How Filtralite® Improved the Elimination of Iron and Manganese in the Pedraza Drinking Water Plant
Filtralite® Pure delivers outstanding performance in fixed-bed water treatment, particularly for raw water containing ammonia, manganese, iron, and other impurities. Unlike conventional filter media, it offers much higher porosity, creating an expanded surface area that supports robust biofilm development. Its structure also provides numerous macropores, low bulk density, and excellent abrasion resistance. Biological filters using Filtralite® have demonstrated reliable operation at flow rates of up to 30 m/h.
Background & Challenge
The drinking water production plant serving the Villa y Tierra de Pedraza community in Segovia, Spain, was constructed in 2012 by the Ministry of Agriculture, Fisheries and Food. The facility draws raw water from the Céguilla River, a high-mountain stream whose flow is insufficient during summer. To compensate, water is stored for redistribution during low-flow periods. However, this process revealed elevated levels of iron (0.15–0.7 mg/L) and manganese (0.07–0.2 mg/L), both in cationic forms and partly complexed with organic matter.
Conventional Treatment Limitations
Until 2021, the plant relied on oxidation using strong oxidants (e.g., potassium or sodium permanganate) and sand-anthracite filtration to remove iron and manganese. This method posed serious challenges:
- Difficulty in real-time oxidation dosage adjustment
- Rapid clogging of surface sand filters due to increased particulates
- High frequency of backwashing, reducing production capacity
- Risk of water discoloration and generation of oxidation by-products
Implementation of Filtralite® Pure
In response, ACUAES and Elecnor SyP initiated column tests in 2019 using Filtralite® Pure as a substitute for the sand-anthracite filter bed. The results demonstrated significantly improved removal of iron and manganese in their cationic forms. This led to a decision to overhaul the filtration media across all four filters at the plant. The replacement was completed at the start of 2021, and monitoring continued throughout the year.
Results & Benefits
- Production capacity rose from 220 m³/h to 300 m³/h—an increase of 36%, allowing summer operation time to decrease from 18 to 13.5 hours per day.
- Backwash frequency plummeted, owing to Filtralite®’s superior retention capacity.
- Water savings reached approximately 140 m³/day, with backwash water consumption dropping from 4.4% to just 0.9% of total production.
- Return on investment achieved within one year, thanks to reduced water use and operational efficiencies.
- Oxidation treatment requirements were greatly reduced, and the plant now produces water with turbidity consistently below 0.3 NTU.
- Overall, OPEX and associated backwashing water and energy wastes decreased by more than 75%, while achieving targeted removal of iron and manganese with minimal oxidant use.
Mohammed Kastawy Area Sales Manager – MENA Region Mobile: +971565503535 Email : mohammed.kastawy@saint-gobain.com LinkedIn: www.linkedin.com
