FilterSmart allows water managers to ‘see’ into backwash processes with media level and turbidity measurements in one sensor.


Gravity filter backwash monitor

ATi’s FilterSmart Backwash Monitor is revolutionizing the way water professionals manage their gravity filters.

Until now, operators have relied on two surrogate measurements to manage the backwash process: flow rate and time. FilterSmart directly measures the parameters of actual interest: media expansion and turbidity. These two trends together present a clear picture of what’s going on during the backwash, allowing operators to ‘see’ into the process like never before. FilterSmart simplifies filter optimization because its 24/7 monitoring takes the place of countless manual hours of data collection.

The FilterSmart sensor is located in the top of a gravity filter just below the top of the wash trough. During a backwash, the ultrasonic sensor tracks the level of the media and the turbidity sensor measures how clean or dirty the wash water is as it flows into the wash trough. These two measurements produce trends that together provide an extremely accurate profile of the backwash and become a powerful tool for optimizing filter performance. Equipped with this insight, operators can virtually eliminate media loss and mud-ball formation, in most cases reduce water usage, and improve overall filter health and efficiency.

Discover how FilterSmart is delivering cost effective solutions for a Florida water treatment plant in this latest case study.


  • See how to optimize backwashes
  • Ensure proper media expansion
  • Eliminate media loss due to over-expansion
  • Easily adjust flow rates for seasonal water temperature changes
  • Determine proper air scour duration and flow rate
  • See how to save money and water
  • Easily determine when to terminate the wash by establishing the proper turbidity endpoint
  • Reduce wash water volumes and backwash duration
  • Help lengthen filter run times
  • Shorten filter ripening time
  • Easily implement ETSW
  • See hidden problems
  • Eliminate mud ball formation
  • Show the presence of leaking, fluttering, or stuck valves and rate-of-flow controllers
  • Indicate when pumps aren’t performing correctly
  • Help determine root cause of unexplained events during failures


  • Drinking water treatment filters
  • Wastewater treatment filters
  • Tertiary filters in wastewater treatment

Key benefits

  • Directly measures media expansion and turbidity
  • Eliminates media loss and mud-ball formation
  • Better long-term filter health and efficiency
  • 24/7 monitoring
  • Simplifies filter optimization



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Click on any of the parameters to learn more.



Even when installing the FilterSmart equipment on multiple filters, the water savings alone can pay for the equipment at most facilities in less than a year after optimizing the backwash sequence.

While not necessary, it can be very beneficial.  Determining the optimal wash sequence for one filter does not mean the same parameters will transfer exactly to other filters since loading and filter dynamics vary and can also change seasonally.

When the flow rate is too high, there’s a higher likelihood of washing out media.  When the wash duration is longer than necessary, valuable treated water is wasted both during the wash and during the filter ripening time post-wash.

In addition to the cost savings of backwash optimization, the data obtained from FilterSmart can be useful in identifying problems that might exist with valves and pumps.

An in-filter turbidity measurement provides immediate feedback during a backwash on when the filter is clean.  Additionally, leaving a small amount of turbidity in the filter can help to ripen the filter.

Air scouring and surface washes stir up organic matter that can be visually interpreted as media, leading to a false sense of expansion.  FilterSmart sensors can distinguish between the true expanded media elevation and organic matter being washed out of the filter.

This information is a great starting point.  Media age, pump performance, and other backwash characteristics can change seasonally and over time.  The data from FilterSmart provides current data on filter performance instead of just a one-time calculation.

Adequate expansion ensures proper cleaning of the filter media, can increase filter run times, and prevents mud ball formation.

Current measurements can be obtained via Modbus RTU from the Controller or via 4-20mA outputs from each sensor connection.  Two 4-20mA outputs are available at each sensor connection with one being dedicated to the turbidity value and the other customizable for media level, media expansion, or expansion percentage.

It is recommended that the sensors be inspected frequently the first 6 months to establish the necessary cleaning regimen for the specific application.  Ensuring the measurement surface of the sensor remains clear of any buildup and that the wiper arm is allowed to rotate freely will allow for uninterrupted performance.

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