กำจัดความขุ่น โดยอุปกรณ์ HWTSTurbidity is a key parameter used to measure the quality of a water source [36]. The recommended limit of turbidity of drinking water by SANS 241 is <1 NTU [16] and the allowable limit is <5 NTU [37]. The average turbidity values of the water samples were found to be 11.98 NTU, 40.4 NTU, 2.17 NTU and 8.39 NTU for surface water of low turbidity, surface water of high turbidity, ground water of low turbidity and ground water of high turbidity respectively. During this study, all devices produced drinking water with turbidity levels within the allowable limit of <5 NTU, but only SIPP produced drinking water with turbidity values <1 NTU. The performance of the two biosand filters in removing turbidity improved as the filters matured (Figure 7b). This was indicated by the decrease in the average turbidity of SWH from 40.0 NTU to 2 NTU. Surface water with a high turbidity was the last and most polluted water source to be filtered. The improvement in the removal of turbidity as the biosand filter matures has been reported by Kaiser, co-authors [38], Ngai, and co-authors [39]. Particle straining is enhanced due to the development of the biological layer, and depth filtration is improved by the decrease in flow rate that increases the retention time [35,39]. The BSF-zeolite (BSF-Z) removed turbidity from all environmental water sources (except SWL) more efficiently than the Biosand- sand (BSF-S). This finding suggests that the zeolites could have played a role in removing turbidity, as this device showed 93% turbidity removal from SWH despite its high flow rate, while the BSF-S with a lower flow rate showed 80% turbidity removal (Figure 7b–d).
การแปล กรุณารอสักครู่..
