News | February 17, 2021

The Water Research Foundation Releases Seminal Drinking Water Guidance Manual

Biofiltration Manual Cover

Carollo-led project advances biofiltration best practices for improved water quality

The Water Research Foundation (WRF) has published the highly anticipated Biofiltration Guidance Manual for Drinking Water Facilities, which gives water utilities a standard set of guidelines and best practices for improving overall water quality and customer satisfaction. Developed as part of WRF Project 4719 and led by Carollo Engineers’ Principal Investigator Jess Brown, PhD, PE, the manual is considered the definitive resource for biofiltration design and operation.

“We are thrilled to present this much-needed manual to the industry,” said Grace Jang, PhD, WRF Research Program Manager. “It will enable utilities to optimize their water treatment processes, effectively manage emerging contaminants, further protect their distribution systems, and provide high-quality water to their communities.”

Biofiltration is increasingly being used throughout the United States to enhance drinking water treatment plant performance and improve finished water quality. Biofilters can remove not only organic carbon and disinfection byproduct precursors, but also trace organic contaminants like taste and odor compounds and algal toxins, as well as inorganic constituents like ammonia and manganese. However, to optimize performance and limit unintended consequences, biofilters should be designed and operated with consideration for both filtration and biological activity.

Over the last 15 years, considerable research has been done to advance the science and engineering of surface water biofiltration. WRF Project 4719 combined that research with extensive biofilter design and operating experience across the water industry to develop a consolidated set of guidelines for the design, operation, maintenance, testing, and monitoring of biologically active rapidÔÇÉrate gravity filters.

“Throughout the project, broad stakeholder input, including expertise from utilities, regulators, academics, manufacturers, and engineers, ensured that the final product would be comprehensive and robust,” said Carollo R&D Practice Director and WRF 4719 Principal Investigator Jess Brown. “I am proud to have been a part of this important research and this dedicated team, and to see this manual finally come to fruition. It’s been a long journey but worth the work and the wait.”

The guidelines are geared toward existing biofiltration plants, filtration plants that intend to convert to biofiltration, and future greenfield biofiltration plants. With biofiltration installations and applications rapidly expanding, the Guidance Manual will serve as an essential water industry resource for many years.

About Carollo Engineers
For more than 85 years, Carollo Engineers has provided a full range of innovative planning, design, and construction management services to meet the water and wastewater needs of municipalities, public agencies, private developers, and industrial firms. Carollo develops robust water management strategies that leverage collaboration, provide multi-benefit solutions, and achieve sustainability and resiliency. Ranked by Engineering News-Record as the largest engineering firm in the United States dedicated solely to water and wastewater, Carollo has nearly 1,400 employees located across 22 states. For more information, visit

About The Water Research Foundation
The Water Research Foundation (WRF) is the leading research organization advancing the science of all water to meet the evolving needs of its subscribers and the water sector. WRF is a nonprofit educational organization that funds, manages, and publishes research on the technology, operation, and management of drinking water, wastewater, reuse, and stormwater systems—all in pursuit of ensuring water quality and improving water services to the public. For more information, visit

Source: Carollo Engineers