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TNW Co., Ltd | Working Principle of Automatic PAM Dosing System: Accurate Chemical Dissolution & Intelligent Dosing for Efficient Wastewater Treatment

 

TNW Co., Ltd | Working Principle of Automatic PAM dosing system: Accurate Chemical Dissolution & Intelligent Dosing for Efficient Wastewater Treatment

In wastewater treatment, sludge dewatering and solid-liquid separation processes, Polyacrylamide (PAM) acts as a core flocculant. Its dissolution concentration, curing condition and dosing accuracy directly determine flocculation performance and overall operation cost. Manual chemical preparation suffers from low efficiency, unstable solution concentration, frequent caking waste, over-dosing or insufficient dosage. The automatic PAM dosing system developed by TNW Co., Ltd realizes full-automatic operations including dry powder feeding, automatic dissolution, constant-temperature curing and precise chemical dosing, eliminating common drawbacks of manual operation and supporting stable and efficient running of environmental protection projects.

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1. Core Working Principle: Coordinated Operation of Four Functional Units for Full-process Precision Control

The core principle of TNW automatic PAM dosing system lies in coordinated operation of mechanical conveying, multi-stage dissolution, liquid-level interlock and PLC intelligent control. Dry PAM powder and clean water are blended at a standard proportion ranging from 0.1% to 0.3%. After sufficient curing into high-activity solution, the system automatically adjusts dosing volume according to fluctuations of water quality and sludge volume without manual intervention, so as to secure stable solution concentration, precise feeding and optimal flocculation effect.
The whole working flow is divided into five closely-linked sections: quantitative dry powder feeding, multi-stage dissolution and curing, liquid storage buffering, intelligent precise dosing and automatic linkage control.

1.1 Quantitative Dry Powder Feeding: Uniform Feeding and Anti-caking Design

As the feeding core of the equipment, the feeding unit consists of sealed storage hopper, variable-frequency spiral feeder and pre-wetting device. PAM powder is stored inside the sealed hopper to avoid damp and agglomeration. The variable-frequency spiral feeder controls feeding speed for steady and even powder supply. The pre-wetting component at feeding inlet enables preliminary mixing between powder and clean water to form suspension liquid, fundamentally preventing caking and pipeline blockage caused by direct contact of dry powder with water.
Besides, the feeding system interlocks with the inlet solenoid valve. Feeding quantity and inflow volume are locked at fixed matching ratio; any parameter change will trigger synchronous adjustment to guarantee accurate initial mixing proportion.

1.2 Multi-stage Dissolution & Curing: Maximize Agent Activity via Full Activation

This is the critical section deciding PAM activity and final flocculation result, adopting a three-chamber layout including dissolution tank, curing tank and storage tank with overflow-type sequential flow.

  • Primary dissolution (rapid mixing): Pre-blended liquid flows into the dissolution tank equipped with high-shear agitator rotating at 30~60rpm. Mild stirring disperses dry powder quickly without damaging long molecular chains of PAM.

  • Secondary curing (full activation): Preliminarily dissolved solution overflows into the curing tank for low-speed stirring lasting 30~60 minutes. Such process fully stretches and depolymerizes PAM molecular chains to form homogeneous high-activity liquid. Insufficient curing leads to poor flocculation while overlong curing causes agent failure; TNW equipment precisely controls curing time to balance chemical efficiency and production rhythm.

1.3 Liquid Storage Buffering: Uninterrupted Chemical Supply

Cured qualified solution overflows into the storage tank for buffering, bridging the time gap between slow chemical preparation and continuous dosing. High and low liquid level transmitters are installed inside the tank following the logic: start new batch preparation automatically when liquid drops to low level and suspend production when reaching high level. This design prevents solution deterioration from long-term storage and ensures round-the-clock continuous chemical supply.

1.4 Intelligent Precise Dosing: On-demand Adjustment to Cut Chemical Waste

Qualified solution inside storage tank is delivered to dosing points such as mixing tank, pipeline mixer or inlet of screw press sludge dewatering machine via high-precision metering pumps from well-known brands including SEKO and NEWDOSE.
Three intelligent dosing modes are available with dynamic linkage adjustment:

  • Proportional dosing by flow: Automatically modify metering pump frequency based on inflow or sludge flow; higher flow brings larger dosage and vice versa to match actual treatment load.

  • Closed-loop concentration control: Connected with online turbidity meter and sludge concentration sensor, the system detects real-time water & sludge indicators and optimizes dosing volume to form closed-loop regulation for stable treatment effect.

  • Constant dosing: Fixed chemical supply set for working conditions with stable water quality.

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1.5 PLC-centered Automatic Linkage Control for Unattended Operation

The whole dosing system is dominated by PLC control cabinet with touch screen interface, integrating interlock logics of liquid level, flow, temperature and fault alarm.

  • Automatic start & stop: Liquid level of storage tank triggers start and stop of chemical preparation without manual operation.

  • Automatic concentration stabilization: Dry powder feeding, water intake and stirring timing interlock mutually to maintain steady solution concentration.

  • Fault alarm & protection: The system gives alert and stops relevant equipment in case of material shortage, water cutoff, feeding blockage or pump breakdown.

  • Optional remote monitoring: Extra communication module supports real-time operating data checking and parameter adjustment via mobile phone or computer.

2. Unique Advantages of TNW Automatic PAM Dosing System

Many low-end dosing units on the market adopt simple dual-tank structure with obvious defects including incomplete dissolution, insufficient curing and poor dosing precision. As an integrated equipment manufacturer of screw press and PAM dosing device, TNW Co., Ltd optimizes structural design based on decades of field experience in sludge dewatering with outstanding strengths as below:

  1. Optimized triple anti-caking structure combining pre-wetting, variable-frequency feeding and multi-stage stirring improves PAM utilization rate by over 20%.

  2. Independent curing tank plus timing control ensures full activation of PAM molecular chains, lifting overall flocculation efficiency by around 30% compared with ordinary products.

  3. Tank body is made of PP or 304 stainless steel with strong anti-corrosion and anti-aging performance, suitable for wastewater and sludge containing acid, alkali or oil pollutants.

  4. Perfect matching with TNW screw press: The device automatically adjusts PAM dosage according to real-time sludge concentration and dewatering load of screw press, stabilizing sludge cake moisture between 75%~85% for superior solid-liquid separation.

  5. Low operation & maintenance cost: Fully automatic running reduces regular labor work; precise dosing cuts unnecessary PAM consumption by 15%~25%.

3. Wide Application across Multiple Industries

Benefiting from mature structural principle and stable performance, TNW automatic PAM dosing system is widely applied in various fields:

  • Municipal wastewater: Sludge dewatering of residual activated sludge and dredged sludge from urban sewage treatment plants;

  • Industrial wastewater: Flocculation and sludge dewatering for papermaking, printing & dyeing, chemical, leather, food processing and electroplating industries;

  • Livestock breeding: Manure wastewater treatment matched with screw press for sludge reduction and resource recycling;

  • Other sectors: Coal washing, mineral processing and river regulation requiring flocculation sedimentation and solid-liquid separation.

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Conclusion

A qualified automatic PAM dosing system is never a simple combination of dissolution and feeding units, but well-implemented technology focusing on accurate proportioning, sufficient curing and intelligent dosing. With years of R&D and manufacturing experience in environmental equipment, TNW Co., Ltd combines deep understanding of PAM properties and practical wastewater treatment pain points to develop reliable automatic PAM dosing equipment. It effectively solves troubles of manual dosing, stabilizes flocculation effect and lowers long-term running expenditure.
If you need supporting dosing equipment matched with screw press, plate and frame filter press or customized PAM feeding solutions, TNW Co., Ltd provides reliable equipment with proven working principle, superior workmanship and complete after-sales service.


 

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