Precipitate dissolved metals, phosphates, and suspended solids through controlled chemical reactions for compliance and water reuse.
Chemical precipitation converts dissolved contaminants into insoluble solid particles through controlled pH adjustment and reagent addition. Metals precipitate as hydroxides or sulphides at specific pH ranges. Phosphates precipitate as calcium, iron, or aluminium salts. Fluorides precipitate as calcium fluoride. The precipitated solids are then removed by clarification, flotation, or filtration. It is one of the most widely applied processes for meeting discharge compliance in demanding industrial wastewater applications.
Removes metals, phosphates, fluorides, sulphates, silica, and many other dissolved ions.
Online pH and ORP sensors with automated reagent dosing maintain optimal precipitation conditions.
Precipitated metals can be refined; phosphate sludge used as fertilizer; calcium fluoride sold to industry.
Most precipitation reactions complete in 5-30 minutes, enabling compact reactor designs.
Step-by-step breakdown of the treatment process from influent to effluent.
Influent equalized to smooth flow and concentration variations. Online pH and metal sensors characterise wastewater.
pH raised to optimal precipitation range (8.5-10.5 for metals) using caustic or lime. Metal precipitants (ferric, alum, sulphide) dosed based on stoichiometry.
Turbulent mixing for 1-2 minutes ensures uniform reagent distribution. Slow flocculation for 15-30 minutes builds settleable floc.
Precipitated solids removed by lamella clarifier (settling), DAF (flotation), or thickener. Sludge at 2-5% solids.
Effluent polished by media filtration or GAC to capture carryover particles. Final pH adjusted to 6.5-8.5 for discharge.
Explore the equipment components that make this process effective.
High-rate settling for precipitated solids separation at 6 m/h upflow.
Automated reagent preparation and metering with day tanks and pumps.
Multi-stage acid and alkali dosing for precise pH control.
Flotation for light precipitates and oily metals that resist settling.
Remove nickel, chromium, zinc, copper from plating rinse water.
Phosphate and fluoride removal from phosphate coating lines.
Iron and heavy metals precipitation from acid mine water.
Phosphate and calcium management in mixed food wastewater.
This treatment stage is engineered to achieve specific contaminant removal targets while providing stable, predictable performance across variable inlet conditions. Design parameters are calculated from wastewater characterisation data, regulatory requirements, and site-specific constraints including footprint, energy availability, and operator capability.
Design validated by CFD modelling and pilot testing to confirm performance guarantees.
Equipment selected for 20-year design life with minimal wearing parts and easy access.
Automated dosing and feedback control minimise reagent consumption and sludge production.
Online monitoring and data logging demonstrate continuous consent compliance.
| Design Flow | 10 – 5,000 m³/h (application specific) |
| Inlet Variability | Designed for 1:3 peak-to-average flow ratio |
| Removal Efficiency | 85 – 99% depending on target contaminant |
| Hydraulic Retention | Calculated from kinetic constants and safety factors |
| Power Consumption | 0.5 – 5.0 kWh/100 m³ (process dependent) |
| Chemical Dose | Auto-controlled based on online analysers |
| Sludge Production | 0.2 – 1.5 kg DS/kg contaminant removed |
| Materials | SS304, SS316L, or carbon steel with coating |
No treatment stage operates in isolation. This process is designed to receive conditioned influent from upstream stages and deliver effluent quality suitable for downstream processes. Hydraulic and organic loading rates are balanced across the complete treatment train to prevent bottlenecking and ensure overall plant efficiency. Our engineers model the complete flowsheet to optimise Capital expenditure and Operating expenditure across the plant lifecycle.
Screening, equalisation, and pre-treatment protect this stage from damage and overload.
Effluent quality ensures downstream biology, filtration, or disinfection performs optimally.
Reject streams, filtrate, and centrate are routed back to appropriate upstream points.
Our engineers design and commission complete treatment systems including all equipment, automation, and commissioning support.
Our expertise spans multiple industries with sector-specific water treatment solutions.