## 3 Results
### Textile WW Treatment Performance Using SD Technology Laboratory Setup
#### 3.1.1 Flowrate Influence on the Effluent Treatment Efficiency Using SD Setup  
The color removal for five different WW flowrates fed on the spinning disc at constant disc rotational speeds is represented in Figure 4a-g. As one can observe in Figure 4a, the highest removals of color at 100 rpm were 45.21% at 10 L/h after 50 min and 41.67% at 15 L/h after 60 min; as the WW flowrate increased, the maximum attained discoloration efficiency decreased. At 250 rpm, the maximum color removal was 33.16% for 20 L/h after 60 min, as seen in Figure 4b, while at 400 rpm the maximum registered value was 46.48% at 20 L/h after 50 min (Figure 4c). The best color removal among these runs was 53.50%, registered at 15 L/h and 550 rpm, after a 50 min operating time interval of the SD setup (Figure 4d). At the 850 rpm disc rotational speed, the maximum discoloration was 48.03% at 15 L/h after 60 min, as shown in Figure 4e, while at 1200 rpm the largest values of color removal was 39.56% at 15 L/h after 60 min (Figure 4f). No relevant data were obtained at 1200 rpm and 30 L/h, thus this flowrate is not represented. One can notice that at the largest investigated rotational speed of 1500 rpm for the 15 L/h flowrate, the discoloration efficiency increased, reaching 49.64%, after 30 min, and then decreased, while the other measured flowrates did not render any improvements regarding the color removal, thus they are not represented in Figure 4g. Figure 3: Variation in the time of the textile WW suspended solids (MS) and colour at a 30 L/h flowrate and three different rotational speeds: (**a**) 100 rpm, (**b**) 300 rpm, (**c**) 500 rpm. The influence of five different WW flowrates on the suspended solids (SS) removal at seven different disc rotational speeds stayed constant, and are shown in Figure 5a-g. Similar to discoloration, the SS removal increases over time, attaining maximum values for certain disc rotational speeds and WW flowrates. However, the experimental conditions for the highest SS removal are not identical to the ones used when the maximum discoloration was obtained. Thus, at a 100 rpm disc rotational speed, the largest suspended solids removals were 57.32% for a 15 L/h feeding WW flowrate and 45.98% at 20 L/h, both after a 60 min measured SD operating time interval (Figure 5a). When the rotational speed was 250 rpm, the suspended solids removal had a maximum of 54.29% at 10 L/h, and reasonably good  
Figure 4: Influence of the WW flowrate on the discoloration at different disc rotational speeds: (a) 100 rpm, (b) 250 rpm, (c) 400 rpm, (d) 550 rpm, (e) 850 rpm, (f) 1200 rpm, (g) 1500 rpm. values of 45.98% and 42.05% at 20 and 15 L/h, respectively, all after 60 min, as shown in Figure 5b. At 400 rpm and 10 L/h, another maximum value of 50% was obtained after 60 min (Figure 5c), while at 550 rpm this value was the highest one recorded for the suspended solids removal--namely, 61.13% at 15 L/h after 50 min, as indicated by Figure 5d. The following working parameters of 850 rpm, at 25, 20, and 15 L/h, respectively, rendered reasonably high values for the suspended solids removal of 54.51%, 51.88%, and 45.53%, respectively, after 40, 50, and 55 min measuring time intervals, as presented in Figure 5e. At 1200 rpm, the best removal was obtained for 15 L/h and had a value of 52.14% after 60 min. The 1500 rpm rotational speed and the 15 L/h WWI flowrate rendered a maximum removal value of 54.98%, followed by a sharp decrease with the operating time (Figure 5g). The other investigated flowrates did not provide promising data, thus they were not included graphically. Figure 5: Influence of the WW flowrate on the suspended solids removal at different disc rotational speeds: (**a**) 100 rpm, (**b**) 250 rpm, (**c**) 400 rpm, (**d**) 550 rpm, (**e**) 850 rpm, (**f**) 1200 rpm, (**g**) 1500 rpm.