Iron Removal in Drinking Water

Iron is present in most groundwaters and can also be found in some surface waters. It is regulated to a Secondary Maximum Contaminant Level (SMCL) of 0.3 mg/L. Iron is non-pathogenic and may stain clothing/fixtures with a brown tint, ranging from a bright rust-color to nearly black. It is commonly removed by oxidation followed by filtration. Iron is also a concern in membrane pre-treatment, being a potential foulant, and can cause irreversible damage. Iron is sometimes organically bound, which can make it resistant to removal by conventional groundwater treatment.



Tonka Water Iron Removal Technologies

The treatment options available for iron removal include combinations of aeration/detention/filtration, oxidation/filtration and for low levels (<0.5 mg/l) direct ion exchange.

Tonka Water’s approach to iron removal starts with a water analysis and definition of treatment goals. Typically, a multi-stage treatment process is the most cost-effective and will be easiest to control and operate. The first step is aeration, where iron oxidation is achieved, allowing the soluble iron to convert to an in-soluble form which can be filtered. Following aeration and adequate detention, our filtration solutions can be either gravity or pressure, in accordance with recommendations by 10 States Standards or the relevant approving authority. Depending on the levels of iron, detention with sedimentation can be provided as well.

Filter medias applicable to iron removal include a wide variety, from anthracite, dual media, or our highly efficient IMAR™, a unique media specially developed by Tonka Water to enhance removal while minimizing backwash waste.

Tonka Water offers pilot testing to optimize an existing plant or to assist in the design of a new plant.  

Dualator®(I, III and VI) Series

This family of multi-process groundwater treatment systems comes in a single pre-engineered package of aeration, detention and filtration.

The Dualator® I is a low profile system, using an integral low profile aerator for oxidation, and 10 minutes of plug flow detention for iron removal. The integral gravity filter also has multi-cell configuration for optimum operational flexibility, and comes with our state-of-the-art backwash system, Simul-Wash™.

The Dualator® III is our most versatile and compact package filtration system for groundwater treatment. The Dualator® III is a low profile system suitable for removal of any combination of iron and/or manganese. It is equipped with a low profile aerator for oxidation, followed by auxiliary oxidant addition, 30 minute detention with baffled setting compartment, and a 4 celled gravity filter. 

The Dualator® VI is a free-standing unit that incorporates aeration, detention and filtration in a circular configuration. In moderate to warm climates, it can be placed exterior to the water treatment plant, with functional piping and valves extended to within the building interior. When placed interior to the water plant, the aerator and detention sections of the unit typically extend through the roof, to prevent freezing and to allow for access to filtration from within the building. The Dualator® VI does not provide baffled detention or solids sedimentation.

Drawing of Dualator III Water Treatment System

OptaCell and VertaCell Pressure Filters

Tonka Water takes pride in our “State of the Art” pressure filtration systems. Our OptaCell Plus™ horizontal pressure filters featuring our isolated cell design are the smallest footprint of any pressurized system. Our unique arched plate underdrain allows for an unobstructed flow-way with low headloss, resulting in superior effluent collection and improved wash water distribution. The Tonka Water arched plate is a fully painted underdrain, extending vessel life and includes easy access for inspection and maintenance. Tonka Water pressure systems incorporate Simul-Wash™, allowing for downsized backwash waste/wastewater recycle chambers, reducing both construction costs and wash water consumption.

4 Vessel Water Treatment System


The Tonka Water Centralator is a four-cell cluster filter suitable for larger flow ground or surface water treatment in a compact, reinforced concrete configuration. It includes a gravity, four-cell common wall concrete structure, stainless steel center control column, central inlet distribution box and effluent/backwash control chamber. Featuring BLEU™ underdrains and Simul-Wash™, the Centralator™ can be highly space-efficient, especially for larger flows where steel construction isn’t practical.

Drawing of a Centralator Water Filtration System
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City of Barnwell

Barnwell, SC
The Tri County Alliance, an economic development board, was promoting a new Advanced Technology Business Park at a former DOE facility. Infrastructure improvements were required to attract new businesses.
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City of South Lyon

South Lyon, MI
Due to the rapid growth in the City of South Lyon, water demands had strained its water production capacity and iron removal capabilities.
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Forge Village and Nutting Road Water Treatment Plants

Westford, MA
Westford is a rapidly growing community outside of Boston and receives its water from eight groundwater wells.
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City of Slippery Rock

Slippery Rock, PA
The City of Slippery Rock is located in Butler County, in western Pennsylvania. The residents of Slippery Rock had dealt with deteriorating water quality concerns related to iron and manganese levels.
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Your first step is to contact Tonka Water with your water treatment needs.

Each water is unique and may require different design parameters involving various chemical feed systems and flexibility in detention times and filtration media for the treatment of iron. And because each water is unique, we offer pilot testing to optimize the design, whether for an existing plant or new one. Call your Tonka Water Representative for more information on iron removal or any other water treatment needs you may have.

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