1. The pretreatment device provided in the system is not suitable for the raw water quality and flow, or the system is not equipped with necessary process devices.
2. The pretreatment device does not operate normally, that is, the original pretreatment equipment of the system has low removal capacity of raw water SDI composition, turbidity, colloid, etc., and the pretreatment effect is not ideal.
3. Improper equipment is selected for the system or incorrect equipment material selection (pump, piping and others).
4. The system chemical injection device fails (acid, flocculation / coagulant aid, scale inhibitor / dispersant, reducing agent and others).
5. Failure to take appropriate protective measures after the equipment operates intermittently or the system is out of use.
6. Unreasonable equipment operation and application by operation management personnel (recovery rate, water yield, concentrated water volume, differential pressure, cleaning and others).
7. Long term accumulation of insoluble sediments in the RO membrane system.
8. The components of raw water have changed greatly or the characteristics of water source have changed fundamentally.
9. A considerable degree of microbial contamination has occurred in the reverse osmosis membrane system.
