China Sea Water Into Drinking Water Suppliers & Turnkey Engineering

To generate an optimized hydraulic projection and mass balance, our process engineering team requires:

• Comprehensive Raw Water Analysis: TDS (Total Dissolved Solids), electrical conductivity, pH, chloride, sulfate, boron, silica, barium, iron, and heavy metals.
• Physical & Biological Indicators: Temperature range (seasonal minimum and maximum), turbidity, and Silt Density Index (SDI15). High algae concentrations require DAF pretreatment.
• Permeate Capacity & Target Water Spec: Daily potable output (m³/day or GPD) and targeted compliance standard (e.g., WHO Potable Guidelines, GCC Drinking Standards, or local health authority limits for Boron <0.5 mg/L).
• Site Utilities: Available electrical voltage, phase, frequency (e.g., 380V/50Hz, 460V/60Hz), and preferred footprint (indoor skid-mounted vs. weather-isolated containerized plant).

Boron exists primarily as uncharged non-ionized boric acid [B(OH)3] at neutral seawater pH, passing easily through standard reverse osmosis membranes (yielding 60-80% rejection, which is insufficient for seawater feeds with 4.5-6.0 mg/L boron). To achieve the World Health Organization (WHO) threshold of <0.5 mg/L, we implement:

1. Alkaline Two-Pass Treatment: The first-pass permeate pH is elevated to ~9.5-10.0 using NaOH dosing, converting boric acid into charged borate ions [B(OH)4]-, which SWRO/BWRO membranes reject at >98%.
2. Specialized Boron-Selective Ion Exchange Resin: For compact footprints without caustic chemical dosing, selective polyol functional resins capture residual boron polish streams.

Standard 304 or 316L stainless steel suffers catastrophic crevice corrosion and pitting within months when exposed to high-pressure seawater (>55 bar with >19,000 mg/L chlorides). Tongjie utilizes:

• High-Pressure Circuit (>10 bar): Super Duplex Stainless Steel 2507 (UNS S32750 / EN 1.4410) with Pitting Resistance Equivalent Number (PREN) > 42, or heavy-gauge FRP (Fiber Reinforced Plastic) pressure vessels certified to ASME Section X.
• Low-Pressure Circuit (<10 bar): High-density polyethylene (HDPE), CPVC, or 316L stainless steel for backwash, flushing, and chemical conditioning loops.

Our containerized seawater desalination systems arrive 100% factory-assembled, pre-wired, and wet-tested at our Shanghai fabrication facility prior to export. Once hoisted onto a reinforced concrete pad on-site:

• Technicians connect the raw seawater feed flange, treated potable water discharge flange, and high-salinity brine rejection outfall.
• Connect main three-phase power supply to the centralized Siemens PLC control cabinet.
• Automated system sanitization, membrane preservation flushing, and initial potable permeate delivery can be accomplished within 72 hours of site arrival.

When operating under recommended parameters (SDI < 3.0, continuous anti-scalant dosing, and regular automated bi-annual CIP cleanings):

• SWRO Membrane Elements: 3 to 5 years before reaching salt passage degradation or flux decline limits.
• High-Pressure Ceramic Pressure Exchangers (ERDs): Over 15 years with zero internal lubrication maintenance.
• High-Pressure Duplex Pumps: 8 to 10 years before seal and impeller overhauls.
• Containerized Shells: 20+ years, featuring marine C5M anti-corrosion exterior coatings and thermal insulation linings.

Yes. As a National High-Tech Enterprise holding Class II Contracting Qualifications, we regularly collaborate with EPC contractors, military camp developers, marine vessel builders, and international system distributors. We engineer custom skids to match stringent container height ceilings, explosion-proof zones (ATEX/IECEx), multi-voltage standards, private branding requirements, and custom telemetry architectures.