Environmental Impact of Sugar

What is our sweet tooth costing the planet?

The environmental impact of growing and refining sugar cane and sugar beets entwines with the health and social consequences of our desire to eat it.

As an environmentalist with a major sweet tooth, I have successfully avoided researching and writing about sugar for many years. It is not that I do not think about sugar or worry about it. I do. Sugar’s environmental footprint does concern me and I am increasingly alarmed about its role in the rise of obesity and other life-threatening diseases in the U.S. and around the world.

What was holding me back? Perhaps it was the hefty time commitment needed for the research phase. More likely it was the fear that I might learn things that would (gulp) require me to change what I eat.

In January, while I was writing 10 Easy and Green Exercise New Year’s Resolutions, I decided to bite the bullet and take on sugar. Publishing a blog post about the environmental impact of sugar became my 2019 New Year’s resolution. I did not quite make my original target publication deadline of June 30, but as you can see I came close.

Along the way, I learned way more than I bargained for so I decided to write two posts. This first post will provide a primer on sugar and an overview of its environmental impact. The second post will discuss health and social implications.

Let’s start with some basic information about sugar.

Sugar 101

Plants Produce Sucrose through Photosynthesis Infographic

Sugar is a generic name for the sweet, colorless, water-soluble compounds that occur naturally in plants and the milk of mammals, including humans.

Green plants produce a type of sugar called sucrose during photosynthesis. (Image credit The Sugar Association.)

You probably know that carbohydrates provide your body with its main source of energy and help keep your brain and internal systems functioning. Sucrose is one type of carbohydrate consisting of glucose and fructose molecules. Food sources of sucrose include fruits, vegetables, and nuts as well as foods with refined sugar added during processing.

Sugar Cane and Sugar Beets

The two major sources of refined (table sugar) are sugar cane and sugar beets because they contain the highest concentration of sucrose (about 16%). Another use for sugar cane and sugar beets is making biofuels and bioplastics (a topic deserving of its own post).

Sugar cane is a tropical grass that reaches 10-20 feet tall. It likes warm humid conditions with lots of rainfall so much of the cultivation takes place in countries near the equator. Sugar cane is a perennial plant meaning that it will grow back from its roots.

Sugar beet is a root crop that produces large off-white beets that can weigh 3-5 pounds each. Temperate climates with warm days and cool nights suit sugar beets but they may be picky about soil and moisture levels. Today, almost all sugar beets in the U.S. are grown from GMO seeds with built-in resistance to the herbicide glyphosate.

Sugar Refining

Sugar cane begins to deteriorate as soon as it is harvested so it must be transported quickly to a processing facility. On the other hand, sugar beets can be stored for several months.

Once the sugar cane or sugar beets arrive at a processing facility the refining process is fairly similar involving a lot of washing, crushing, heating, filtering, clarifying, crystallizing, and drying. This is a water and energy-intensive process.

The end product of the refining process is crystallized sugar.

Byproducts are produced along the way including fiber, press mud, and molasses. After the sugar has been extracted from the crushed cane or beets, the remaining fiber is used to generate electricity, manufactured into paper goods, or pelletized for animal feed. Press mud from the clarifying process is spread on fields as fertilizer. The molasses that is separated from the sugar crystals during centrifuging finds a ready market with the alcoholic beverage industry.

This short video will give you a quick overview of how sugar is made from sugar cane and sugar beets. There are more videos in the resources section at the end of the post.

Now, let’s talk about the environmental impact of sugar.

Environmental Issues

Both sugar cane and sugar beets are grown as monoculture crops meaning that a single type of plant covers large swaths of land uninterrupted by other crops or plants. This industrial agriculture practice is not unique to sugar and results in a host of problems.

Land

Monoculture crops crave land…well…their farmers do.

Aerial View of Sugar Cane Plantations in Northeast Brazil
This aerial view shows sugar cane plantations as far as the eye can see in Northeastern Brazil –photo credit iStock/VelhoJunio.

Nowadays, massive machines and agrochemicals make it possible for farmers to cultivate huge areas of a single crop. This encourages clearing more land for farming. Rainforests, grasslands, and wetlands are being destroyed at an alarming rate to make way for crops such as sugar cane and sugar beets.

Besides storing carbon these critical ecosystems provide habitat for a wide array of flora and fauna, nourish the soil, provide food and medicine for people, filter water, and prevent erosion and flooding.

Pesticides

Lack of biodiversity makes monocrops like sugar cane and sugar beets especially vulnerable to insects, weeds, and diseases which can wipe out an entire crop.

To combat this problem farmers rely on pesticides (poisons) to kill insects, weeds, fungi, nematodes, and rodents. Pesticides are applied to fields by low flying airplanes (crop dusters) and sprayed from tanks pulled by tractors or that are strapped onto the backs of farmworkers.

Pesticides endanger the health of farmworkers, their families, and people living, working, or going to school near fields where pesticides are applied. They kill beneficial insects, non-targeted plants, and wildlife. Toxic runoff from fields pollutes streams, lakes, and oceans as well as groundwater and drinking water supplies.

Many, if not most pests are able to quickly evolve resistance to the pesticides made to kill them. This results in agrochemical companies developing increasingly more powerful pesticides in an unending vicious cycle.

Fertilizers

Growing sugar cane and sugar beets deplete the soil of essential microorganisms and nutrients.

Farmers turn to fertilizers (usually made from fossil fuels) to provide nitrogen, phosphorus, and potassium, but it does not last so fertilizer has to be applied for each new crop.

Wet Season Runoff from Sugar Cane Fields in Queensland, Australia
Wet season runoff from a sugar cane plantation in Queensland, Australia flows toward the Coral Sea and the Great Barrier Reef – photo credit CSIRO. Click here to read the article.

Fertilizers runoff fields into waterways and water bodies. Because the runoff is rich in nutrients it depletes the water of oxygen creating dead zones in streams, estuaries, and lakes where nothing can live. It also contributes to problems like toxic algae blooms in the ocean.

Water

Sugar cane is a thirsty crop with water requirements similar to rice and cotton, sugar beets less so. Producing 1 kilogram (2.2 pounds) of sugar from sugar cane requires 390 gallons of water; sugar beets require 243 gallons of water.

To put this into perspective, one person’s drinking water requirements for slightly more than two years would be fulfilled by the water required to make just 1 kilogram of sugar.

Damming rivers and diverting streams to irrigate sugar cane and sugar beet crops jeopardize the water supply for people who live downstream. Changes in hydrology significantly impact ecosystems and the wildlife whose habitats are altered or destroyed.

Everglades Example

You have probably heard the real estate phrase, “Location, location” meaning that where a property is located is a top priority for buyers. This concept translates to farmland, too. Some locations provide better conditions for crops than others and some result in substantially more environmental damage than others.

Let’s talk about the Florida Everglades.

Sawgrass Prairie at Everglades National Park
Sawgrass prairie at the Everglades National Park – photo credit G. Gardner/Everglades National Park Service.

The Everglades watershed is a one-of-a-kind subtropical wetland ecosystem that has been known as the river of grass ever since Marjory Stoneman Douglas published her book The Everglades: River of Grass in 1947.

The amazing biodiversity of the Everglades draws tourists from all over the world. It teems with wildlife including more than 360 species of birds and an extensive variety of plants from sawgrass to pine trees to orchids.

Florida Panther in Everglades National Park

The Everglades is home to dozens of threatened or endangered species such as the Florida panther (shown here), American crocodile, snail kite, wood stork, and West Indian manatee. (Photo credit Rodney Cammauf/NPS.)

Wetlands filter out pollutants, replenish aquifers and reduce flooding. About a third of Floridians rely on the Everglades watershed for drinking water as do the farmers of hundreds of thousands of acres of agricultural fields.

Growing sugar cane is a major contributor to the destruction of the irreplaceable Everglades.

Converting the northern sections of the Everglades watershed into agricultural land, mostly to grow sugar cane, has resulted in a major loss of habitat. Phosphorus runoff from the sugar cane fields and water flow disruptions from Lake Okeechobee represent some of the gravest dangers to the health of the Everglades.

If you are interested in learning more about Florida sugar cane and the multi-billion dollar state and federal project to restore the Everglades, there are links in the resources section.

This is a prime example of how taxpayers end up footing the bill for the damage caused by businesses and industries that externalize health and environmental costs.

Sustainability Efforts

There are some farmers growing sugar cane and sugar beets in a more environmentally and people-friendly manner, but this represents only a small segment of the enormous sugar industry. Organizations supporting these efforts include Bonsucro, Fairtrade, and Rainforest Alliance.

In addition, people concerned about GMOs in their food are pushing for more organic sugar, which precludes the use of GMOs and synthetic pesticides and fertilizers.

These are steps in the right direction that you can support with your wallet whenever you buy sugar and foods that contain sugar.

Featured Image at Top: Sugar beets growing in a field – photo credit iStock/stevanovicigor.

Related Posts

Resources

Resources – Everglades

Anaerobic Digesters are Good for the Environment

Don’t waste your green waste.

An anaerobic digester can magically transform your yard trimmings and food scraps into electricity and other good stuff so please do not send it to a landfill.

A reasonable question is “What the heck is an anaerobic digester?” In short, it is a giant tube that uses an anaerobic (without oxygen) fermentation process to convert the contents of your green waste bin into renewable energy (electricity or vehicle fuel), liquid fertilizer, and compost.

Kompogas Anaerobic Digestion Process Infographic
Kompogas anaerobic digester plant process infographic – source Hitachi Zosen Inova.

You cannot imagine my amazement and delight, when several weeks ago, I spotted a social media post from SLO Natural Foods Co-op offering a tour of the anaerobic digester plant in San Luis Obispo, CA. I had wanted to visit it for months, but I did not expect that my Co-op membership would be my ticket in.

My spouse and I were already scheduled for a long-awaited tour of the Cold Canyon Landfill and Materials Recovery Facility (MRF) the morning of the same day. Fortunately, the anaerobic digester tour was in the afternoon.

In the previous post entitled, All Americans Should Visit a Landfill, I covered our visit to the landfill and MRF. This post will focus on the anaerobic digester.

First, let’s talk about your green waste bin.

Green Waste Bin

The waste industry refers to the stuff you put into your green waste bin as organic waste because it comes from a plant or animal organism and contains carbon compounds. Examples include tree branches, leaves, grass clippings, fruit and vegetable peelings, meat bones, coffee grounds, eggshells, and cooked, processed, and spoiled food.

Depending on where you live, you may or may not even have a green waste bin. If you do, you may or may not be allowed to put all or only some of the items listed above in it. Check with the company that provides waste removal services for your household.

U.S. Solid Waste Generation by Material 2015 Pie Chart

According to the U.S. Environmental Protection Agency, in 2015, organic waste (wood, yard trimmings, and food) accounted for a whopping 34.6% of the total solid municipal waste generated in the United States.

The purpose of a green waste bin is to keep organic waste out of landfills where it emits CO2 in the early stages of decomposition and methane after it is buried and deprived of oxygen. Methane is a greenhouse gas twenty times more potent than CO2 and is a significant cause of global warming.

San Luis Obispo Kompogas Plant

The San Luis Obispo Kompogas Plant uses the Kompogas® patented dry anaerobic digestion technology owned by Hitachi Zosen Inova (HZI).

Aerial View of Kompogas Plant in San Luis Obispo, CA
This is an aerial view of the Kompogas Plant in San Luis Obispo, CA. The rounded rectangular building houses the anaerobic digester –source Hitachi Zosen Inova.

Bringing the anaerobic digester to San Luis Obispo County was a multi-year effort initiated by Bill Worrell, the former general manager of the San Luis Obispo Integrated Waste Management Authority. He first became aware of the Kompogas technology during a trip to Europe in 2010. At the time, the company that owned the patent was not interested in doing business in the United States.

HZI acquired Kompogas in 2014 and they did want to expand into North America. In 2015, HZI and Waste Connections collaborated on a proposal to build an anaerobic digester in San Luis Obispo.

Over the next several years, the project was approved, underwent environmental review, obtained grants and funding, and was constructed. It opened for business on November 15, 2018.

Revenue is generated from several sources.

  • 65% – tipping fees based on the weight of the green waste each truck delivers and dumps
  • 30% – electricity generated by burning the biogas produced in the anaerobic digester (enough to power about 600 homes)
  • 5% – liquid fertilizer and compost (that remain at the end of the process)

Touring the Plant

After my spouse and I finished our landfill and MRF tour, we stopped by SLO Natural Foods Co-op to grab lunch before heading over to the anaerobic digester plant.

Truck Carrying Green Waste on Weight Scale

While we were waiting for our group to assemble in the parking lot, this truck pulled onto the weigh scale. The plant receives about 100 tons of organic waste a day five days a week.

Thomas Gratz U.S. Sales Manager HZI at San Luis Obispo Kompogas Plant

Thomas Gratz, the U.S. sales manager for HZI was our tour guide.

He knows every inch of the plant and did an excellent job explaining its operations in a way non-technical people like me could understand.

Intake Area at San Luis Obispo Kompogas Plant

In the waste receiving building, Thomas talked about how various machines screen out non-organic materials.

As you can see from this pile, most of the green waste currently received at the plant is yard waste (about 90%).

Green Waste Chip Storage and Automated Crane at San Luis Obispo Kompogas Plant

After screening, everything is chopped into 2″ feedstock pieces and stored in concrete bunkers.

The yellow automated crane (it reminded me of the claw in Toy Story) grabs chips and deposits them on a staging platform for a conveyor.

Chip Conveyor Intake Area to Anaerobic Digester at San Luis Obispo Kompogas Plant

This is part of the conveyor that transports the feedstock chips from the intake building on the right to the anaerobic digester building on the left.

Pipe Feeding Chips into Anaerobic Digester at San Luis Obispo Kompogas Plant

The black tube structure delivers the chips from the conveyor into the anaerobic digester.

The digester has a plug-flow design meaning that the chips being fed into the tube push the material down the digester.

Motor that Turns Agitator Blades in Anaerobic Digester at San Luis Obispo Kompogas Plant

This motor, which is lower on the building than the tube above, turns agitator blades that run the length of the anaerobic digester to keep the contents mixed up.

I am sure Thomas told us the dimensions of the anaerobic digester but I did not record them. I estimate it is about 140 feet long with a diameter of 30 feet or so. This construction photo depicts its scale – source Hitachi Zosen Inova.

Inside the anaerobic digester bacteria and heat ferment the feedstock chips turning them into biogas and digestates (more on this later).

Anaeraboic Digester at San Luis Obispo Kompogas Plant
This shot is from the door of the building that houses the anaerobic digester. The digester is the black structure running the length of the building.
Earthquake Footings and Heating Pipes for Anaerobic Digester at San Luis Obispo Kompogas Plant

Thomas explained the seismic features of the digester like the footing show here.

You can also see some of the pipes and tubes that connect the heating system to the bottom of the digester to keep the bacteria happy during fermentation.

After walking up several flights of metal stairs, we reached the top platform from which we could survey the grounds of the plant and the hills surrounding San Luis Obispo.

The plant has several safety measures to ensure that no pressure builds up inside the anaerobic digester.

  • The first line of defense is a domed storage tank that can hold several days of produced biogas if for some reason it cannot be burned in the combined heat and power plant on site.
  • If the tank is full, then the excess biogas would be burned inside a concrete flare tube.
  • As a last resort, a gas overpressure valve would burst to release the methane-containing biogas into the air.

An environmentally friendly feature of the plant is that everything is surrounded by curbs and drains. Stormwater runoff is collected in stormwater ponds. Cleaning and wash down water are contained on site and reused in the anaerobic digester.

Combined Heat and Power Equipment and Pipes at San Luis Obispo Kompogas Plant

The combined heat and power plant burns the biogas (methane) produced by the anaerobic digester.

The heat is used to keep the inside of the digester at the proper temperature. Electricity not used to run the plant is sent to the electric grid.

Various impurities are removed prior to and after burning the biogas. For instance, hydrogen sulfide, a highly corrosive chemical compound is converted into sulfur that can be used to make fertilizer.

Tour Group and Conveyor to Compost Building at San Luis Obispo Kompogas Plant

The pipe on the right returns about 30% of the liquid digestate to the digester. The remaining liquid is stored in a tank for later sale.

The conveyor on the left moves solid digestate to the composting building.

Tanker Truck Pumping Out Liquid Digestate at San Luis Obispo Kompogas Plant

This tanker truck pulled up while we were admiring the back end of the anaerobic digester building.

The liquid digestate being pumped from the storage tank was destined for a local vineyard to be used as fertilizer.

Compost Bunkers at San Luis Obispo Kompogas Plant

The solid digestate is stored in these bunkers while it is aerated to create compost for sale.

Inside the composting building, it was extremely humid and the air felt heavy to breathe. Negative air pressure keeps any odors inside the building.

Tree Root Air Filter for Compost Building at San Luis Obispo Kompogas Plant

Microorganisms growing on this mass of tree roots absorb the volatile organic compounds (smelly stuff) in the exhaust air from the composting building.

Dan Kallal in our group took this photo.

Lastly, Thomas showed us how the plant is monitored 24/7/365 via an online system linked with the home office overseas.

My impression of the Kompogas Plant is that it has been carefully designed and constructed to safely take in green waste and food waste and convert it to biogas, fertilizer, and compost. The process is both straightforward and complex.

I know I barely scratched the surface of the anaerobic digestion process in this post, but hopefully, you got the gist. There is more information in the resources section.

A Few Words about Food Waste

I cringe whenever I read or hear the words “food waste.”

Growing, transporting, processing, distributing, and preparing food requires a tremendous amount of land, resources, water, energy, and people power.

Our first option should always be to eat the food we buy and to make sure everyone else has enough food to eat. Sending food to an anaerobic digester or a composting facility should be the last option.

You can do your part by eating the food you buy and putting your yard trimmings and food scraps in your green waste bin.

Featured Image at Top: this infographic shows the Kompogas process ecological cycle – source Hitachi Zosen Inova.

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Resources