GreenPrima ProLev800 Ultrasonic Sludge Interface Level Gauge

Overview

The GreenPrima ProLev800 is an industrial-grade ultrasonic sludge interface level gauge engineered for continuous, non-contact measurement of sludge blanket height and thickness in wastewater treatment sedimentation basins. It operates on the principle of time-of-flight ultrasonic pulse reflection: a transducer emits low-frequency ultrasonic pulses downward into the liquid column; the instrument precisely calculates the distance to the sludge–liquid interface by measuring the elapsed time between pulse transmission and echo return from the density discontinuity at the suspended solids boundary. This physics-based methodology ensures stable, drift-free detection without reliance on conductivity, optical clarity, or chemical composition—making it suitable for highly turbid, chemically variable, or aerated environments common in primary clarifiers, secondary settling tanks, thickeners, and ash settling ponds. Designed for integration into plant-wide SCADA and DCS systems, the ProLev800 delivers real-time data essential for optimizing sludge return flow rates, managing hydraulic load fluctuations, diagnosing abnormal settling behavior (e.g., bulking or rising sludge), and validating performance of gravity thickening processes.

Key Features

• Large-format backlit LCD display supporting simultaneous numeric depth readout, real-time ultrasonic echo waveform visualization, and dynamic trend plotting (configurable from 5 minutes to 48 hours)
• Dual-probe capability: single transmitter unit supports up to two independently mounted ultrasonic sensors—enabling differential profiling across tank width or multi-zone monitoring in large-diameter clarifiers
• Embedded microprocessor with adaptive signal filtering algorithms to suppress noise from surface turbulence, floating scum, or mechanical vibration—ensuring robust interface tracking under variable operational conditions
• No moving parts or immersed electronics: transducers are externally mounted on tank walls or submerged via fixed brackets, minimizing maintenance requirements and eliminating risk of fouling-related calibration drift
• Field-configurable parameters via intuitive menu navigation—including echo gain, threshold sensitivity, averaging window, and alarm hysteresis—without requiring PC software or service tools
• Adjustable display brightness and contrast for optimal legibility under varying ambient lighting, including outdoor installations with direct solar exposure
• Compliant with IEC 61000-6-2 (immunity) and IEC 61000-6-4 (emissions) for electromagnetic compatibility in electrically noisy plant environments

Sample Compatibility & Compliance

The ProLev800 is validated for use in municipal and industrial wastewater streams containing suspended solids concentrations ranging from 100 mg/L to >30 g/L, including activated sludge, primary sludge, anaerobically digested sludge, and coal-washing tailings. It maintains measurement integrity in liquids with pH 4–11, temperature gradients up to 20 °C/m, and moderate gas entrainment (e.g., denitrification zones). The device meets IP68 ingress protection per IEC 60529 for permanent submersion up to 10 m depth. Its construction materials—stainless steel 316L housing, PTFE-sealed transducer face, and UV-stabilized cable jacket—are certified compliant with ISO 9001:2015 manufacturing standards. While not intrinsically safe, optional ATEX-certified variants (II 2G Ex db IIB T4 Gb) are available for hazardous area deployment per EN 60079-0 and EN 60079-1.

Software & Data Management

Data acquisition and configuration are managed locally via the integrated LCD interface; no external software is required for routine operation. The unit logs timestamped interface position values internally at user-defined intervals (1–300 seconds), retaining up to 72 hours of historical trend data for immediate diagnostic review. RS-232C serial output enables connection to PLCs or local HMIs for protocol-based data exchange (Modbus RTU optional via firmware update). Analog 4–20 mA output is linearly scaled to full measurement range (e.g., 4 mA = 0.4 m, 20 mA = 10.0 m) and includes NAMUR NE43 fault signaling. For enterprise-level integration, GreenPrima provides optional OPC UA server support through third-party gateway hardware, facilitating alignment with ISA-95 hierarchical models and enabling audit-trail logging compatible with GLP/GMP documentation workflows.

Applications

• Real-time optimization of return activated sludge (RAS) pump control in secondary clarifiers
• Monitoring sludge blanket rise during shock loading events or nitrification failure in municipal WWTPs
• Quantifying thickening efficiency in gravity thickeners and dissolved air flotation (DAF) units
• Interface level supervision in coal preparation plant settling ponds and ash sluice water basins
• Process validation for regulatory reporting under EPA NPDES permits and EU Urban Wastewater Treatment Directive Annex I monitoring requirements
• Commissioning support for new clarifier retrofits, including baseline settling velocity profiling and zone settling analysis

FAQ

What installation methods are supported for the ProLev800 transducer?
The sensor can be mounted vertically on the tank wall using a stainless-steel bracket (side-mount), suspended from a fixed bridge (top-mount), or affixed to a submerged platform—provided acoustic coupling to the liquid is maintained and beam path remains unobstructed.
Does the ProLev800 require periodic recalibration?
No. The device uses time-of-flight measurement referenced to the speed of sound in water (automatically compensated for temperature via integrated Pt100 sensor), eliminating need for field recalibration under normal operating conditions.
Can the ProLev800 distinguish between multiple sludge layers?
It detects the dominant density interface—the primary sludge–supernatant boundary—with ±1 cm resolution. Multi-layer stratification (e.g., scum–sludge–supernatant) requires complementary instrumentation such as multi-point conductivity or gamma densitometry.
Is the 4–20 mA output isolated and HART-enabled?
The standard output is galvanically isolated but does not support HART communication; however, a HART-enabled variant (ProLev800-H) is available upon request with FSK modulation and device descriptor support.
What is the maximum recommended cable length between transmitter and probe?
Standard configuration supports 20 m; extended-length versions (up to 100 m) are available with low-capacitance shielded cable and signal repeater module to maintain echo fidelity.