The new landscape of increasingly rigorous regulations and expanding populations means owners and operators of water treatment plants need to apply strategic approaches to their challenges. Generally, space and budget concerns pose significant challenges, which lead many facilities to pursue retrofitting and rehabilitation rather than new construction.

For owners looking to rehabilitate a water treatment plant, the evaluation of plant filters can often provide benefits in operational costs and overall capacity. Filter evaluations utilize a combination of proven engineering concepts, operational knowledge from plant staff, and simple tests to analyze filter performance. Typically, there are a few major indicators that point to the benefits of a filter evaluation. Careful technical analysis can help identify how to best optimize and improve the filters, and gain more treatment capacity.

Indicators You Might Benefit From a Filter Evaluation

A water plant experiencing any of the following conditions will likely find a filter evaluation beneficial:

  • Addition of a new process (granular activated carbon (GAC), ozone, etc.)
  • Increased filter head loss or effluent turbidity
  • Loss of filter media
  • Low filter run times
  • Need for additional plant capacity
  • Poor performance of treatment processes upstream of the filters

Once an owner or operator makes the decision to conduct a filter evaluation, an across-the-board examination of several key aspects should take place. These key aspects include historical filter performance and backwash efficiency, as well as media and underdrain condition.

Multiple Benefits From Multiple Approaches 

When a team conducts a comprehensive filter evaluation and makes subsequent recommended improvements, considerable benefits are realized. This important work not only increases capacity, backwash efficiency, run time and filter performance, but also operator knowledge about plant operations across the board.

  • Little things. From minor improvements that enable better cleaning of filter media during backwash to those that allow plant operators to better monitor filter health, filter evaluations can lead the way to improved operational and regulatory consistency.
  • Bigger things. Smart, targeted capital improvements can be particularly impactful and can help to increase the life of filter media, increase solid storage capacity and remove any source of upstream issues.

Smart Retrofitting and Rehabilitation

Owners and operators of water treatment plants that are likely ready for filter evaluations — and any subsequently recommended improvements — need to assemble a team of engineers who specialize in these services. From looking at the big picture to understanding facility details to realizing the specific needs of a community for a successful project, the team needs to work together with the owner and operators as a collaborative unit. Using a simple yet holistic approach for a project, a savvy team can incorporate the knowledge needed to examine and solve the toughest challenges and get the project done quickly, while also saving on costs.

When it comes to considering a filter evaluation, it is important to optimize what owners and operators already have. There is no one-size-fits-all solution when it comes to solving water treatment plant filter challenges.


Learn how one water treatment plant addressed a decrease in filter efficiency that was a result of lime carryover from upstream processes.

Read the Case Study

Allison Morris, PE, is a civil engineer at Burns & McDonnell. She has experience in a broad range of water projects, including gravity and force main sewer design, inflow and infiltration removal, filter evaluations and pump stations.