AQUATREEIndustry and Construction

Quality Assurance

Tested before it leaves. Documented when it arrives.

Our in-house laboratory runs a full test suite on every production lot. Nothing ships without a signed certificate of analysis reporting the values measured on that batch.

Testing

What we test, and why

Every test on this list exists because of a specific way a filter bed fails in service.

  • Sieve analysis

    Method: EN 933-1 / ASTM C136
    What it measures
    The full particle size distribution, from which effective size (D₁₀) and uniformity coefficient (D₆₀/D₁₀) are derived.
    Why it matters
    A uniformity coefficient above specification means the bed compacts unevenly, head loss climbs faster than designed, and backwash either fluidises the top layer only or carries fines out of the vessel.

  • Acid solubility

    Method: EN 12902
    What it measures
    The mass fraction that dissolves in hydrochloric acid under controlled conditions.
    Why it matters
    Soluble content dissolves out in service, shifting the gradation upward over time and releasing fines into the filtrate — the classic cause of a bed that passed on commissioning and fails two years later.

  • Chemical analysis

    Method: XRF
    What it measures
    SiO₂, Fe₂O₃, Al₂O₃ and loss on ignition.
    Why it matters
    Iron content governs whether material is acceptable for glass batches, and elevated iron in filter media can discolour treated water at low pH.

  • Specific gravity

    Method: ASTM C128
    What it measures
    Particle density, and by extension the bulk density of the packed bed.
    Why it matters
    In a multimedia bed the whole design depends on density separation. If anthracite and sand densities are not correctly spaced, the layers intermix on the first backwash and never re-stratify.

  • Hardness & attrition

    Method: Mohs / attrition loss
    What it measures
    Resistance to abrasion and breakdown under repeated backwash cycles.
    Why it matters
    Soft media grinds itself into fines. Those fines then either wash out — reducing bed depth — or migrate down and blind the support layer.

  • Grain shape & roundness

    Method: Visual / Krumbein comparison
    What it measures
    Sphericity and angularity of the grain population.
    Why it matters
    Sub-angular grains interlock enough to resist migration during backwash while keeping the void ratio a rapid gravity filter needs. Fully rounded grains migrate; sharply angular grains pack too tightly.

  • Turbidity & fines

    Method: Wash-water NTU
    What it measures
    Clarity of the wash water after a standard agitation, indicating residual fines carried on the grain.
    Why it matters
    Fines carried into a new bed produce a long, expensive commissioning wash — and in a potable plant, days of water going to waste before the filter can be brought into service.

  • Moisture content

    Method: Oven dry, 105 °C
    What it measures
    Free water retained on the grain surface at the point of packing.
    Why it matters
    Decisive for resin-bound and stone carpet grades — resin will not wet a damp grain, and the surface ravels within a season. Also affects screening accuracy on fine cuts.

Release Process

From sample to certificate

The release process, including the part where quality can stop a shipment.

  1. 01

    Sampling

    A representative sample is drawn from each production lot by incremental sampling across the run, not a single grab from the top of a pile.

  2. 02

    Testing

    The full test suite is run against the grade's specification. Results are recorded against the lot number, not the product name.

  3. 03

    Release or hold

    Quality holds release authority independently of production targets. Out-of-specification material is re-screened or downgraded — never re-labelled.

  4. 04

    Certification

    A certificate of analysis is issued for the released lot, carrying the measured values and the test method behind each one.

  5. 05

    Retention

    A retained sample is held against the lot number, so a query raised months later can be tested against the material that actually shipped.

Laboratory

Laboratory equipment

  • Mechanical sieve shaker

    Full-series sieve stacks with timed agitation for reproducible gradation curves

  • XRF analyser

    Elemental oxide composition — silica, iron, alumina

  • Drying oven & precision balance

    Moisture content and loss on ignition to four decimal places

  • Turbidimeter

    Wash-water clarity in NTU for fines carry-over

  • Pycnometer set

    Specific gravity and absorption on graded fractions

  • Stereo microscope

    Grain shape, roundness and visual contamination check

Standards

Certifications & standards

The standards our media is manufactured and tested against.

  • ISO 9001:2015

    Quality management

  • ISO 14001:2015

    Environmental management

  • EN 12904

    Silica sand & gravel for water treatment

  • AWWA B100

    Granular filter material

What a certificate of analysis actually tells you

It reports the sieve curve, effective size, uniformity coefficient, acid solubility and specific gravity measured on your lot — with the test method behind each figure. It is not a datasheet range reprinted with a new date.

Download a specimen certificate

Need documentation for a pre-qualification file?

Certificates, test methods, specimen COAs, safety data sheets and certificates of origin — tell us what your approval process requires and we will issue it.

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