Guide to WRR Anaerobic Digester Process

While there are many moving pieces of Wasatch Resource Recovery, it is a relatively straightforward system that allows natural processes to happen more efficiently. In addition to reducing landfill use and capturing harmful greenhouse gasses and utilizing it to warm our homes. Read on for a step-by-step guide to how the Anaerobic Digester at Wasatch Resource Recovery operates.

  1. Waste Collection

Wasatch Resource Recovery is able to accept organic waste in many forms. Organic waste is trucked in from participating organizations. These trucks can enter any number of loading bays depending on what waste they are providing.

Unpackaged liquid waste (Up to 200,000 gallons per day) can be deposited directly into holding tanks. Fats, oils, and grease (FOG) are released into a screened intake and held in a warming tank to allow it to remain in liquid form. (Up to 50,000 gallons per day)

Flats of consistent beverage containers will be deposited in the loading warehouse (Up to 10,000 gallons per day). Inconsistently packaged waste, such as bagged food waste from restaurants or grocery stores is dropped off in a holding bay. (Up to 80,000 gallons per day)

  1. Depackaging

Solid waste enters a warehouse where it will be deposited in one of three machines depending on the packaging type. Consistent glasses, plastic, or aluminum beverage loads are crushed up allowing the liquid organic waste to separate from the material. The recyclable material will be transferred to a material recycler.

Bagged and boxed organic waste enters through a similar depackaging machine that pulps the organic material and allows it to separate from the packaging.

  1. Pre-Digester

Once the organic waste is separated and macerated it enters an additional machine in order to remove any remaining grit that could build up in the digester.

The individual organic waste collections are then blended in a tank with water in order to produce the desired ratio of solids required for the next stage of the process.

  1. Digester

The mixture is pumped into one of two 2.5 million-gallon Anaerobic Digesters (An additional two digesters will be built in phase two) This slightly warmed tank allows for the natural decomposition process to occur. First naturally occurring fermentation bacteria break down the waste into simple sugars and organic acids, next methanogens (methane-producing organisms) consume the organic acids and release methane.

  1. Solid Waste Collection

From the digestion process, gas and liquefied waste will be collected. Phosphorus is collected from the liquefied product, and the remaining liquid is channeled to a dewatering machine. This results in a nutrient-rich dry fertilizer (up to 194 cubic yards produced a day) which can be used by farmers to grow crops. The resulting water is heated up to recover the ammonia produced in the digester. The remaining clean water will be processed to remove potassium and nitrogen (great in our soil, but harmful in our lakes and streams) through South Davis Sewer District.

  1. Gas Collection

The gas released from the digester is up to 65% methane. On a daily basis, a single digester can produce 2600 cubic feet of gas. This gas is conditioned and released into the Dominion Energy’s natural gas line to provide renewable energy for up to 40,000 people.

What Does Anaerobic Digestion Really Mean?

Anaerobic Digestion is a miraculous process that occurs within all humans and animals. Anaerobic is a word used to describe an environment without oxygen, and digestion is a process in which organic material is broken down into simpler organic products.

The giant tanks at WRR’s project site are sealed to prevent any seepage of oxygen and heated to approximately 100 degrees Fahrenheit. These conditions mimic the digestive tracts of animals where microorganisms breakdown organic material most efficiently. The tiny “bugs” eat the organic material and convert it into methane and carbon dioxide (along with water vapor and a few other trace gasses). In our system, the gasses are separated; the methane is used as an energy source, while the carbon is used to aid the growth of algae in greenhouses.

Additionally, the microorganisms leave behind a sludge that can be separated into liquids and solids. The liquid is recycled back into the Wastewater Treatment Plant while the solid is used as a bio-based fertilizer. This model imitates a phenomenon that takes place in nature known as “nutrient cycling.” In a world where 40% of food is wasted, Anaerobic Digestion is a modern, technological supplement to nutrient cycling in our own concrete jungle.

To learn more, visit the EPA’s webpage dedicated to anaerobic digestion.  

Strategic Partner Alder Construction Recognized by WCF

Wasatch Resource Recovery has a lot of moving parts, partnering organizations, and employees that have delivered the project at its current stage in development. Alder Construction is one of WRR’s main driving forces: building the complex facilities required to implement anaerobic digestion technology on such a large scale. To ensure the success of the project, construction had to begin over a year before test loads could run; and still before that, hours of planning, designing, piloting, and financing occurred.

WRR would like to recognize Alder Construction for all the great work that they do – and congratulate them on their Charles Caine Workplace Safety Award from the Worker’s Compensation Fund. We truly appreciate their commitment to creating a safe work environment for both their employees and clients. We could not be where we are today without them. 


Pioneer Day – Remembering Utah’s History

On July 24th, 1847 Utah pioneers arrived in the Salt Lake Valley and famously stated “This is the place.” In an era of hardship and scarcity, these pioneers engrained aspects of sustainability into their culture out of necessity. Brigham Young, a leader of the first Mormon settlers to arrive in Salt Lake once said “Learn to sustain yourselves: lay up grain and flour, and save it against a day of scarcity.” Without the guarantee of food supply, people learned to conserve their resources, waste little, and save for the future – skills mastered by Native Americans long before.

Times have changed, but a focus on securing future prosperity has not. People today are still concerned about adequately providing for their families. However, a culture of excess in the modern United States often creates barriers to prioritizing thoughtful consumption and awareness of waste that is produced. Still, the need remains, and sustainability in Utah has changed accordingly: from conserving morsels of food to implementing large-scale technological solutions.

The Utah Governor’s Office of Energy Development website claims: “As Utah’s population is set to nearly double by 2050, our energy demands will increase. To that end, the Utah Energy Action Plan has been developed to help OED meet its objectives and deliver results to the residents of Utah through a disciplined approach to the management and execution of its programs.” Wasatch Resource Recovery is excited to play a role in the evolving history of sustainability that is a part of Utah and its development. From pioneering the western frontier, to pioneering the frontier of renewable energy, Utah stands out – as Governor Gary Herbert states in his Energy Summit Video – “as a crossroads of global innovation.”

Photosynthesis: Growing Algae, and the State Too

Wasatch Resource Recovery is a facility operated under public-private partnership between ALPRO Energy & Water and the South Davis Sewer District. The WRR facility will produce nitrogen and phosphorus as a byproduct of anaerobic digestion. These nutrients will then be discharged to the South Davis wastewater treatment plant where the district has started a project that removes them from all of its wastewater. The project is currently in its pilot stages, operating in a single greenhouse. 

The technology, provided by ClearAs Water Recovery, uses algae to remove the nutrients. The full scale project will utilize 140 miles of 4-inch glass pipe installed in a 200 x 450 foot greenhouse. This process cleans wastewater to a level that satisfies Utah State regulations while recovering valuable nitrogen, phosphorus, and carbon. Carbon dioxide scrubbed from renewable natural gas produced by our digestesrs will be used to supply necessary carbon for the algae to grow. The digesters will also produce additional nitrogen and phosphorus that can be used to supplement the algae’s nutrient requirements if needed. The project will produce 8,000 to 10,000 pounds of algae per day which will be harvested, dewatered, dried, and sold.  The dried product can be marketed for a variety of uses including bioplastic production, cosmetics, fish feed, livestock feed, bio-diesel, and succinic acid, among others. A few weeks ago, the Utah Division of Water Quality Board toured the pilot facility and seemed pleased with the progress of the project.

Effective and economical from both a regulatory and operational standpoint – the project has the potential to revolutionize the way nutrients are treated and water is recycled in Utah. Producing useful byproducts from waste is a major focus of both Wasatch Resource Recovery and South Davis Sewer District. Revenue derived from a resource that is otherwise seen as a pollutant is exciting and produces both economic and environmental benefits. This project will shed light on the immense potential our refuse harbors in solving problems related to limited resources, space in landfills, and excess waste. 

4th of July Sets Stage for Reflection on Sustainability in America

As the United States celebrates its 242nd birthday, it boasts a 132-fold increase in population since its start, a number quickly approaching 330 million people. With a larger population comes stimulation in the economy, a greater workforce, and additional individuals available to problem solve and innovate. Alternatively, this growth equates to depletion of viable resources, limited space, and access to nature, clean air, and drinking water.

Though it hasn’t always been the biggest priority, the U.S. is beginning to realize the importance and urgency of resource conservation and efficient land use. With initiatives that support air and water quality testing, the progress of renewable energy, and technological innovations regarding waste, wasted resources are being recognized for their true potential. Wasatch Resource Recovery’s project is a pioneer in both Utah and the nation – serving as an example of utilizing waste in ways that benefit surrounding populations and the environment.

In an era of tech, electronic gadgets, plastic, and convenience, it can be easy to forget about our natural counterparts – the resources we consume daily, fill our cars with, or use to power our homes. Even in 2018 it isn’t always easy to alter the way we think about waste, or the way society handles it. On this 4th of July, we hope you’ll join us in taking a moment to appreciate how far this country has come and attempt to make a difference by paying attention to your waste, how you can conserve resources, and notice ways in which you impact the environment.

Waste360 Recognizes WRR’s Morgan Bowerman for Excellent Work in Waste

As sustainability grows and large scale environmental projects become increasingly more common, it is imperative that motivated professionals drive the success of such innovations. At Wasatch Resource Recovery we are proud to host a talented group of engineers, builders, sustainability professionals, scientists, project managers, and more. Managing a $43 million project is no simple task, and without them, none of this would be possible.

In our previous post, Morgan Bowerman represented Wasatch Resource Recovery in the Governor’s 2018 Energy Summit Video. Morgan has championed environmentalism not only with us, but with other organizations in Utah and around the world. In the article above, she describes her experiences in sustainability, most notably: starting a recycling program in Uganda and how that expanded her outlook on environmental change.

Wasatch Resource Recovery aims to revolutionize the way Utah handles its waste by developing technology and infrastructure that allows communities to get involved. This project demonstrates the immense impact that the actions of every corporation, hotel, restaurant, grocery store, and individual has on the world around us. Without the positivity and tenacity of our employees and partners, we could not have come so far or engaged with so many different people. Morgan exemplifies WRR’s vision and our collective desire for change, highlighting the far-reaching impact of individual efforts. In light of her inspiring work, we are excited to acknowledge and congratulate her Waste360 40 Under 40 award. 

WRR Featured at 2018 Governor’s Energy Summit

“Utah’s wired for success, thanks to breakthrough energy technologies and partnership designed to transform our future.” Utah’s current governor Gary Herbert chimes in the video produced for the 2018 Governor’s Energy Summit. As Utah’s population, economy, and dependence on resources grow, alternative energy is becoming a hot topic that has begun to peak the interest of officials in a state predominately powered by fossil fuels.

Wasatch Resource Recovery has played a significant role in this wave of support for alternative and renewable energy sources – offering a solution that not only produces green energy but reduces waste at the same time. Landfills in Utah are reportedly “filling up fast;” seeing as many of them are not far from reaching their full capacity. WRR’s anaerobic digesters will divert organic waste from the landfill, subsequently freeing up space and buying more time, while simultaneously using the food waste to produce useful byproducts for local communities.

Renewable energy is an extremely interconnected aspect of sustainability that has the potential to address other environmental solutions such as waste reduction, resource conservation, and even sustainable architecture or agriculture. As the state strives to support a rapidly growing population, it is of the utmost importance that renewable energy and sustainable technology are incorporated into the infrastructure that sustains millions of Utahns.


Special thanks to the Governor and his Office of Energy for their continued support in our project and for featuring WRR at the 2018 Energy Summit. 

A Closer Look at our Anaerobic Digesters

Wasatch Resource Recovery’s sister tanks fall nothing short of impressive. Each anaerobic digester is built to hold 2.5 million gallons of food waste, with the combined capacity to accept 1000 tons of food waste per day. Once operational, the digesters will produce enough biogas to power 40,000 homes – a town equivalent to the size of Bountiful. The capture and prevention of these greenhouse gases from reaching the atmosphere can also be compared to taking 75,000 cars off the road.

Structurally speaking, the tanks are not only impressive in size, but in their durability as well. The anaerobic digesters are expected to last for decades into the future, providing long term benefits to numerous communities along the Wasatch Front. While diverting waste from the landfill is an obvious perk, digesters also output several useful byproducts. Firstly, biogas captured during this process is a clean-burning renewable energy source that can be used to power homes and vehicles. Secondly, digestate can be used to produce bio-based fertilizer for use on local farms – providing a great alternative to chemical fertilizers that have the potential to pollute groundwater and soil. Finally, excess carbon can be used to grow algae; which can be dried and used as a bioplastic, to grow hydroponic crops, or even create energy. This system of recycling emulates the sustainable and cyclic natural systems we as humans rely on – and will stand as a hallmark of sustainability in Utah for years to come.