A textile dyeing factory located in Rayong experienced serious sludge dewatering problems in its plate-and-frame filter press system after expanding production capacity. The sludge generated from the DAF and physicochemical treatment systems contained high levels of surfactants, dye residues, and organic matter, resulting in poor dewatering performance.

The plant faced high sludge moisture content, sticky sludge cakes, frequent filter cloth blockage, and unstable filter press operation. By introducing Hengfeng Nonionic 1185 and optimizing the sludge conditioning process, the factory successfully improved dewatering efficiency and stabilized long-term operation.

Site Overview

Industry: Textile dyeing & finishing
Location: Rayong
Sludge treatment capacity: 70–90 tons/day (wet sludge)

Sludge Characteristics

· High organic and surfactant content

· Strong viscosity and compressibility

· Fine colloidal particles and fiber residues

· Sludge concentration: 1.5–2.5%

Dewatering System

· Filter press units

· Polymer prepared at 0.1% concentration

· High-pressure mechanical filtration system

Initial Issues

Before optimization, the plant experienced:

· Sludge cake moisture content of 82–85%

· Sticky sludge cakes difficult to discharge

· Filtration cycles exceeding 3–4 hours

· Frequent filter cloth clogging

· High polymer consumption with unstable performance

· Sludge leakage between filter plates

Frequent shutdowns for cleaning and maintenance reduced overall production efficiency.

Problem Analysis

After on-site inspection and sludge testing, Hengfeng’s technical team identified several key issues.

1. Weak Sludge Conditioning

The previously used polymer produced loose flocs that collapsed easily under high-pressure squeezing, resulting in poor filtration permeability.

2. High Organic & Surfactant Interference

Residual surfactants and organic matter increased sludge viscosity and water retention, making dewatering more difficult.

3. Improper Polymer Preparation

Insufficient polymer aging time reduced molecular chain extension and weakened flocculation performance.

4. Excessive Shear Force

Strong agitation after polymer addition damaged floc structure before entering the filter press.

Technical Solution

Optimized Polymer Selection

Hengfeng recommended Nonionic Polyacrylamide 1185, featuring:

· Strong adsorption and bridging capability

· Excellent compatibility with textile sludge

· Improved sludge cake permeability

· Better resistance to pressure filtration shear

The product significantly improved floc density and filtration performance.

Process Optimization

Polymer Preparation

· Polymer concentration increased to 0.15%

· Aging time extended to 60–90 minutes

Dosage Optimization

· Dosage adjusted to 4.0–5.0 kg/t DS

· Fine-tuned according to cake dryness and filtrate clarity

Mixing Optimization

· Polymer injection point moved closer to the filter press feed tank

· Mixing intensity reduced after polymer addition

This preserved floc integrity and improved filtration efficiency.

Equipment & Operation Optimization

Hengfeng engineers also assisted in optimizing:

· Feed pressure sequence

· Filtration cycle timing

· Plate squeezing pressure

· Filter cloth cleaning frequency

These adjustments reduced cloth blockage and improved continuous operation stability.

Performance Results

After optimization and continuous monitoring:

· Sludge cake moisture decreased to 72–76%

· Filtration cycle time shortened to 2–2.5 hours

· Sludge cakes became firm and easy to discharge

· Filtrate clarity improved significantly

· Filter cloth clogging was greatly reduced

· Polymer consumption decreased by 15–20%

· Overall system achieved stable continuous operation

The plant successfully reduced sludge disposal costs and maintenance downtime.

Project Outcome

Through optimized polymer selection, improved sludge conditioning, and standardized process control, Hengfeng successfully enhanced the performance of the plate-and-frame filter press system in textile sludge dewatering.

This project demonstrated that efficient sludge dewatering depends not only on equipment, but also on proper polymer selection, dosing strategy, and operational optimization.

Hengfeng Commitment

At Jiangsu Hengfeng Fine Chemical Co., Ltd., we provide more than flocculants —

We deliver complete sludge dewatering solutions supported by:

· Advanced polymer technology

· Site-specific product optimization

· On-site technical support

· Operator training

· Long-term operational guidance

With Hengfeng Nonionic 1185, textile sludge dewatering systems can achieve lower sludge moisture, higher filtration efficiency, and stable long-term operation.