Abstract: A process for treating water is provided where the water is mixed with an inorganic reagent powder such as powder activated carbon. Organics and micropollutants are absorbed by the reagent powder. After the reagent powder has been mixed with the water, the water is directed to a setting tank and sludge from the water settles to produce a clarified effluent. Forming a part of the sludge is the reagent powder previously added. Sludge is collected and directed to a separator that separates the reagent powder from the sludge. Separated reagent powder is recycled and mixed with the water being treated.

Abstract: A process for treating water is provided where the water is mixed with an inorganic reagent powder such as powder activated carbon. Organics and micropollutants are absorbed by the reagent powder. After the reagent powder has been mixed with the water, the water is directed to a setting tank and sludge from the water settles to produce a clarified effluent. Forming a part of the sludge is the reagent powder previously added. Sludge is collected and directed to a separator that separates the reagent powder from the sludge. Separated reagent powder is recycled and mixed with the water being treated.

Abstract: The invention concerns a water treatment method which consists in introducing coagulated water in a flocculation zone, to enable flocculation of microflocs in the presence and around a ballast; introducing the mixture in a decantation zone; separating the treated water in overflow and a mixture of sludge and the ballast in underflow; conveying at least part of said mixture to a sludge/ballast separating system and recycling into or upstream of the flocculation zone the ballast and part of the sludge introduced in said separation system.

Abstract: The invention concerns the use of a coagulation-flocculation-decantation device for water treatment to degrease water inside the device itself so as to eliminate therefrom more than 20% of hexane-extractable matter without resorting to separate degreasing means by flotation. The invention also concerns a plant comprising a coagulation-flocculation-decantation device by ballasted flocs having a coagulation zone (1), means supplying (4) a granular material denser than water (4), a flocculation (6), a decantation zone (8) and means for recycling (15) granular material including at least a hydrocyclone (17). The characterised in that it does nut comprise degreasing means provided upstream of the coagulation-flocculation-decantation device, the grease being removed from the water inside the coagulation-flocculation-decantation device itself without means for injecting air or an equivalent gas.

Abstract: A method is provided for thickening sludge produced through a ballasted flocculation process. The sludge and granular material from the ballasted flocculation process are directed to a sludge separator where the sludge is separated from the granular material. Thereafter the separated sludge is sent to a degassing area and the sludge is degassed. A flocculating agent is mixed or injected into the sludge. The sludge is directed to a sludge thickener with a load at a sill calculated on the surface of the thickener greater than 200 kgMIS/m2/day. This process produces a thickened sludge having a concentration greater than 10 gm/l.

Abstract: The invention relates to a method for treatment of water, permitting the physico-chemical treatment of water, including a ballasted flocculation stage using a granular ballast material with a density greater than water, followed by, a stage of gravity separation of the treated water and the flocculent mass, a stage of separation of the granular material, recycled for the flocculation stage and the muds. Said muds are sent to a stage for treatment of the muds, characterised in comprising a stage in which the functional mode passes from a mode using ballasted flocculation and gravity separation using coagulation and flocculation reagents to a mode functioning by simple gravity separation, without using coagulation and flocculation reagents. The passage from one mode to another is determined using at least one item of information on the water obtained at any stage of the treatment thereof or before said treatment.

Abstract: A method is provided for thickening sludge produced through a ballasted flocculation process. The sludge and granular material from the ballasted flocculation process are directed to a sludge separator where the sludge is separated from the granular material. Thereafter the separated sludge is sent to a degassing area and the sludge is degassed. A flocculating agent is mixed or injected into the sludge. The sludge is directed to a sludge thickener with a load at a sill calculated on the surface of the thickener greater than 200 kgMIS/m2/day. This process produces a thickened sludge having a concentration greater than 10 gm/I.

Abstract: A method is provided for thickening sludge produced through a ballasted flocculation process. The sludge and granular material from the ballasted flocculation process are directed to a sludge separator where the sludge is separated from the granular material. Thereafter the separated sludge is sent to a degassing area and the sludge is degassed. A flocculating agent is mixed or injected into the sludge. The sludge is directed to a sludge thickener with a load at a sill calculated on the surface of the thickener greater than 200 kgMIS/m2/day. This process produces a thickened sludge having a concentration greater than 10 gm/l.

Abstract: The invention concerns an acoustic sensor (44) for identifying obstruction of a circular grit trap for recycling fine sand in an industrial water clarifying plant. The circular grit trap comprises a cylindrical body having an outer wall and having at one first end a first sand-containing fluid inlet for receiving sludge and fine sand and a first overflow outlet of fluid not containing sand orthogonal to the fluid inlet, to evacuate said sludge, and at a second end a second sand-containing fluid underflow outlet coaxial with the first fluid outlet, to recover said sand. The acoustic sensor is sensitive to the noise radiated by the flow of the sand-containing fluid in the circular grit trap and is applied against the outer wall of the cylindrical body of the circular grit trap, in the plane of the fluid inlet but not coaxially therewith.

Abstract: The invention concerns a water treatment method which consists in introducing coagulated water in a flocculation zone, to enable flocculation of microflocs in the presence and around a ballast; introducing the mixture in a decantation zone; separating the treated water in overflow and a mixture of sludge and the ballast in underflow; conveying at least part of said mixture to a sludge/ballast separating system and recycling into or upstream of the flocculation zone the ballast and part of the sludge introduced in said separation system.

Abstract: The invention concerns an installation for measuring the concentration in dense granular material in a flow comprising a liquid, a dense granular material and suspended fine particles. The invention is characterised in that it comprises: at least a member for separating the dense granular material from the liquid and the suspended fine particles, at least a device for measuring (12, 12a, 13) at least a parameter representing the amount of separated dense granular material for a specific time interval T. Such an installation may be integrated in a ballasted-floc water treatment system.

Abstract: The invention relates to a method for treatment of water, permitting the physico-chemical treatment of water, including a ballasted flocculation stage using a granular ballast material with a density greater than water, followed by, a stage of gravity separation of the treated water and the flocculent mass, a stage of separation of the granular material, recycled for the flocculation stage and the muds. Said muds are sent to a stage for treatment of the muds, characterised in comprising a stage in which the functional mode passes from a mode using ballasted flocculation and gravity separation using coagulation and flocculation reagents to a mode functioning by simple gravity separation, without using coagulation and flocculation reagents. The passage from one mode to another is determined using at least one item of information on the water obtained at any stage of the treatment thereof or before said treatment.

Abstract: The invention concerns the use of a coagulation-flocculation-decantation device for water treatment to degrease water inside the device itself so as to eliminate therefrom more than 20% of hexane-extractable matter without resorting to separate degreasing means by flotation. The invention also concerns a plant comprising a coagulation-flocculation-decantation device by ballasted flocs having a coagulation zone (1), means supplying (4) a granular material denser than water (4), a flocculation zone (6), a decantation zone (8) and means for recycling (15) granular material including at least a hydrocyclone (17). The invention is characterised in that it does nut comprise degreasing means provided upstream of the coagulation-flocculation-decantation device, the grease being removed from the water inside the coagulation-flocculation-decantation device itself without means for injecting air or an equivalent gas.

Abstract: The invention concerns a method for thickening sludge derived from a water treatment plant by flocculation-decantation with floc ballasted with micro-sand or other dense granular material using a liquid cyclone treatment (1) of the decantation sludge. The invention is characterised in that it comprises successive steps which consist in: degassing (3) the overflow sludge of the liquid cyclone treatment (1) from the ballasted flocculation decantation unit, said degassing step being carried out on a corresponding degassing surface at a degassing surface velocity of less than 100 mph; injecting at least a flocculating reagent (4) into said sludge; and thickening said sludge in at least a laminar sludge thickener (6), with a stilling floor load calculated at the thickener floor surface higher than 200 kg of suspended matter per m2 per day and the extracted sludge concentration higher than 10 g/l.

Abstract: The invention concerns a flocculation-decantation method by ballasted flocs using a granular material and a step which consists in treating the sludge derived from flocculation-decantation in a circular grit trap wherein the auxiliary liquids tangentially injected into the sludge substantially in the same direction as the latter. The invention also concerns a circular grit trap with a cylindrical part of diameter D tangentially supplied with the suspension to be treated and a conical part and provided with a cylindrical chamber injecting wash-water provided at the conical part outlet and having a diameter D′ ranging between 0.35 D and 0.65 D, said cylindrical chamber having at least a tangential supply of auxiliary liquid along the same feeding direction as said tangential supply of the suspension to be treated.

Abstract: The invention concerns an installation for measuring the concentration in dense granular material in a flow comprising a liquid, a dense granular material and suspended fine particles. The invention is characterised in that it comprises: at least a member for separating the dense granular material from the liquid and the suspended fine particles, at least a device for measuring (12, 12a, 13) at least a parameter representing the amount of separated dense granular material for a specific time interval T. Such an installation may be integrated in a ballasted-floc water treatment system.

Abstract: In a method of treating an untreated flow of liquid charged with particles and/or colloids, the flow is caused to flow in a coagulation zone that is kept turbulent and in which the flow is mixed with a coagulant. The untreated flow and a granular material which is insoluble in and more dense than the flow are caused to flow in an intermediate zone in which the granular material is maintained in suspension. The flow with substantially all of the added granular material and the colloids or particles aggregated therein is caused to flow in a sedimentation zone in which a clarified effluent is separated from sludge consisting of the granular material and the aggregated particles or colloids. The sedimentation zone has an undivided flow cross section, with no separator plates and the effluent is caused to flow therein at an average settling speed of at least 15 m/h.

Abstract: In a method of treating an untreated flow of liquid charged with particles and/or colloids, the flow is caused to flow in a coagulation zone that is kept turbulent and in which the flow is mixed with a coagulant. The untreated flow and a granular material which is insoluble in and more dense than the flow are caused to flow in an intermediate zone in which the granular material is maintained in suspension. The flow with substantially all of the added granular material and the colloids or particles aggregated therein is caused to flow in a sedimentation zone in which a clarified effluent is separated from sludge consisting of the granular material and the aggregated particles or colloids. The sedimentation zone has an undivided flow cross section, with no separator plates and the effluent is caused to flow therein at an average settling speed of at least 15 m/h.

Abstract: An untreated flow of waste water is normally introduced into a plain sedimentation unit during plain sedimentation periods to separate it into sand and a flow treated by plain sedimentation. During other periods, for example periods of heavy rain, a coagulating agent, ballast sand and a flocculating agent are introduced. The coagulated flow is passed into a maturation intermediate area and then, with substantially all the sand and colloids of particles attached to it, into the plain sedimentation unit. Here effluent is separated by plain sedimentation and evacuated and sludge made up of the sand and the adhering colloids and particles is extracted and evacuated via an extraction system and the sand outlet channel of the plain sedimentation unit. The sludge is collected, the ballast sand is separated from it to be recycled into the sand injection area and the sludge and excess sand are extracted.

Abstract: In a method of treating an untreated flow of liquid charged with particles and/or colloids, the flow is caused to flow in a coagulation zone that is kept turbulent and in which the flow is mixed with a coagulant. The untreated flow and a granular material which is insoluble in and more dense than the flow are caused to flow in an intermediate zone in which the granular material is maintained in suspension. The flow with substantially all of the added granular material and the colloids or particles aggregated therein is caused to flow in a sedimentation zone in which a clarified effluent is separated from sludge consisting of the granular material and the aggregated particles or colloids. The sedimentation zone has an undivided flow cross section with no separator plates and the effluent is caused to flow therein at an average settling speed of at least 15 m/h.