Analysis of sludge aggregates produced during electrocoagulation of model wastewater

Abstract

This paper presents the results of the study of sludge aggregates produced during electrocoagulation of model wastewater of a composition corresponding to the effluents from the cellulose and paper industry. Wastewater was electrocoagulated statically using aluminium electrodes with a current density of 31.25 A m−2 and 62.50 A m−2. In subsequent stages of the treatment, sludge flocs were collected, their size was studied and their floc settling velocity (30–520 μm s−1) and fractal dimension (D) were determined. The values of D ranged from 1.53 to 1.95 and were directly proportional to the degree of wastewater treatment. Higher values of D were determined for sludge with lower water content (after 24 hours’ settling). Fractal dimension can therefore be used as an additional parameter of wastewater treatment control.