ParticleSense

Across the developed world failures in coagulation and filtration have led to outbreaks of Cryptosporidiosis and other illnesses caused by organisms such as Cryptosporidia and Giardia.

Continuous monitoring of the turbidity at the outlet of a filter is essential and even a legal requirement in some countries. Turbidity is a good measure of the clarity of the water and gives a single, understandable output for operators and is most sensitive to smaller particles (particles <1µm in size).

Particle Counters look at larger particles (usually larger than 2µm) and provide additional information over and above that provided by turbidity meters, particularly information regarding the break down of a filter and the passing of Crypto sized particles, often undetectable by a turbidity meter.

In the past many water companies, water authorities, local county councils, etc. have put turbidity meters on filters but not particle counters, largely due to the higher cost of particle counters.

Coagulation Failure Vs Filter Breakthrough

In most Cryptosporidium outbreaks there has been a failure of both coagulation and filtration. If coagulation fails then un-coagulated particles can pass straight through a filter. A turbidity meter would pick this up and show the operator that there was something wrong.

If, however, the filter starts to pass large, crypto sized particles, or to break down, or to ‘channel’ (a channel opens in the filter from top to bottom) it is unlikely that this will be picked up by a turbidity meter, but can clearly be seen with a particle counter.

Costs

In the past, to install a bank of 8 filters with a particle counter would have meant a capital cost of approximately €45,000 which has been a stumbling block for many.
Now Pi has made a multipoint analyzer providing the same functionality for approximately €25,000 taking away much of the price objection.

Particle Counter Vs Turbidity…..Which One?

Turbidity Meters are more sensitive to smaller particles which are present if coagulation fails.

Particle Counters are more sensitive to filtration failures.
So which do you need?
You need both.
Why not contact us and see what we may be able to do to help you reduce your risk of a Cryptosporidia outbreak.

You probably know that Particle Counters are really expensive, complex to run, give out too much information and have to be sent-off for re-calibration? NO LONGER! Particle Counter technology has come on in leaps and bounds in the last few years!

… did you know that the price per point can often be even lower then turbidity?
… did you know that calibration of a particle counter can now be done easily on site and by the customers?
… did you know that a particle counter can now give a single ‘ppb’ output (as well as size and count information)?

CounterSense, FilterSense and ParticleSense

Working closely with Chemtrac Inc. one of the worlds leading particle counter sensor manufacturers, Pi has developed a stunning range of Particle Counters for the online measurement of particles in water.

Filter Optimization

Nearly every filter used in portable water treatment has a turbidity meter monitoring the outlet. Turbidity is a great tool for measuring the cloudiness of the water but it is only telling you half the story!

Filter Monitoring to prevent Cryptosporidia Outbreaks

Improvements in water treatment have greatly reduced the risk posed by possible cryptosporidia outbreaks following well published outbreaks around the world in the 1990’s and later. As part of these improvements most filters have been fitted with turbidity meters that are great at picking up coagulation failures. In some regions filter banks have also been fitted with Particle Counters as they have proven to be better at picking up the initial stages of filter breakthrough or ‘channelling’ (where the water meter finds a way through the filter media without being filtered).

Using Turbidity Meters AND Particle Counters on the outlet of a filter not only provides an indication when there are more small particles (turbidity) but also when the larger Cryptosporidia size particles are coming through (particle counter).
Improvements in technology now means that a filter bank can be fitted with particle counters for a similar price to turbidity.

Process Optimization using a Particle Counter

Filters are typically backwashed based on time and pressure differential.

Each time a filter is backwashed it involves significant cost, both financial and environmental. When filters start to break down they pass larger particles first and these are not seen by turbidity meters. Using a particle counter to control the backwashing of filter could lead to significant cost saving and better water leaving the plant.