SoliSense Inline Tip.

SoliSense® Inline Tip

Whatever level of suspended solids or turbidity monitoring you want to measure, the SoliSense® is the solution. A sophisticated sensor that ranges from 10 NTU to 2% solids, this turbidimeter suspended solids monitor, is the solution, and is unique in its ability to measure from low NTU to percent solids in one sensor. Suitable for potable water monitoring, mixed liquor suspended solids monitoring, return activated sludge, centrate monitoring, filtrate monitoring, sludge, and many more applications where a traditional turbidimeter or suspended solids analyzer would be used.

With the SoliSense® range of Suspended Solids/Turbidity analyzers you get a world’s first sensor. The first sensor to successfully incorporate four measuring technologies. For multiple measuring ranges the one sensor can monitor Turbidity and Suspended Solids from 10 NTU to 2% solids in one sensor.

The SoliSense® Turbidity Meter Suspended Solids Analyzer instrument uses two light emitters and four detectors arranged around a circular aperture. This eliminates interference from extraneous light sources and compensates for detector soiling and the aging of the optical modules. The arrangement of this 8 beam technology allows measurement of the light transmitted, scattered or reflected by a medium. This allows for the most precise measurement of turbidity or suspended solids in a liquid from 10 NTU up to 2% solids!

The SoliSense® suspended solids meter is suitable for dip monitoring, in line monitoring and flow through monitoring.

  • Auto-clean optical sensor
  • Stable and reliableexcellent process control
  • Suitable for all potable, waste and process waters
  • Up to 6 months between maintenance
  • Up to 3 months between calibration
  • From 10 NTU to 2% Solids

The SoliSense® suspended solids sensors are available with different controllers giving you the same great performance with different communication, display, and control options. With the SoliSense® range of suspended solids meters, you get everything that you need – and nothing that you don’t, without sacrificing the quality of measurement.

  • Inlet monitoring (turbidity 10-4,000 NTU)
  • Effluent monitoring (suspended solids 5-1,000 mg/l)
  • Distribution monitoring (turbidity 10-100 NTU)
  • Hydrant monitoring (turbidity 10-20,000 mg/l)
  • Fire hydrant monitoring (turbidity 10-20,000 mg/l)

Traditional monitoring applications where the SoliSense® is particularly suited:

  • RAS (Return Activated Sludge)
  • MLSS (Mixed Liquor Suspended Solids)
  • WAS (Waste Activated Sludge)
  • Thickened sludge
  • Centrate
  • Filtrate
  • Effluent
  • Inlet
  • Filter

Each probe is equipped with 2 light sources and 3 detectors. Each light source uses long-life emitters (at least 20,000 operating hours), and these are turned off when not required to conserve energy and extend the life.

By using multiple light emitters and detectors in a single probe it is possible to:

  • Measure solids from 10 NTU to 2% solids
  • Monitor and compensate for fouling of the optics
  • Monitor and compensate for aging of the optics
  • Measure the side scattering of light (ISO7027 requires a 90° side scatter measurement). (NTU)
  • Measure transmitted light (low % solids)
  • Measure the back scatter of light (higher % solids)

The electronics provide a fully scalable output allowing the SoliSense® to measure any part, or the whole of the scale. The sensor probe comes equipped with the capability of having a water jet regularly sweep over the optical lenses keeping them clean. If you have an application that ranges from low NTU all the way to %age solids then the SoliSense® is certainly the monitor for you! With only 3 or 4 calibration points you can accurately monitor your process all the way from low NTU to medium solids.

The probes are stainless steel and are built to work in the demanding environment of a WwTW. If you want to monitor solids at any point in your waste water treatment plant, this instrument has the self cleaning sensor and accessories to do it, even if other instruments have failed.

Remote Water Treatment Plant

Small water treatment plants, secondary disinfection plants etc. tend to suffer from similar problems wherever they are in the world. The first is lack of communications SCADA infrastructure. The cost of which to install can be prohibitive. The second is the lack of a central DCS control infrastructure, again the installation of which can be cost prohibitive. The third is the remote location. Often these water plants are in remote and difficult to access locations when the weather can sometimes cut them off for weeks at a time.

With these three issues facing many water engineers around the world a low cost solution providing solutions to all three issues is available from Pi. A CRIUS® controller has the on board capacity to provide small scale SCADA, and full online PID control whilst the sensors (e.g. chlorine, pH, Turbidity etc.) are suitable for long term operation without operator intervention.

When, in 2009 Cork County Council in Ireland needed exactly this functionality on 20 small, remote sites they installed CRIUS analyzers from Pi to great effect.

To demonstrate the remote access capability of the CRIUS® please click here.

To learn more about the control capability of the CRIUS® please click here.

To hear more about other customers in your country using the CRIUS® multiparameter controllers in a similar way why not contact us?


What are Suspended Solids?
Suspended solids are particles suspended in water. They occur naturally and can be seen for example in rivers after a rainfall event when the river appears ‘muddy’.

How is the measurement used in Water Treatment?
Water treatment is largely about; removing particles and organics, and then disinfecting water. Being able to measure suspended solids can help in determining the best treatment for example by measuring the suspended solids in the raw water coming in to a plant.

Typically suspended solids in waste water treatment has specific names such as MLSS (Mixed Liquor Suspended Solids) or RAS (Return Activated Sludge) etc.

What units are Suspended Solids measured in?
Typically suspended solids are measured in mass per volume units such as mg/l or mgl-1.

What is the relationship between Suspended Solids and Turbidity?
Suspended solids is a ‘unit per volume measurement’ e.g. 1 mg of suspended solids in 1 litre of water. Turbidity is a measurement of ‘ cloudiness’. Although each suspended material will have a different relationship (which will change over the range) a useful ‘rule of thumb’ is that 1 mg/l = 2 NTU.

What is the highest level of solids you can measure with SoliSense?
This depends entirely on how ‘optically clean’ the medium is. So for example if we are measuring sand (silica) in a clean water suspension we can measure up to 50%. If, however, we are measuring black sludge in a waste water plant it may be as low as 2%. Typically in most waste water works it is 3%.

What if I have a measurement over a large dynamic range?
This can happen, for example with a water treatment plant inlet where for much of the time the raw water is in the range 0-20 mg/l but when it rains it can go to 0-700 mg/l. The SoliSense® allows several outputs for the same sensor. This means for example you might have 2 output ranges; one scaled 0-20 mg/l and one scaled 0-750 mg/l. Up to four outputs are possible.

How will temperature affect the SoliSense®?
Each SoliSense® has temperature compensation built in so the effect of temperature is negligible. It should be noted though that the SoliSense® is a large mass that can take time to reach thermal equilibrium so any process where the temperature is changing rapidly >2°C per 10 min is probably not an ideal application.