Applied Research

Hazen and Sawyer is conducting indirect potable reuse pilot research in Hollywood (FL) to demonstrate acceptable emerging contaminant oxidation using treatment technologies that are more cost-effective and have a smaller carbon footprint than traditional options.

As part of an international collaboration, we are building a tool to help utilities and support agencies in preparing for and adapting to extreme weather-related events that impact water quality/treatability, as well as tracking/monitoring impact trends on an ongoing basis.

For Henrico County, we are assessing the impact of OpenCel™ treated WAS on full-scale BNR performance. Initial estimates suggest that WAS lysis has the potential to save Henrico Co. ~$9,000,000 over 20 years compared to using glycerol as the supplemental carbon donor for ENR.

Hazen and Sawyer recently completed a National Science Foundation Small Business Innovation Research grant (NSF-SBIR) with MIOX Corporation investigating the use of advanced oxidation processes (AOPs) generated by a combined ultraviolet light (UV)/chlorine process. The application of the UV/chlorine AOP was effective at oxidizing the contaminants without negatively impacting the formation of regulated disinfection byproducts (DBPs).

Hazen and Sawyer is working with NYSERDA, the Water Research Foundation, and several water utilities in NY State to investigate the impacts of climate change on natural organic matter and DBP formation and to develop on-line, field-deployable sensors to help predict DBP formation. Our state of the art 3-D Fluorometer is a key component of this study and other process optimization research projects around the US.

To address struvite issues and a stringent phosphorus limit (0.08 mg/L) at F. Wayne Hill Water Resources Center, Gwinnett County undertook a pilot program and business case evaluation to assess the potential for a nutrient recovery process that treats phosphorus and ammonia while producing marketable fertilizer as a by-product.

We're currently researching the most cost-effective single carbon supplement for 5-stage BNR with denitrification filter technology, from a chemical delivery and safety standpoint, for the Neuse River WWTP, the largest wastewater treatment facility meeting “Limits of Technology” Total Nitrogen limits on the East Coast.

Hazen and Sawyer conducted in-situ coupon testing to quantify struvite accumulation rates and batch testing to optimize ferric dosing at two Miami-Dade facilities. Nutrient recovery via struvite crystallization was estimated to save ~ $5,720,000 and ~ $6,840,000 over the 20 year project life at South District Plant and Central District plants respectively.

Hazen and Sawyer is currently working with the Hampton Roads Sanitation District to pilot fermentation of fats, oils, grease (FOG) and primary sludge to generate electron donors for denitrification and phosphorus removal. Preliminary estimates suggest that HRSD can save up to $25,000,000 over 20 years compared to using glycerol as the supplemental carbon donor for ENR.

Hazen and Sawyer, in collaboration with World Water Works, is piloting the DEMON™ sidestream deammonification process at the Bay Park Sewage Treatment Plant. Through this work, we have demonstrated up to 85% removal of total inorganic nitrogen from the dewatering stream.

Hazen and Sawyer has spent decades advancing the science behind environmental engineering, from design of the first declining-rate filtration system to influencing regulations on the disinfection contact time necessary to meet permit requirements.

Our areas of expertise include:


  • Helping clients plan for and respond to supply and demand challenges brought about by climate change and extreme weather events
  • Developing operation support tools to help manage water supply and water quality challenges
  • Evaluating advanced oxidation processes for control of taste and odor compounds, groundwater contaminants, and emerging contaminants
  • Developing innovative treatment strategies to manage contaminants such as arsenic and chromium in water


  • Helping clients to benchmark and minimize energy use during wastewater treatment
  • Demonstrating co-digestion of high strength food wastes and municipal solids for boosting biogas production and enhancing energy recovery
  • Assessing and designing next generation nutrient removal and recovery technologies
  • Utilizing advanced process optimization tools for optimizing treatment plant performance while minimizing operating costs

Recycled Water

  • Designing, testing, and evaluating potable reuse treatment processes including full advance treatment and new alternatives such as ozone and biologically active carbon (BAC)
  • Developing communication tools to help advance potable and non-potable reuse nationwide
  • Providing guidance on decentralized, community- and building-scale water reuse systems
  • Assessing the energy implications of recycled water, desalinated water, and alternative water supply options


  • Conducting green infrastructure feasibility studies
  • Planning, designing, implementing, and monitoring stormwater pilot projects
  • Performing extensive watershed modeling to better inform proposed designs
  • Developing models and designing facilities for rainwater harvesting

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