Introduction
Desalination serves as a comprehensive solution for providing drinking water in regions facing water scarcity. This technology generates additional resources that were previously unavailable, and the produced effluent meets quality standards suitable for human consumption, which is crucial for effective water resource management. The increasing investments in desalination across areas like the Middle East, the United States, and Latin America under- score this reality.
The Global Water Desalination Market size is expected to reach US$ 36.98 billion by 2032, up from US$ 16.19 billion in 2023, with a CAGR of 9.61% from 2024 to 2032
The viability of a desalination process, both from a technical and economic standpoint, largely hinges on the pretreatment of the sourced water. Effective pre- treatment is essential to prevent and minimize issues such as membrane fouling, incrustation, and damage. Thus, ensuring high-quality water for the osmosis units is critical. Moreover, it is vital to lower operating costs during this phase to maintain sustainable pricing per cubic meter by reducing energy and reagent consumption, as well as equipment maintenance expenses. Filtralite® Pure addresses these needs by enhancing water quality and minimizing operating costs while increasing production capacity and reducing head loss.
Developing the Right Solution
The Filtralite® Pure filter media substitutes conventional granular materials—sand and anthracite—used for filtering suspended solids (SS) during the pretreatment phase before desalination. Filtralite® Pure is an advanced expanded clay product created by Leca, Saint Gobain. Designed specifically for this application, it provides exceptionally high-efficiency filtration, enhancing both effluent quality and cost savings. The reasons behind this superior performance and extended filter lifespan are found in the material’s structural properties and composition. Filtralite® Pure boasts high porosity with a significant specific surface area of approximately 3 m²/g and exhibits low hydraulic resistance; many pores in the material facilitate flow. In summary, it serves as the ideal filtering medium: it captures most SS with minimal head loss accumulation, delivering deep filtration and prolonged clogging intervals.
Filtralite® Pure performance in numbers
- In single media filters, the interval between back- washes can be increased by as much as 500%.
- In dual media filters, backwashing can occur up to eight times less
- In biofilters, Filtralite® Pure achieves up to 98% iron removal, 80% manganese removal, and 90% ammonia
- Current Filtralite® filters function at flow rates ranging from 1 gpm/ft² to 8 gpm/ft² for physical filtration, and up to 13 gpm/ft² for biofilters.
Filtralite® Pure media options
Filtralite® solutions can be applied in mono media filters as well as in dual media configurations, These solutions combine two types of Filtralite® Pure filter media with different densities and sizes, further enhancing filter run durations and production capacity.
- Filtralite® Pure NC 1,5-2,5
Filtralite® Pure NC 1,5-2,5 is a high-quality filter media made from expanded clay, used in drinking water treatment. Its porous structure enhances filtration efficiency, allowing longer filter runs between backwashes, which reduces energy and water consumption. This results in higher water production and lower operating costs, making it an effective choice for water treatment applications.
- Filtralite® Pure HC 2,5-5
Filtralite® Pure HC 2,5-5 is ideal for biological treatment in drinking water facilities. Made from crushed clay aggregates with high density, ranging from 2.5 to 5 mm, this media features a highly porous structure that provides a substantial surface area for microbial growth, enhancing biological filtration while lowering operational costs.
- Filtralite® Pure NC 0,8-1,6
Filtralite® Pure NC 0,8-1,6 is a high-quality filter media made from expanded clay, used for drinking water treatment and desalination pre-treatment. With crushed clay aggregates of 0.8-1.6 mm, its porous structure enhances filtration efficiency, allowing longer filter runs between backwashes. This results in lower energy and water consumption, increased water production, and reduced operating costs.
- Filtralite® Pure HC 0,8-1,6
Filtralite® Pure HC 0,8-1,6 is a high-quality filter media made from expanded clay, used in drinking water treatment. When combined with Filtralite® Pure NC 1,5-2,5, they create the Filtralite® Pure Mono-Multi solution. Its porous structure enhances filtration efficiency, allowing longer runs between backwashes.
Filtralite® MC 1.5-2.5 significantly extends filter run lengths by 50-150% compared to conventional setups
Efficient Desalination by Filtralite® Pure
Mohammed Kastawy, Area Sales Manager for Filtralite® in the Middle East, highlighted the operational and capital expenditure savings provided by Filtralite® in desalination processes. Filtralite® reduces backwash frequency by two to four times, allows for higher filtration velocities, and produces biologically stable water, which decreases biofouling and ex- tends the lifespan of reverse osmosis (RO) membranes. This innovation also lowers the frequency of cartridge filter cleaning and replacement while effectively managing higher suspended solids in input water.
On the capital expenditure side, Filtralite’s lighter weight and higher efficiency lead to fewer required filtration cells, resulting in savings on pumps, concrete, and steel.
Filtralite® Pure offers two dual media solutions for desalination. The first solution combines Filtralite® MC 1.5-2.5 in the top layer with sand (1.0-0.8 mm) in the bottom layer, serving as a natural alternative to anthracite in traditional dual media systems. This configuration extends filter run lengths by 50-150% compared to conventional setups and improves effمuent quality, achieving a 0.5-1 reduction in the silt density index (SDI), especially effective during turbidity peaks.
The second solution, Filtralite® Pure Mono-Multi, combines Filtralite® Pure HC (0.8-1.6 mm) and Filtralite® Pure NC (1.5-2.5 mm). This combination boosts filter efficiency, allowing for longer intervals between backwashes, thereby reducing operational costs and making it ideal for low turbidity and low SDI conditions in desalination pre-treatment.
- Filtralite® Media Boosts Beni-Saf Desalination Efficiency
The Beni Saf desalination plant in Algeria, owned by the Beni Saf Water Company and operated by Tedagua (Grupo Co- bra), produces 200,000 m³/day, making it one of the largest in the Mediterranean. To address challenges posed by increased suspended solids (SS) from concentrated rainfall, the plant re- placed sand in its first filtration stage with Filtralite® filter media made from expanded clay.
This change aimed to minimize downtime during high SS events and optimize operating costs through reduced back- washing and improved filtration quality. The replacement was executed in two phases: 24 filters in October 2020 and the remaining 24 in October 2021. A comparison between Filtralite® and sand revealed that the filtration cycle with Filtralite® lasted 200% longer during intense rain events from November 2020 to February 2021. Additionally, the maturation period for filters using Filtralite® decreased by nearly 66%.
Production losses during this period dropped significantly, from 673,000 m³ in 2019-2020 to 380,000 m³ in 2020-2021, marking a 45% reduction. With the second phase completed, further reductions in downtime are anticipated, potentially exceeding 85%.Water quality improved by 0.3 to 0.5 SDI points, leading to less frequent cartridge filter replacements.
”The amount of energy saved in the pre-treatment area is estimated at around 10%. It is thousands of dollars we can save every year. Our estimated return on investment is 4 years due to the increase in the SS limit.’’ Mr. Mohamed Chaffi, Director of the Beni Saf desalination plant stated that.
- Filtralite® Powers Thames Gateway Water Desalination
Built to lessen the possibility of a water shortage in the London area, the new Thames Gateway Water Treatment Plant is the first large-scale desalination facility in the United Kingdom. It is situated at Beckton, outside of London. It takes the raw water from the outlet of the River Thames, which means that the water is brackish water.
The salinity changes by the tide and the maximum salinity is about 11 000 ppm. The plant is built by the Spanish contractor Acciona Agua, and was opened in June, 2010. Before the salt is removed by RO membranes the water is pre-treated in a three stage process. The first stage is coagulation, flocculation and lamella clarification. The second stage is horizontal single media pressure filters where Filtralite Pure is used as filter media. As a third pre-treatment step Ultra Filtration membranes are used.
The desalination plant have a production capacity of 150 000 m3/day and will provide water for around 900 000 people in London. The single media pressure filter consists of 17 filters containing a bed of Filtralite® Pure HC 0.8-1.6 mm. These filters each have a filtration area of 50 m2 and operate at a peak filtration rate of 12 m/h. This filtration step is to remove the carryover of fine suspended solids not removed by the lamella clarifiers. Production losses during this period dropped significantly, from 673,000 m³ in 2019-2020 to 380,000 m³ in 2020-2021, marking a 45% reduction. With the second phase completed, further reductions in downtime are anticipated, potentially exceeding 85%.Water quality improved by 0.3 to 0.5 SDI points, leading to less frequent cartridge filter replacements.
Mohammed Kastawy
Area Sales Manager – MENA Region
Mobile: +971565503535
Email : mohammed.kastawy@saint-gobain.com
LinkedIn: www.linkedin.com
