This study, conducted at the Haikou Jiangdong Water Plant, applied a direct ultrafiltration process to treat the Nandu River water for potable use. Pilot-scale experiments were performed to optimize key operational parameters, including filtration cycle, backwash regime, and chemical-enhanced backwash (CEB) dosing and frequency. Under the optimized condition, the study comprehensively evaluated treatment performance, membrane-fouling characteristics, and techno-economic outcomes. The results showed that with a filtration cycle of 90 min and a high-intensity, short-duration backwash regime (170 L/(m2·h) flux, 150 s air scouring, 10 s combined air-water top backwash, 10 s combined air-water bottom backwash), together with CEB using 500 mg/L sodium hypochlorite at a frequency of 7 days, the system exhibited robust adaptability and stable performance across varying raw-water qualities. The system maintained regulatory-compliant effluent even when raw-water CODMn reached 7.01 mg/L during high-turbidity periods (≥50 NTU). However, when raw-water CODMn approached 3.6 mg/L during low-turbidity periods (<50 NTU), there was a potential risk of the effluent CODMn exceeding the applicable drinking-water standard. Over 42 days of operation, the transmembrane pressure increased by a cumulative 8.48 kPa but stabilized following a short-term high-turbidity perturbation. Membrane-fouling analyses confirmed that the optimized operating conditions effectively limited fouling and identified siliceous-aluminous inorganic residues as the primary irreversible foulant fraction. A techno-economic assessment indicated water production costs of RMB 0.226/m³ (low-turbidity) and RMB 0.243/m³ (high-turbidity), both lower than the RMB 0.261/m³ estimated for a conventional coagulation-sedimentation-filtration-disinfection process. The operational-parameter framework established in this study provides experimental evidence and technical support for applying direct ultrafiltration as a primary pretreatment unit in engineering practice.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |