Filtralite® Pure filter media has a unique porous structure that creates ideal conditions for water to flow through the filter bed, enhancing its ability to retain contaminants. This characteristic, inherent to the lightweight expanded clay material, allows for larger volumes of water to be filtered through the same space by increasing the contact area.
Project Background
Located in southern Sweden, the Olofström waterworks—originally constructed in 1969–1970—supplies clean drinking water to roughly 10,000 residents. The facility processes just over 3,000 m³ per day, amounting to about 120,000 m³ annually. Raw water inflows hail from both groundwater and surface sources, with some groundwater containing elevated levels of manganese—a contaminant known for causing pipe deposits and staining of dishes and laundry.
Innovative Filter Upgrade
In 2015, the plant undertook an upgrade, converting an existing sand filter into a biological one. The sand media was replaced with Filtralite® Pure NC 1.5–2.5, a highly effective substrate for microbial activity. This material’s high specific surface area and internal pore structure create optimal conditions for biological oxidation.
System Design & Operational Enhancements
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Filter Configuration: 25 m² surface area, 1 m filtration depth, and a filtration rate of ~2 m/h—delivering over 1,000 m³/day of treated water.
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pH Optimization: To bolster the oxidation of dissolved manganese into MnO₂, the water’s pH was increased from ~6 to ~8 using a gas stripper to remove dissolved carbonic acid.
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Backwashing Frequency: Only 2–3 times per year, markedly lower than traditional sand filters.
Biological Activation & Performance
Within approximately 4 months of start-up, naturally occurring bacteria (without external seeding) established a biofilm that achieved manganese removal rates exceeding 90%. Influent manganese levels of up to 0.3 mg/L were reduced to around 0.01 mg/L in the effluent.
Why This Project Stands Out
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Eco-efficient: Significantly reduces operational demands through minimal backwashing and chemical-free microbial activation.
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Resource-optimized: Uses an existing filter infrastructure, enhanced only by media replacement and pH adjustment.
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Sustainable Performance: Once established, the biological system runs robustly with low maintenance and high contaminant removal efficiency.
Mohammed Kastawy
Area Sales Manager – MENA Region
Mobile: +971565503535
Email : mohammed.kastawy@saint-gobain.com
LinkedIn: www.linkedin.com
