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Example ApplicationMetro & Tunnelling

Tunnel Boring Machine Slurry Treatment

This is an illustrative scenario showing how Reynolds & Bauhm equipment can be configured for this application. Every site has unique requirements — contact us for a solution tailored to your specific wastewater characteristics.

Process Requirements & Constraints

Metro extension project with two TBMs producing 180 m3/h of slurry containing bentonite, rock cuttings, and groundwater. Slurry density 1.15-1.25 kg/L with particle sizes from clay to 20mm gravel. Excavated material must be dewatered to <30% moisture for truck transport while recovered bentonite is recirculated to the TBM.

Key Performance Targets
28%
Cake solids
<100
TSS mg/L return
85%
Bentonite recovery
180
m3/h capacity
40%
Load reduction
24/7
TBM operation

Treatment Approach

Step-by-step process configuration from raw wastewater to compliant discharge.

01

Coarse Screening

Vibrating screen with 5mm aperture removes coarse rock and gravel fraction. Oversize material at 15-25% moisture conveyed directly to trucks. Reduces downstream solids load by 40%.

02

Hydrocyclone Desanding

Two-stage hydrocyclone battery separates sand fraction (63-2000 micron) from bentonite slurry. Underflow sand at 65% solids discharged. Overflow fines returned to processing.

03

Thickening & Clarification

High-rate lamella thickener raises slurry concentration from 8% to 18% solids. Flocculant polymer dosed at 350 g/tonne dry solids. Overflow water at <100 mg/L TSS returned to TBM circuit.

04

Centrifuge Dewatering

Decanter centrifuge processes thickened underflow to 28% cake solids. Counter-current bowl design handles variable feed concentrations. Cake conveyed to stockpile for transport.

05

Bentonite Recovery

Clarified water and recovered bentonite pumped back to TBM slurry circuit at 35-45 g/L concentration. Online density monitoring maintains optimal slurry viscosity for face support.

Equipment Configuration

The specific equipment selected for this application, sized for the flow rate and contaminant load.

Vibrating Screen

Double-deck vibrating screen, 5mm top deck, 1mm bottom deck, 200 m3/h capacity, rubber-lined deck.

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Hydrocyclone Battery

10-inch desanding cyclones, PU-lined, 2-stage, 50 m3/h each, automatic underflow control.

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Lamella Thickener

High-rate thickener, 120 m2 settling area, flocculant dosing, automatic rake lift.

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Decanter Centrifuge

Horizontal decanter, 420mm bowl, 3,200 RPM, 15 m3/h slurry capacity, 28% cake solids.

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Performance Achieved

Representative performance data based on typical operating conditions for this equipment configuration.

28%
Cake solids
<100
TSS mg/L return
85%
Bentonite recovery
180
m3/h capacity
40%
Load reduction
24/7
TBM operation

Related Equipment

Explore the full range of equipment used in this and similar applications.

Progressive Cavity Pump

Abrasion-resistant PC pump for thickened slurry transfer.

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Polymer Dosing System

Automated flocculant preparation and dosing for thickening.

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Slurry Density Meter

Nuclear density gauge for online slurry concentration monitoring.

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Conveyor System

Belt conveyor for dewatered cake transport to stockpile.

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Related Treatment Processes

Discover how these treatment processes connect to form complete wastewater treatment solutions.

Project Approach & Engineering

Reynolds & Bauhm follows a structured engineering methodology for every project. We begin with detailed wastewater characterisation, process selection based on contaminant profiles, pilot testing where required, and full-scale design with performance guarantees. Our multidisciplinary team of chemical, mechanical, and electrical engineers ensures seamless integration of process, mechanical, and control disciplines.

Characterisation

Comprehensive influent analysis including COD, BOD, TSS, heavy metals, pH, temperature, and flow profiling.

Process Design

Process flow development with P&IDs, mass balances, and hydraulic modelling validated by CFD where appropriate.

Pilot Testing

On-site pilot trials validate performance guarantees under actual operating conditions before capital commitment.

Commissioning

FAT, SAT, performance trials, operator training, and handover documentation ensuring operational readiness.

Equipment Configuration

Pre-TreatmentScreening, grit removal, and flow equalisation
Primary TreatmentDAF or lamella clarification for solids and oil removal
Secondary TreatmentBiological oxidation (activated sludge, MBBR, or SBR)
Tertiary TreatmentFiltration, UV disinfection, or chemical polishing
Sludge ManagementThickening and dewatering via belt press or centrifuge
Control SystemPLC with HMI touchscreen and optional SCADA integration
Chemical DosingAutomated coagulant, flocculant, and pH correction
MaterialsSS316L, duplex, or rubber-lined carbon steel

Performance Outcomes

COD Removal

85 – 98% chemical oxygen demand reduction depending on process configuration and influent variability.

TSS Removal

90 – 99% suspended solids reduction through combined physical and biological treatment stages.

Water Reuse

Tertiary treatment enables up to 80% water recycling for non-potable process applications.

Apply This Configuration to Your Site

Our engineers will adapt this equipment configuration to your specific wastewater analysis, flow rate, and discharge requirements.

Industries We Serve

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