Lake dredging project construction case

The project is located at a lake in Yueyang City, Hunan Province, along the Yangtze River. The lake plays an important role in flood regulation, water storage, landscape improvement, and ecological conservation. Due to long-term sediment deposition and external pollution inflow, a large amount of sludge accumulated on the lakebed, resulting in reduced water depth, high turbidity, unpleasant odor, and negative impacts on the surrounding residential environment.Pre-construction surveys showed that the sludge thickness ranged from 0.5 m to 1.0 m, with an estimated dredged sludge volume of approximately 15,000 m³ within the treatment area.

To restore the lake’s storage capacity and improve water quality, the project adopted geotextile tube (Geo Tube) dredging and dewatering technology. High-strength, UV-resistant geotextile tubes were used to contain and dewater the dredged sludge, achieving an efficient, environmentally friendly, and sustainable lake dredging solution.

The project adopted a hydraulic dredging + geotextile tube dewatering integrated treatment scheme, specifically designed for long-term outdoor exposure conditions.
Key technical features include:

• High-Strength, UV-Resistant Geotextile Tubes
  Manufactured from PP woven geotextiles, the tubes provide excellent tensile strength and outstanding UV resistance, ensuring long-term structural stability under continuous sunlight exposure.
• Multi-Layer Stacking Arrangement
  Due to limited dewatering yard space, a multi-layer stacking design was adopted, allowing more sludge to be treated within a compact area while facilitating centralized collection and management of filtrate water.
• Flocculation-Assisted Sedimentation
  Environmentally friendly flocculants were injected into the slurry pipeline, causing fine suspended particles to rapidly agglomerate and settle inside the geotextile tubes, accelerating sludge consolidation and water separation.
• Excellent Filtration Performance
  The geotextile tube fabric allows water to pass through while effectively retaining sludge and suspended solids inside the tube, achieving a clear “water-permeable, solids-blocking” effect.
• Efficient Dewatering and Volume Reduction
  Continuous drainage significantly reduced sludge moisture content, resulting in substantial volume reduction.
• Compliant Water Discharge
  The filtrate water exhibited low turbidity and was collected and conveyed to a sedimentation pond for further settling. The treated water met discharge and reuse standards.

HOKBG® provided customized high-strength, UV-resistant geotextile tubes and full technical services for the project. The supply scope included:

• PP woven geotextile tubes with high tensile strength, excellent UV resistance, and superior filtration performance, totaling approximately 60,000 m², with a fabric weight of 200 g/m²
• Structural design compatible with flocculant dosing systems
• Slurry inlet, outlet, and drainage control accessories
• On-site technical guidance for filling, dewatering, and stability monitoring

• Successfully completed dredging and centralized treatment of lake sludge
• Achieved efficient solid–liquid separation, allowing only water to pass through while retaining suspended solids inside the geotextile tubes
• Reduced sludge volume by more than 90% through flocculation-assisted dewatering
• Maintained excellent structural stability of geotextile tubes under long-term sunlight exposure
• Created favorable conditions for subsequent aquatic vegetation planting and reconstruction of a sustainable biological ecosystem, enhancing the lake’s natural self-purification capacity
• Provided a high-efficiency, durable, and environmentally friendly benchmark solution for lake dredging and water environment restoration