Propensity for density

PROPENSITY

for density

Monitoring the level of sludge in water treatment plants (WTPs) and wastewater treatment plants (WWTPs) in real time makes it possible to control equipment such as valves, pumps and scrapers automatically. This increases the life expectancy of equipment and enables maximised operation efficiency of the WTP/WWTP.

ENV120-S controller ENV120-S sensor ENV200-C controller ENV200-C Sensor

Further to this, operators can ensure that sludge extraction pumps are used efficiently, and excess sludge does not wash out into effluent paths, preventing costly over-spills and regulation breaches.

Further sludge handling processes such as dewatering equipment and thickeners will all perform better when fed with an optimum concentration of sludge. The diluted and lower-concentration sludge will require increased dosing, digestor heating costs and pumping costs.

If the density is too high, then there is a risk that the system will become overloaded, requiring more oxygen, which is costly. If the sludge density is too low, then the biological agents will run out of nutrients and start to die, leading to a drop in efficiency and an expensive ‘re-stocking’ process.

Optimal sludge levels and density also enable companies to save on labour costs, as less manual sampling is required, and a wealth of instant feedback is available for greater overall system control.

In the South African context, there are tight budgets and a shortage of skilled workers. Products that can cut costs, give real-time feedback and make the sludge handling process easier to automate will go a long way to help in making WTPs/ WWTPs more effective and reliable.

Sludge solutions Royce Water Systems offers a range of specialised measurement and control products for wastewater treatment. The company distributes Wess Global products, which are installed at more than 10 000 sites in more than 40 countries in the world. Here are some of the products:

The ENV120-S Ultrasonic Sludge Blanket Level Meter utilises enhanced ultrasonic technology to measure the sludge interface level in various types of clarifiers, settling tanks and thickeners with superior accuracy and reliability.

The ENV120-S has the following features: • continuous and real-time measurement, enabling quick response times and optimal system control • a high-temperature and chemicalresistant sensor • superior patented signal control and tracking algorithms that filter out subtle sludge signals from suspended solids or unclear layer signals, as well as field structures such as bottom scrapers and floating debris • a dual-frequency sensor to measure light and heavy level layers • up to 400 days of data logging and monitoring • built-in automatic air jet sensor cleaning device to minimise maintenance. The ENV200-C Clamp-on Sludge Density Meter is used for sludge flow measurement in the pipeline at water and wastewater treatment processes in municipal and industrial applications. It features: • a sensor installed on the outside of pipes, avoiding exposure to corrosive and abrasive sludges • minimised maintenance, as the clamp-on sensor is free from contamination on the sensor surface, so frequent sensor cleaning is eliminated • no bypass pipeline • no special gear and installation costs • patented Envelope Energy Average

Method, which converts the signal to a density value after filtering abnormal signals and electric noise • at sewage plants – the meter is applied at raw, return, excess, thickening and dewatering processes, measuring sludge density in real time for accurate and stable process control • at drinking water plants – the density meters are operated at the sedimentation and thickening process.