Advanced dissolved air flotation, chemical dosing, and polymer preparation systems for effective removal of suspended solids, fats, oils, and contaminants.
Reynolds & Bauhm chemical and process engineering calculations.
Precision chemical dosing systems for pH adjustment, coagulation, flocculation and disinfection in wastewater treatment.
Automated pH Neutralisation systems for acidic and alkaline wastewater.
Chemical industry wastewater treatment for atex-certified equipment.
A proven multi-stage process combining chemical conditioning with physical solid-liquid separation
Physico-chemical conditioning and treatment combines chemical reactions (coagulation and flocculation) with physical solid-liquid separation processes (flotation or sedimentation) to remove suspended solids, colloidal particles, fats, oils, and other contaminants from wastewater.
Wastewater mixed with coagulants and flocculants
Gentle mixing creates larger floc particles
Water saturated with air under pressure
Bubbles attach to contaminant particles
Sludge rises to surface for removal
Click any process step above to view detailed engineering parameters and design considerations.
From colloidal stability to the Camp number — the physical chemistry behind every coagulant dose
Suspended colloids (clay, organic matter, oil droplets, bacterial cells) carry a net negative surface charge. The resulting electrical double layer creates a repulsion that keeps particles dispersed indefinitely — raw water zeta potential typically sits at −15 to −30 mV. DLVO theory describes the net interaction as the sum of attractive London–van der Waals forces and repulsive electrostatic forces; coagulation reduces ζ toward −5 to +5 mV, collapsing the repulsion barrier and letting particles aggregate on first collision.
Metal salts hydrolyse to form polynuclear hydroxide species that neutralise charge and sweep colloids into a precipitate:
Mixing intensity is quantified by the root-mean-square velocity gradient G = (P / μV)1/2 (units: s−1). The dimensionless Camp number Gt is the integrated product of G and residence time and controls the floc-collision yield.
| Stage | G (s−1) | t (min) | Gt |
|---|---|---|---|
| Rapid mix (coagulation) | 500–1,500 | 0.5–1 | 3×104–1×105 |
| Flocculation, stage 1 | 60–80 | 5–10 | 3–5×104 |
| Flocculation, stage 2 | 30–50 | 5–10 | 2–3×104 |
| Flocculation, stage 3 | 10–25 | 5–10 | 1–1.5×104 |
Tapering G downwards through the flocculation train prevents shear-breakage of mature flocs while still driving orthokinetic collisions.
The rate of particle aggregation under fluid shear (orthokinetic regime) is dN/dt = −(4/π)·α·G·φ·N, where N is the particle number concentration, α the collision efficiency (post-coagulation: 0.3–1.0), G the velocity gradient and φ the floc volume fraction. Integrating gives N/N0 = exp(−(4/π)·α·G·φ·t) — particle count drops exponentially with Gt, which is why the Camp number is the master design variable. Floc size grows until the shear-breakage limit dmax ∝ G−1/2, typically 0.5–3 mm at G = 20–80 s−1.
Jar test → design dose. The optimum coagulant dose, polymer type and pH for a real wastewater cannot be calculated from first principles — they must be measured with a six-paddle jar test (G = 100 s−1, 1 min → G = 30 s−1, 15 min → 30 min settle). Residual turbidity and zeta-potential vs dose define the operating curve; we use the inflection point at ζ = −5 to +5 mV as the design dose, then validate at pilot scale.
Complete range of equipment for chemical conditioning and treatment applications
Effective removal of suspended solids, fats, oils, and grease
Dissolved Air Flotation (DAF) is a proven physico-chemical conditioning and treatment process that removes suspended solids, fats, oils, and other contaminants by introducing micro-bubbles that attach to particles and float them to the surface for removal. Design is governed by four interdependent parameters: hydraulic loading rate (5–15 m/h), air-to-solids ratio (0.01–0.05 kg/kg), saturator pressure (400–600 kPa), and recycle ratio (8–25%).
Removes up to 95% of fats, oils, and suspended solids
Smaller footprint than conventional sedimentation
Quick response to flow and load variations
Concentrated sludge with higher solids content
Compact flotation with inclined plate separation
Flotation system with internal partition walls reducing unit size without losing efficiency. Removable stainless steel lamella packs allow easy cleaning without cranes. Plate spacing of 50–120 mm and angle of 55–60° provide equivalent settling area = plan area × (cos θ / sin θ) × number of plates.
Internal partition walls reduce footprint
Removable lamella packs enable easy cleaning
Reduced installation and maintenance requirements
Precise coagulant and pH adjustment dosing
Automated chemical dosing systems for coagulants, pH adjustment, and other treatment chemicals. Systems include diaphragm or peristaltic pumps (10:1 turndown), calibration columns, pulsation dampers, back-pressure valves, and injection quills in SS316 or Hastelloy. Full SCADA integration with flow-paced dosing and residual feedback control.
Flow-proportional dosing with real-time adjustment
Handle coagulants, flocculants, pH adjusters
Full automation and remote monitoring
Automated polyelectrolyte preparation and dosing
Our polymer stations ensure precise preparation and dosing of polyelectrolyte solutions for optimal flocculation. Powder systems require 2–5 minute wetting and 30–60 minute maturation; emulsion systems activate in 10–20 minutes. Concentration ranges: 0.1–0.5% for powder, 0.2–1.0% for emulsion. Tank materials: PE or SS316.
Flow-through, batch, pendulum, and compact systems
Automated preparation ensures optimal activation
Minimises polymer consumption
Turbulent mixing for optimal chemical reactions
Preliminary wastewater treatment device effectively mixing wastewater with chemicals. Turbulent flow ensures effective preparation for subsequent flotation processes.
Chemical principles, jar testing protocols, G-value optimisation, and troubleshooting.
Coagulant selection, dosing calculations, pump configurations, material compatibility, and automation options.
Technology selection matrix, design parameters, coagulation chemistry, G-values, and process integration diagrams.
Explore our comprehensive guides to physico-chemical conditioning and treatment
Technology selection matrix, design parameters, coagulation chemistry, G-values, and process integration diagrams.
Engineering methodology for hydraulic loading, A/S ratio, saturator sizing, salinity compensation, and interactive calculator.
Complete guide to dissolved air flotation including design principles, sizing, applications, and performance data.
Coagulant selection, dosing calculations, pump configurations, material compatibility, and automation options.
Polyelectrolyte types, powder vs. emulsion trade-offs, preparation methods, and dosing optimisation.
Chemical principles, jar testing protocols, G-value optimisation, and troubleshooting.
Physico-chemical conditioning and treatment requires specialised mixing, reaction and separation tanks.
Aeration sits alongside coagulation, flotation and sedimentation as a core physicochemical unit operation.
Explore the connected unit processes and their engineering guides
Grit, sand, silt and colloidal solids removal across the full particle-size spectrum, with Stokes-law settling theory and discharge compliance.
ExploreAcid-base chemistry, buffer capacity and titration-curve-led neutralisation with CO2 and acid/alkali dosing systems.
ExploreThe physical chemistry of charge neutralisation, the Camp number and floc formation behind every coagulant dose.
ExploreOur engineering team can design a system tailored to your specific wastewater characteristics and treatment requirements. Contact us for a free consultation.
Stokes’-law sizing, API Publication 421 design methodology, rectangular API / CPI / TPI configurations and refinery-train integration.
Sizing, components, types, materials, codes & compliance — the full engineering reference for gravity oil-water separation.
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CFD EngineeringOur expertise spans multiple industries with sector-specific water treatment solutions.