3.3. The activated sludge (AS) experiments
Fig. 4, Fig. 5 and Fig. 6 show the wastewater quality such as COD, cyanide concentrations, TS and pH in two both sets of AS: control set (C-AS) and experimental set (E-AS). The effluents of both AS systems achieved similar COD and TS removals of about 74.5% and 26.1% respectively. The pH of wastewater in both AS ranged from pH 7 to pH 9 which lies within the discharging wastewater standard. This implies that both systems have similar efficiencies for treating the wastewater.