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Treatability Testing of Dredged Materials

In 2023, Brennan acquired the dredging and dewatering division of Infrastructure Alternatives, Inc (IAI). IAI served clients in dredging, dewatering, and water treatment for over two decades, including Brennan. With the acquisition, IAI's team of skilled operators and water treatment experts joined Brennan, bringing with them their expertise, equipment, and system designs. Together, we perform high-quality dredging, environmental remediation, dewatering, and water treatment services to clients throughout the United States.

Treatability Testing

We perform treatability testing on dredged materials, sediments, industrial residuals, and sludges in our laboratory. After testing is complete, we recommend and select the most efficient means and methods for dewatering the material and the separated water.

Geotextile Tube Dewatering Test (GTDT)

A specialized test we perform is called a geotextile tube dewatering test (GTDT). This test may also be referred to as a pillow test and replaces the hanging bag test.  A GTDT involves pouring sediment or other material to be dewatered into a small-scale geotextile tube. The flow rate, turbidity, and suspended solids content of the water passing through the geotextile tube fabric, weep water, or filtrate are evaluated.

Chemical Conditioning

Prior to the GTDT, our in-house chemist will perform a polymer screen and rapid dewatering test (RTD) to identify a chemical conditioning program for the material to be dewatered. These programs may be single or dual applications, depending on the chemical composition and physical properties of the material. The results of the polymer screen are provided to the client with our recommended LB per dry TON dose(s).

Water Treatment Bench Testing

Our team has lab-scale filters for evaluating the performance of various types of media. We can also perform flocculation and settling tests to evaluate chemical addition and clarification processes for removing solids and associated contaminants. 

Treatability tests we perform in-house: 

  • Solids and grain size analysis of the in-situ material 
  • Polymer screen with jar testing to select a chemical application, flocculants, coagulants, polymers, and a target dose for both single-product and dual-product applications. 
  • Rapid dewatering test (RDT)
  • Geotextile tube dewatering test (GTDT)
  • Filtrate or weep water turbidity and suspended solids (TSS) analysis 
  • Sample collection, packaging, and shipment of weep water samples for chemical analysis by others
  • Dewatered material percent solids after 24 hours in the geotextile tube 
  • Paint filter and unconfined compressive strength tests on the dewatered material
  • Bench-scale performance and target dose of soil amendments 
  • Bench-scale performance and target dose of chemical flocculants for water treatment, post-sediment dewatering 
  • Bench-scale performance of water treatment processes 

Treatability Test Results, Reporting, and Recommendations

Treatability test results are summarized and provided to clients with a photo log. Based on our experience with geotextile tube dewatering and water treatment, we can also provide recommendations for full-scale project design and implementation.

What are your dewatering options?

High-speed material separation and dredged material dewatering are imperative to any environmental dredging project. Dewatering details are on our website here.


Through an acquisition in February of 2023, the dredging and dewatering division of Infrastructure Alternatives, Inc. (IAI) became a part of J.F. Brennan Company, bringing its services and team members to the Brennan family. More details are available in the news release: Brennan Acquires Dredging & Dewatering Division of IAI With Recent Purchase of Assets.