Disinfection

Chlorination & Dechlorination SystemsGerm-free from plant to tap.

Chlorination kills the bacteria and viruses that cause waterborne disease and leaves a residual that keeps protecting water in the pipes. Dechlorination removes it where chlorine would do harm.

Request a proposalHow it works
  1. 01Filtration first
  2. 02Chlorine dosing
  3. 03Contact tank
  4. 04Residual check
  5. 05Dechlorination
  6. 06Supply or discharge

What it is

In plain words.

Chlorine has disinfected public water for more than a century because it is effective, economical and leaves a residual that keeps working through the pipes. How well it works depends on dose, contact time, temperature and pH, and on filtration beforehand, because sediment shields germs from it. After a sewage treatment plant, chlorination brings faecal coliform down from around 10^5 to 10^6 MPN/100 ml to about 10^3.

Chlorine is not always wanted downstream. It can damage RO membranes and ion exchange resins, harm aquatic life when treated water is discharged, and react with natural organic matter to form by-products such as THMs and HAAs. Dechlorination removes the excess. We design dosing for the right residual, measure free and total chlorine, and add dechlorination where your process needs it.

How it works

Stage by stage.

  1. Filtration first

    Suspended matter is removed upstream, so it cannot use up chlorine or shield germs from it.

  2. Chlorine dosing

    Gas chlorine or sodium hypochlorite is dosed in proportion to the flow of water.

  3. Contact tank

    The water is held long enough for chlorine to kill bacteria, viruses and cysts.

  4. Residual check

    Free and total residual chlorine are measured to confirm disinfection and set the dose.

  5. Dechlorination

    Where needed, a reducing agent or carbon filter removes the excess chlorine.

  6. Supply or discharge

    Disinfected water goes to storage and supply, or treated effluent is safely discharged or reused.

Options

Built to suit the site.

  • Gaseous chlorination

    Chlorine gas fed through a vacuum chlorinator. Typical for larger public water and sewage plants.

  • Liquid chlorination

    Sodium hypochlorite dosed by metering pumps. Simple to handle for small and medium plants.

  • Dechlorination

    Dosing of a reducing agent such as sodium metabisulphite, or a carbon filter, to remove excess chlorine.

Where it's used

Industries and sites.

  • Drinking water supply
  • Sewage treatment
  • Housing societies
  • Hospitals
  • Swimming pools
  • Cooling water
  • RO pre-treatment

See how we work with each industry →

What we deliver

One team, from survey to service.

  • 01

    Design

    Survey, water or effluent analysis, process design and sizing for your site.

  • 02

    Build

    Supply, fabrication, civil and mechanical works, installation and commissioning.

  • 03

    Automate

    PLC, SCADA and remote monitoring, so the plant can be seen and controlled from anywhere.

  • 04

    Maintain

    Operation, preventive maintenance and AMC under Zeal-Care, with written reports.

Questions

Asked before every project.

Is chlorinated water safe to drink?

Chlorination at the right dose is a widely used way to make drinking water safe. Good filtration before chlorination and correct dosing keep by-products such as THMs low, which is why we measure residuals rather than guess.

Gas or liquid chlorine: which should I choose?

Gas suits large plants where cost per kilogram matters and trained staff are on site. Liquid hypochlorite is easier and safer to handle for smaller plants. Electro-chlorinators are a third option that make hypochlorite on site.

Why would I need dechlorination?

Chlorine damages RO membranes and resins and can harm rivers and streams. If treated water feeds a membrane plant or is discharged, removing excess chlorine protects both.

Water treatment

Often built together.

Tell us about your site.

Share your flow, location and timeline. An engineer will review your requirement and call you back within one working day.

Talk to an engineerWhatsApp
WhatsApp