## 3 Results and Discussion
### Clarification Tank Performance  
In the secondary clarifier, the processed raw wastewater from the aeration tank was held in a tank such that the aggregated biological flocs settled at the bottom due to gravity and density dissimilarities that were adequate to subdue suspension due to turbulence. The function of the secondary clarifier is to ensure that the wastewater nutrients such as FOG, TSS, proteins, and COD are removed through sludge sedimentation and ensures that the wastewater that is discharged into the environment has fewer contaminants. Additionally, the efficiency of the secondary clarifier is dependent on the activated sludge biofloculants. FOG accumulation in the secondary clarifier results in sludge defloculation [37]. The aeration tank product was fed into the sedimentation tank or clarifier, where further FOG removal occurred. The highest FOG removals observed during the steady state in Figure 5C for Bio-AS, Syn-AS, and CAS were 64.3%, 64%, and 63.3%, respectively. Despite the decrease in Bio-AS FOG removal on day 2, from days 5 to 8, the Bio-AS secondary clarifier efficacy improved. The secondary clarifier FOG influent concentration was relatively low, hence the reduction in FOG concentration.  
Figure 5F graphically illustrates the reduction of soluble protein when the AS was operated under the Bio-AS conditions. During the steady state (day 4), the Bio-AS achieved a maximum of 99% protein reduction because the defoamer functional group was a polysaccharide that has multiple charges on its surface, and this allows the proteins (depending on the wastewater's pH, either negatively or positively charged) to attach to any of these sites leading to flocculation of compact flocs that can easily settle at the bottom of the secondary clarifier [21], whereas during the steady state (day 5), the Syn-AS removed a maximum of 92.2%; moreover, the CAS minimized soluble protein concentration by 89.3% during the steady state (day 4). Furthermore, liquid-solid separation was noted due to TSS concentration removal. The highest TSS removal for the Bio-AS of 88% was obtained during steady state (day 7), which shows that the macro flocs with higher density than the presence of the biodefoamer created sludge flocculation, which ensured good solid-liquid separation. During the unsteady state (day 1), the Bio-AS obtained the highest protein reduction of 88%, whereas the Syn-AS achieved the highest removal of 86%, and the CAS attained 77%. This shows that if there is optimum sludge flocculation in the aeration tank and the secondary clarifier, liquid-solid separation will improve.  
The Bio-AS removed COD concentrations by 67% during the steady state (day 9). In contrast, the Syn-AS achieved the highest COD removal of 44.1% during the unsteady state (day 1), and the CAS achieved a COD removal of 43.2% during the steady state (day 7). The removal of COD was higher in Bio-AS because organic TSS was removed. It can be observed that the Bio-AS was consistent in the removal of FOG, protein, COD, and TSS, as it removed FOG up to 10 mg FOG/L in the final effluent, which was less than 400 mg FOG/L that is acceptable according to the Cape of Town (CoCT) discharge standard. It also reduced the TSS concentration of the wastewater up to 100 mg TSS/L which was less than the acceptable CoCT discharge standard concentration of 1000 mg TSS/L. It depreciated COD concentration up to 400 mg/L, less than the \(\leq\)5000 mg COD/L according to the City of Cape Town (CoCT) discharge standards.  
Figure 5: Clarification tank FOG (feed: (**A**); product concentration: (**B**), reduction: (**C**); protein (feed: (**D**); concentration product: (**E**); reduction: (**H**)); TSS (feed: (**G**); product: (**H**); reduction: (**I**)); COD (feed: (**I**); product concentration: (**K**); reduction: (**L**))—profiles carried out under Bio-AS, Syn-AS, and CAS.