Introduction
For utilities and water authorities, managing iron and manganese levels in drinking water is a growing challenge. These elements, if untreated, can lead to the clogging of pipes, discoloration, and reduced efficiency in water distribution networks. Traditional treatments often demand extensive facilities and increased maintenance, pushing operational costs higher and impacting overall sustainability. Filtralite provides a high-efficiency solution that can tackle these issues at their core. Its innovative filter media enhances the biological filtration process, enabling higher filtration rates and effectively removing iron and manganese without requiring costly infrastructure upgrades. Through case studies, the article demonstrates Filtralite’s ability to effectively remove iron, manganese, and other contaminants, while also reducing maintenance requirements and improving overall treatment efficiency, making it a compelling choice for both wastewater and drinking water treatment applications.
The Urgent Challenge
Water Utilities face numerous challenges in managing iron and manganese in drinking water. These metals can discolor water, leading to customer complaints and the need for additional treatment to restore clarity. They also form solid precipitates that clog pipes, filters, and valves, reducing water flow and increasing maintenance costs. Over time, this accumulation can damage infrastructure, raising repair and replacement expenses. Iron and manganese contribute to the corrosion of metal pipes and equipment, shortening their lifespan and causing further contamination. They can also diminish filtration system efficiency, increasing operational costs and potentially lowering water quality.
While iron and manganese pose minimal risks at low levels, elevated concentrations, particularly of manganese, can present health hazards, necessitating additional monitoring and treatment. Removing these metals often involves costly processes, including chemical treatments and filtration, adding to operational expenditures. Furthermore, the removal process generates sludge that requires proper disposal, leading to environmental and financial challenges. Overall, managing iron and manganese requires robust treatment systems, regular maintenance, and long-term planning to ensure safe, high-quality water.
Performance Improvement & Efficiency Gains
Filtralite‘s filter media differs significantly from traditional filtration solutions like sand, gravel, or activated carbon. In terms of composition, Filtralite is made from a type of expanded clay that is fired at high temperatures, making it lightweight, chemically stable, and highly resistant to degradation, unlike traditional media that can become clogged or less effective over time. The structure of Filtralite is unique, with highly porous, irregularly shaped particles that create an extensive surface area for filtration. This open, porous structure allows water to flow through more easily, reducing the risk of clogging compared to the more uniform, compact grains of traditional media.
In terms of filtration efficiency, Filtralite outperforms traditional solutions. Its high porosity and large surface area enable it to trap a wide range of particles, from larger debris to finer suspended solids, resulting in superior contaminant removal. Filtralite’s filtration rates range between 4 m/h and 12 m/h, whereas traditional dual media filters experience high head loss at these rates and are more expensive to operate and maintain. Additionally, Filtralite’s unique structure helps reduce backwashing requirements, improving operational efficiency and lowering water and energy consumption during maintenance cycles, unlike traditional media that can suffer from intermixing between layers and low efficiency for poor water quality. Overall, Filtralite’s innovative composition and structure provide significant advantages over traditional filtration solutions, offering higher efficiency, better flow rates, and reduced maintenance needs.
Key advantages
Filtralite® is an innovative filter media that offers significant operational and capital expenditure (OPEX and CAPEX) savings, as well as superior filtration performance compared to traditional options like sand or anthracite. As highlighted Mohammed Kastawy, Area Sales Manager for Filtralite in the Middle East and Egypt, “A traditional filter media typically consists of sand or anthracite, or a combination of the two, forming mono-media or dual-media filters. Filtralite, on the other hand, stands out with its high porosity compared to conventional options. While standard media like sand may need replacement every 4 to 5 years, Filtralite can operate for up to 25 years without replacement, maintaining its quality throughout its lifespan,” he explained.
Key OPEX advantages of Filtralite® include:
- 2 to 4 times fewer backwashes
- Higher filtration velocity, allowing more water treatment in the same period
- In reverse osmosis (RO) plants, Filtralite® produces more biologically stable water, reducing membrane fouling and extending RO membrane lifetime
- Less cleaning and replacement of cartridge filters
- Ability to handle higher suspended solids (SS) rates in the input water
- Filtralite® can support filtration rates of up to 20 m/h, significantly higher than the 4-12 m/h range of traditional media.
In terms of CAPEX, Filtralite® offers:
- Smaller footprint, requiring half the filtration cells compared to sand
- Savings in backwash pumps, concrete, steel, and other infrastructure
- Smaller backwash pumps needed due to Filtralite®’s lightweight nature
- Long lifetime of up to 25 years, significantly outlasting traditional media
Filtralite Application
Filtralite is a highly versatile ceramic material manufactured from expanded clay in Norway, making it an optimal choice for wastewater and drinking water treatment. The manufacturing process involves heating the clay to temperatures up to 1200°C, followed by crushing and sieving to achieve a grain size of 0.8 – 5.0 mm. Filtralite’s key physical properties include a bulk density ranging from 800-900 kg/m³, a highly porous structure with a specific surface area exceeding 1500 m²/m³, an irregular shape and uniform size resulting in a high voids volume, a Mohs hardness of over 5.5 for high attrition resistance, and an effective operational lifespan of more than 20 years.
Within wastewater treatment, Filtralite can be used in both biological filtration and granular filtration processes. The naturally occurring bacteria in the wastewater form a biofilm on the porous Filtralite beads, enabling efficient biological treatment through nitrification and denitrification. Geir Norden, Research and Development Manager at Filtralite, Stated “Filtralite is a ceramic material that is crushed and sieved into particle sizes typically ranging from 0.8 to 5.0 mm. Due to its highly porous structure, we recommend soaking before use. With a specific surface area exceeding 1500 m²/m³, Filtralite is exceptionally well-suited as a biofilm carrier.” For drinking water treatment, Norden emphasized Filtralite’s ability to simultaneously remove ammonia, iron, and manganese through the development of biofilms on its surface. The biofilm contains bacteria that oxidize dissolved iron and manganese, causing them to precipitate and get trapped in Filtralite’s pores. The material’s unique properties also enable high-rate biofiltration, with biofilters using Filtralite capable of operating at filtration rates up to 20 m/h.
Case in Point
- Wastewater Treatment
In Norway’s largest wastewater treatment plant, VEAS in Oslo, Filtralite filter media has proven to be an exceptionally durable and efficient solution for both bio-substrate and filtering purposes. After 25 years of continuous operation with daily backwashing, there has been no need for replenishing the Filtralite media. The Vestfjorden Wastewater Plant (VEAS) serves a population of 600,000 people, processing a maximum of 11 m³ of wastewater per second, with an annual volume of 100 million m³. Removal of nitrogen is a crucial objective, and Filtralite plays a leading role in the nitrification and denitrification processes. The unique biofiltering process at VEAS consists of eight “nitrification” bio-filters, each followed by “denitrification” bio-filters, where Filtralite HC 2.5-5 and Filtralite HR 3-6 act as both a substrate and a filtering medium, maintaining a robust bioculture. The exceptional durability and performance of Filtralite have led VEAS to expand its use, demonstrating its reliability and suitability for large-scale water treatment applications.
- Drinking Water Treatment
To meet the increasing demand for drinking water in Hong Kong, the new Tai Po Water Treatment Works was built with a production capacity of 1200 Ml/day. The plant draws raw water from the Dongjiang River, which has an average turbidity of around 11 NTU and contains ammonia and manganese. During the planning phase, the use of primary aerated biological filters (PABF) was selected for the removal of ammonia and manganese, and pilot tests showed that the expanded clay filter media Filtralite® Pure was the best solution. The test column containing Filtralite® Pure HC (High-density, Crushed) 2.5-5 mm achieved a stable ammonia removal of 80-90% and a manganese removal of 75%. Leca Norge AS delivered 3000 m³ of Filtralite® Pure HC 2.5-5 mm to the total 12 PABFs at the Tai Po Water Treatment Works, and the plant’s operating data has shown that the PABFs effectively remove both ammonia and manganese to levels below the specified requirements, demonstrating Filtralite’s suitability for addressing the challenges of water quality and treatment in high-demand urban areas.
Conclusion
The case studies presented in this article showcase the exceptional performance and versatility of Filtralite, an innovative filter media that can effectively address the challenges of managing iron and manganese in both wastewater and drinking water treatment applications. The VEAS wastewater treatment plant in Norway and the Tai Po Water Treatment Works in Hong Kong have demonstrated Filtralite’s ability to deliver superior contaminant removal, enhanced operational efficiency, and significant cost savings compared to traditional filtration solutions. These real-world examples highlight Filtralite’s potential to transform the water treatment industry, providing a high-efficiency, sustainable solution that can help utilities overcome the urgent challenge of managing iron and manganese in their water systems.
Mohammed Kastawy Area Sales Manager – MENA Region Mobile: +971565503535 Email : mohammed.kastawy@saint-gobain.com LinkedIn: www.linkedin.com
