Pharmaceutical pollution is a silent scourge on health and the environment. Next-gen cleantech offers solutions.
The drugs in our water
Active pharmaceutical compound (API) pollution is one of cleantech’s greatest challenges. From antipsychotics to antibiotics, mind and body-altering drugs are poisoning rivers and lakes around the world. In 2018, researchers detected 13 APIs in fish from 25 urban sites in the US. Antiepileptics and antidepressants were the most common. In a cross-continental study of 258 rivers published 2022, more than a quarter of surveyed waterways contained dangerous drug residue levels. Since no global monitoring system for this exists, we should assume that the severity of the problem is greater than current estimates.
Pharmaceutical pollution rarely reaches the public consciousness. Although its effects may be less visually dramatic than those of oil spills or urban smog, the damage wrought by drug pollutants is arguably more insidious. While occasional media reports surface linking fish mutations with hormone disrupters, clear physical indicators like deformity or mortality are rare. Instead, the symptoms of API toxicity are usually cumulative, long-lasting, and subtle. Trace pharmaceutical compounds impair animal reproduction, nervous system function, development, and behaviour in ways that disrupt whole ecosystems. API pollution also poses a risk to human health. Antibiotic pollution, for example, incubates super-resistant microbes, something that now kills more people worldwide than AIDs or malaria. Drug compounds can also bioaccumulate in the organisms we eat.
APIs enter aquatic environments from five sources. These are pharmaceutical manufacturing plants, hospitals, livestock farms, farmland fertilised with treated sewage, and toilets where they are excreted or disposed of. Invisible and easily dispersed, APIs must be intercepted at the source for effective treatment. The collected contaminants must either be destroyed or at least degraded enough to inactivate their biological effects.
Conventional methods for sewage, stormwater, or industrial wastewater can only treat a few of the approximately 4000 drugs on the global market. Wastewater treatment systems were not designed to tackle this immense range of complex and chemically stable compounds. Antiepileptics, antibiotics, and trimethoprim simply pass through our treatment facilities unprocessed. However, a handful of cleantech companies have made headway in implementing cost-effective tech for pharmaceutical waste treatment.
How does cleantech help?
Chemical methods are the most efficient way of degrading these pollutants, oxidisation being the most common. This chemical reaction pulls apart active medical compounds into their simpler molecules. Most API cleantech companies induce this reaction electrically. When two specially coated electrodes in a liquid solution generate an electrical current, hydroxyl radicals form on their surfaces. These highly reactive molecules decompose API pollutants on contact by turning them into simpler carbon dioxide, water, and organic anions. Axine Water Technologies based in Vancouver takes this approach. In one case study, used it to reduce the concentration of an antiparasitic in rinse water from 8,000 μg/L to < 2 μg/L, well below the legal requirement.
For most companies, the treatment process ends here. One, however, is turning to resource recovery from wastestreams.
Making pharma circular
Pharmaceutical companies usually incinerate drug waste. Although this is one of the few methods that reliably destroys ecotoxic compounds, it poses its own environmental hazards. Not only does it emit toxic gas, it also prevents resource recovery.
This is where Belgian cleantech company Inopsys, founded in 2015, saw an opening. This KU Leuven University spin-off researches and develops treatments for endocrine-disrupting chemicals and steroids. On top of treating the wastewater, they recover marketable chemicals and clean water to be fed back into the manufacturing process. The materials that Inopsys recovers from pharmaceutical wastewaters include metals and solvents. The latter is heavily used in refining pharmaceutical products.
Inopsys’ circular approach to pharmaceutical waste streams stands out in the API cleantech industry. Its founder Steven de Laet set up the company to move away from the linear manufacturing models that he observed across his career in the chemicals industry.
Like Axine Water and other cleantech companies, Inopsys’ mobile, modular installations are custom-built add-ons to existing treatment facilities. Cleantech service providers generally take on the cost burden for running the facilities they install since treatment and resource recovery may take several years to bring a return for manufacturers. Inopsys for example design, build, finance, operate, and maintain the tech on behalf of the client. This business model is critical to ensuring that pharmaceutical filtration becomes appealing for drugs manufacturers and water treatment businesses.
Research is still ongoing into techniques for recovering reusable pharmaceutical ingredients. It remains costly and difficult to recover drug compounds to the quality specifications demanded by pharmaceutical companies. RECOPHARMA is the most pioneering EU-funded project in this field, with partners that include international research institutions as well as two private companies: Europe for Business Ltd, a scientific consultancy based in London, and Aeris, a Spanish biological wastewater treatment company. Together, they are working to design, develop, and validate ways to recover cytostatic drugs used in cancer treatments.
Most API cleantech companies rely on electrochemical oxidisation to degrade pharmaceutical pollutants. Pharem Biotech, a Swedish company founded in 2013, is different. They are unique in the industry for using biological methods, selecting natural enzymes and modifying them to boost their compound-degrading capabilities. In some cases, these natural enzymes are modified to be 200 times more effective against drug residue. Their patented biological filtration tech removes drugs like bisphenol A, antibiotics, and hormone disruptors such as Estriol from water.
Like Axine Water Technologies and Inopsys, Pharem offer solutions for industrial waste streams. Their innovative Zymatic, a sand-like material that contains active enzymes, can be integrated into filtration systems at manufacturing sites or wastewater treatment plants. Between 2018 and 2020, Zymatic was at the centre of an EU-funded project for developing cost-efficient pharmaceutical removal techniques for wastewater. The project trialled the tech to showcase its viability as an add-on for conventional wastewater treatment facilities across the EU.
Pharem is also targeting pharmaceuticals in flushed human waste. Our bodies can only metabolise around 60 – 70 percent of active pharmaceutical ingredients meaning that unabsorbed compounds are excreted, predominantly in urine. Pharem is trying to prevent flushed pharmaceuticals ending up in the water cycle with their pCure filter. This is a small device that can be attached to toilet rims. Its blend of customised enzymes targets specific mixtures of pharmaceutical compounds before they enter the sewage stream.
Photocatalysis and resource recovery: Next-gen cleantech
Antibiotics are one of the most common pharmaceutical pollutants found in waterways. It is also one of the most challenging to remediate. Every trace must be removed to prevent any remaining residue fostering resistant microbe populations.
Many researchers believe photocatalytic treatment is the answer. Photocatalysis oxidises drug compounds, just like under conventional electrochemical oxidisation used by companies like Axine Technologies. The difference is that photocatalysis uses light instead of electrical currents to produce the reaction. Dr. Sudhagar Pitchaimuthu of Heriott Watt University explains that the advantage of photocatalytic oxidation is its energy efficiency: more pollutants are degraded per unit of energy. Light-based oxidisation is also far more targeted. It degrades pollutants even when present at very low concentrations.
Photocatalysis may be the future of API cleantech. Although still in its pre-market phase, a barrage of research institutions around the world are working to commercialise the technology for wastewater treatment. The biggest question is how to industrially scale light reactors that have so far only been used in lab contexts. Prof. Peter Robertson (Queens University Belfast, UK), Prof. Wongyong Choi (Pohang University of Science and Technology, South Korea), and Prof. Dionysios Dionysiou’s group (University of Cincinnati Cincinnati, USA) have been focused on benchmarking the process.
Researchers who study photocatalytic wastewater treatment are already pushing to integrate the tech within a circular system. Resource-recovery technology could be twinned with photocatalytic reactors to turn pharmaceutical waste streams into valuable feedstock for industry. Scientists advocate recovering tnon-pharma materials leftover when pollutants are treated with light. When broken down by light radiation, the drug groups oxytetracycline, doxycycline, and ciprofloxacin yield economically valuable intermediates: 1,4-benzene dicarboxylic acid widely used in making PET plastics, propanedioic acid used in anti-UV coatings, hydoxymalonic acid used as a food additive E334, and glycerine, a widely used skin and healthcare ingredient.
The technical advances coming out of cleantech companies offer solutions that often exceed regulatory requirements for pharmaceutical wastewater treatment. Electrochemical oxidisation (Axine Water Technologies) and biological remediation (Pharem) are the two main approaches on the market today. Inopsys mixes its methods, using conventional strategies like filtration, flotation, and coagulation on top of electrochemical oxidisation. Looking ahead, commercialising photocatalytic oxidisation for pharmaceutical waste would be a major breakthrough for the industry, given the huge range of chemicals this method can target.
Inopsys currently leads the way on resource recovery from pharmaceutical wastewater but cost-effective ways of recovering high-grade reusable APIs are still some way off. Recovering non-pharmaceutical compounds for the chemical industries presents a more feasible next step in building circular pharma production since feedstock quality requirements are generally lower.