Jiangsu Hengfeng Fine Chemical Co., Ltd.

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 & finishingLocation: RayongSludge 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.

A municipal wastewater treatment plant recently faced challenges in its sludge dewatering system, where belt filter press performance had declined, resulting in high sludge moisture, excessive polymer consumption, and unstable cake formation. By introducing Hengfeng Cationic 9802 and optimizing the conditioning process, the plant significantly improved dewatering efficiency, reduced operating costs, and achieved stable, continuous operation. Site Overview Industry: Municipal wastewater treatmentSludge type: Mixed primary and secondary (biological) sludgeTreatment capacity: 1,800–2,200 m³/day (sludge processing line) Sludge characteristics:High organic content, poor dewaterability, sludge concentration 0.8–1.2%, with high extracellular polymeric substances (EPS), making flocculation difficult. Dewatering system configuration: · Belt filter press units · Polymer prepared at 0.1% concentration · Gravity thickening + pressure zone dewatering   Initial Issues · Sludge cake moisture content remained high at 82–85%  · Filtrate turbidity was high, with visible solids carryover · Flocs were small and weak, breaking easily under shear · Polymer consumption was high, yet performance remained unstable · Belt blinding and clogging occurred frequently, increasing cleaning frequency   Problem Analysis After on-site evaluation, several key issues were identified: 1. Inadequate Polymer Performance The previously used flocculant had insufficient charge density and molecular weight, leading to poor charge neutralization and weak bridging ability. Flocs formed were loose and easily destroyed in the press zone. 2. Poor Sludge Conditioning The sludge was not fully conditioned before entering the belt press. Mixing intensity and reaction time were insufficient, resulting in incomplete floc formation. 3. High Organic Content Interference Municipal biological sludge contains high levels of EPS and organic matter, which increases viscosity and water retention, requiring stronger cationic polymers for effective dewatering. 4. Non-Standardized Operation Polymer preparation and dosing lacked consistency. Solution aging time was insufficient, and operators relied heavily on experience rather than structured control, leading to fluctuating performance.   Technical Solution Optimized Polymer Selection Hengfeng recommended Cationic Polyacrylamide 9802, featuring: · Optimized cationic charge density · High molecular weight for strong bridging · Excellent adaptability to biological sludge The product significantly improved floc size, density, and resistance to shear.   Process Optimization Polymer preparation: · Concentration increased to 0.15%  · Aging time extended to 45–60 minutes to ensure full dissolution Dosage control: · Adjusted to 4.0–5.5 kg/t DS (dry sludge)  · Fine-tuned based on cake dryness and filtrate clarity Mixing optimization: · Improved flocculation tank mixing to ensure sufficient reaction time · Reduced shear before entering the belt press   Equipment Operation Adjustment · Optimized belt speed and pressure distribution · Balanced gravity drainage and الضغط zones · Reduced over-squeezing, which previously caused floc breakage   Operator Training & Standardization Hengfeng technical team provided on-site guidance to: · Standardize polymer preparation procedures · Establish visual floc evaluation standards · Train operators to adjust dosage based on real-time performance · Implement routine monitoring and record-keeping This ensured stable and repeatable operation.   Performance Results After implementation and continuous monitoring: · Sludge cake moisture reduced to 75–78%  · Filtrate became clear, with significantly reduced suspended solids · Polymer consumption decreased by 15–20%  · Flocs became large, dense, and resistant to shear · Belt clogging was eliminated, reducing downtime and cleaning frequency · Overall system achieved stable, continuous operation   Project Outcome Through optimized polymer selection, improved sludge conditioning, and standardized operation, Hengfeng successfully enhanced belt filter press performance in municipal sludge dewatering. This case highlights that effective sludge dewatering depends not only on equipment, but also on selecting the right flocculant and implementing proper process control.

Hengfeng PAM test- Electronic factory wastewater   Electronic manufacturing wastewater exhibits distinct characteristics primarily due to complex chemical processes involved. Its key features include: l  Elevated Heavy Metal Content‌: Contains significant concentrations of toxic heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), nickel (Ni), arsenic (As), and copper (Cu), originating from etching, plating, and component manufacturing processes‌;   l  High Levels of Per- and Polyfluoroalkyl Substances (PFAS)‌: Includes both legacy compounds like perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), as well as emerging short-chain PFAS (e.g., PFBA, PFHxA) and novel fluorinated compounds (e.g., hexafluoroisopropanol, bistriflimide). These stem from fluoropolymer coatings, circuit boards, and photolithography chemicals‌;     l  Presence of Specific Organic Solvents and Additives‌: Characterized by high concentrations of tetramethylammonium hydroxide (TMAH, 5–66 g/L), glycerol (5–66 g/L), pyrazole, acetone, and other organic residues used in cleaning, degreasing, and photoresist stripping;   l  Inorganic Contaminants and High Salinity‌: Contains fluorides (e.g., calcium fluoride, CaF₂), ammonium, sulfates, and exhibits variable pH (often alkaline or acidic), alongside elevated total dissolved solids (TDS) and conductivity due to chemical additives and process rinsates;   l  Complexity and Persistence‌: Comprises a mixture of persistent organic pollutants (POPs), dioxin-like compounds, polycyclic aromatic hydrocarbons (PAHs), and halogenated organics. These contaminants are often bioaccumulative, resistant to conventional degradation, and pose significant ecotoxicity risks‌ These characteristics collectively contribute to high chemical oxygen demand (COD), low biodegradability (BOD/COD ratio typically 0.11–0.15), and necessitate advanced treatment strategies.   Materials Needed Electronic factory wastewater sample Polyacrylamide powder (prepared as per the previous guideline) Beakers or containers Magnetic stirrer pH meter Flocculation testing apparatus (e.g., jar test apparatus) Chemical dosing equipment   Testing Procedure 1. Sample Collection: Receive electronic manufacturing wastewater from partner. Check the background and demand of partner. 2. Preparation of Polyacrylamide powder: Ensure that you have a prepared solution of polyacrylamide, as discussed in the previous procedure. This can be used for the flocculation process. 3. Flocculation Test (Jar Test): Setup: Prepare a series of beakers for different doses of polyacrylamide Add Wastewater: Add equal volumes of the wastewater sample to each beaker (in this case, 50 mL). Add Polyacrylamide: Add the specified amount of polyacrylamide to corresponding beakers. Mixing: Stir the solutions at a rapid speed (in this case, 200 rpm) for about 1-2 minutes, then stop for an additional 3 minutes to allow floc formation.     4. Post-Treatment Analysis: Visual Assessment: Observe and note the clarity and color of the treated water. pH Measurement: Measure the final pH of the treated samples. Safety Precautions Wear appropriate PPE (gloves, goggles, lab coat) while handling wastewater samples and chemical agents. Handle all chemicals and equipment according to safety guidelines. Conclusion This procedure provides a systematic approach to assessing the effectiveness of polyacrylamide on treating electronic manufacturing wastewater. It's important to optimize the concentration of polyacrylamide based on the characteristics of the specific wastewater being treated for best results.