Inclined Tube Settler
The inclined tube settler is a core physico-chemical pretreatment unit, specifically designed and applied to address the characteristics of printing and dyeing wastewater, such as high chroma, high suspended solids concentration, and the presence of dyes, sizing agents, and colloidal substances.
Working Principle
Based on the "shallow tank theory," it efficiently removes fine suspended particles, flocs formed by coagulation, and some colloidal pollutants (which are significant contributors to COD and color). Its high-efficiency separation is crucial for ensuring the performance of subsequent biological treatment processes.
It significantly reduces both the organic load and hydraulic load on the biological system, prevents sludge washout, and ensures stable operation of the biological system.
Shallow Tank Theory
Removes COD & Color
Reduces Load on Biology
Prevents Sludge Washout
Design & Operational Features
High-Efficiency Settling Capacity
The densely arranged inclined tube assembly significantly increases the effective settling area, allowing excellent effluent clarity to be maintained even at high surface loading rates (typically 1.5–3.0 m³/m²·h). Its compact structure is especially important for plants with limited space.
Targeted Pretreatment Positioning
It is primarily installed after the coagulation/flocculation process, specifically designed to capture flocs formed by coagulants interacting with dyes, fiber fines, unreacted sizing agents (from the sizing process), and other fine impurities. The removal rate for suspended solids (SS) can typically exceed 80%.
Adaptability to Water Quality Fluctuations
Capable of handling variations in wastewater quality generated from different textile processing stages (e.g., desizing, scouring, dyeing). The targeted selection and use of coagulants are key to optimizing its performance.
Sludge Characteristics & Management
The settled sludge consists mainly of chemical sludge, dyes, and fibers, typically exhibiting a gelatinous, viscous consistency. Therefore, the design emphasizes efficient sludge hopper collection and requires a reliable, frequent sludge discharge system to prevent clogging of the inclined tubes and maintain treatment efficiency.
Typical Treatment Process Sequence
Textile Dyeing Wastewater
→
Grid / Screen
→
Equalization Tank
→
Coagulation Reaction Tank
→
Inclined Tube Settler
→
Subsequent Biological Treatment
→
Advanced Treatment
※ Biological Treatment Options: A/O Process, Bio-contact Oxidation, etc.
Core Advantages
01
Stable Effluent Quality
Provides consistent, clarified influent to downstream treatment units — especially sensitive biological or membrane systems — playing a crucial protective role.
02
Effectively Reduces Load
Removes bio-resistant suspended solids and some colloidal COD, significantly alleviating load on biological treatment and reducing aeration energy consumption.
03
Saves Space
Compact structure with small footprint — ideal for retrofitting existing plants or new projects with limited land availability.
04
Reliable Operation
Simple in principle, stable and reliable in operation, adapting to common operational environment requirements of industrial wastewater treatment.
The inclined tube settler is not merely a solid‑liquid separation device but a critical cornerstone for ensuring pretreatment effectiveness and the overall stability of the system. Its operational efficiency directly impacts the performance of subsequent treatment stages, the system's operating costs, and final compliance with discharge standards.