What Happens to Our Waste?

Just as it is imperative to understand the sources and categories of waste that are seen in our laboratories, it’s equally important to examine the possibilities for the end of the life of these items. Understanding what may happen to your waste can help you prioritize what you should address in order to meet your lab or organization’s waste or climate goals. Whether it’s a used pipette tip, a broken mass spectrometer, or a cardboard box – you might be surprised at the path waste takes once it leaves the lab.

Handling of waste is extremely regulated, region-specific, and at times a confusing process. The options available to your lab, company or school will be dictated by the regional policies in place, local ordinances, organizational programs, and at times monetary returns.

The summary below is not meant to be comprehensive, but to give you a working knowledge of waste disposal options so you can understand basic terminology, challenges, and opportunities. We hope to educate you on many the various options that exist for disposing of waste worldwide, understanding that not all systems will be available to every institution in every region.

LANDFILLS

According to WorldBank, around 37% of the material humans throw out finds its way into ‘some form of a landfill’. Depending on the country and the regulations which dictate the handling of the waste there, landfills can be anything from strategic, sanitary systems to open pits filled with trash.

A properly managed landfill can have a place in modern sustainable waste management, for example one containing methane recovery systems or that separates recyclables from the input stream. However, regardless of the level of modernization or care taken to properly design a landfill, they are all subject to some of the same issues and environmental hazards, including but not limited to:

• The creation of Greenhouse Gases (GHG) such as methane and carbon dioxide, which are created as organic matter decomposes naturally
• Leaching of toxic materials, heavy metals, and carcinogens into the surrounding soil and waterways
• Real estate – landfills take up space. They can be thousands of acres in size, and new data suggests Europe is home to almost half a million landfills

In addition to these problems, landfills regularly contribute to social justice issues as well. According to Population Connection, housing policies like exclusionary zoning and redlining have concentrated minority populations into communities with restricted access to wealth and resources. This translates to more landfills being built in areas with lower-income and often higher minority populations, leaving inhabitants of those areas more susceptible to the negative effects described above.

Non-hazardous lab waste, if not disposed through one of the waste-to-energy methods described above, will be landfilled with municipal waste. Hazardous waste can also be landfilled in a special hazardous waste landfill. Biohazardous waste, while typically incinerated, can also be treated via autoclave, ozone disinfection or chemical treatment, and then disposed in a  landfill.  A large quantity of E-waste also ends up in landfills, where its eventual breakdown releases a wide variety of heavy metals and other toxins.  If wastes from your lab are being landfilled, you want to focus on minimizing the waste generated in these waste streams.

As an example, if your organization is landfilling biohazardous waste which must be treated beforehand, to minimize the footprint of this process you should ensure that your lab personnel only throws biohazardous waste in the biohazard bin.

WASTE TO ENERGY (WTE)

In many parts of the world, energy recovery engineering is utilized in order to process waste into electricity via combustion. In theory this is a great option – using discarded materials to create energy to power our grids and heat our buildings, in the form of liquid fuels, gases, or steam generators.

The benefits are fairly obvious – by incinerating, pulverizing or digesting our trash, we are creating energy that can be harnessed and distributed back to the grid. However, each option comes with its own positive and negative effects.

Let’s consider a few of the top WTE options available today:

Incineration – This is by far the most widely used technology, and the simplest. Waste is collected, dried, and burned as fuel to heat water – this produces steam, which powers generators to produce electricity. Modern incinerators can be up to 80% efficient, and reduce the original mass of the waste by up to 96%. However, concerns continue regarding emissions of GreenHouse Gases (GHGs), pollutants such as dioxins, and toxic fly ash which is created and released during the process.

Much of your chemical and biohazardous waste will likely end up being incinerated.  Your non-hazardous waste bin may also end up being incinerated or put through a gasification plant. Because of the potential to release harmful gases, and the energy needed to burn the waste, it is important to minimize waste that is incinerated – either by reducing the overall amount you are generating or diverting the waste to other disposal methods like recycling.

Gasification – By heating waste along with steam and oxygen to temperatures just below combustion, synthesis gases or ‘syngases’ (such as CO, CO₂ and H₂) can be produced; these gases are then combusted for fuel. This process is often more costly, yet cleaner than incineration as no GHGs are released. Japan has a growing number of these facilities, but they are not yet common on a global scale.

Anaerobic Digestion – By using bacteria to break down organic matter into gases, primarily methane, WTE plants can capture methane which is burned as natural gas. This is a fantastic option for waste streams that are composed primarily of organic biomass, as all GHGs are captured and the efficiency rates are typically quite high. However, the need for a waste stream free of contaminants – plastics, metals, etc – make this a somewhat specialized technology. It is mainly used for WTE treatment of agricultural waste, and has limited application for laboratory waste at this time.

COMPOSTING

Organic matter makes up 55% of all municipal solid waste (MSW), this includes items like food waste, paper, and wood products. Anything which is composed of entirely organic matter – carbon based compounds which are derived from plant and animal sources – can be broken down naturally or using accelerated, industrial methods.

In large-scale composting, the feedstock – or raw material to supply or fuel a machine or industrial process – is typically sourced from grocery stores and restaurants; however, consumer foodscraps and yard waste also contribute in many locations.

The basics of composting are not novel and haven’t been improved upon much in thousands of years – the employees at the facility will continually rotate and add to large piles of organic material in order to promote conditions in which bacteria can thrive and break down the matter. Drawbacks of composting include the large land areas needed, as well as potential to release uncaptured GHGs. However, considering the massive amounts of food waste in the developed world, composting is a sustainable and attractive option to tackle the issue.

In the lab world, there aren’t many options for materials that can be legally or practically composted. An exception, however, may be obvious to any of you working in vivariums – animal bedding is a great source of organic material, and there are examples of schools and companies who have successfully started programs to collect their animal bedding and send it to industrial composters. For more information, please review the Course Materials for a presentation by Colorado University Boulder on this topic.

RECYCLING

When we think of “recycling”, it’s likely that we imagine tossing a soda bottle or soup can into a bin, which is collected and then somehow transformed into more bottles and cans. While this may be the case sometimes, it’s important to realize that there are not only many processes and end goals for recycling materials, but that the procedures involved in recycling vary greatly in technique, energy required, manpower needed, and prevalence of use. Even in 2019, the worldwide recycling rate for plastics was only 9%. Areas such as Europe, Canada, the United States and elsewhere may boast rates as high as 20-30%, but strains on the systems in place to collect and process the material are continually affecting the recycling industry’s ability to keep up with society’s production of these materials.

In short, recycling is by no means an easy option to dispose of our waste, and as such we should never consider recycling as our initial course of action in reducing our waste footprint. While recycling continues to be a testament to modern engineering and human ingenuity, in order to appreciate the process – and support it correctly – we need to understand how it works, how it can be disrupted, and how our actions affect the system.

Below are three tiers of recycling, as described by the Applied Plastics Engineering Handbook:

PRIMARY RECYCLING
The recovered material is used in products with performance characteristics that are equivalent to those made using virgin material. Ideally, closed-loop recycling takes the recovered material and uses it back in the original application.
Example: PET recovered from post consumer bottles is used in the production of new bottles.

SECONDARY RECYCLING
After processing, the recovered material is used in products that have less demanding performance requirements than the original application.
Example: production of flooring tiles from mixed polyolefins, or the use of rubber from tires in roadways.

TERTIARY RECYCLING
Waste is used as the feedstock in a process that generates chemicals and fuels. Gasification and pyrolysis can be categorized as tertiary ‘recycling’ rather than waste to energy.
Example: glycolysis of PET into diols and dimethyl terephthalate that can then be used to make virgin PET.

Just because an item is made from a potentially ‘recyclable material’, it doesn’t mean that the item has a place in your recycling bin. For example, the 7 plastic identification codes below have misdirected consumers for many years, who believe that the three arrows around a number indicate that the material is able to be recycled. In reality, the numbers are simply to indicate the type of plastic resin that the item is made from – whether or not the item will be accepted into recycling depends on many factors.

The techniques and methods to recycle materials differ greatly depending on the material being processed.

My Green Lab was excited to sit down with Oakley Jennings-Fast of Level Up Planet and Sarah Fuentes of Smart Waste, to discuss some big issues with Recycling – contamination, ‘wishcycling’, what processes are considered recycling, and ways that all of us can help to keep the recycling industry running smoothly. 

As discussed by LevelUp Planet, contamination in waste loads destined for recycling facilities has become a major issue in recent years, and is one of the main reasons that much waste (both laboratory and otherwise) is not actually processed for recycling. Again, please have frank, clear discussions with the waste management team at your organization as to the items that are currently accepted as recycling by your recycling hauler. Since the implementation of the “National Sword” policy that was discussed in the video, the collectors that service many companies and schools with scientific facilities have elected to stop accepting items such as pipette tip boxes or chemical jars.

Now that you’re more aware of the fascinating yet complicated world of waste management, we hope you’re equipped to make better decisions regarding materials in your lab. More importantly, however, we want you to feel confident to have conversations with sales reps, manufacturers, waste haulers, and your lab mates – to ensure that the entire life cycle of materials are taken into account.

After all, making a product out of recyclable materials isn’t important if there isn’t a buyer for that product. And buying lab items made of previously recycled material won’t work if your lab mates don’t use and endorse them. The term circular economy, according to the UK’s Waste and Resources Action Program (WRAP), refers to a system “in which we keep resources in use for as long as possible, extract the maximum value from them whilst in use, then recover and regenerate products and materials at the end of each service life.”