Landfill Leachate Basin Level Measurement and Pump Control

Landfill leachate composition changes with waste, rainfall, age and treatment. It may release corrosive gases, create foam, deposit scale and carry suspended solids or floating debris. Non-contact radar reduces wetted exposure, but its antenna, process connection, housing and mounting still need material, contamination and maintenance review. Establish usable basin volume, overflow elevation, pump submergence limit and residual inflow after a stop command before selecting alarm points. The review should cover blocked pumps, a failed duty unit, treatment-plant flow restrictions and temporary storage during maintenance. These operating cases turn a level value into a defensible control and environmental-protection strategy instead of an isolated instrument reading. Assign responsibility for acknowledging alarms, arranging standby storage and restoring a failed pump. Define the maximum permitted response time and verify notification paths during unattended periods. This operational layer is as important as sensor accuracy when rainfall can continue adding volume after equipment or communications fail.

Define the changing medium

Record pH, conductivity, salts, ammonia, organics, solids, temperature and cleaning chemicals over the credible range. Include gas composition, condensation and seasonal dilution. A single laboratory sample cannot represent the full service life.

Specify whether the measurement controls transfer pumps, prevents overflow, supports treatment inventory or monitors environmental containment. Assign separate acceptance and alarm requirements.

Select a representative target

Keep the beam away from inflow cascades, aerators, mixers, floating pumps and structural obstructions. Map minimum and maximum surface positions and consider floating layers, foam and debris that may become the strongest target.

Define whether operations need liquid beneath foam or total occupied height. Test representative conditions rather than assuming radar always penetrates foam.

Control corrosion and deposits

Verify antenna, flange, gasket, process barrier, housing, glands and bracket against liquid, gas and washdown. Corrosive vapour may attack components above the liquid even when the antenna is chemically resistant.

Avoid a recessed nozzle where condensate, scale or biological deposits accumulate. Provide safe inspection and cleaning access; do not rely on unapproved shields or purge air.

Integrate pump and overflow protection

Set pump start and stop levels from basin geometry, pump submergence and inflow rate. Include response delays and liquid continuing to enter. Use deadband and minimum run time without concealing rapid rise.

Where overflow has significant environmental consequence, provide independent protection and notification according to the risk assessment. Level does not replace liner integrity or leak monitoring.

Handle invalid data

Transmit raw level, quality, lost echo, device fault and communication health. A held value must be marked stale and drive the approved pump or alarm response. Avoid automatic actions based on a replayed historical value.

Store time-synchronized trends with rainfall, pump state and treatment flow. These comparisons help distinguish process change from sensor fouling.

Commission and maintain

Verify low, normal and high points using a safe reference. Test local value, PLC, SCADA, pumps, alarms, lost echo and power recovery. Record foam, rainfall and chemistry with results.

Inspect after storms and cleaning for scale, corrosion, debris and mount movement. Use as-found condition and signal trends to set maintenance intervals.

Engineering checklist

• Record liquid and gas chemistry ranges.
• Define foam and floating-layer target.
• Verify all exposed materials.
• Integrate pump control and independent overflow protection.
• Mark held and stale values invalid.
• Commission with rainfall and pump states.

Frequently asked questions

Is non-contact radar free from corrosion risk?

No. Vapour, condensate and washdown still expose antenna, flange, housing and mounting.

Can level monitoring detect liner leakage?

No. Leak detection and containment integrity require separate systems.

How should cleaning intervals be set?

Use site scale, deposit, corrosion and signal-quality evidence rather than a universal calendar.

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