Integrated wastewater treatment equipment, despite appearing to be operating normally and with no alarms detected on the instruments, still produces persistently turbid and excessively polluted effluent. This deceptive "operational malfunction" is highly misleading, often causing businesses to overlook potential risks and ultimately leading to environmental fines or production shutdowns for rectification.
Many factories disregard design thresholds and arbitrarily adjust their discharge volumes. One food factory, during the rainy season, experienced a sudden spike in influent COD to 620 mg/L (click to view: How to rectify excessive COD and ammonia nitrogen in MBR wastewater treatment equipment effluent), far exceeding its rated load. Such a surge disrupts the activated sludge flocculent structure, causing fine particles to remain in the water, resulting in turbid effluent.
If the treatment is delayed for more than 24 hours, the sludge system may become paralyzed, and it takes 3 to 5 days to restore normal operation. In such circumstances, the manufacturer's after-sales response speed becomes particularly crucial. Timely intervention can significantly reduce losses caused by maintenance, prevent further escalation of the fault, and ensure continuous production.
Abnormal Sludge System Operation
Frequently occurring causes are sludge aging and bulking, which users often neglect to monitor regularly. A certain health center's equipment had not discharged sludge according to regulations for six consecutive months, resulting in sludge levels far below the standard range of 2500-3500 mg/L, with MLSS concentrations dropping below 1800 mg/L. The aged sludge flocs were loose and brittle, exhibiting extremely poor settling performance. The SV30 detection value was only 12%, indicating that a large amount of fine sludge could not settle and was discharged with the effluent (click to view: Solutions for Insufficient Aeration and Sludge Floating in Integrated Wastewater Treatment Equipment). Small plants often only focus on whether the power is on, neglecting dynamic control, ultimately leading to excessive sludge levels.
Chemical Dosing and Filter Component Malfunction
Imbalanced dosing of coagulants or damage to the filter cloth are also common causes. In one industrial park, to save costs, the PAC dosage was reduced by 30%, preventing colloidal impurities from flocculating. Even though sedimentation and filtration were functioning normally, the effluent still appeared milky and turbid, severely impacting water quality standards.
After long-term use, the pores of precision filter cloths are easily clogged by fine impurities. If not cleaned or replaced after a year of operation, the filtration throughput will drop by more than 40%. If the filter cloth has even minor damage, unblocked impurities will penetrate the filter layer, becoming a key cause of turbidity.
Improper Aeration Parameter Control
Excessive aeration continuously agitates the water in the sedimentation zone, breaking up the formed sludge flocs. A guesthouse project had its aerobic tank's dissolved oxygen (DO) level consistently at 5.8 mg/L, far exceeding the reasonable range of 2-3 mg/L. Excessive aeration kept the sedimentation zone constantly disturbed.
Impurities, unable to settle, remained suspended in the water, causing recurring turbidity issues in the effluent. Precisely controlling the aeration rate to maintain dissolved oxygen within a reasonable range is a crucial step in ensuring good sludge settling performance and high-quality effluent, and it cannot be overlooked.
