Smart Phosphorus Removal Control Project

Solve the phosphorus removal compliance dilemma at a large wastewater plant under the Lianjiang River Basin remediation program.

Xiashan Wastewater Treatment Plant is located in the core area of the Lianjiang River Basin in Chaonan District, Shantou City, with a total design capacity of 110,000 tons/day. It is one of the main battlegrounds in the Lianjiang comprehensive remediation campaign. The plant uses an A²/O micro-aeration oxidation ditch process, with synchronous chemical phosphorus removal. Before the retrofit, phosphorus removal chemical dosing relied on manual experience-based control, dosing pumps were oversized, and influent flow meter readings fluctuated significantly — resulting in an effluent total phosphorus (TP) compliance rate persistently below 15%. Meanwhile, the Lianjiang River Basin continuously tightened its effluent water quality requirements, with the Xiashan plant required to meet Surface Water Environmental Class V standards. How to control chemical costs and reduce manual dependence while ensuring compliance became the core challenge for plant operations.

Smart Phosphorus Removal Dosing Control System Achieves Precise Closed-loop Dosing Control

The project adopted a smart phosphorus removal dosing control system, built on electrical automation and combined with numerical simulation, industrial IoT technology, and neural network algorithms to achieve real-time precise adjustment of phosphorus removal chemical dosing. The system automatically calculates the optimal dosage based on dynamic changes in key parameters such as influent flow rate, pre-dosing orthophosphate concentration, and effluent total phosphorus concentration — transforming the traditional manual, extensive operation mode. It also provides early warning and alarm functions for important process parameters, greatly reducing the management burden on operating personnel.

Dual Benefits of Stable Effluent Compliance and Significant Chemical Cost Reduction

After the system was commissioned, the Xiashan plant achieved 100% stable compliance in effluent total phosphorus — completely reversing the previous passive situation of a compliance rate below 15%. Under the same treatment volume, phosphorus removal chemical consumption dropped by more than 30%, with significantly lower chemical costs. The smart phosphorus removal control system also saves at least RMB 200,000 per year in labor costs. This project provides a replicable technical path for refined operation of large wastewater plants in the Lianjiang River Basin, and validates the engineering value of smart dosing control in synchronous phosphorus removal processes.