Pressure and gravity filtration solutions including dual-chamber pressure filters, rapid filtration kits, and vertical pressureless systems for diverse water treatment applications.
CFD, P&ID, SCADA and commissioning for critical water treatment plants.
Plant layouts, piping isometrics and construction-ready engineering drawings.
Flow, mixing and thermal CFD across treatment and process equipment.
Full mechanical, physico-chemical, biological and sludge equipment range.
Depth Filtration — Transport, Attachment, Detachment
Granular depth filtration is not surface straining. Particles are transported to the surface of each grain by sedimentation, interception and Brownian diffusion, then held there by van der Waals and electrostatic forces. The captured load distributes through the depth of the bed, which is why a 1 m anthracite/sand filter outperforms a 30 cm mono-medium one despite identical surface area.
The depth profile of suspended solids follows the Iwasaki equation: −∂C/∂L = λ·C, with the filter coefficient λ = λ0(1 + b·σ/σu)x(1 − σ/σu)y. Particle removal is therefore exponential with depth, modulated by specific deposit &sigma. A clean dual-media bed at 10 m/h typically reaches λ0 ≈ 3–8 m−1.
Clean-bed pressure drop through a packed media bed: ΔP/L = (180·μ·v / dp2)·(1 − ε)2/ε3. Porosity ε for sand is 0.40–0.45, anthracite 0.50–0.55. As deposit accumulates, effective porosity drops and head loss climbs roughly as ΔP ∝ (1−εeff)2/εeff3 — backwash is triggered at ΔP = 1.5–2.5 m WC.
Effective cleaning requires the bed to fluidise to 20–50% expansion. Minimum fluidisation velocity from the Wen–Yu correlation: Umf = (μ/ρwdp)·(33.72 + 0.0408·Ar)0.5 − 33.7, where Ar is the Archimedes number. Typical Umf at 15 °C: 0.6–0.7 mm sand → 12–15 m/h; 1.2 mm anthracite → 28–35 m/h. Air-scour at 50–60 m³/(m²·h) is used first to break up mud-balls before water rinse.
| Media | Effective Size d10 (mm) | Uniformity (d60/d10) | SG | Typical Bed (mm) | Primary Function |
|---|---|---|---|---|---|
| Silica sand | 0.55–0.75 | ≤1.5 | 2.65 | 600–900 | Polish / final particle removal |
| Anthracite | 0.90–1.20 | ≤1.5 | 1.40–1.60 | 400–600 | Coarse upper layer, deposit storage |
| Garnet | 0.20–0.40 | ≤1.6 | 3.80–4.20 | 50–100 | Tri-media polishing bed |
| Granular activated carbon | 0.55–1.10 | ≤1.8 | 1.30–1.45 | 1,500–3,000 | Taste/odour, DOC, micropollutants |
| Catalytic MnO2 media | 0.40–0.85 | ≤1.6 | 2.00–3.00 | 800–1,200 | Fe/Mn oxidation & capture |
Specific gravities are chosen so that, after backwash, the lighter coarse media re-stratifies above the denser finer media — this gives the “coarse-to-fine” flow direction that flattens the head-loss curve and extends run-time by 2–3× over mono-medium sand.
Filtration Solutions
Patented dual-chamber vertical pressure filter enabling two-stage filtration in a single device. Water flows sequentially through two autonomous filtration chambers with independent backwash capability, providing enhanced contaminant removal in a compact footprint.
Rapid pressure filtration system available in two versions: simplified (filtration tank only) or complete (with filtration bed). Designed for quick filtration with media selection based on water parameters and small investment costs.
Gravity-fed vertical filter for downward-flow filtration. Available with various filtration media selections based on water chemistry. Can be fully sealed for use as carbon filter in ozonized water treatment. Features 0.2 or 0.5mm filtration nozzles for precise outlet control.
Operational Benefits
Compact design and modular construction reduce installation costs by 30-40% compared to conventional filtration systems.
Optimised flow distribution and low head loss design minimise pumping energy requirements.
Multi-media configurations and optimised bed depths extend time between backwashes, reducing water waste.
Consistent effluent quality meets drinking water standards and industrial discharge requirements.
Simple mechanical design with standard components ensures low maintenance requirements and quick repairs.
Multiple media options and customizable designs adapt to changing water quality requirements.
Where Our Filters Excel
Iron and manganese removal, turbidity reduction, and pre-treatment for disinfection in municipal and private water supplies.
Filtration for boiler feed, cooling towers, manufacturing processes, and rinse water applications.
SDI reduction and particulate removal to protect reverse osmosis membranes and extend their operational life.
Tertiary treatment for recycled water applications including irrigation, vehicle washing, and industrial reuse.
SCADA Integration Available
Our filtration systems can be equipped with SCADA integration for automated backwash cycles, pressure differential monitoring, and media condition tracking. Optimise filter performance and schedule maintenance based on actual operating conditions.
Our engineering team will analyse your water quality data and recommend the optimal filtration system configuration for your application.
Five technical subpages on the workhorse depth filter
For RO pretreatment, tertiary polishing, cooling-tower make-up and boiler-feed duties the multimedia filter is the depth-filtration workhorse. We have dedicated pages on each part of the engineering — pick the topic.
Product page with full design parameters, process-train context and links into every technical subpage.
ViewAnthracite, sand, garnet — ES, UC, SG, depths, alternatives (greensand, GAC cap, pumice).
ViewSizing, freeboard, distributors, nozzle-plate underdrain, pressure code, pressure vs gravity.
ViewSix-step air-scour-then-rinse sequence, fluidisation hydraulics, valve interlocks, SCADA logic.
ViewEight train positions — RO pretreatment, tertiary polish, cooling, boiler feed, Fe/Mn, reuse, mining.
ViewMudballs, channelling, breakthrough, media loss, biofouling, greensand failures. Annual inspection checklist.
ViewPressure and gravity sand filters for suspended solids removal, polishing, and pretreatment.
ViewSS316L cartridge filter housing with polypropylene or stainless steel cartridges.
ViewAutomatic self-cleaning filters for continuous operation. Remove suspended solids without shutdown or manual intervention.
ViewUltrafiltration (UF) membrane systems for suspended solids, bacteria, and virus removal.
ViewOur expertise spans multiple industries with sector-specific water treatment solutions.