a wire mesh preferably a nylon mesh more preferably nylon mesh of 130 micrometer pore size when in operation the flocs are retained on the filter while the clarified liquid is recycled back to the chamber typically the filter area is related to the flow rate in such a way that the permeate flow rate is between 500 and 5000 lmh litre m2 hr preferably at least 800 lmh more preferably at least 1000 lmh ore even more than 1200 lmh while typically less than 4000 lmh more preferably less than 3000 lmh or even less than 2200 lmh typically a filter will give a back pressure of between 0 1 to 2 bar preferably less than 1 5 bar or even less than 1 bar depending on the flow rate and the surface area and pore size of the filter alternatively the solid liquid separator unit may be a settler tank however since a settler tank inherently involved a large dead volume this is not the most preferred option the solid liquid separator unit may also be centrifugal separators like hydro cyclone wherein the solid flocs are collected in a detachably attachable sump while the clarified liquid is returned to the chamber for the avoidance of doubt the solid liquid separation techniques based on gravity e g settler tanks may yield a deposit of flocs at the bottom of the tank when the flocs have a density that is greater than the density of the liquor while the flocs may float on top when the density of the.