An electroflotation apparatus for removing impurities from waste water comprising: an electrolytic cell for treating the waste water and having a cylindrical space where waste water is electrolysed and a flock containing the impurities is generated; a water outlet to remove treated water from the apparatus; an outlet pipe having a linear central axis located co-axially with the electrolytic cell for passing the treated water and flock rising up and out of the electrolytic cell to the separation area, the outlet pipe comprising: a first end having a cylindrical portion that is connected to the top of the electrolytic cell and having a first diameter (d 1); a second end through which the treated water and flock exit the outlet pipe, the second end having a second diameter (d 2); and a length extending between the first diameter (d 1) and the second diameter (d 2); wherein the ratio of the second diameter (d 2) to the first diameter (d 1) is between 1.5:1 and 6:1; and wherein the ratio of the length to the first diameter (d 1) is between 7:1 and 45:1; in order that the outlet pipe reduces the turbulence of the treated water from the electrolytic cell before the treated water is passed to the separation area such that aggregation of the flock in the separation area is increased; wherein the separation area is a cylindrical tube extending above the outlet pipe having a cylinder diameter, and the ratio of the cylinder diameter to the second diameter is at least 1.5:1, preferably between 2:1 and 30:1, more preferably between 6:1 and 24:1. an electrolytic cell for treating the waste water and having a cylindrical space where waste water is electrolysed and a flock containing the impurities is generated; a water outlet to remove treated water from the apparatus; an outlet pipe having a linear central axis located co-axially with the electrolytic cell for passing the treated water and flock rising up and out of the electrolytic cell to the separation area, the outlet pipe comprising: a first end having a cylindrical portion that is connected to the top of the electrolytic cell and having a first diameter (d 1); a second end through which the treated water and flock exit the outlet pipe, the second end having a second diameter (d 2); and a length extending between the first diameter (d 1) and the second diameter (d 2); wherein the ratio of the second diameter (d 2) to the first diameter (d 1) is between 1.5:1 and 6:1; and wherein the ratio of the length to the first diameter (d 1) is between 7:1 and 45:1; in order that the outlet pipe reduces the turbulence of the treated water from the electrolytic cell before the treated water is passed to the separation area such that aggregation of the flock in the separation area is increased; wherein the separation area is a cylindrical tube extending above the outlet pipe having a cylinder diameter, and the ratio of the cylinder diameter to the second diameter is at least 1.5:1, preferably between 2:1 and 30:1, more preferably between 6:1 and 24:1. a first end having a cylindrical portion that is connected to the top of the electrolytic cell and having a first diameter (d 1); a second end through which the treated water and flock exit the outlet pipe, the second end having a second diameter (d 2); and a length extending between the first diameter (d 1) and the second diameter (d 2); wherein the ratio of the second diameter (d 2) to the first diameter (d 1) is between 1.5:1 and 6:1; and wherein the ratio of the length to the first diameter (d 1) is between 7:1 and 45:1; in order that the outlet pipe reduces the turbulence of the treated water from the electrolytic cell before the treated water is passed to the separation area such that aggregation of the flock in the separation area is increased; wherein the separation area is a cylindrical tube extending above the outlet pipe having a cylinder diameter, and the ratio of the cylinder diameter to the second diameter is at least 1.5:1, preferably between 2:1 and 30:1, more preferably between 6:1 and 24:1.