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Chemical & Process Calculations

Equipment sizing from first-principles engineering science. Mass balance, reaction kinetics, equilibrium analysis, and hydraulic design. Every dimension is calculated, not estimated. Every material is selected from chemical compatibility data, not catalogue availability.

Calculated from First Principles

The science behind every dimension, every flow, every reaction

There is a difference between sizing equipment by rule of thumb and sizing it by calculation. Rule of thumb gives you something that works. Calculation gives you something that is optimal. At Reynolds & Bauhm, we do not approximate. We calculate. Every vessel volume, every plate angle, every retention time, every chemical dose is derived from chemical engineering science and verified against your specific process conditions.

Mass Balance Modelling

Complete steady-state and dynamic mass balances across every unit process. Flow rates, concentrations, and loads are calculated at each treatment stage to verify hydraulic and contaminant continuity.

Reaction Kinetics

Biological growth rates, chemical oxidation rates, and coagulation kinetics are calculated from Monod, Michaelis-Menten, and Arrhenius equations applied to your effluent characteristics.

Hydraulic Design

Flow profiles, headloss, velocity gradients, and mixing intensity are calculated using Bernoulli, Darcy-Weisbach, and continuity equations for laminar through turbulent regimes.

Our Calculation Disciplines

The engineering science applied to every design

Stoichiometric Analysis

Chemical reactions are balanced and quantified from stoichiometry. Dosing rates for coagulants, oxidants, and precipitants are calculated from molar ratios, not empirical factors. This ensures optimal chemical consumption and minimal residual.

Equilibrium Calculations

pH, solubility product, and redox potential are calculated from thermodynamic equilibrium constants. Metal precipitation, phosphorus removal, and ammonia stripping are all designed from equilibrium data, not trial and error.

Settling & Sedimentation

Clarifier design is calculated from settling velocity analysis, zone settling theory, and solids flux. Plate spacing, angle, and tank depth are all dimensioned from the calculated settling characteristics of your suspended solids.

Air Dissolution & Flotation

DAF air-to-solids ratios, bubble size distributions, and rise velocities are calculated from Henry's law, Stokes' law, and bubble coalescence theory. Not from manufacturer tables, but from fluid mechanics.

Biological Growth Kinetics

MBBR carrier surface area, SBR cycle times, and activated sludge MLSS are calculated from Monod kinetics, yield coefficients, and decay rates specific to your organic load and nutrient profile.

Structural & Pressure Design

Vessel wall thickness, weld specifications, and reinforcement are calculated from ASME and EN pressure vessel codes. Stress analysis, fatigue life, and buckling resistance are all verified before fabrication.

Process Fundamentals & Design

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.

Process Optimisation

Design validated by CFD modelling and pilot testing to confirm performance guarantees.

Mechanical Reliability

Equipment selected for 20-year design life with minimal wearing parts and easy access.

Chemical Efficiency

Automated dosing and feedback control minimise reagent consumption and sludge production.

Compliance Assurance

Online monitoring and data logging demonstrate continuous consent compliance.

Design Parameters

Design Flow10 – 5,000 m³/h (application specific)
Inlet VariabilityDesigned for 1:3 peak-to-average flow ratio
Removal Efficiency85 – 99% depending on target contaminant
Hydraulic RetentionCalculated from kinetic constants and safety factors
Power Consumption0.5 – 5.0 kWh/100 m³ (process dependent)
Chemical DoseAuto-controlled based on online analysers
Sludge Production0.2 – 1.5 kg DS/kg contaminant removed
MaterialsSS304, SS316L, or carbon steel with coating

Integration with Treatment Train

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.

Upstream Protection

Screening, equalisation, and pre-treatment protect this stage from damage and overload.

Downstream Conditioning

Effluent quality ensures downstream biology, filtration, or disinfection performs optimally.

Recycle Streams

Reject streams, filtrate, and centrate are routed back to appropriate upstream points.

Related Pages & Equipment

Equipment Catalogue

Browse our full range of water treatment equipment and systems.

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DAF Systems

Dissolved air flotation for solids and oil separation.

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Lamella Clarifiers

High-rate settling for primary and secondary clarification.

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Biological Treatment

Activated sludge, MBBR, and SBR systems for organic removal.

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Sludge Dewatering

Belt press, centrifuge, and screw press dewatering.

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Chemical Dosing

Automated coagulant, flocculant, and pH correction systems.

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Pilot Testing

Validate process performance with on-site pilot trials.

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Speak to Our Engineers

Request a consultation or quotation for your project.

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Industry-Specific Design Considerations

Temperature Extremes

Equipment specified for operational temperatures from -20°C to +60°C with appropriate insulation and heating options.

Corrosion Protection

Material selection based on detailed water chemistry analysis. Cathodic protection and coating options for aggressive duties.

Power Supply Variations

Equipment designed for 380-415V 50Hz, 460-480V 60Hz, and generator-backed installations for remote sites.

Site Constraints

Compact vertical layouts, containerised skids, and modular expansion options for space-restricted installations.

Engineered by Calculation, Not Approximation

Speak with our process engineers to understand how first-principles chemical engineering calculations can optimise your treatment plant design, reduce chemical consumption, and improve long-term reliability.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.