OdourPro on 1 September 2016

What is Ferrous Dosing?

Ferrous dosing is the use of iron compounds to interrupt a commonly occurring odorous chemical reaction in sewers. Due to the halting of this process, less H₂S ('rotten egg') gas is produced. Ferrous dosing is an effective approach to odour control because it treats the problem at the cause rather than just covering it up with fragrances or masking agents.

The Chemical Explanation

Hydrogen Suphide gas

Bad odours in sewers are often caused by hydrogen sulphide.

The generation of hydrogen sulphide (H₂S) gas in sewers is via an anaerobic chemical reaction in which sulphates in solution break down to form sulphides.

The sulphides then bond with free ranging hydrogen molecules to make H₂S gas.

By interrupting this process, Ferrous Chloride (Fe 2+) reduces odours and the percentage of H₂S gas created. Iron (Fe 2+) binds with sulphides in solution to make an insoluble precipitate.

This irreversible reaction ‘ties up’ the sulphides, drastically reducing the formation of H₂S and other volatile compounds.

Benefits of Ferrous Dosing

Rotten egg gas in sewers

Ferrous dosing can be used in sewer systems in effective ways.

  • H₂S reduction
  • VOC reduction
  • Proven technology
  • Corrosion reduction
  • Asset protection
  • Custom design
  • Maintenance available
  • Simple process
  • Cost-effective
  • Versatile odour control
  • SCADA compatible

How do I use Ferrous Dosing?

Ferrous dosing system diagram

Dosing amounts are managed by connecting up the dosing pump controls with the sewer pump.

Ferrous dosing can be used in a sewer system in numerous ways, depending on customer needs.

One simple way of implementing ferrous dosing in your system is to add the chemical to the rising main. In this case, the dose rate is easily regulated by the sewer flow rate.

Dosing amounts are managed by connecting up the dosing pump controls with the sewer pump.

Alternatively, in the case of a pressure sewer system, an inline flow meter is best used to link up to the dosing controls.

What industries use Ferrous Dosing Units?

H₂S emissions are particularly problematic for the municipal wastewater and the industrial water treatment and processing industries.

H₂S gas can not only cause offensive odours, but it also corrodes the system infrastructure.

To find out how ferrous dosing units can be implemented to reduce odour and corrosion, view our Hunter Water case study.

OdourPro’s Ferrous Chloride Dosing Units

Ferrous dosing unit

Ferrous dosing units interrupt odorous chemical reactions in sewers.

We have a variety of ferrous dosing units available for your site, to help control odours and corrosion. They range from 500L to 25,000L depending on the application.

Customisations are available. However, units typically come with the following components:

  • Dosing pump
  • Programmable PLC control
  • High and low pressure cut out
  • SMS alarm
  • Anti-syphoning protection
  • Calibration cylinder
  • Safety shower and eye wash
  • Chemical resistant tank and bund

Where do I source the chemicals for my dosing unit?

At OdourPro, we offer ferrous chloride supply and delivery to your site in our dedicated vehicles with either a 6,000L or 12,500L capacity. Take advantage of our extensive experience in odour control and chemical dosing.

Let us handle all the WHS precautions and organise regular deliveries so you are never caught short of chemicals.

What kind of dosing unit do I need?

If you’re not sure what system you need, why not call us to talk to one of our expert team on 1800 510 704? We also offer services such as ongoing maintenance, consulting and installation.