Go Back

Thermoplastic-Lined FRP Sewage Tanks

Thermoplastic-Lined FRP Tanks (also called dual-laminate FRP tanks) combine a corrosion-resistant thermoplastic inner liner with a structural FRP outer shell. The inner liner (e.g. HDPE, PP, PVDF) provides a flawless barrier against the harshest chemicals and sewage contents, while the FRP shell gives the vessel strength and rigidity. This dual-layer construction is ideal for sewage treatment scenarios involving aggressive conditions—such as acid or alkali wastewater—where pure FRP or pure plastic tanks alone might fail. The liner is typically thermally welded on-site to ensure a leak-proof fit, and the FRP exterior is laminated with high-performance resins. Together they deliver outstanding durability and chemical resistance. These tanks are commonly used where highest corrosion protection is needed in STP processes.

Product Inquiry

Key Features

  • Thermoplastic Inner Liner: Continuous, corrosion-proof liner made from polymers like HDPE, Homopolymer/ C-PVC, PVDF or PP, resistant to acids, alkalis, solvents, and sewage gases.
  • FRP Structural Shell: Outer composite shell (vinylester or isophthalic polyester) provides strength, stiffness, and pressure-resistance to the tank.
  • Thick Corrosion Barrier: Liners can be up to 2 inches thick for severe service, offering wear and impact resistance.
  • Machine-Welded Joints: Seamless butt-welded liner assemblies ensure no leaks; industrial welding methods deliver chemical-tight seals.
  • Dual-Laminate Design: FRP overliner supports the tank structurally while the liner serves as the primary corrosion barrier, essentially combining the benefits of two materials.
  • High Temperature Capability: Many thermoplastic liners can handle elevated temperatures (e.g. PP up to ~100°C, PVDF up to ~150°C).

Benefits

  • Unmatched Chemical Resistance: Superior protection against extreme pH, oxidizers, or concentrated chemicals present in industrial wastewater.
  • Long Service Life: The durable plastic liner prevents permeation and corrosion of the tank wall, greatly extending life in aggressive environments.
  • Leak-Proof Safety: Fully bonded liners eliminate pinholes and leaks, protecting both the tank structure and the environment.
  • Versatile Compatibility: Can store acids (e.g. HCl, H2SO₄), alkalies (e.g. NaOH), solvents, salts, slurries, as well as raw sewage.
  • Low Maintenance: No need to re-coat or replace lining; routine inspections suffice. Liners are resistant to abrasion from solids.
  • Regulatory Compliance: Suitable for storing stringent process fluids; lining materials often meet FDA/NSF 61 for potable uses if needed.

Applications

  • Industrial Effluent Tanks: For sectors like chemical manufacturing, metal finishing, pulp and paper, and mining where wastewater contains harsh chemicals.
  • Acid & Alkali Waste Storage: Collecting acid pickling or caustic waste streams before treatment.
  • Raw Sewage with High Corrosion Potential: In plants handling tannery, food processing, or petrochemical sewage.
  • Intermediary Tanks in STP: As buffer/equalization tanks when influent quality varies or contains toxic spikes.
  • Pickling, Plating & Electrochemical Plants: Where spent process chemicals are stored safely.

Technical Specifications

  • Liner Materials: Options include HDPE, PP (homopolymer or copolymer), PVC/CPVC, PVDF, FEP, ETFE, PTFE, etc. Material chosen for chemical compatibility.
  • Wall Construction: Typical tank wall is ~4–10 mm FRP laminate over a thermoplastic liner of ~2–5 mm (or thicker as required).
  • Temperature Range: Dependent on resin/liner: up to ~65°C for PVC, 80–100°C for PP/HDPE, 150°C for PVDF/PTFE.
  • Pressure Rating: Usually atmospheric; can be engineered for slight positive pressure.
  • Certifications: Tanks fabricated under quality systems (e.g., ISO 9001) with traceability; some liners meet NSF or FDA.
  • Accessories: Laminated FRP reinforcement rings, flanges, mixers/agitators mounts, heating coils, etc., as needed.

Unique Selling Points (USPs)

  • Dual-Laminate Expertise: Industry-leading designs that combine thick plastic liners with robust FRP, providing redundancy and reliability.
  • Chemical Processing Heritage: Proven in hundreds of chemical and effluent plants, with experience in the toughest waste streams.
  • Custom Fabrication: In-house welding and winding capabilities allow fully customized shapes (vertical/horizontal, cone-bottom, rectangular) to fit any process.
  • Quick Lining Process: On-site butt-welding of liners by certified technicians ensures fast, bubble-free installation and minimizes downtime.
  • One-Stop Supply: We provide the lined tank, plus any needed support structures or piping, delivering a complete solution to the customer.