Wastewater discharge systems have strict requirements on pipes, which must meet the following key properties:
Corrosion resistance: resistance to chemicals in sewage, acidic/alkaline media
Impact resistance: withstand underground pressure, vehicle load or construction impact
Sealing: prevent sewage leakage from contaminating soil and groundwater
Low flow resistance: reduce sedimentation risk and maintain drainage efficiency
Long life: maintenance-free operation for at least 50 years
|
Pipe Material |
Advantages |
Disadvantages |
Wastewater Suitability |
|
Concrete Pipe |
High load-bearing capacity |
Heavy weight, prone to joint leakage, poor acid/alkali resistance |
Only suitable for non-corrosive wastewater |
|
PVC Pipe |
Low cost, quick installation |
Brittle in low temperatures, thermal deformation, multiple joints |
Suitable for small-diameter short-term projects |
|
Cast Iron Pipe |
High mechanical strength |
Prone to corrosion, heavy weight, high cost |
Being phased out |
|
HDPE Pipe |
Excellent flexibility, zero leakage, chemical corrosion resistant |
Slightly higher initial cost |
Optimal choice |
1. Excellent chemical corrosion resistance
Can withstand acidic and alkaline environments with a pH value of 2-12 (far exceeding the corrosion resistance range of PVC)
Not corroded by sulfides, salts, and organic solvents in sewage
Case: After the wastewater pipes in a chemical park were replaced with HDPE, the service life was increased from 15 years of concrete pipes to 50+ years
2. Leak-free hot-melt connection
Adopt electric hot-melt or butt welding technology to form a molecular-level seal
Compared with traditional socket-type concrete pipes, the leakage rate is reduced by more than 95%
Long-term sealing performance certified by German standard DIN 16963-2
3. Super strong impact resistance and flexibility
Elongation at break>350%, can resist crustal settlement (concrete pipes will crack when settlement is 5mm)
Still maintain toughness at -40℃ (PVC has a significant risk of embrittlement below 0℃)
Case: In the Hanshin earthquake in Japan, HDPE drainage pipes were the only pipes that were not damaged on a large scale
4. Ultra-low fluid resistance
The inner wall is smooth (roughness coefficient is only 0.009), and the flow rate is 20% higher than that of concrete pipes
Self-cleaning design reduces sludge deposition (the measured deposition amount is only 1/3 of that of concrete pipes)
5. Lightweight and convenient construction
The weight is only 1/10 of that of concrete pipes, and no heavy lifting equipment is required
Can produce 6-12 meter long pipe sections, reducing the number of joints
Supports trenchless laying (directional drilling, liner repair and other technologies)
{C}6. {C}Cost advantage throughout the life cycle
|
Cost Item |
HDPE Pipe |
Concrete Pipe |
|
Initial Purchase Cost |
Relatively High |
Low |
|
Installation Cost |
30% Reduction |
High (Requires Heavy Machinery) |
|
Maintenance Cost |
Nearly Zero |
Annual Maintenance ~3% of Construction Cost |
|
50-Year Total Cost |
>40% Savings |
High Hidden Costs |
{C}1. {C}Recommended common specifications
|
Flow Requirement (L/s) |
Recommended Diameter (IPS) |
Ring Stiffness Class (SN) |
Application Scenario |
|
<10 |
200mm (8") |
SN4 |
Residential Drainage |
|
10-30 |
315mm (12") |
SN8 |
Municipal Sewer Mains |
|
>30 |
500mm (20") |
SN16 |
Industrial Wastewater Mains |
2. Key certification standards
Pressure pipe: in accordance with ISO 4427 (PE100 grade raw material)
Non-pressure drainage: EN 13476-3 (structured wall pipe standard)
Ring stiffness: SN4/SN8/SN16 (corresponding to 4/8/16 kN/m² load capacity)
1. Trench preparation
A 10cm sand cushion is laid on the base to prevent sharp objects from damaging the pipe
Bending radius ≥ 25 times the pipe diameter (DN500 pipe minimum bending radius 12.5m)
2. Hot melt connection
Use a special welding machine (temperature control 210±10℃)
Flange width = pipe wall thickness × 1.5 (resection inspection is required)
3. Backfill requirements
Layered compaction, each layer ≤30cm
Fine-grained soil backfill is preferred, and the stone particle size is <40mm
Conclusion: In the field of wastewater discharge, HDPE pipes have become the first choice for global municipal engineering due to their zero leakage, corrosion resistance and long life. For projects that pursue system reliability and full-cycle economy, HDPE sewer pipes are the most future-oriented solution.
