Bellingham’s plans to convert wastewater into compost: What you need to know

Bellingham plans to treat its solid waste and sell it as compost, which could have health implications. Here’s what you need to know and how to give input on alternatives. (Photo: City of Bellingham) | May 5, 2021

Give the City your input

Imagine this: When you use your sink, shower or flush the toilet, the solid parts of that wastewater gets processed into usable compost that can be sold to use on crops and gardens, reducing waste while funding the production of said compost and saving taxpayer money. It sounds like a great alternative to what currently happens when organic materials are filtered out of our wastewater: getting thrown into the City’s 50-year-old gas-burning furnace that belches out climate-heating emissions and air pollution every day.

In theory, using this waste for productive purposes is a great idea. And maybe it could still be, because there are some noted benefits to updating our wastewater treatment infrastructure, including air quality and sunsetting a large fossil fuel user. But knowing what we know about common wastewater contaminants (and knowing just how much we don’t know about them, such as pharmaceuticals and forever chemicals), converting our sewage waste into stuff that we grow food with raises a few alarms.

The City of Bellingham knows that this furnace at its only wastewater treatment plant, Post Point, is aging and generates pollution. So they recently went through a multi-year evaluation process to plan its replacement. They landed on something called an anaerobic digester to turn the solid waste into compost, or biosolids.

The lowdown on biosolids

First, let’s look at the technology under consideration. Biosolids are made of the solid, organic stuff that people, businesses, and industries send cascading down sinks, drains and toilets. It gets processed into either Class A or B biosolids, depending on the desired use. There are several ways to make biosolids from sewage waste, and the City of Bellingham has chosen anaerobic digestion. Here, bacteria breaks down the organic matter in the sewage waste in the absence of oxygen.

Sewage waste that is heated to 135°F is labeled as Class A biosolids; it claims to have no detectable pathogens and is allowed to be immediately applied on gardens and agricultural lands. It is often packaged and sold as compost in stores. Class B biosolids have been only treated to 100°F and need additional processing time to be considered safe. Class B biosolids are more typically used on rangeland, reclamation land, and on forested land. The City of Bellingham is proposing to make Class A biosolids.

Unstudied combinations of chemicals in your compost?

Along with the totally compostable stuff like food scraps and, well, human waste, there are also potentially harmful substances from household products that cannot really be separated out.

The City says that biosolids are safe because they are being regulated by the EPA. But the EPA is only regulating nine metals, when thousands of chemical contaminants have been identified in sewage sludge including: 27 metals, PFAS (per- and polyfluoroalkyl substance), PCBs, microplastics, flame retardants, pesticides, personal care products, pharmaceuticals, and hormones. Even the EPA acknowledges that they cannot determine the safety of biosolids. There is also evidence that synergistic effects between chemicals can be an issue — meaning interactions between chemicals can have unknown effects. Nobody has tested the various combinations of medications, cleaners, and everything else that goes down drains for safety on the food we grow or in the air we breathe.

Only certified organic agricultural land is restricted from using biosolids. All other land is fair game and does not need to be disclosed, meaning if you eat conventionally grown food, you are most likely eating food grown with biosolids. There is ample evidence that biosolids are harmful, as well as a lack of research to scientifically determine if they are safe or not. There are just too many contaminants and soil conditions to be able to test each permutation.

What Bellingham could do: Find non-food crop uses, or test rigorously

Here are two possible ways we can remove the currently-used gas-fired incinerator and then safely use the biosolids produced at Bellingham’s wastewater treatment plant:

1. Find an alternative use for the biosolids, such as for fuel or to be fired into glass or bricks.

2. Show the community that the biosolids are safe by conducting extensive tests on some of the more concerning chemicals, such as PFAS.

Have your voice heard

On the survey, you can request a meeting or “community briefing” with Rob Johnson, Project Manager, Superintendent Operations, Public Works (, (360) 778-7735) and ask that some alternative perspectives be heard and that the City hold a question and answer session.

You can also tell the City that they must test the sewage sludge for hazardous contaminants so we all know what could end up in the biosolids. Remember — the City is only required to test for 9 metals. Will the biosolids contain other toxic metals? What about PCBs, PFAS, flame retardants, dioxins, phthalates, pesticides, or microplastics? What chemicals concern you? Let the City know!

If any of this information is causing you to raise your eyebrows, please speak up and speak out. Together, we can tell the City that we have concerns and we need to know more about their plans to allow biosolids in our neighborhoods and on our crops.

Suggested reading

EPA, 2009: Targeted National Sewage Sludge Survey

EPA, 208: EPA Unable to Assess the Impact of Hundreds of Unregulated Pollutants in Land-Applied Biosolids on Human HEalth and the Environment

EPA Biosolids Laws and Regulations

Survey of Organic Wastewater Contaminants in Biosolids Destined for Land Application

Biosolids, Animal manure, and Earthworms: Is There a Connection?

Uptake of Pharmaceutical and Personal Care Products by Soybean Plants from Soils Applied with Biosolids and Irrigated with Contaminated Water

Microplastics in farm soils: A growing Concern

Fate of Antibiotics and Antibiotic Resistance during Digestion and Composting: A Review

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