Tag Archives: Anaerobic Digestion

The Fremont Food Waste-to-Energy Plant Shut Down


The Fremont food waste-to-energy plant, located in Fremont, Michigan, touted as the first of its kind in the nation has closed a little more than two years after it opened because it hadn’t paid its electric bill.

The plant, operated by Novi Energy, agreed to sell renewable energy — enough to power 1,200 homes — to Consumers Energy. But on Monday, a Consumers Energy crew was at the vacant plant to shut off the power.

The plant manager claims it is a legal fight over ownership that led to the shutdown in January but nearby businesses say nobody has been seen working at the plant since late last year. Fences were locked and the lawn was choked with weeds.

The $22 million Fremont Community Anaerobic Digester, built with help from a $12.8 million U.S. Department of Agriculture loan guarantee, was designed to take in 100,000 tons of waste each year from West Michigan food processors, most notably nearby baby food producer Gerber Products Co., and turn that into energy.  The Fremont project also benefited from a 2008 state law that requires Michigan utility companies to obtain at least 10% of their power from renewable sources in the state by 2015.

Anaerobic digestion has been around for centuries, although only recently evolved to where it can produce energy on a utility-use scale from a variety of food waste.   The plant is not the first anaerobic digester power site in Michigan, but is considered the largest and the only one in the state that can harness energy from waste sources other than manure.

While there is opportunity for more of these plants in the United States, the price of digester electricity is considerably higher than conventional energy. Government incentives would be key.

The City of Fremont is keeping a close eye on what’s happening at the plant, since it helped it out with a $120,000-per-year tax abatement and was relying on helping the state make progress on their sustainability goals.


The Clock is Ticking


Starting October 1st, food waste from large institutions and supermarkets — not residents — will be collected. And only some of that will be headed to anaerobic digesters.

Massachusetts’ state-wide food waste ban, which was a decade in the making, puts the commonwealth among leaders in the United States in addressing an indulgence that is not unique to our modern existence: throwing away large quantities of food.

The Massachusetts Department of Environmental Protection is hoping to find alternative methods of disposal because landfilling is expensive as well as send the message to discourage the creation of waste altogether.   The hope is that ordering and preparing will be questioned to ensure less ends up going to the trash as a part of their process.

The more complete solution however, according to many environmentalists and an increasing number of businesspersons, is utilizing the process of Anaerobic Digestion. Food scraps fed to microbes in a heated tank without oxygen is converted, in a month or less, into biogas — mostly methane — that can be captured and used to generate electricity.

There are currently six wastewater treatment plants in the state that use the process. The egg-shaped buildings visible on Deer Island in the Boston Harbor do that to make power for the sewage treatment process.

There are also three Anaerobic Digesters in Massachusetts, which will gladly be accepting food waste under the new regulations, however there is a considerable amount of pre-sorting and processing of the food waste before it can be converted into a pumpable slurry for injection into the digesters.

While Anaerobic Digestion is a forward thinking option, it is still scarce in the United States because it is an expensive undertaking. When Anton Finelli and his partners did the research they were shocked to discover you could count on one hand the anaerobic digestion projects in North America designed specifically to take and process food waste. So, his company, Common Wealth Resource Management Corporation decided to build a pilot plant at the landfill site in Dartmouth, and hopes it attracts customers.

The state hopes the ban will spur construction of more anaerobic digestion and other solutions to turn organic waste into a resource.

Sewage Treatment Facilities to Turn Food Waste into a Resource

new energy

Months ago, waste trucks in Los Angeles County, California started collecting food scraps from restaurants, grocery stores, hotels, and food processing plants, grinding them into a slurry and dropping off the liquid to a wastewater treatment plant, where it is mixed in with sewage and processed in an anaerobic digester.

What was the end result? Biogas, that can be burned as fuel.

This plant is hardly the first sewage treatment plant to take in food waste, and it certainly won’t be the last. Efforts to recycle food waste are growing nationwide, and many are doing it the traditional way, by collecting and composting food scraps. But there is increasing interest in sending food waste, particularly from commercial sources, to facilities that use anaerobic digesters to convert the food into biogas in place of composting.

About 15 wastewater treatment facilities in the U.S. have started taking in food waste to co-digest with sewage in tanks or large digester eggs — a small number, but that’s up from one or two about a decade ago, according to the American Biogas Council. Following the lead of Europe, more U.S. cities are trying new ways to harvest energy from food that otherwise would have rotted in landfills and emitted methane, a powerful greenhouse gas.

New York City, as part of an ongoing pilot program, sent tons of food waste from Brooklyn and Staten Island to the Newtown Creek wastewater treatment plant in Brooklyn and processed it in an anaerobic digester to produce biogas for the facility. They are hopeful the project will continue in order to keep the material as close to NYC as possible because their only other alternative is to turn it into traditional compost at their facility, more than 216 miles away round trip. Turns out, renewable energy provides more value than composting for the city.

Hopefully, NYC will be  successful in turning the pilot program into an expansion project because Newton Creek couldn’t possibly handle the volume of food waste New Yorkers produce in a day, especially with the commercial food waste ban to being in early 2015.

According to the American Biogas Council, about 860 sewage treatment plants in the U.S. already produce biogas using anaerobic digestion, in which bacteria break down matter in an oxygen-free environment and produce biogas that powers the facilities.  Adding food waste to the mix is the tricky part.

Experts agree that anaerobic digestion is growing quickly, but the cost of building an anaerobic digestion system ranges widely, depending on the size of the plant, the feedstock, types of end products produced, and other variables. It’s not cheap. The anaerobic digesting process is also complex as the food waste brought in must be processed to remove contaminants then converted into a pumpable slurry for injection into the digesters.

On-site aerobic digesters, like the Eco-Safe Digester, that could tank the pre-sorted, pre-digested food waste as a means of generating ready-to-use AD feedstock for the 860 sewage treatment plants would certainly help to transform something complex into something quite simple.

The wave of innovation in food waste recycling is picking up speed globally. Food waste is something we should all try to manage as a resource.

Turning Food Waste Into Fuel Takes Trillions Of Bacteria


A Brooklyn waste treatment plant has become an unlikely lab for an ambitious effort to turn millions of tons of food scraps from New York City’s apartments and restaurants into renewable energy.

Every year, Americans send millions of tons of food to the landfill.  What if you could use all of those pizza crusts and rotten vegetables to heat your home?  That’s already happening in one unlikely laboratory:  the Newtown Creek Wastewater Treatment Plant in Brooklyn.

The plants longtime superintendent, Jimmy Pynn, shows off the plant’s crown jewels:  eight huge, shiny, oval-shaped steel tanks knows as digester eggs.  Each one contains millions of gallons of black sludge that’s roughly the consistency of pea soup.  Pynn calls it ‘black gold.”

“The digesters like to be fed like us:  three times a day.” He says.  “They like to be kept warm, 98 degrees.  And whether we want to admit it or not, we all make gas.  And that’s what we have these guys for:  to make gas.”

In this case, the gas is methane, which can be used to heat homes or make electricity.  Right now, what these bacteria re digesting is mostly sewage sludge.  But they’re being introduced to a new diet:  food scraps.  The hope is that this plant will soon take in hundreds of tons of organic waste from houses and apartments.

“Rather than paying millions of dollars to send it to landfill, we could be taking all of Brooklyn’s organics to the Newtown facility and converting it into clean renewable energy,” says Ron Gonen, New York’s Deputy Commissioner for recycling.

The Newtown facility is an example of anaerobic digestion, which is not a brand new idea.  What is new is the idea of adding food waste in to the mix.

Past-prime produce, rotten tomatoes, fats, oils, greases from fryers, past-prime dairy products and loaves of moldy bread are all great food-stuffs for anaerobic digestion.

The problem lies in the complexity of implementing a food waste system in New York City because of its huge quantities of waste.  One challenge is the amount of extra work it would be to separate the organic material from the rest of the trash in a city as dense as New York.  Another challenge is that the Newtown Creek facility can only handle a small fraction of what is coming in.  The costliest part will be finding enough locations to build more facilities to handle the volume.

Still, this is a great first step.

A Wastewater Treatment Facility’s New Best Friend


Food waste is the second largest category of municipal solid waste (MSW) sent to landfills in the United States.  Over 30 million tons of food waste is sent to landfills each year.  Shrinking landfill space, escalating landfill taxes, and reducing harmful emissions from landfills, are creating strong incentives for local authorities and businesses to find other treatment options for their food waste.  Many are turning to wastewater treatment facilities.

The volume of organic waste that needs to be treated is growing due to an increasing population and more stringent regulations designed to reduce organic waste being sent to landfill.  For the treatment of food waste, Anaerobic Digestion (AD) offers the greatest environmental benefit of any treatment option.

Anaerobic digestion technology is commonly used throughout the United States to break down sewage sludge at wastewater treatment facilities already.  In the past few months, there has been a movement to start adding food waste.

So, why is it a better treatment option than sending the food waste to a composting facility?

  1. Because the energy capturing infrastructure is already in place at many waste water treatment facilities.

  2. Because wastewater treatment facilities already have the on-site expertise and years of experience dealing with anaerobic digesters which are difficult to operate without thorough knowledge.

  3. Wastewater treatment facilities are located in urban areas where compost facilities are typically located farther away.

  4. Wastewater facilities offer an opportunity to employ more people.

  5. Anaerobically digesting food waste prior to composting reduces the emissions of volatile organic compounds (VOCs) which contribute to air pollution.

  6. Renewable energy is source of revenue and is in high demand.

As energy prices continue to climb, capturing the energy from food waste, using it to operate these facilities and selling the excess energy back to the grid is a great outcome for both the wastewater treatment plants and local municipalities.  In addition, the production of renewable energy will make wastewater treatment facilities eligible for Government incentives.

Organic waste is a hugely valuable resource, and the United States needs to get the most out of it.  Expanding the use of anaerobic digestion inside the wastewater industry is a great way to get this done.

Putting Food Waste to Work


Kroger Supermarkets is now the first company to utilize the process of anaerobic digestion as a way of powering its facilities.  But what exactly does this mean and how are they achieving that goal?  The answer is simple: BIOGAS.

We all know that food gives us energy, but how could our food generate enough energy to power an entire supermarket? Many different forms of organic waste can be used to run anaerobic digestion; however, food waste holds the most stored energy of all these ‘ingredients.’ Carbohydrates, proteins and lipids are all readily converted to biogas as is the wastewater that contains food waste by means of anaerobic digestion.  Therefore, food waste alone has the potential to sustain entire businesses.

When anaerobic digestion occurs, a mixture of methane, carbon dioxide and other trace gases combine to form biogas. Because biogas is renewable it offsets non-renewable resources, such as coal, oil, and fossil fuel-derived natural gas. Producing biogas creates U.S. jobs and benefits local economies. Biogas can be used to replace natural gas in many applications including: cooking, heating, steam production, electrical generation, vehicular fuel, and as a pipeline gas.

In nature, biogas comes from locations such as landfills, covered lagoons, livestock operations, etc. anywhere there exists organic decomposition. In controlled environments, like at Kroger’s Compton Facility, the food waste is fed into the anaerobic digester, where it will be shredded, mixed, processed, exposed to heat, and stripped of pathogens while promoting the growth of microbes all to aid in the breakdown of the waste producing biogas.

Eventually, the usable biogas is stored in gas holders until it is needed for its energy. This biogas contains so much thermal energy that it can very easily be converted into a source of electricity.

Instead of land-filling spoiled apples, Kroger decided to capitalize on their energy potential by means of anaerobic digestion. As a result, Kroger is not only being eco-friendly by reducing methane emissions, but it is also being smart economically, as the company is now saving enormous amounts of money on energy.

Is The Journey Worth the Ride?


I often wonder if the anaerobic digesters located at wastewater treatment facilities really use the food waste once it arrives.  The Eco-Safe Digester does a great job of digesting a complex mix of food waste on-site for supermarkets, hotels, etc, dumping the liquid grey water into the municipal sewer pipes eventually ending up at a waste water treatment facility.  But is the facility happy to have the grey water?

The answer is yes.  Sending digested food waste to anaerobic digesters located at a wastewater treatment facilities delivers multiple benefits:

–      Increased energy production reduces energy purchases

–      Increased efficiency creates a more effective treatment of the waste and sludge

–      Increased revenue from increased fertilizer production

–      Reduced organic materials directed to landfills delivers a whole list of environmental benefits which includes but are not limited to lowering emissions from less truck traffic, reducing groundwater and soil contamination at the landfills and reducing harmful greenhouse gases that contribute to global climate change.

It sounds like the journey IS worth the ride.