered;   a first recirculation loop;   said source of water connected to said first recirculation loop;   a ceramic filter element in said first recirculation loop;   said ceramic filter element includes abrasion resistant ceramic filter membranes;   said abrasion resistant ceramic filter membranes of said ceramic filter elements are tubular and oriented in-line with the direction of the flow of said water;   said tubular abrasion resistant ceramic filter membranes have pores, said pores have a diameter;   particles in said water having a diameter greater than said diameter of said pores are retained within said recirculation loop;   filtrate, which said filtrate is the cleaned water, is removed perpendicularly from said ceramic membrane filter system into to a filtrate discharge header;   said reverse osmosis membrane filter system includes:   a second recirculation loop:   said filtrate of said ceramic membrane filter system connected to said second recirculation loop;   a high temperature low fouling membrane assembly in said second recirculation loop;   said high temperature low fouling membrane assembly includes: a perforated central tube which carries permeate axially therein; a spiral wound thin film polymeric concentric membrane in a cross-flow configuration; and, said concentric membrane separated by a spacer which carries concentrate therein, said concentric membrane being a spiral wound reverse osmosis membrane; and,   said permeate of said reverse osmosis filter system, which said permeate is the cleaned water emanating perpendicularly from said concentric membrane, exits said reverse osmosis membrane filter system for reuse or discharge.   
     
     
         23 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 22 , further comprising:
 said concentric membranes have no detectable pores and separation of said permeate occurs through solution-diffusion mechanisms.   
     
     
         24 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 22 , further comprising:
 a first prefilter resides upstream of said ceramic membrane filter system; and,   a second prefilter resides upstream of said reverse osmosis membrane filter system.   
     
     
         25 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 22 , further comprising:
 a first recirculation pump in said first recirculation loop in which said ceramic membrane filter system resides; and,   a second recirculation pump in said second recirculation loop in which said reverse osmosis membrane filter system resides.   
     
     
         26 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 25 , further comprising:
 said first recirculation loop includes a first recirculation loop conduit from the concentrate discharge of said ceramic membrane filter system to said first recirculation pump;   a concentrate discharge header connected to said first recirculation loop conduit;   a modulating valve in said concentrate discharge header for controlling the removal of discharge from said ceramic filter system; and,   said second recirculation loop includes a reject output conduit from the concentrate discharge of said reverse osmosis membrane filter system to said second recirculation pump; and,   a second modulating valve in a concentrate reject conduit from said reject output conduit, said concentrate reject conduit is connected to a reject concentrate tank.   
     
     
         27 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 22 , further comprising:
 a programmable logic controller;   a first pH sensor in said first recirculation loop of said ceramic membrane filter system communicating with said programmable logic controller;   said programmable logic controller modulates a second control valve in a conduit supplying base to said source of water to be filtered; and,   said programmable logic controller modulates a first control valve in a conduit supplying acid to said source of water to be filtered.   
     
     
         28 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 22 , further comprising:
 a programmable logic controller;   a second pH sensor in said second recirculation loop of said reverse osmosis membrane filter system communicating with said programmable logic controller; and,   said programmable logic controller controls the admission of acid in said permeate of said ceramic membrane filter system connected to said second recirculation loop.   
     
     
         29 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 25 , further comprising:
 said reverse osmosis membrane filter system includes a control valve in said second recirculation loop; and,   said control valve controls the differential pressure across said reverse osmosis membrane filter system.   
     
     
         30 . The water filter comprising a ceramic membrane filter system and a reverse osmosis membrane filter system as claimed in  claim 25 , further comprising:
 said first recirculation pump is driven by a variable frequency drive; and,   said second recirculation pump is driven by a variable frequency drive.