In the process of urban modernization, wastewater treatment plants have become crucial facilities for maintaining ecological balance and public health. However, the ultimate byproduct of wastewater treatment—is Sludge , yet it remains a complex and challenging issue. Sludge is characterized by its high water content, strong adhesion, and large volume—features that not only drive up transportation and disposal costs but also potentially lead to secondary pollution during storage, such as odors and leachate. Therefore, Sludge Dewatering Becoming a crucial component of the municipal wastewater treatment system.

Among various dewatering equipment, the belt filter press stands out for its low energy consumption, continuous operation, and high degree of automation, making it widely used in municipal sludge dewatering projects. And at the heart of this system lies the most critical filtration medium— Spiral Filter Belt , directly determining the equipment's operational efficiency, sludge cake moisture content, and maintenance costs.

This article will delve into the working principle, technical advantages, structural features, and engineering applications of spiral mesh belts in municipal sludge belt press filter machines for sludge dewatering.

I. Process Background and Challenges of Sludge Dewatering

1. Sludge characteristics are complex

Municipal sludge comes from a wide range of sources, including primary sedimentation sludge, biochemical sludge, and chemical sludge. Its main components include organic matter, inorganic particles, bacteria, oils, and residual chemical agents, resulting in high water content—typically over 95%—as well as strong adhesiveness. Sludges from different sources exhibit significantly varying properties, placing higher demands on the adaptability of filter belts.

2. The bottleneck in the dehydration process

During the belt press filtration process, the sludge needs to pass through Gravity Dewatering, Low-Pressure Pressing, and High-Pressure Pressing Three stages.
However, common issues in actual operation include:

• Filter belt clogging, leading to obstructed discharge of filtrate;

• Uneven sludge distribution leads to inconsistent cake thickness and insufficient dewatering;

• The filter belt surface is covered with a layer of sludge, making cleaning difficult and increasing energy consumption;

• Filter belt wear or stretching leads to reduced lifespan.

Therefore, a high-performance filter belt must simultaneously possess Excellent drainage performance, good peelability, abrasion resistance, and structural stability This is precisely where the value of the spiral mesh conveyor belt lies.

II. Structure and Working Principle of the Spiral Mesh Belt

Unlike traditional plain-woven filter cloths, the spiral mesh belt features Open-ended spiral ring structure Construct three-dimensional drainage channels to enhance their hydraulic permeability and mechanical stability during sludge dewatering.

1. Work Process

In a belt press, the spiral mesh is typically installed between the two running belts—upper and lower—creating a continuously operating pressing system.

• Gravity Dewatering Zone :The high permeability of the spiral mesh allows free water to drain away quickly;

• Wedge-shaped area As the upper and lower filter belts gradually converge, the sludge begins to experience slight pressure, while the spiral mesh structure maintains uniform support, preventing the sludge layer from cracking.

• High-pressure area : By applying multi-stage pressure through multiple compression rollers, the filter cake is further compressed and dewatered;

• Stripping Zone : The mud cake is separated from the mesh belt, and the smooth surface of the spiral mesh helps ensure the filter cake is discharged intact.

2. Structural Features

• Porosity is adjustable (20–40%) , to match different sludge particle characteristics;

• Uniform thickness, high flatness , ensuring consistent filter cake pressure distribution;

• The surface is smooth and resists mud adhesion;

• Available in double-layer splicing or with a mesh-lined structure , enhancing pressure resistance and dehydration efficiency.

III. Technical Advantages of Citiuss Spiral Mesh Conveyor Belt

1. High drainage efficiency

The three-dimensional channel design of the spiral mesh provides more flow pathways for the filtrate, enabling a filtration discharge rate that is over 30% faster than with plain-woven filter cloths under the same pressure conditions, thereby significantly enhancing dewatering efficiency.

2. Excellent anti-clogging and self-cleaning performance

The fine particles in the sludge do not easily get trapped within the spiral mesh's pore structure, allowing rinse water to quickly penetrate the inside of the mesh belt, ensuring continuous cleaning and minimizing downtime for maintenance.

3. High strength, resistant to deformation

The mesh belt undergoes high-temperature heat-setting treatment, giving it exceptional tensile strength and dimensional stability. During prolonged operation, it remains highly resistant to deformation, slippage, or breakage—even under the continuous pressure of high-pressure roller sets.

4. Excellent filter cake release performance

The spiral mesh surface is smooth and flat, making it resistant to mud adhesion. During discharge, the filter cake can be easily detached naturally, reducing cleaning frequency and extending the equipment's service life.

5. Corrosion-resistant and highly chemical-resistant

Municipal sludge often contains flocculants, dewatering agents, and some acidic or alkaline substances. The spiral mesh is made from chemically resistant polyester or modified polyamide materials, enabling long-term operation even in challenging environments.

6. Customizable Design

Citiusas Helical Net Customization is available based on different equipment types (such as domestically produced filter presses, ANDRITZ, Bellmer, Monobelt, and more) and sludge characteristics.

• Mesh size (ranging from 200 to 3,400 microns);

• Thickness and porosity;

• Splicing methods (such as spiral edging, joints, and loops);

• Special features (non-stick, antistatic, oil-resistant, and anti-clogging treatments).

IV. Xiamen Citius' Spiral Mesh Belt Solutions

As China's leading brand in industrial filtration materials and technical textiles , Xiamen Citius Filter Media Technology Incorporated Company specializes in R&D and Manufacturing of Industrial Filtration Systems For three decades, we have been the drafting organization for the industry standard of filter belts used in belt filter presses.

Citiuss' spiral mesh conveyor belt products have been widely used in Municipal wastewater treatment plant, sludge drying system, paper-making wastewater, food industry sludge, and chemical wastewater treatment projects China. Its products possess the following technical advantages:

1. High-performance monofilament raw material

It possesses higher tensile strength, fatigue resistance, and hydrolysis resistance, making it suitable for long-term exposure to hot and humid environments.

2. Precise Weaving and Heat Setting

Ensure consistent mesh belt thickness, uniform aperture size, and a smooth surface to enhance operational stability.

3. Special Surface Treatment Technology

For high-viscosity sludge, Citiuss can provide Anti-stick layer coating With Microporous Calendering Treatment , effectively reducing mud cake residue.

4. High Compatibility

The spiral mesh perfectly matches mainstream domestic and international belt press machines, enabling quick installation, easy replacement, and on-site splicing—thus minimizing downtime.

5. Prioritizing both environmental friendliness and durability

The mesh belt is reusable and easy to clean, reducing both water usage for cleaning and energy consumption. Additionally, the mesh belt typically lasts more than 40% longer than conventional filter cloths.

Amid ongoing technological innovation, Citiuss' independently developed Ultra-high-pressure belt filter mesh belt Breaking through the traditional dehydration bottleneck, this product effectively addresses the challenge of "high moisture content and difficulty in achieving deep dewatering" found in municipal and industrial sludge. The product features High strength, low elongation, and exceptional permeability , it can maintain structural stability under high-pressure conditions, achieving higher pressing efficiency with lower energy consumption.
This innovation provides Sludge reduction, resource utilization, and energy conservation with reduced consumption It laid the foundation and also propelled the widespread adoption of ultra-high-pressure belt filter presses in the field of advanced sludge dewatering.

Citius consistently adheres to “ High-quality filtration media, building a clean production system "Driven by this philosophy, we deliver cutting-edge solutions to the urban wastewater treatment industry through rigorous production standards and technological innovation. Reliable, economical, and sustainable support for solid-liquid separation.

V. Application Cases

• A Municipal Wastewater Treatment Plant Renovation Project in Fujian

The originally used filter cloth resulted in less-than-ideal dewatering performance, with the filter cake maintaining a moisture content of around 82%. After replacing it with Xudias spiral mesh belt, the moisture content dropped to 74%, and the frequency of equipment cleaning was reduced by nearly 40%. As a result, annual maintenance costs decreased by approximately 25%.

• A sludge drying project in Jiangsu

After adopting the high-strength polyester spiral mesh belt, the filter belt's service life has been extended from the original 6 months to over 12 months, and the clarity of the filtrate has significantly improved.

• Overseas Project (Southeast Asia Wastewater Treatment Plant)

The Citiuss spiral mesh belt maintains stable performance even in high-humidity and high-temperature environments, effectively preventing mold growth and hydrolysis-induced aging—operating reliably for over a year.

VI. Conclusion

As the "Dual Carbon" strategy and environmental regulations are increasingly implemented, municipal sludge treatment is shifting from "reduction" toward "resource utilization, harmlessness, and智能化 (intelligentization)." The belt press filter, with its advantages of energy efficiency, high performance, and continuous operation, will continue to play a critical role in sludge dewatering. Meanwhile, the spiral mesh belt—serving as the core filtration unit—will also keep evolving toward Efficient, durable, and intelligent Directional evolution.

Xiamen Xedia Filter Materials Technology Co., Ltd. We will continue to drive forward with innovation and build on quality as our foundation, providing more comprehensive filtration system solutions for the municipal and environmental protection industries, and helping pave the way for a clean, sustainable future in urban development.