Tube Settlers in Waste Water Clarification Systems

Clarification is a fundamental process in wastewater treatment, responsible for removing suspended solids and reducing turbidity. When space is limited or higher efficiency is needed, a tube settler system is an effective enhancement over conventional clarifiers. This article explores the technical aspects, operational benefits, and application scope of tube settlers as a wastewater clarification unit. It is designed to help engineers, plant managers, and buyers understand the design parameters and performance improvements delivered by tube settler technology.


What is a Tube Settler System?

A tube settler system is a compact inclined plate or tube module installed within a clarifier to increase the settling area and enhance solids removal efficiency. The tubes are inclined at 55–60 degrees, which allows solids to settle rapidly and slide down into a sludge hopper while clarified water flows upward and out.

A tube settler acts like multiple shallow sedimentation tanks stacked vertically, making clarification faster and more efficient.


How a Tube Settler System Works

Working Principle of a Tube Settler System

  1. Inlet Zone
    Wastewater enters the clarifier and flows evenly across the bottom of the tubes.

  2. Settling Zone (Tubes)
    The tubes, arranged at an angle (typically 60°), allow solids to settle on their surface and slide down due to gravity.

  3. Sludge Collection
    The settled solids accumulate in the bottom hopper and are removed periodically or continuously.

  4. Clarified Water Outlet
    Water rises between the tubes to the top collection trough and exits the unit.


Advantages of Tube Settlers as Wastewater Clarification Units

Why Use Tube Settlers in a Wastewater Clarification Unit

Advantage Description
Space Saving 5–10× more surface area per footprint compared to open tanks
Higher Settling Rate Up to 4× faster than conventional clarifiers
Modular Design Easy retrofitting in existing clarifiers
Low Maintenance No moving parts inside tubes
Reduced Sludge Volume Better solid-liquid separation
Uniform Flow Distribution Avoids short-circuiting and dead zones

Design Criteria for Tube Settler Systems

Key Considerations in Tube Settler System Design

Parameter Typical Range/Guideline
Tube Inclination 55–60°
Tube Cross-section Hexagonal or rectangular
Tube Size 50–100 mm side length (hexagonal)
Tube Length 1–2 m typical
Surface Overflow Rate (SOR) 1.2–2.4 m³/m²/hr
Hydraulic Retention Time (HRT) 20–30 minutes
Material PVC, PP, FRP, HDPE

Material of Construction for Tube Settler Modules

Material Characteristics Application Suitability
PVC Lightweight, economical Municipal and general industrial
FRP Chemical and corrosion resistant Aggressive effluents
HDPE Tough and UV-resistant Outdoor tanks, long life

Applications Across Industries

Industrial Uses of a Wastewater Clarification Unit with Tube Settlers

Industry Application Use Case
Municipal STPs Secondary clarification after aeration
Food Processing Clarification after DAF units or coagulation tanks
Textile & Dyeing Clarification post-flocculation and pH correction
Chemical & Pharma High TSS removal from batch effluents
Power Plants Pretreatment in ash water recovery or raw water system

Comparison: Tube Settler vs. Conventional Clarifier

Feature Tube Settler System Conventional Clarifier
Settling Surface Area Higher (compact design) Lower (requires more space)
Footprint Requirement 30–40% of conventional size Large
Sludge Removal Rate Higher efficiency Moderate
Cost Moderate upfront, lower OPEX Higher civil costs
Maintenance Minimal (static modules) Moderate (requires mechanical parts)

Case Study: Tube Settler in Beverage Industry Effluent Plant

  • Location: UAE

  • Flow: 120 m³/day

  • Influent TSS: 350 mg/L

  • Clarifier Type: Tube settler retrofitted in concrete tank

  • Result:

    • TSS reduced to <30 mg/L

    • COD decreased by 45%

    • Plant footprint reduced by 50% compared to original plan

    • Maintenance cost down by 40%


Installation Guidelines

Installing a Tube Settler System in Clarifiers

  • Tank Preparation
    Ensure smooth and clean tank walls, proper inlet weirs, and sludge hoppers.

  • Module Placement
    Place modules in rows with uniform spacing for flow distribution.

  • Support Structures
    Use corrosion-resistant SS or FRP brackets for long-term stability.

  • Outlet Launders
    Must be designed to avoid short-circuiting and ensure equal withdrawal.


Maintenance and Cleaning

  • Flush tubes periodically with air or water jets to avoid algae/scum buildup

  • Remove modules annually for inspection if installed in aggressive effluents

  • Replace modules every 10–15 years based on material and exposure

Compact Effluent Treatment Plants


SAZ ENVIRO’s Tube Settler Systems

SAZ ENVIRO, a reputed manufacturer of wastewater treatment equipment, supplies tube settler systems for municipal, textile, food, and chemical plants. Key features include:

  • Hexagonal PVC/FRP tubes

  • Complete structural frame and SS launders

  • Custom sizing for concrete and MS tanks

  • Installations across India, Kenya, Qatar, Oman, and Saudi Arabia

  • Optional aeration integration for upstream treatment stages


Conclusion

The tube settler system is a game-changing enhancement to traditional clarifiers. As a wastewater clarification unit, it offers higher settling rates, compact footprint, and low maintenance, making it ideal for both retrofits and new installations.

Whether you’re working on a space-constrained site or looking to boost your clarifier’s efficiency, tube settlers provide a reliable and proven solution.

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