Filter-grade quartz grit and pH-correction dolomite for municipal and industrial water treatment — supplied to Australian and global operators with full AS/NZS 4020 and NSF/ANSI 61 compliance documentation.
Water treatment relies on the physical filtration performance of quartz grit and the chemistry of dolomite. PIME supplies both from audited Indian producers to exacting specifications.
Graded quartz grit is the standard filter medium in rapid sand filters (RSF) and multi-media filtration systems used in municipal drinking water plants, wastewater treatment works, and industrial process water systems. The medium functions by physically straining suspended solids — turbidity, algae, floc particles — as raw water passes downward through a stratified bed.
High-purity silica (SiO₂ ≥ 99%) is essential. Calcite contamination — common in lower-grade silica sands — introduces alkalinity and carbonate hardness into treated water, undermining downstream disinfection chemistry and pH control. PIME's filter-grade quartz grit is sourced from primary quartz deposits, not crushed river sand, ensuring mineralogical purity.
The angular, sub-rounded grain shape of our quartz grit delivers the roundness coefficient (≥ 0.6) required for uniform packing, predictable hydraulic conductivity, and backwash efficiency. Mohs hardness of 7 ensures grains resist attrition under repeated backwash cycles.
Dolomite [CaMg(CO₃)₂] has a well-established role in water treatment beyond filtration: it is the principal mineral used for raising the alkalinity and pH of acidic, soft, or desalinated water through the CO₂-dolomite equilibrium process.
As water equilibrated with CO₂ passes through a packed bed of dolomite granules, carbonate minerals dissolve at a rate governed by the partial pressure of carbon dioxide and the water's ionic strength. The process simultaneously raises pH (typically to 7.5–8.5), increases calcium hardness, and introduces magnesium — remineralising reverse-osmosis permeate and desalinated water to levels that protect distribution pipes from corrosion and meet drinking water aesthetic standards.
For municipal desalination post-treatment, the CO₂-dolomite contact bed is often the preferred alternative to lime dosing because it avoids the handling hazards of quicklime while delivering balanced hardness rather than purely calcium-dominant mineralisation.
The following specifications define filter-grade quartz grit per the requirements of AS/NZS 4020, NSF/ANSI 61, and standard water industry procurement practice. PIME supplies to all parameters below.
| Parameter | Specification | Significance |
|---|---|---|
| SiO₂ Content | ≥ 99% | Prevents alkalinity contribution from calcite impurities |
| Acid Solubility | < 0.5% | AS/NZS 4020 and NSF/ANSI 61 threshold; prevents leaching of minerals into treated water |
| Roundness Coefficient | ≥ 0.6 | Ensures predictable hydraulic conductivity and backwash effectiveness |
| Mohs Hardness | 7 | Resists grain crushing under hydraulic backwash pressure and long service life |
| Fe₂O₃ | < 0.05% | Low iron ensures no iron leaching into filtered water |
| Al₂O₃ | < 0.3% | Controls aluminium solubility in contact with water |
| Moisture | < 0.5% | Ensures accurate dosing weight and prevents clumping in bags |
| Turbidity (10% HCl wash) | < 20 NTU | Verifies absence of fine clay coating on grain surfaces |
| Packaging | 25 kg bags · 1-tonne jumbo bags · bulk container | Available to suit plant loading equipment |
Compliance note: AS/NZS 4020 governs the testing of products intended to contact drinking water in Australian and New Zealand distribution systems. NSF/ANSI 61 is the corresponding North American standard. PIME provides CoA and acid-solubility test reports with every shipment. Third-party verification by SGS, Bureau Veritas or Intertek is available on request.
A correctly designed filter bed uses multiple mesh grades in stratified layers, from coarse support gravel at the base to fine filter sand at the surface. PIME supplies all standard grades for complete bed construction or selective layer replacement.
Bottom support layer providing underdrain protection and structural support for finer media above. Prevents migration of filter sand into underdrain laterals.
Intermediate transition layer between the coarse support gravel and filter sand. Prevents intermixing between layers and stabilises the bed during backwash.
Primary filter layer in multi-media beds used alongside anthracite. Removes larger suspended solids including floc and biological material from clarified water.
Fine-grade filter medium for high-efficiency turbidity removal. Used in the upper working layer of RSF beds where particle capture efficiency is critical.
Custom mesh ranges outside these standards are available on request. PIME's technical team can advise on effective size (d10), uniformity coefficient (UC), and specific gravity matching for your system's hydraulic loading rate.
Not all silica filter media is equal. The choice between washed river sand and primary-deposit quartz grit has direct consequences for treatment efficiency and regulatory compliance.
| Parameter | Natural / River Silica Sand | PIME High-Purity Quartz Grit |
|---|---|---|
| SiO₂ Content | 85–95% (variable; calcite and feldspar present) | ≥ 99% — guaranteed per CoA |
| Acid Solubility | Often 1–5% — calcite dissolves readily in acidic water | < 0.5% — meets AS/NZS 4020 and NSF/ANSI 61 |
| Alkalinity Impact | Calcite releases alkalinity, raises pH unpredictably | Minimal — chemically inert in treated water |
| Grain Morphology | Rounded — lower specific surface area, reduced particle capture | Sub-rounded, roundness ≥ 0.6 — optimised backwash performance |
| Hardness | Variable — softer minerals crush under backwash | Mohs 7 — durable across thousands of backwash cycles |
| Iron Content | Often elevated — risk of iron leaching | Fe₂O₃ < 0.05% — minimal iron release |
| Batch Consistency | Variable by source — requires frequent re-qualification | Uniform primary-deposit source — consistent between batches |
| Compliance Documentation | Typically limited — spot test reports only | Full CoA, acid solubility report, and mine audit available |
| Packaging Options | Bulk or loose bags only | 25 kg bags, 1-tonne jumbo bags, or bulk container |
Water treatment operators require absolute consistency in their filter media. A substandard batch can mean compliance failures, unplanned shutdowns, and costly media replacement. PIME's sourcing model is designed around these demands.
Our quartz grit is sourced from primary igneous and metamorphic quartz deposits — not crushed alluvial sand — guaranteeing SiO₂ ≥ 99% and acid solubility below 0.5% batch after batch.
Every shipment is accompanied by a Certificate of Analysis covering SiO₂, acid solubility, Fe₂O₃, roundness, and sieve analysis. Third-party inspection (SGS, Bureau Veritas, Intertek) is available on request.
Available in 25 kg multi-wall bags, 1-tonne FIBC jumbo bags, or in bulk container for large plants. We work with your logistics team on delivery scheduling and port of discharge requirements.
PIME is one of very few Australian importers able to supply both quartz grit filter media and dolomite for pH correction from audited Indian producers — simplifying procurement and reducing freight cost.
Our team can advise on mesh grade selection, bed depth, effective size and uniformity coefficient to match your system design — whether for a new installation or a media replacement project.
PIME is an Australian company with direct experience supplying to water authorities under AS/NZS 4020 procurement requirements. We understand the regulatory environment and how to meet it.
Questions we regularly receive from water treatment plant operators, engineers, and procurement teams.
Tell us your mesh grade requirements, plant capacity, and delivery port — we will respond with specifications, pricing, and estimated lead time within one business day.