Sea water Chlorination

Seawater contains various microorganisms, bacteria, protozoan, that would contributes to a biofilm formation on the membrane surface. A biofilm is a bacteria colony that grows on a designated surface where a carbon source and nutrients are available. Killing bacteria and microorganism before entering the membranes will prevent biofouling.

The typical chlorine dose is about 3 mg/L of active chlorine. It gas be injected by dosing Sodium Hypochlorite (NaOCl) for small scale plant or Chlorine gas (Cl2) for medium scale plants.

Large Scale plant (> 300 m3/h) uses electrochlorination to produce sodium hypochlorite (NaOCl) from the excess of sodium chloride salt (NaCl) present in seawater at about 30 to 40 g/L:

NaCl + H2O + direct current --> NaOCl + H2

pH should be corrected around 7.5 to have optimized chlorine disinfection potential.

More details on Chlorine disinfection mechanisms, click here.

Desalination Key Issues

Seawater Intake

Desalination Pretreatments

• Chlorination
• Coagulation / Multi-media Filtration
• Dechlorination
• Antiscalant
•  Fine filtration
• Ultrafiltration
• Flocculation / Sedimentation

Desalination Post-treatments

Reverse Osmosis Desalination Process

Desalination and Energy Costs

Brine Disposal

Membranes cleaning

Storage and Distribution

Containerization / Tropicalization

Instrumentation and Control (SCADA)