GreenPrima PROLEV800 Sludge Interface Level Meter

Overview

The GreenPrima PROLEV800 Sludge Interface Level Meter is an industrial-grade ultrasonic interface detection system engineered for continuous, non-contact measurement of sludge blanket depth and thickness in clarifiers, thickeners, and settling basins. It operates on the principle of time-of-flight ultrasonic pulse-echo analysis: a high-frequency acoustic signal is transmitted vertically into the liquid column; the instrument precisely measures the elapsed time between emission and reception of echoes reflected from distinct acoustic impedance boundaries—primarily the clear liquor/sludge interface and, optionally, the sludge/bed interface. This enables real-time quantification of both interface elevation and suspended solids layer thickness with ±1 cm repeatability under typical wastewater conditions. Designed for integration into plant-wide process control architectures, the PROLEV800 delivers stable, drift-free measurements without requiring immersion, calibration against reference samples, or routine transducer cleaning—making it suitable for long-term deployment in aggressive, high-solids environments such as primary sedimentation tanks, secondary clarifiers, anaerobic digesters, coal washing thickeners, and fly ash settling ponds.

Key Features

• Large backlit LCD display supporting simultaneous numerical depth readout, real-time ultrasonic echo waveform visualization, and dynamic trend plotting (configurable time windows from 5 minutes to 48 hours)
• Dual-transducer capability: single transmitter unit supports two independent ultrasonic probes—enabling redundant measurement or multi-zone profiling (e.g., surface and mid-depth interface tracking)
• Embedded microprocessor with adaptive signal processing algorithms that suppress noise from turbulence, scum layers, and floating debris while maintaining sub-centimeter resolution
• No moving parts or submerged electronics: transducers are top-mounted and sealed to IP68; transmitter housing rated for harsh ambient conditions (−20 to +60 °C)
• Configurable 4–20 mA analog output with linear or square-root scaling, plus two independently programmable solid-state relay outputs for high/low interface alarms
• RS-232C serial interface (up to 10 m cable length) for local configuration, firmware updates, and raw data extraction via terminal emulation or SCADA integration
• On-device parameter setup with intuitive menu navigation; adjustable screen brightness for optimal visibility under varying ambient light

Sample Compatibility & Compliance

The PROLEV800 is validated for use across heterogeneous aqueous suspensions containing organic and inorganic particulates—including activated sludge flocs, primary settleables, coal fines, lime softening precipitates, and fly ash slurries. Its ultrasonic frequency and pulse energy are optimized to penetrate turbid media with total suspended solids (TSS) concentrations up to 30,000 mg/L without signal attenuation failure. The system complies with IEC 61326-1 (EMC for industrial environments), IEC 60529 (IP68 ingress protection), and meets CE marking requirements for electromagnetic compatibility and low-voltage safety. While not certified to SIL or ATEX standards out-of-the-box, its architecture supports integration into safety instrumented systems (SIS) when deployed with appropriate external logic solvers. Data logging and alarm event records adhere to GLP-aligned traceability principles, supporting audit readiness for wastewater utilities operating under ISO 14001 or EPA-approved pretreatment programs.

Software & Data Management

Configuration and diagnostics are performed locally via the front-panel interface; no proprietary software is required for basic operation. For advanced data acquisition, the RS-232 port enables connection to third-party HMI platforms or custom Python/Node-RED scripts using standard ASCII command protocols (e.g., “READ_DEPTH”, “GET_ECHO”, “SET_ALARM”). Raw echo amplitude vs. time profiles can be streamed at 1 Hz for offline waveform analysis. Although the device does not include built-in Ethernet or cloud connectivity, its 4–20 mA output is compatible with all major DCS and PLC analog input modules (e.g., Siemens S7, Rockwell ControlLogix, Schneider Modicon). All parameter changes and alarm triggers are timestamped and retained in non-volatile memory—even during power interruption—ensuring continuity of operational history for regulatory reporting.

Applications

• Optimization of return activated sludge (RAS) and waste activated sludge (WAS) flow rates based on real-time interface position
• Prevention of sludge blanket overflow in secondary clarifiers through predictive control loops
• Monitoring solids accumulation in gravity thickeners and dissolved air flotation (DAF) units
• Process support for coal preparation plants: dense-medium cyclone feed thickener level control and wash water recovery optimization
• Condition monitoring of ash handling systems in thermal power stations, including bottom ash hoppers and dewatering lagoons
• Troubleshooting abnormal settling behavior (e.g., bulking, rising sludge) by correlating interface dynamics with influent load fluctuations

FAQ

Can the PROLEV800 measure both the supernatant/sludge interface and the sludge/bed interface simultaneously?
Yes—when equipped with two calibrated transducers mounted at different heights or configured for dual-pulse sequencing, the system can resolve multiple acoustic boundaries within its 0.4–10 m range.
Is calibration required after installation?
No field calibration is needed; the instrument uses factory-trimmed time-of-flight constants and compensates for temperature-induced sound velocity changes using integrated ambient sensors.
What maintenance is recommended for long-term reliability?
Annual visual inspection of transducer face cleanliness and cable integrity; no scheduled recalibration or consumable replacement is specified due to solid-state design.
Does the device support Modbus RTU or other industrial protocols?
Not natively—only RS-232 ASCII commands are supported. Protocol conversion to Modbus RTU or TCP requires an external gateway.
How is the 4–20 mA output scaled?
Scaling is fully configurable: users define minimum and maximum depth values corresponding to 4 mA and 20 mA, respectively—supporting linear or custom segmented mapping.