Bioremediation
The limit on cleaning up a site is almost never whether an organism can degrade the compound — it is transport and mass balance; and the pages are honest about the negatives.
Nineteen subjects, from PFAS to human composting, built around one negative result stated positively: the limit on cleaning up a site is almost never whether an organism can degrade the compound. It is transport and mass balance. A biofilter’s ceiling is getting the pollutant from gas into the water film; an oil spill’s loss curve flattens because nothing can oxidise what is left; biosorption is stoichiometry with a fixed capacity, not catalysis; a hyperaccumulator’s ceiling is an arithmetic of biomass and concentration; stormwater systems work by contact time and media chemistry.
Two more ideas recur. When the substrate poisons the organism eating it, reactor configuration stops being a preference and becomes the mechanism. And the economics are decided by whether chemistry concentrates the stream for you — the free feedstock is the only free thing, and a side stream becomes an ingredient only if its protein can be released with its functionality intact.
The pages are honest about negatives: PFAS is not mineralised at useful rates, treatment plants remove microplastics without destroying them, and for polyolefins there is no enzyme at all.
Start with microbial bioremediation — the case for why degradation is rarely the question.
Articles 19
| Air biofiltration Why a biofilter's ceiling is set by getting the pollutant out of the gas and into the water film, not by how fast the bacteria eat it. |
| Bioremediation of drilling waste Why the base fluid on drill cuttings usually degrades and the brine, the barite and the seabed usually decide the outcome anyway. |
| Green burial and human composting Why burial depth decides whether a body decomposes or is preserved, and what a thermophilic phase can and cannot sterilise. |
| Biomining, phytoremediation and tailings valorisation Iron(III) does the leaching and the bacteria only regenerate it — and a hyperaccumulator's ceiling is a mass balance, not a physiology. |
| Biosorption of rare earths and critical metals Binding a metal to a cell surface is stoichiometry with a fixed capacity, not catalysis — which decides everything about how it can be used. |
| Biological treatment of hazardous effluents When the substrate poisons the organism eating it, reactor configuration stops being an engineering preference and becomes the mechanism. |
| Microbial bioremediation Why the limit on cleaning up a contaminated site is almost never whether an organism can degrade the compound. |
| Biological treatment of municipal wastewater Nitrifiers grow slowly and grow far more slowly when cold — which is why a treatment plant in a cold climate is physically larger. |
| Upcycled food ingredients A side stream is not an ingredient because of where it came from — it becomes one only if its protein can be released and its functionality survived the first process. |
| Urban biorefineries and biowaste processing Recovering something from sewage works only where the chemistry concentrates it for you — and one upstream decision can foreclose it entirely. |
| Home composting kits Two different microbial processes are sold under one word, and neither delivers at kitchen scale what a windrow delivers. |
| Bio-based flotation reagents Replacing a frother is a problem in interfacial physics; replacing a collector is a problem in selectivity, and that one is not solved. |
| Biological microplastic removal in wastewater Treatment plants remove microplastics very efficiently, and destroy none of them. |
| Oil spill bioremediation on land Crude is a mixture, not a compound, and its loss curve flattens not because the process is slow but because nothing can oxidise what is left. |
| Stormwater bioretention systems What works is the contact time between water and media, and the chemistry of that media — not the plant in the photograph. |
| Coffee-ground upcycling: the biorefinery test of a circular promise Spent coffee grounds arrive pre-aggregated and chemically consistent — the rare side stream a biorefinery can plan against — and the segment's proof is a running plant in Denmark processing 500 tons a year into cosmetic-grade ingredients, with everything else still at studio scale. |
| Microplastic biodegradation on land For polyester there is an enzyme, and it works on the amorphous phase. For polyolefins there is no enzyme — not a slow one, none. |
| PFAS biodegradation No organism is known to mineralise a perfluoroalkyl chain at a useful rate, and most published PFAS bioremediation converts precursors into the very analyte that is regulated. |
| Upcycling biowaste into valuable products The feedstock is free and nothing else is: recalcitrance, water content and compositional variability decide which product is worth making at all. |