The Particle Sizing Breakdown: Why NextSand Outperforms Multi-Media Across the Board

In water treatment, “multi-media” has long been considered the standard benchmark for depth filtration. By layering coarse anthracite over fine garnet and silica sand, multi-media filters attempt to catch larger solids at the top and finer solids near the bottom.

However, comparative particle-size studies reveal that NextSand delivers superior performance in a single-media bed, eliminating the need for complex, multi-layered vessels.

Let’s look at the data from two real-world head-to-head field tests.

Field Test 1: Ground Water RO Pre-Filtration (Bottled Water Plant)

Over a 5-month evaluation conducted by plant operators and a consulting Chemical Engineer, a bottled water production facility tested parallel 48-inch FRP filter tanks using groundwater drawn from a storage tank:

Tank A (Multi-Media): 36-inch bed depth composed of #16 Garnet, #50 Garnet, 20×40 mesh sand, and anthracite.
Tank B (NextSand): 36-inch bed depth of $14\times40$ mesh NextSand over a gravel support bed.

Results

NextSand outperformed the multi-layered bed across Total Suspended Solids (TSS), Turbidity, and Silt Density Index (SDI). Crucially, NextSand operated at half the backwash frequency of the multi-media system. Because NextSand’s deep-bed structure allows solids to load throughout the entire depth of the bed rather than surface-blinding, the plant halved its backwash water consumption while producing higher-purity feed water for its RO unit.

Field Test 2: Surface Water Particle Removal (San Antonio River Water)

To test extreme turbidity conditions, a 6-day head-to-head trial was conducted using river surface water laden with silt and clay particles following a heavy rain event in San Antonio. Both systems were operated side-by-side at a flux rate of $12\text{ gpm}/\text{ft}^2$ with a 36-inch bed depth.

When analyzing filtration efficiency across specific particle size ranges, the difference between the media became stark:

Key Efficiency Metrics:

Coarse Particles (20–50 microns): NextSand achieved 99.9% removal, compared to 97% for multi-media and 95% for standard sand.
Medium Particles (5–10 microns): NextSand removed 95% of particles, whereas multi-media only captured 50% and sand captured 35%.
Fine Particles (1–5 microns): NextSand maintained a 90% removal efficiency. Multi-Media plummeted to 25%, and standard sand dropped to a negligible 10%.

Why NextSand Wins on Physics and Economics

How does a single-media bed drastically outperform a multi-layered garnet and anthracite filter?

Surface Area & Sub-Micron Capture: Standard silica sand relies entirely on physical straining between grains. NextSand’s mineral structure contains extensive internal micro-porosity and a high surface area, capturing fine silt and colloids through both straining and surface-charge attraction.
Replacing Cartridge Filters: The particle size analysis proved that NextSand performs as well as—or better than—most 5-micron disposable cartridge filters. Incorporating NextSand upstream can extend downstream cartridge filter life or eliminate the need for routine cartridge replacements altogether.
Double the Solids Holding Capacity: In both field tests, NextSand required half as many backwash cycles. Less frequent backwashing means higher net water yield, lower pumping costs, and less wastewater generation.

Check out our other case studies under our literature tab above!

Whether handling groundwater or challenging river water after a rain storm, the data is clear: NextSand delivers higher flow rates, lower backwash demands, and fine-particle capture that conventional multi-media simply cannot match.