A process for the rendering of an effluent stream from a food processing plant, in which the effluent has or is made to have an acidic pH and carries proteinaceous material. The effluent is contacted with an inorganic coagulant (clay) that together with the acidic pH effectively neutralizes ionic charges on the proteinaceous material to cause the proteinaceous material to precipitate out of solution. The effluent stream is contacted with a biologically derived polymeric flocculant to facilitate settling of the precipitated proteinaceous material as flocs. The inorganic coagulant is present in an amount by weight of at least 1.5 times or 2.5 times the amount by weight of polymeric flocculant. Flocs are removed from the effluent stream to thereby render the effluent stream. A biologically derived co-flocculant is added to the effluent stream after contact with the effluent stream by coagulant and flocculant. Insoluble salts of alkaline earth metals are added to the effluent stream after contact with the effluent stream by coagulant and flocculant. The process may be applied to unit operations within the food processing plant. Apparatus for floc treatment include a mixing and acidity settling tank, a conical settling vessel with baffled outlet, a floc seed supply for effluent entering the settling vessel, an effluent diffuser at the inlet to the settling vessel and an agitator set to delay agitation until floc settles in the settling vessel.