Apparatus for treating liquid containing impurities

Abstract

An apparatus for treating a liquid containing impurities may comprise: a filtering chamber for receiving liquid containing impurities, the filtering chamber containing granular media and configured to permit the granular media to interact with the liquid containing impurities, thereby removing impurities from the liquid to produce filtrate; a filtrate section in communication with the filtering chamber for receiving the filtrate, the filtrate section being in communication with a first outlet for outflow of the filtrate; a gas supplying system for delivering gas to the granular media in the filtering chamber for transport of a portion of the granular media to a granular media washer; and a reject section in communication with the granular media washer for receiving a reject mixture comprising liquid and impurities from the granular media washer. The reject section may be in communication with a second outlet for outflow of a portion of the reject mixture.

What is claimed is: 
     
         1 . An apparatus for treating a liquid containing impurities, comprising:
 a filtering chamber for receiving liquid containing impurities, the filtering chamber including a lower portion containing granular media and configured to permit the granular media to interact with the liquid containing impurities, thereby removing impurities from the liquid to produce filtrate;   a filtrate section in fluid communication with the filtering chamber for receiving the filtrate, the filtrate section being in fluid communication with a first outlet for outflow of the filtrate;   a gas supplying system for delivering gas to the granular media in the filtering chamber for transport of a portion of the granular media to a granular media washer;   a reject section in fluid communication with the granular media washer for receiving a reject mixture comprising liquid and impurities from the granular media washer, the reject section being in fluid communication with a second outlet for outflow of a portion of the reject mixture;   a valve disposed at the second outlet; and   a control unit that is configured to:   (i) determine whether the portion of the granular media is being transported properly;   (ii) control the gas supplying system; and   (iii) control the valve.   
     
     
         2 . The apparatus of  claim 1  in which the control unit is configured to open the valve to allow outflow of a portion of the reject mixture or to close the valve to preclude outflow of a portion of the reject mixture. 
     
     
         3 . The apparatus of  claim 1  in which the control unit is configured to initiate, maintain, or terminate gas flow from the gas supplying system. 
     
     
         4 . The apparatus of  claim 1  in which the initiation, maintenance, or termination of gas flow is carried out either at predetermined times or in response to an outcome of a determination of whether the portion of the granular media is being transported properly. 
     
     
         5 . The apparatus of  claim 4  in which the determination of whether the portion of the granular media is being transported properly is based on an amount of reject mixture in the reject section. 
     
     
         6 . The apparatus of  claim 5  in which the amount of reject mixture in the reject section is determined with the valve open. 
     
     
         7 . The apparatus of  claim 6  in which the amount of the reject mixture in the reject section is based on a level of reject mixture flowing over a reject weir. 
     
     
         8 . The apparatus of  claim 3  in which the airflow comprises a steady flow of gas, a burst of gas, or a combination thereof. 
     
     
         9 . The apparatus of  claim 3  in which the airflow comprises a burst of gas having a duration ranging from three to sixty seconds. 
     
     
         10 . The apparatus of  claim 1  in which the gas supplying system comprises at least two separate paths for supplying gas. 
     
     
         11 . The apparatus of  claim 10  in which the at least two separate paths terminate at the lower portion of the filtering chamber. 
     
     
         12 . The apparatus of  claim 11  in which one of the at least two separate paths terminates at an upper position in the lower portion of the filtering chamber and the other of the at least two separate paths terminates at a lower position in the lower portion of the filtering chamber, the upper position being above the lower position. 
     
     
         13 . The apparatus of  claim 12  in which the control unit is configured to independently initiate, maintain, or terminate gas flowing through each of the at least two separate paths of the gas supplying system. 
     
     
         14 . An apparatus for treating a liquid containing impurities, comprising:
 a filtering chamber for receiving liquid containing impurities from a liquid feed line, the filtering chamber including a lower portion containing granular media and configured to permit the granular media to interact with the liquid containing impurities, thereby removing impurities from the liquid to produce filtrate;   a plurality of feed arms in fluid communication with the liquid feed line, which extend radially in the lower portion of the filtering chamber, for feeding liquid to the granular media through one or more openings along each feed arm, a top of each feed arm presenting one or more cutting edges;   a filtrate section in fluid communication with the filtering chamber for receiving the filtrate, the filtrate section being in fluid communication with a first outlet for outflow of the filtrate;   a gas supplying system for delivering gas to the granular media in the filtering chamber for transport of a portion of the granular media to a granular media washer;   a reject section in fluid communication with the granular media washer for receiving a reject mixture comprising liquid and impurities from the granular media washer, the reject section being in fluid communication with a second outlet for outflow of a portion of the reject mixture;   a valve disposed at the second outlet; and   a control unit that is configured to:   (i) receive one or more signals from at least one sensor;   (ii) control the gas supplying system; and   (iii) control the valve.   
     
     
         15 . The apparatus of  claim 14  in which the one or more openings are located along a bottom of each feed arm. 
     
     
         16 . The apparatus of  claim 14  in which each edge is formed by two planar surfaces meeting at an angle ranging from 10 to 90 degrees. 
     
     
         17 . The apparatus of  claim 14  in which the one or more edges are provided by one or more gussets. 
     
     
         18 . The apparatus of  claim 14  in which each edge comprises an edge of an angular prism. 
     
     
         19 . The apparatus of  claim 18  in which the angular prism comprises a triangular prism. 
     
     
         20 . The apparatus of  claim 14  in which the control unit controls the gas supplying system to deliver gas to the granular media at one or more intervals sufficient to inhibit or prevent bridging of the granular media across adjacent feed arms. 
     
     
         21 . The apparatus of  claim 20  in which the one or more intervals is determined by a sensor that determines head loss between the feed line and the first outlet. 
     
     
         22 . The apparatus of  claim 20  in which the one or more intervals is determined by a sensor that determines an amount of reject mixture in the reject section. 
     
     
         23 . The apparatus of  claim 22  in which the amount of reject mixture in the rejection section is determined by a level of water flowing over a reject weir. 
     
     
         24 . An apparatus for treating a liquid containing impurities, comprising:
 a filtering chamber for receiving liquid containing impurities from a liquid feed line, the filtering chamber including a lower portion containing granular media and configured to permit the granular media to interact with the liquid containing impurities, thereby removing impurities from the liquid to produce filtrate;   a plurality of feed arms in fluid communication with the liquid feed line, which extend radially in the lower portion of the filtering chamber, for feeding liquid to the granular media through one or more openings along each feed arm, a top of each feed arm presenting one or more cutting edges;   an annular space in fluid communication with the liquid feed line and the plurality of feed arms, the annular space equipped with a bottom plate having a plurality of openings;   a filtrate section in fluid communication with the filtering chamber for receiving the filtrate, the filtrate section being in fluid communication with a first outlet for outflow of the filtrate;   a gas supplying system for delivering gas to the granular media in the filtering chamber for transport of a portion of the granular media to a granular media washer; and   a reject section in fluid communication with the granular media washer for receiving a reject mixture comprising liquid and impurities from the granular media washer, the reject section being in fluid communication with a second outlet for outflow of a portion of the reject mixture.   
     
     
         25 . The apparatus of  claim 24  further comprising an airlift pump through which the portion of the granular media is transported. 
     
     
         26 . The apparatus of  claim 24  further comprising a valve disposed at the second outlet. 
     
     
         27 . The apparatus of  claim 26  further comprising a control unit that is configured to:
 (i) receive one or more signals from at least one sensor; 
 (ii) control the gas supplying system; and 
 (iii) control the valve. 
 
     
     
         28 . The apparatus of  claim 24  in which each of the plurality of openings is positioned between adjacent feed arms. 
     
     
         29 . The apparatus of  claim 28  in which each of the plurality of openings is semicircularly shaped. 
     
     
         30 . The apparatus of  claim 28  in which each of the plurality of openings comprises eye-shaped cutouts. 
     
     
         31 . The apparatus of  claim 28  in which the gas supplying system is operated intermittently. 
     
     
         32 . The apparatus of  claim 31  in which the intermittent operation of the gas supplying system is sufficient to inhibit or prevent bridging of the granular media across adjacent feed arms. 
     
     
         33 . The apparatus of  claim 31  in which the control unit includes a timer that tracks one or more time intervals between the intermittent operations of the gas supplying system. 
     
     
         34 . The apparatus of  claim 33  in which the one or more time intervals is sufficiently short to inhibit or prevent bridging of the granular media across adjacent feed arms. 
     
     
         35 . The apparatus of  claim 24  in which each of the plurality of openings empties into a conical space at a lower portion of the filtering chamber. 
     
     
         36 . The apparatus of  claim 35  in which the airlift pump passes through a central portion of the conical space.