Apparatus for the treatment and the clarification of waste water

Claim 1

An apparatus for the treatment of water containing solid particles in suspension, comprising: an outer basin centered on a vertical axis and provided with an inlet for water to be treated; a downwardly diverging open-bottomed housing centered on said axis within said basin above said inlet, said housing being spaced from the bottom of said basin by a peripheral clearance whereby a mixing chamber in said housing communicates with a surrounding annular space in said basin; an agitator in said chamber having a body in the form of a stepped cylinder with a larger-diameter portion and a smallerdiameter portion centered on said axis for rotation therearound, said body being provided with upper and lower peripheral vanes of opposite pitch on said larger-diameter portion and said smaller-diameter portion, respectively; drive means for rotating said body in a sense causing said upper vanes to exert a generally radially outward thrust with an upward component and said lower vanes to exert a generally radially outward thrust with a downward component upon a mixture of said water with a flocculating agent in said chamber with resulting circulation and homogenization of the mixture; and collector means in said annular space for discharging clear water from a supernatant liquid layer overlying a layer of sludge formed by the flocculation of solid particles upon emergence of said mixture from said chamber.

Claim 2

An apparatus for the treatment of water containing solid particles in suspension, comprising: an outer basin centered on a vertical axis and provided with an inlet for water to be treated; a downwardly diverging open-bottomed housing centered on said axis within said basin above said inlet, said housing being spaced from the bottom of said basin by a peripheral clearance whereby a mixing chamber in said housing communicates with a surrounding annular space in said basin; an agitator in said chamber having a body in the form of a stepped cylinder with a larger-diameter portion and a smallerdiameter portion centered on said axis for rotation therearound, said body being provided with upper and lower peripheral vanes of opposite pitch on said larger-diameter portion and said smaller-diameter portion, respectively; drive means for rotating said body in a sense causing said upper vanes to exert a generally radially outward thrust with an upward component and said lower vanes to exert a generally radially outward thrust with a downward component upon a mixture of said water with a flocculating agent in said chamber with resulting circulation and homogenization of the mixture; and collector means in said annular space for discharging clear water from a supernatant liquid layer overlying a layer of sludge formed by the flocculation of solid particles upon emergence of said mixture from said chamber.

Claim 9

An apparatus for the clarification of water containing solid particles in suspension, comprising: an outer basin centered on a vertical axis and provided with an inlet for water to be treated; a downwardly diverging, open-bottomed housing centered on said axis within said basin above said inlet, said housing having a lower edge spaced from the bottom of said basin by a narrow peripheral clearance whereby a treatment chamber in said housing communicates with a surrounding, upwardly diverging annular space in said basin; an agitator in said chamber having a body centered on said axis for rotation therearound, said body being provided with upper and lower peripheral vanes of opposite pitch; a set of relatively small, inclined stationary first baffles on an inner wall surface of said housing above the level of said upper vanes; a set of relatively large, inclined stationary second baffles on said wall surface beneath the level of said lower vanes; drive means for rotating said body in a sense causing said upper vanes to exert a generally radially outward thrust with an upward component, resulting in a circulation in an upper zone past said first baffles, and said lower vanes tO exert a generally radially outward thrust with a downward component, resulting in a circulation in a lower zone past said second baffles, upon a mixture of said water with a flocculating agent in said chamber, thereby homogenizing the mixture and directing a portion thereof downwardly along said wall surface to said clearance for expulsion into said annular space; collector means in said annular space for discharging clear water from a supernatant liquid layer overlying a layer of sludge formed by the flocculation of solid particles upon emergence of said mixture from said chamber; and extraction means for excess sludge opening into said annular space substantially at the level of said clearance.

Claim 10

An apparatus for the clarification of water containing solid particles in suspension, comprising: an outer basin centered on a vertical axis and provided with an inlet for water to be treated; a downwardly diverging, open-bottomed housing centered on said axis within said basin above said inlet, said housing having a lower edge spaced from the bottom of said basin by a narrow peripheral clearance whereby a treatment chamber in said housing communicates with a surrounding, upwardly diverging annular space in said basin; an agitator in said chamber having a body centered on said axis for rotation therearound, said body being provided with upper and lower peripheral vanes of opposite pitch; a set of relatively small, inclined stationary first baffles on an inner wall surface of said housing above the level of said upper vanes; a set of relatively large, inclined stationary second baffles on said wall surface beneath the level of said lower vanes; drive means for rotating said body in a sense causing said upper vanes to exert a generally radially outward thrust with an upward component, resulting in a circulation in an upper zone past said first baffles, and said lower vanes tO exert a generally radially outward thrust with a downward component, resulting in a circulation in a lower zone past said second baffles, upon a mixture of said water with a flocculating agent in said chamber, thereby homogenizing the mixture and directing a portion thereof downwardly along said wall surface to said clearance for expulsion into said annular space; collector means in said annular space for discharging clear water from a supernatant liquid layer overlying a layer of sludge formed by the flocculation of solid particles upon emergence of said mixture from said chamber; and extraction means for excess sludge opening into said annular space substantially at the level of said clearance.