INDUSTRY 09

Water & Wastewater

09 / WATER

Municipal sludge density across thickeners, digesters and dewatering inlets; coagulation control in drinking-water treatment.

2 applicable products 1 application cases
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Overview

Municipal wastewater plants run a sludge-handling line — thickening → digestion → dewatering → disposal — where inline density is the bottleneck for energy and polymer optimisation. Thickener underflow (2-6%), digester recirc (3-8%), centrifuge / belt-press inlet (4-10%) are the canonical measurement points. Drinking-water plants also monitor floc concentration in settling basins and MLSS in activated sludge tanks.

Process challenges

  • Sludge carries fibres, hair and plastic shards that clog intrusive sensors
  • Digester gas (methane) interferes with differential-pressure measurement
  • Plant environments are humid and corrosive — IP65+ enclosure mandatory
  • Cs-137 gauge phase-out is accelerating across municipal plants
  • Highly variable composition (rain events, industrial slugs) demands adaptive sensors

Recommended solutions

Measurement pointPrincipleModels
Thickener underflowUltrasonic acoustic impedancePS7000
Digester recirc / outletUltrasonic + gas compensationPS7000
Centrifuge / belt press inletUltrasonic acoustic impedancePS7000
DWTP floc tank / MLSSUltrasonic / opticalPS7000 / PS7110
RECOMMENDED PRODUCTS

Products that fit this industry

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PS7000

Slurry density meter

The PS7000 series ultrasonic acoustic‑impedance slurry density meter completely eliminates the radiation safety risks and cumbersome environmental‑approval maintenance costs associated with conventional gamma‑ray density meters. By employing an innovative chirp acoustic‑impedance analysis algorithm, it overcomes measurement blind spots in complex operating conditions, enabling high‑precision continuous measurement.
PS7400

Online tuning fork density meter

The PS7400 series online tuning fork density meter monitors liquid density in real time by leveraging piezoelectric excitation and changes in the tuning fork’s resonant frequency, requiring no maintenance while delivering highly accurate, repeatable measurements. Its built-in PT1000 temperature compensation eliminates drift due to temperature variations, making it suitable for diverse industrial applications such as pipelines and storage tanks, and widely used in the petrochemical, chemical, and pharmaceutical industries.
APPLICATION CASES

Cases in this industry

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Slurry density meter · PS7000

Sludge Thickening / Digestion / Dewatering / Alum Flower Online Monitoring Solution

In the sludge thickening, digestion, and dewatering processes of municipal wastewater treatment plants, conventional gamma-ray density meters pose radiation safety risks, while insertion-type instruments are prone to clogging from hair and fibers. This results in PAM flocculant dosing being based on empirical estimates, leading to chemical waste and fluctuating cake moisture content. The PS7000 series ultrasonic acoustic impedance slurry concentration meter employs a non-contact ceramic probe installed at the thickener underflow, the digester recirculation line, and the dewaterer feed pipe, enabling online density monitoring that is radiation-free, clog-free, and responsive within seconds, thereby supporting precise closed-loop PAM dosing.

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Industry FAQ

What are the common challenges in municipal water / sludge density monitoring?

Challenges in water treatment and sludge processes:

  1. Diverse impurities—fibers, hair, plastic fragments, and other filamentous materials that can easily wrap around contact-type instruments;
  2. Serious scaling—phosphate and calcium ions in the sludge dewatering stage lead to solid deposits adhering to probes;
  3. Corrosiveness—wastewater pH fluctuates widely (4–10);
  4. High gas content—abundant bubbles in the aeration section interfere with conventional ultrasonic and refractometric instruments.

Recommended solutions: PS7000 ultrasonic acoustic impedance (for aeration tanks with numerous bubbles), PS7010 external‑mounted ultrasonic (for non‑perforable older pipelines, with zero hair entanglement), PS7400 tuning fork with PTFE coating (for the sludge dewatering stage, resistant to scaling), PS7600 microwave (for advanced dewatering of municipal sludge).

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