A floating media filter comprising: a. a filter housing having an influent inlet and an effluent outlet ; b. a floating media positioned in the housing for forming a media bed when the filter is in a filtration stage, the media bed having a lower surface ; c. a diffuser trough extending at least a part of the width of the filter housing, the diffuser trough including an upper edge , the diffuser trough: (i) positioned in the filter housing such that the lower surface of the media bed , when the filter is in the filtration stage, is below the upper edge of the diffuser trough ; and (ii) having a shape which directs influent in a predominantly upward direction into the media bed , wherein the influent inlet directs influent flow in a path substantially along an interior length of the diffuser trough ; and d. a backwashing mechanism , which during a backwashing stage, causes dispersion of the media bed , and the backwashing mechanism is at least one from the group consisting of: (i) a charge chamber selectively discharging air into the media bed while allowing liquid to enter the charge chamber ; (ii) a constricted throat in the filter housing below the media bed and a valve allowing discharge of sufficient liquid to cause a rapid drop of the media bed into the throat ; (iii) at least one propeller positioned in the filter housing and rotated with sufficient speed to disperse the media bed ; and (iv) at least one paddle positioned in the filter housing and rotated with sufficient speed to stir the media bed . a. a filter housing having an influent inlet and an effluent outlet ; b. a floating media positioned in the housing for forming a media bed when the filter is in a filtration stage, the media bed having a lower surface ; c. a diffuser trough extending at least a part of the width of the filter housing, the diffuser trough including an upper edge , the diffuser trough: (i) positioned in the filter housing such that the lower surface of the media bed , when the filter is in the filtration stage, is below the upper edge of the diffuser trough ; and (ii) having a shape which directs influent in a predominantly upward direction into the media bed , wherein the influent inlet directs influent flow in a path substantially along an interior length of the diffuser trough ; and (i) positioned in the filter housing such that the lower surface of the media bed , when the filter is in the filtration stage, is below the upper edge of the diffuser trough ; and (ii) having a shape which directs influent in a predominantly upward direction into the media bed , wherein the influent inlet directs influent flow in a path substantially along an interior length of the diffuser trough ; and d. a backwashing mechanism , which during a backwashing stage, causes dispersion of the media bed , and the backwashing mechanism is at least one from the group consisting of: (i) a charge chamber selectively discharging air into the media bed while allowing liquid to enter the charge chamber ; (ii) a constricted throat in the filter housing below the media bed and a valve allowing discharge of sufficient liquid to cause a rapid drop of the media bed into the throat ; (iii) at least one propeller positioned in the filter housing and rotated with sufficient speed to disperse the media bed ; and (iv) at least one paddle positioned in the filter housing and rotated with sufficient speed to stir the media bed . (i) a charge chamber selectively discharging air into the media bed while allowing liquid to enter the charge chamber ; (ii) a constricted throat in the filter housing below the media bed and a valve allowing discharge of sufficient liquid to cause a rapid drop of the media bed into the throat ; (iii) at least one propeller positioned in the filter housing and rotated with sufficient speed to disperse the media bed ; and (iv) at least one paddle positioned in the filter housing and rotated with sufficient speed to stir the media bed . <EOS>