## 3 Results and Discussion
### Coagulation Test in Pilot Scale  
The pilot-scale PMC-based coagulation experiments were conducted with varying doses of PMC (from 10 to 40 mg/L) at 109 m\({}^{3}\)/h flow rate. The algae removal performance of the PMC-based coagulant in the pilot-scale tests is shown in Figure 8. The chlorophyll-a removal efficiencies in the pilot-scale tests were found to be from 78.0-96.0%, 80.0-98.7%, 90.0-99.6% and 78-95% (depending on the period of experiment) at PMC-based coagulant doses of 10, 20, 30, and 40 mg/L, respectively (Figure 8). The removal trends of algae and turbidity were similar. The coagulation process with PMC showed good algae removal efficiencies in the pilot-scale tests.  
Figure 9 shows the turbidity and UV\({}_{254}\) data before and after PMC coagulation process. The raw water turbidity was varied from 1.6 to 11.8 turbidity (NTU). The turbidity removal efficiencies in the pilot-scale tests were found to be from 33.3-41.4%, 41.2-77.4%, 48.3-84.0% and 36.7-78.9% (depending on the period of experiment) at PMC doses of 10, 20, 30, and 40 mg/L, respectively (Figure 9a). Additionally, the average UV\({}_{254}\) removal efficiencies in the pilot-scale tests were approximately 35.6-45.7%, 41.4-48.9%, 36.7-62.4%, and 42.6-57.6% (depending on the period of experiment) at PMC doses of 10, 20, 30, and 40 mg/L, respectively (Figure 9b). Moreover, the turbidity removal efficiency of the coagulation process increased as the level of turbidity increased. Even though the turbidity removal efficiency was not as high as the lab-scale test, the turbidity level after treatment was low.  
The optimum PMC-based coagulant dose was 20 mg/L for all levels of turbidity in the lab-scale tests. However, the optimum dose for the pilot-scale tests was varied depending on the level of turbidity from 20-30 mg/L, which is 10 mg/L higher dose than the lab-scale. The maximum levels of turbidity of the test water were 4.6 and 11.8 NTU for the lab-scale and pilot-scale tests, respectively. Further increase in PMC dose (40 mg/L) decreases the turbidity removal efficiency. This indicates the occurrence of charge reversal which causes the particles in the test water to be positively charged during the coagulation process and therefore the particles start to restabilize at high PMC coagulant doses. Similarly, chemical coagulants, such as polyaluminium chloride have been reported to decrease turbidity removal efficiencies at doses above the respective optimum doses [42; 43; 44]. The turbidity  
Figure 7: Trends in geosmin and 2-MIB removal by the UV/Cl\({}_{2}\), and UV/H\({}_{2}\)O\({}_{2}\) processes at the lab-scale (initial geosmin concentration: 134.58 ng/L; initial 2-MIB concentration: 159.02 ng/L; UV dose: 0, 200, and 700 mJ/cm\({}^{2}\); Cl\({}_{2}\) dose: 5 mg/L; H\({}_{2}\)O\({}_{2}\) dose: 5 mg/L; initial pH: 6.9).  
removal was higher in the lab-scale than the pilot-scale test at the optimum dose of PMC (20-30 mg/L). For instance, in case of the turbidity of 4.7 NTU, the removal efficiency in the lab scale was 93.4% but the obtained value from the pilot-tests was approximately 70.2%. Even though the turbidity removal efficiency was not as high as the lab-scale test, the turbidity level after treatment was low. The optimum PMC doses difference for the turbidity removal efficiency in the lab-scale test and pilot-scale tests could be due to the differences in the water matrices. Therefore, a PMC dose of 30 mg/L was used for the removal of both T&O compounds in the pilot-scale tests.