5 Steps for Effective Removal of Iron from Water
Water with excess iron is such a headache to homes and businesses. It is not just a matter of how bad it tastes and smells; the presence of iron in water can stain your sinks, ruin appliances, and aid bacteria growth. High levels of iron can even cause many issues for human health. If water is contaminated with iron, there is also a chance for a metallic taste. Though traditional methods can be effective in removing iron from water, they may not be sufficient for high levels of iron. Even heavy metals like iron can be removed effectively with the use of advanced technology like iron removal filters. Removing iron from the water system is the main way to enjoy clean water while protecting your piping system.
Different Steps to Eliminate Iron from Water
Identify the type and concentration of iron
To conclude the treatment process, it is necessary to identify the type and concentration of iron content in water. Typically, iron appears in three different forms in water such as:
- Dissolved Iron (Ferrous Iron): Appearing clear, unless exposed to air, then oxidizes and becomes rust-coloured particles.
- Particulate Iron (Ferric Iron): Reddish-brown appearance; often in suspended particles settling at the bottom of water.
- Organic or Bacterial Iron: Combined with organic matter or present in biofilms, this form is tough to remove
Oxidize the Iron
Oxidation of iron is vital for converting dissolved ferrous iron to insoluble ferric iron and that can then be filtered out from water. The most common methods of oxidation are:
- Air injection: The water is exposed to air or oxygen causing the iron to oxidize naturally.
- Chemical oxidants: Applying specific agents, such as chlorine, potassium permanganate, or ozone to enhance the process.
- Filtration media:
- Sand-Based media: Ferrous iron (Fe2+) is the most common form of dissolved iron in water. Oxidation of this is supported by the media with the conversion of Ferrous iron (Fe2+) into Ferric iron (Fe3+), from which insoluble particles get formed and are retained within the filter bed. Silica sand, manganese-coated sand, etc, are the different kinds of media available. Silica sand is useful for the physical filtration of oxidised iron particles whereas manganese-coated sand supports oxidation and also improves the efficiency of filtration
- Manganese Greensand: It consists of silica and is coated with manganese dioxide. The manganese dioxide acts as a catalyst to oxidize Fe²⁺ to Fe³⁺ and adsorb the ferric iron. It requires periodic backwashing and regeneration with potassium permanganate to restore the oxidation capacity.
- Birm (Burgess Iron Removal Media): Light-weight filtration medium with a thin layer of manganese oxide. In this, Fe²⁺ reacts with the dissolved oxygen that has been adsorbed within it, yielding ferric hydroxide Fe(OH)₃ (insoluble and filtered), np chemical regeneration required, just requires sufficient dissolved oxygen in the water
- Catalytic Media: Catalytic media such as Filox, Pyrolox, etc., is a high-purity manganese dioxide media. It oxidises and filters iron, manganese, and hydrogen sulfide from water. It has a high capacity and long life. It needs a water pH above 7.0 to operate properly.
- Zeolite-Based Media: It removes iron by ion exchange and physical separation of oxidized particles. This needs brine solutions for ion exchange media.
- Biological Media: The iron-oxidizing bacteria stimulate the growth of the bacteria, and they convert Fe²⁺ to Fe³⁺. Then, the ferric iron is filtered out. It is eco-friendly and cost-effective for community-level water treatment systems.
The oxidizing method to be used depends on the concentration of iron and other parameters in water.
Filter the Iron
Following oxidation, ferric iron particles can be filtered out. The following are possible methods of filtration:
- Sediment Filters: They are effective for low concentrations of particulate iron.
- Greensand Filters: Utilize manganese greensand to remove both iron and manganese.
- Multi-Media Filters: Layered systems that trap particles of different sizes.
Make sure it is designed to filter at a certain level of iron in the water, and it needs maintenance so it will not clog up.
Addressing Organic and Bacterial Iron
Organic and bacterial iron pose specific treatment problems in the treatment of water. As noted above, dissolved iron is not difficult to treat by oxidation followed by basic filtration. However, these organic and bacterial iron are hard to eliminate since they come in more complicated forms.
- Organic Iron:
Organic iron is the naturally occurring organic bound iron, either as humic or fulvic acids. In this form, it is usually resistant to filtration and oxidation methods. Organic iron typically presents water as reddish or yellowish-brown, causing staining, as well as a bad taste or odour - Bacterial Iron:
Bacterial iron occurs when specific bacteria, such as iron bacteria, interact with dissolved iron. These bacteria form a sludge-like biofilm which has a characteristic rust colour and clogs up pipes, filters, and water systems. It is very common in wells and water and creates maintenance problems.
Treatment Methods:
- Chlorination
Chlorine is added to water to kill the iron bacteria and oxidize organic iron into insoluble particles that can be filtered out. Chlorination is highly effective in disinfecting and preparing the water for subsequent filtration. It kills bacterial growth, reduces odours, and improves the quality of the water. - UV Disinfection
Ultraviolet (UV) disinfection is a clean and environmentally safe destruction method by damaging the DNA of bacteria. It is also not by introducing chemicals. UV disinfection does not oxidize iron; therefore, it is to be used in combination with filtration to remove precipitated iron. - Biological Filtration:
Microbes are used to metabolize organic matter, including the organic compounds of iron, to their simpler form, which can be removed.
Combination Treatments:
In many cases, one method alone may not be enough. For example, chlorination in combination with filtration or UV disinfection that is married to biological filtration can prove to be a complete solution. The exact combination is contingent upon the concentration of iron, the water chemistry, and particular contaminants.
Implementing Post-Treatment Measures
After the removal of iron, post-treatment measures are carried out to preserve the quality of water, overcome any remaining problems and protect the treatment system for the future. Different steps for post-treatment are as follows:
- Water Softening:
It removes residual minerals like iron, magnesium, and calcium that can cause scaling and decrease the efficiency of water systems. Water softeners normally use ion exchange, where sodium ions replace calcium, magnesium, and iron ions. However, it requires regular replenishment of salt in the softener and may not be advisable for people whose diet is restricted to sodium unless potassium-based softeners are used. - Periodic Maintenance:
Periodic maintenance ensures the durability of the system by preventing its clogging. Maintenance activities include cleaning filters, backwashing media, replacing tampered components, and inspecting systems for any wear and tear. - Regular Testing:
The water quality parameters to monitor for the treatment system to operate effectively. Parameters monitored include iron levels, pH, bacterial contamination, and residual chlorine levels. It provides insights into system adjustments to maintain consistency in water quality.
Post-treatment ensures that treated water is hygienically and safely sound. The water shall be free of contaminants that have not been covered or introduced at any stage in the process. This also means prevention of scaling, bacterial growth, or fouling, which could compromise efficiency in the long term. Together, these processes bring you water of better quality but also for a longer and cost-effective duration.
Conclusion
Effective iron removal from water needs a customized approach that depends on the type and concentration of iron in the water. Once the particular contaminants are recognized, iron can be oxidized, impurities filtered out, complex forms like organic iron treated, and the system maintained, ensuring clean, iron-free water for your home or business.
As treatment for iron removal involves many processes, certain filtration can be difficult. For example, while removing insoluble iron from water is not a hurdle, it will be challenging to remove soluble iron. However, advanced water purification systems can effectively do the job. As a trusted water treatment company, Alanteh offers a wide range of high-performing and effective solutions. With over 12 years of industrial experience and a dedicated team, Alantech is committed to providing high-quality water treatment systems that meet diverse needs. With a focus on sustainability, Alantech has successfully completed over 500 installations.
The right water treatment system protects your plumbing and appliances from long-term damage besides improving the quality of your water. Our solutions include, but are not limited to, wastewater treatment systems, conveying systems, global pressure tanks, pumps, and bottling machinery.
