Water treatment apparatus

Abstract

An apparatus for an ozone-based treatment of polluted water is disclosed. The apparatus generally comprises three stages. The first stage is an ozone treatment stage wherein the polluted water is treated with ozone gas. The second stage is a degassing stage wherein excess undissolved gases are removed from the water whereby the water exiting the degassing stage is essentially saturated with gases. The last stage of the apparatus is a membrane filtration stage wherein the gas-saturated water generally undergoes micro-filtration or ultra-filtration. Microbubbles formed during this final stage generally prevent the accumulation of particles and pollutants on the surface of the membranes and/or inside the openings or pores thereof; thereby acting as a self-cleaning mechanism for the membrane filter.

1 ) A water treatment apparatus for treating water, said apparatus comprising:
 a) an ozone treatment module for treating said water with ozone;   b) a degassing module, located downstream said ozone treatment module and fluidly connected thereto, for removing undissolved gases from said water and for providing substantially gas-saturated water;   c) a filtration module, located downstream from said degassing module and fluidly connected thereto, for filtering said gas-saturated water, said filtration module comprising a membrane adapted to cause a pressure drop as said gas-saturated water passes therethrough, said pressure drop causing the formation of microbubbles.   
   
   
       2 ) A water treatment apparatus as claimed in  claim 1 , wherein said membrane comprises openings and wherein a portion of said microbubbles are formed within said openings of said membrane. 
   
   
       3 ) A water treatment apparatus as claimed in  claim 1 , wherein said apparatus further comprises an ozone source, connected to said ozone treatment module, for providing said ozone thereto. 
   
   
       4 ) A water treatment apparatus as claimed in  claim 1 , wherein said ozone treatment module further comprises an ozone injecting unit for injecting said ozone into said water. 
   
   
       5 ) A water treatment apparatus as claimed in  claim 4 , wherein said ozone injecting unit is a venturi. 
   
   
       6 ) A water treatment apparatus as claimed in  claim 3 , wherein said ozone source is comprised within said ozone treatment module. 
   
   
       7 ) A water treatment apparatus as claimed in  claim 3 , wherein said ozone treatment module further comprises a contacting chamber, located downstream said ozone injecting unit and fluidly connected thereto, for favouring the dissolution of at least a portion of said ozone into said water. 
   
   
       8 ) A water treatment apparatus as claimed in  claim 6 , wherein said ozone treatment module further comprises a contacting chamber, located downstream said ozone injecting unit and fluidly connected thereto, for favouring the dissolution of at least a portion of said ozone into said water. 
   
   
       9 ) A water treatment apparatus as claimed in  claim 1 , wherein said membrane filtration module comprises at least one membrane filter. 
   
   
       10 ) A water treatment apparatus as claimed in  claim 1 , wherein said membrane filtration module comprises a plurality of membrane filters. 
   
   
       11 ) A water treatment apparatus as claimed in  claim 10 , wherein said membrane filters are disposed in parallel. 
   
   
       12 ) A water treatment apparatus as claimed in  claim 1 , wherein said membrane comprises openings and wherein said pressure drop is caused as said gas-saturated water passes through said openings in said membrane. 
   
   
       13 ) A water treatment apparatus as claimed in  claim 1 , wherein said apparatus is fully pressurized. 
   
   
       14 ) A water treatment apparatus for treating raw water, said apparatus comprising:
 a) a ozone treatment module comprising:
 i) an ozone injecting unit for injecting ozone into said raw water; 
 ii) a contacting chamber, located downstream said ozone injecting unit and fluidly connected thereto, for dissolving at least a portion of said ozone into said raw water; 
   b) a degassing module, located downstream said contacting chamber and fluidly connected thereto, comprising a degasser for removing undissolved gases from said ozone treated water and for providing substantially gas-saturated water;   c) a filtration module, located downstream said degassing module and fluidly connected thereto, comprising at least one membrane itself comprising a plurality of openings through which said gas-saturated water can pass;   whereby the passage of said gas-saturated water through said membrane provokes the formation of microbubbles which dislodge and prevent the accumulation of particles therein.   
   
   
       15 ) A water treatment apparatus as claimed in  claim 14 , wherein said apparatus further comprises an ozone source, connected to said ozone injecting unit, for providing said ozone thereto. 
   
   
       16 ) A water treatment apparatus as claimed in  claim 14 , wherein said ozone injecting unit is a venturi. 
   
   
       17 ) A water treatment apparatus as claimed in  claim 14 , wherein the passage of said gas-saturated water through said openings provokes a depressurization of said gas-saturated water, whereby said depressurization provokes the formation of said microbubbles. 
   
   
       18 ) A water treatment apparatus as claimed in  claim 14 , wherein said ozone treatment unit further comprises a retentate water recirculation means to recirculate a portion of said gas-saturated water before it passes through said openings. 
   
   
       19 ) A water treatment apparatus as claimed in  claim 18 , wherein said retentate water recirculation means comprise a retentate water injecting unit for injecting said portion of said gas-saturated water into said raw water, said retentate water injecting unit being fluidly connected to a retentate water outlet of said filtration module. 
   
   
       20 ) A water treatment apparatus as claimed in  claim 19 , wherein said retentate water injecting unit is a venturi. 
   
   
       21 ) A water treatment apparatus as claimed in  claim 19 , wherein said retentate water injecting unit is disposed in parallel to said ozone injecting unit, whereby said ozone injecting unit receives a first portion of said raw water and said retentate water injecting unit receives a second portion of said raw water. 
   
   
       22 ) A water treatment apparatus as claimed in  claim 20 , wherein said ozone treatment unit further comprises a mixer, located downstream said ozone injecting unit and said retentate water injecting unit and upstream said contacting chamber, for mixing said first portion of said raw water, second portion of said raw water, said retentate water and said ozone. 
   
   
       23 ) A water treatment apparatus as claimed in  claim 14 , wherein said apparatus is fully pressurized. 
   
   
       24 ) A water treatment apparatus for treating raw water, said apparatus comprising:
 a) an ozone treatment module comprising:
 i) an ozone injecting unit for injecting ozone into a first portion of said raw water, said ozone injecting unit being connected to an ozone source; 
 ii) a retentate water injecting unit for injecting retentate water into a second portion of said raw water; 
 iii) a mixer, located downstream said ozone injecting unit and said retentate water injecting unit and fluidly connected thereto, for mixing said first and second portions of said raw water and for providing mixed water; 
 iv) a contacting chamber, located downstream said mixer and fluidly connected thereto, for favouring the dissolution of at least a portion of said ozone into said mixed water; 
   b) a degassing module, located downstream said contacting chamber and fluidly connected thereto, comprising a degasser for substantially removing any undissolved gases from said ozone-treated mixed water and for providing substantially gas-saturated water;   c) a filtration module, located downstream said degassing module and fluidly connected thereto, comprising at least one membrane filter itself comprising openings through which said gas-saturated water can pass, an inlet for receiving said gas-saturated water, a first outlet for allowing filtered water to exit said filtration module and a second outlet connected to said retentate water injecting unit;   wherein the passage of said gas-saturated water through said membrane provokes the formation of microbubbles which prevent the accumulation of particles therein.   
   
   
       25 ) A water treatment apparatus as claimed in  claim 24 , wherein said apparatus further comprises an ozone source, connected to said ozone injecting unit, for providing said ozone thereto. 
   
   
       26 ) A water treatment apparatus as claimed in  claim 24 , wherein said ozone injecting unit is a first venturi. 
   
   
       27 ) A water treatment apparatus as claimed in  claim 24 , wherein said retentate water injecting unit is a second venturi. 
   
   
       28 ) A water treatment apparatus as claimed in  claim 24 , wherein the passage of said gas-saturated water through said openings provokes a depressurization of said gas-saturated water and the formation of said microbubbles. 
   
   
       29 ) A water treatment apparatus as claimed in  claim 24 , wherein said apparatus is fully pressurized.