Todd Williams, CH2M HILL Wastewater Global Service Team Deputy Leader, will attend and speak on water resource recovery technologies at the U.S. Department of Energy (DOE) Bioenergy Technologies Office (BETO) Annual Conference, on Wednesday, July 30. BETO is working to transform the nation’s renewable and abundant biomass resources.

By: Todd Williams, CH2M HILL Wastewater Global Service Team Deputy Leader

Todd Williams will speak on “Resource Recovery Opportunities at America’s Water Resource Recovery Facilities” during the Department of Energy Bioenergy Technologies Office (BETO) Annual Conference on Wednesday, July 30, from 1:40-3:10 p.m. Todd’s presentation is part of Breakout Session III, which is focused on the topic: “Energy from Our Waste—Will we Be Rich in Fuel or Knee Deep in Trash by 2025?”

This week, the U.S. Department of Energy’s BETO is hosting its seventh annual conference—Biomass 2014: Growing the Future Bioeconomy, in Washington, D.C. Biomass 2014 will bring together top government officials, as well as members of Congress, with industry leaders and experts spanning the bioenergy market. I am looking forward to participating in the discussions and sharing some of the innovative technologies and solutions being developed to capture energy from waste at America’s water resource recovery facilities.

In July 2013, a resource recovery study was released by the Water Environment Federation and the National Biosolids Partnership which looked at Water Resource Recovery Facilities (WRRF) in the United States. More than 5,100 facilities participated in the survey. The majority of facilities treat more than 1 MGD, and about 50% of them currently use anaerobic digestion to process solids.

The study produced some interesting findings that I would like to characterize as “3-3-6”—3 times as many WRRF’s do not have anaerobic digestion as those with; 3 times as many WRRF’s with anaerobic digestion don’t generate power or operate plant equipment with recovered energy as those that do; and 6 times as many WRRF’s don’t import fats, oil, and grease (FOG) or high strength waste to feed digesters as those that do. Given these results, I believe there is significant opportunity for development of energy recovery at WRRF’s in the next decade.

The Resource Recovery Model is not complicated. Rather than just accepting and treating wastewater, to recover energy, water resource recovery facilities with anaerobic digestion can accept additional materials beyond wastewater, including:

  • High-strength liquid wastes (HSW)
  • FOG

Using these materials and anaerobic digesters, the facility can produce multiple products, such as:

  • Recycled water
  • Biosolids (which provided carbon and nutrients for agriculture/farmland)
  • Renewable energy (power and heat)

Resource recovery offers numerous benefits to utilities; several facilities that have implemented anaerobic digestion to create biogas are achieving significant value and savings on their bottom line. Gwinnett County, Georgia and Johnson County, Kansas, for example, have both reduced their overall plants electric usage by about 50% through the development of facilities to receive and process FOG and HSW in their existing anaerobic digesters.

The East Bay Municipal Utility District is a prime example of how one utility has incorporated resource recovery into its business model. The utility added a 4.6-megawatt advanced biogas turbine to increase its capacity from 6.5 to 11 megawatts in 2011. On average, the expansion enables the utility to produce enough biogas to generate 6 megawatts of electricity. The plant only requires about 5 megawatts to operate, so by selling its surplus energy (“renewable energy”) back to the grid at a premium price, East Bay MUD has become the first wastewater treatment plant in the U.S. that is a net electricity provider.

Another good example of how one utility is putting resource recovery to work to improve its bottom line is DC Water’s biosolids management program. DC Water is leading the industry and truly reinventing biosolids technology at the 391 MGD Blue Plains Advanced Wastewater Treatment Plant in Washington D.C. Developing the first Cambi thermal hydrolysis/digestion/combined heat and power system in the U.S., Blue Plains will reduce biosolids quantities by 50%; cut greenhouse gas emissions dramatically; generate 14 megawatts of clean, renewable power; and greatly improve product quality (Class A). When the facility begins operating late this year or early next year, it will save millions of dollars annually through its biosolids program alone.

The City of Green Bay, Wisconsin is also implementing a combined anaerobic digestion and incineration facility that in combination will reduce the plant’s overall electrical energy usage by nearly 75%.

Utilities in Canada are also implementing resource recovery technologies to generate energy from waste at their facilities. The City of Hamilton in Ontario is one example of how combining heat and power (CPH) and biogas purification (BP) systems can increase biogas production rates more than 50% by increasing digester solids residence time and improving digester control. Renewable energy is available at a premium in Hamilton, so incorporating the new CHP and BP yielded net positive benefits for the utility.

Other utilities in North America are implementing similar projects to reduce their energy footprint and add power back to the grid. There are so many more opportunities to leverage resource recovery. It’s an exciting field to be in right now as we seek innovative solutions to address energy optimization at water resource recovery facilities.

Todd is an expert in residuals and biosolids management. “I’m passionate about developing sustainable solutions and identifying ways for our water and wastewater clients to turn waste into something positive, like renewable energy—netting benefits for both the utility and the environment,” said Todd.

Todd has made numerous presentations and is a contributing author for several articles and books significant to biosolids and residuals management, composting, and odor control including the recently published WEF/WERF/EPA Solids Process Design and Management Manual. He graduated from Virginia Tech and is the past Chair of the Water Environment Federation’s Residuals and Biosolids Committee. Todd works out of CH2M HILL’s Richmond, Virginia office.