Friday, September 20, 2013

Siemens Weighing and Remote Monitoring solution for reliable wastewater treatment



Siemens (Canada) - Wastewater treatment can be a dirty job – but someone has to do it. At a Canadian wastewater treatment plant (WWTP) serving around 75,000 citizens, between 240 and 300 cubic meters of digested sludge are treated each and every day!

Known simply as “sludge,” biosolids are nutrient-rich organic materials left over from the wastewater treatment process. Since this type of organic material from domestic sewage can’t simply be taken to the nearest garbage dump, biosolids must be managed to reduce or eliminate pathogens and minimize odors. They are therefore carefully monitored in accordance with regulatory requirements.

The result is an excellent fertilizer used for improving soil quality in farms, gardens, and parks. This wastewater treatment plant completes this process safely and efficiently with the help of weighing and remote monitoring technology from Siemens.

De-watering made easy:
Biosolids are often just 3-5 percent solids, so the wastewater treatment plant must remove water from the material to reduce both the material’s weight and the cost of further treatment or disposal.

Operators use a variety of technologies to de-water biosolids – including filterpresses, belt presses, and other devices.


The Siemens Milltronics MSI belt scale features two parallelogram stainless steel load cells dynamically joined to ensure reliable and repeatable results in light loading applications.


The SITRANS WF330 solids flowmeter is ideal for materials that can build up on the sensing plate, as it only reacts to horizontal movement caused by material flow.


SITRANS RD500 remote data monitor connects seamlessly to the Milltronics BW500 and SF500 integrators through standard on-board Modbus RTU protocol.

This particular plant uses freeze-drying to de-water, to remove insects, and to reduce odors.

A conveyor belt feeds sludge material into the freezedryer. Operators installed a Siemens Milltronics MSI belt scale combined with a Milltronics BW500 integrator and a SITRANS WS300 speed sensor to monitor the amount of material being delivered to the dryer.

Accurate monitoring is necessary, as the WWTP keeps detailed processing reports for quality and validation purposes, capturing the amount of material going in and out. Since the material is conveyed very sporadically and the loading is light, this process required a highly sensitive solution.

Frozen sludge to fertilizer for farms:
Once the material is loaded into the freeze-dryer, it is fed into trucks for landfill or storage for further processing. The secondary process incinerates the freeze-dried sludge so it can be turned into fertilizer for agriculture.

A solids flowmeter was also needed to monitor the infeed of the incinerator. The WWTP installed a SITRANS WF330 flowmeter with a Milltronics SF500 integrator, as the flowmeter is suitable for the incinerator’s high internal temperature of 200 °C (392 °F).

The company connected both of the integrators to a SITRANS RD500 remote monitor and data logger. The remote monitor is configured to e-mail the process engineers the amount of material that has been conveyed into the dryer and also fed into the incinerator.

The WWTP uses these totalized amounts to compare incoming and outgoing totals to account for material loss during transport or processing. These amounts are then used for regulation and reporting purposes to local environmental authorities.

The amount of inter-office communication is reduced as the SITRANS RD500 automatically sends data when it is required.

This solution from Siemens takes a dirty process and cleans it up with innovative and unique products that ensure accuracy and continuous reliability.

For more information about the Siemens Milltronics MSI belt scales click here.

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