Applications and Advantages of Ferrous Dosing Systems

OdourPro on 24 May 2017

What is Ferrous Dosing?

Ferrous Dosing is a type of chemical dosing used to eradicate up to 95% of industrial odours. One of the major advantages of ferrous dosing is that it treats odours at the cause. Ferrous dosing systems work to break down odour at the molecular level, by reducing the levels of H₂S gas formed by chemical reactions in sewerage.

What are Ferrous Dosing Units?

Ferrous Dosing units range in size from 500L to 25,000L and include:

Caged Ferrous Dosing Unit Main Support
  • Dosing Pump
  • Programmable PLC Control
  • High/Low Pressure Cut Out
  • SMS Alarm
  • Anti-Syphoning Protection
  • Calibration Cylinder
  • Safety Shower and Eye Wash
  • Chemical Proof Tank and Bund

Choose from the 3 high security options for Ferrous Dosing units; a fenced compound, metal-clad enclosure or a concrete hut enclosure.

How do Ferrous Dosing Systems Work?

Sewer odours usually become a problem due to the production of high levels of hydrogen sulphide (H₂S) gas. This gas production is caused by sulphates breaking down in an anaerobic reaction to form sulphides. Hydrogen then bonds with these sulphides to create H₂S gas.

Ferrous Dosing systems involve adding Ferrous Chloride (Fe 2+) to the sewer, which interrupts the hydrogen-sulphide chemical reaction, thereby lowering the amount of H₂S gas produced. Ferrous Dosing systems allow Iron (Fe 2+) to bond with the sulphides, instead of the hydrogen, resulting in the formation of an insoluble precipitate. This reaction is irreversible and stable, and is proven to reduce the creation of sulphur based compounds that cause odours.

How can Ferrous Dosing Units be Introduced to Systems?

Ferrous Dosing units can be introduced to sewer systems in a range of ways, with controls custom designed to suit your particular application. The best way of introducing Ferrous Dosing into sewer systems is to dose directly into the rising main. In this instance, the dose rate is easily controlled by the flow of the sewer.

The chemical dosing rate of Ferrous Dosing systems can also be regulated by a straight connection between pump controls and the sewer pump, or an inline flow meter can be used to send information to the dosing controls. The latter is a good option for pressure sewer systems.

Client Results with Ferrous Dosing Systems

Client: Hunter Water

2017 odourpro chemical dosing ferroues supportive image5Problem: Very high H₂S levels were being caused by a high wastewater retention time at the Dora Creek wastewater treatment plant, owned by Hunter Water. Odour complaints and corrosion of assets were resulting from the production of this toxic gas. Fortunately, OdourPro has 25 years of experience, and is well versed in odour control for wastewater treatment facilities.

Solution: A chemical dosing unit was custom designed, fitted and operated at the Windermere Park common rising main. This process required no action on the part of our client. The whole process was managed by our team of experts, including the necessary chemical deliveries and chemical dosing monitoring. By altering the chemical reactions occurring in the wastewater using chemical dosing, the extreme levels of H₂S were lowered by 95%.

Ferrous Dosing Systems and Alternative Odour Control Strategies

Some of the most common commercial options for controlling odours include:

Chemical Absorption
(Chemical Wet Scrubbing)
(Bio-oxidation using inorganic media)
(Bio-oxidation using organic media)
Ferrous Dosing (Chemical Dosing)
Good choice for reducing high H₂Slevels at headworks and sludge facilities Use inorganic compounds to effectively remove moderate to high levels of H₂S Best for treating a mixture of odorous organic compounds Reduces H₂S gas by up to 95%, reducing corrosion and increasing asset life
Can be effective at ammonia removal at sites such as composting facilities Best suited for use at wastewater treatment plants Can treat low levels of H₂S Good choice for wastewater systems
High maintenance needs restrict best applications to manned wastewater plants Not recommended for low or variable H₂Slevels Not recommended for high or variable levels of H₂S Requires supply of chemical agent*

*Although Ferrous Dosing units do require a continuous supply of chemicals, this can be conveniently and safely managed with OdourPro’s chemical delivery service.

Get the Right Advice with OdourPro

As you can see, there are advantages and disadvantages to most forms of industrial odour control. It is important to get the right advice on odour management to choose the most appropriate technology for your specific application. OdourPro have extensive experience in odour management for wastewater facilities. We treat the odour problem at its chemical cause for a lasting solution.

Need help with an Odour Problem?

Call OdourPro now on 1800 510 704 to get expert advice on how to best manage odours at your facility.