Antibiotics, the wonder drug that has mended millions if not billions of us, may just be our undoing if we don’t act quickly to curb its contagion. A recent article revealed that nearly 2/3 of rivers surveyed were tainted with antibiotics, some with levels 300 times what is considered safe. In the developed world drugs are excreted into toilets that flow into wastewater treatment plants that are ill-equipped to filter out what are known as ‘emerging contaminants of concern’, a term which doesn’t set off nearly the alarm bells that it should. The pathway for animals fed a steady diet of antibiotics to prevent disease and boost feed efficiency is even more direct: in one end and out the other of the animal (70 – 90% of what goes in, may come out!), and then into the soil and perhaps into groundwater. A brief sojourn in a manure lagoon may occur before soil application, but this is unlikely to fully degrade all of the various types of drugs. Lest you think anaerobic digestors are the answer, antibiotic laden manure can significantly reduce methane emissions in digesters yet there is concern that the antibiotics are not fully killed off during digestion. Paradoxically it appears that antibiotics might boost methane emitted from cow paddies deposited in the field.
In addition to the methane madness caused by antibiotics, these superfluous drugs (by that I mean the 80% of anti-biotics that are fed to livestock for prophylactic reasons) are leading to super bugs and super strange looking fish. To clean up current contamination and prevent prospective pollution will require a multi-pronged strategy and some seriously smart money. Biochar could be a major player in both alleviating existing issues and avoiding future problems. Here’s how:
- Replace antibiotics in animal feed with biochar…at least with animals that are using them for better weight gain or preventing ailments. Though not yet legal everywhere, this one does the most to keep anti-biotics out of the environment and it also has cascading benefits such as improving soil carbon, reducing enteric emissions, etc.
- Carbonize livestock manure especially when animals are fed antibiotics. Many different types of antibiotics can be completely removed when pyrolyzed at 600C or higher. (Tien et al 2019) Ditto for human manure (aka sludge, biosolids). Not only does the heat kill off the contaminants, but manure and sludge volumes are reduced significantly which can help avert excess nutrient leaching into water bodies.
- Blend biochar with manure. This can either be done by adding it to bedding material or during composting. Biochar helps to degrade antibiotics and antibiotic resistant genes (ARGs) in manure. (Qian et al 2019) It will also help control odors and emissions while building long term soil carbon.
- In remote areas without access to wastewater treatment facilities, use biochar in composting toilets. Note that this biochar should not be used for growing food but could be fine for putting into biochar bricks.
- Use specially designed biochar for removing antibiotics in wastewater treatment. (Chen et al 2019)
- Antibiotics abatement in soil: Apply biochar to soils contaminated with antibiotics to reduce leaching and bioavailability. (Liu et al 2018)
- In developing world areas that lack adequate drug disposal (e.g. health care clinics), dispose of unused or out of date antibiotics into metal barrels filled with biochar. These should be buried in safe areas not prone to flooding or leaching.