Access to clean and safe drinking water is one of the most pressing global challenges. Across the world, communities are struggling with groundwater contamination particularly from nitrates caused by intensive agricultural activity. Traditional solutions such as reverse osmosis or ion exchange often come with high costs and complex operation, making them less practical for small and medium-sized water treatment facilities.

This is where Filtralite® Pure makes a difference. As an advanced filter media, it enables highly efficient biological denitrification, delivering safe drinking water while lowering both operational and investment costs. By combining performance, durability, and sustainability, Filtralite® Pure is redefining how utilities approach nitrate removal in drinking water treatment plants.

Why Biological Denitrification?

Biological denitrification has emerged as one of the most advanced, selective, and cost-effective solutions. This process removes nitrate through dissimilatory reduction, transforming it into harmless nitrogen gas.

It has already been applied successfully in wastewater treatment and contaminated groundwater, with biofilm-based technologies achieving the highest nitrate removal rate per volume. For drinking water treatment plants (DWTP), biological denitrification has proven to deliver outstanding results.

How the Process Works

Biological denitrification relies on the biological oxidation of organic substrates in water, using nitrate or nitrite as the electron acceptor instead of oxygen.

To achieve this, an organic carbon source (such as methanol, ethanol, acetic acid, or glucose) must be added to the water. In the absence or limitation of dissolved oxygen (DO), the nitrate reductase enzyme is activated, helping transfer hydrogen and electrons to nitrate as the terminal electron acceptor.

This step-by-step reduction ultimately converts nitrate into nitrogen gas.

In a DWTP, this entire process can be achieved inside an anaerobic biofilter filled with the right filter media.

Here, Filtralite® Pure serves as the optimal carrier for the denitrifying biofilm, ensuring reliable, efficient, and long-lasting performance.

Filtralite performance: 60% nitrate removal & cost savings

Filtralite® Pure in Action: Nitrate Removal at the Formiche Alto Drinking Water Plant, Spain

A practical example of this technology can be found in the Drinking Water Treatment Plant of Formiche Alto in Teruel Province, Spain.

Built in 2017 by Ingeobras, the plant was designed to treat groundwater that otherwise meets Spanish regulations for drinking water quality (RD 140/2003), except for nitrate levels of around 60 mg/L (variable depending on the season).

Since the regulatory limit in Spain is 50 mg/L, the municipality needed a reliable, small-scale solution. A 5 m³/h DWTP was therefore built with four treatment stages:

Anaerobic Denitrification Biofilter with Filtralite® Pure for nitrate removal.
Physical Filtration to remove suspended solids.
Biological Aerated Filter to eliminate remaining organic matter.
Chlorine Disinfection to kill any bacteria or pathogens from the biological steps.

Performance Results

The Formiche Alto DWTP was designed to achieve a

60% nitrate removal rate, bringing the final concentration down to below 25 mg/L.

This ensures compliance with Spanish regulations while maintaining a safe margin for public health.

Backwash and Water Reuse

The backwash water produced accounts for 5–10% of the total filtered water. Its quality allows safe discharge into the sewage network or reuse in agriculture.

Since the DWTP is located far from the sewage system, the wastewater is instead collected in a sedimentation tank, where it is stored and managed accordingly.

Automation and Operating Costs

The plant operates automatically, reducing the need for continuous supervision and minimizing labor costs.

According to Ingeobras, for a DWTP treating 60 mg/L of nitrates at a daily flow of 1,000 m³, the total operating cost is around €0.16/m³.

Divided as follows:

€0.08/m³for reagents (mainly organic matter),
€0.04/m³for energy,
€0.04/m³for maintenance.

Filtralite® Pure: Long-Term Durability

The heart of the system is Filtralite® Pure, which offers a lifespan of more than 20 years. This long durability minimizes the need for replacement, reducing both costs and environmental impac.

Advantages of Filtralite® Pure

High nitrate removal efficiency (70–95%).
Low operating & investment costs.
Long lifespan (20+ years).
Lightweight, porous structure for strong biofilm growth.
Reliable, simple operation with low energy use.
Environmentally sustainable (backwash reuse, low impact)

Comparing with Alternative Technologies

When compared with conventional nitrate removal technologies,

the CAPEX and OPEX of the Formiche Alto plant is significantly lower due to the simplicity of the biological design.

Typical removal efficiencies are as follows:

Biological Denitrification: 70–95%
Ion Exchange: 80–90%
Chemical Reduction: 33–90%
Electro-dialysis: 30–50%
Reverse Osmosis: 50–96%

This makes biological denitrification with Filtralite® Pure one of the most reliable and efficient solutions for nitrate removal.

Sustainability and Environmental Benefits

In addition to technical and economic advantages, the system also contributes to environmental sustainability. Its low energy use, minimal maintenance needs, and potential for reusing backwash water support both ecological responsibility and cost savings.

Conclusion

The Formiche Alto DWTP demonstrates the real-world benefits of using Filtralite® Pure in drinking water treatment. It delivers:

Safe water quality well within regulations.
Lower capital and operational costs.
Long-lasting performance with minimal maintenance.
Strong environmental sustainability.

This project stands as a model for small communities worldwide, showing how innovative filtration media can ensure safe, sustainable, and affordable drinking water for future generations.

Mohammed Kastawy 
Area Sales Manager – MENA Region
 Mobile: +971565503535 
Email : mohammed.kastawy@saint-gobain.com 
LinkedIn: www.linkedin.com