Every drop of treated tunnel water leaves under a Trade Effluent or environmental consent. We design the treatment, monitoring and reporting that keeps the discharge inside its limits — and proves it.
Tunnel water is discharged either to the public sewer under a Trade Effluent consent or to a watercourse under an environmental permit, each with limits on pH, suspended solids and often hydrocarbons, metals and flow. Meeting them is part treatment and part evidence: the plant has to hold the limits, and the monitoring has to prove it to the water company or environmental regulator. We design both together so the discharge is compliant and fully auditable.
Treatment Plus Evidence
We start from the consent and work back: the limits set the treatment train, the sampling schedule and the instrumentation. Continuous pH, turbidity and flow monitoring with data logging, composite and grab sampling to the consent schedule, out-of-limit alarms with automatic diversion, and clear reporting give the regulator confidence and protect the contractor. Where no consent yet exists, we support the application with treatability data.
Limits drive the treatment train, sampling and instrumentation.
pH, turbidity and flow logged for the regulator.
Composite and grab sampling matched to the consent.
Out-of-limit water recirculated, never discharged.
What the Regulator Expects
A consent is only met if the plant holds the limits and the records prove it through the whole drive.
pH, TSS, hydrocarbons, metals and flow may all be capped.
Regulators expect logged, auditable data, not spot checks.
Treatment must hold limits as load swings through the drive.
From Consent to Compliant Discharge
The limits and sampling points define the design basis.
Continuous pH, turbidity and flow monitoring is installed.
Sampling to the schedule with logged, auditable records.
Out-of-limit water is recirculated automatically.
Indicative — the actual consent governs
| Parameter | Typical limit | Control |
|---|---|---|
| pH | 6–9 | Closed-loop neutralisation |
| Suspended solids | 30–50 mg/L | Clarification + filtration |
| Hydrocarbons | site-specific | Oil separation + carbon |
| Flow | capped rate | Buffer + discharge control |
| Metals | site-specific | Precipitation if required |
Plant We Build Into This Stage
Automated acid or CO² dosing neutralises high-pH cement-affected water.
View EquipmentHigh-rate inclined-plate settlers cut suspended solids in a compact footprint.
View EquipmentMultimedia and pressure filters polish settled water to tight TSS limits.
View EquipmentCoalescing and API separators remove free and dispersed hydrocarbons.
View EquipmentSediment and suspended-solids removal for tunnel construction water.
View EquipmentPre-assembled, road-transportable treatment trains that relocate as work advances.
View EquipmentWhy Choose Reynolds & Bauhm
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Our expertise spans multiple industries with sector-specific water treatment solutions.