Per- and polyfluoroalkyl substances (PFAS) are a highly dangerous family of “forever chemicals” present in consumer goods ranging from dental floss to personal electronics. They are toxic at minuscule concentrations, as low as parts per trillion, and have been linked to testicular cancer, infertility, heart issues, and immune disorders. Seventy years of PFAS use have resulted in significant contamination of our soil and water. Toxic levels have been detected in everything from beef cattle to wild deer.
The scope of the challenge to contain and remove PFAS contamination is daunting. There is no single solution because PFAS will take centuries to degrade on their own. Public and private organisations will both play important roles in combating this challenge. Wastewater treatment facilities will be essential partners in minimising the spread of PFAS in our environment.
Sewage sludge is a known hot spot for PFAS concentration and environmental spread. While some sludge is incinerated, the majority is either landfilled, where PFAS can leach out into surrounding land and water, or used as fertiliser to condition soil for growing crops, further dispersing PFAS into the environment.
RI-HTL has the potential to destroy PFAS and reduce the volume of sludge waste requiring disposal while producing beneficial green energy
Plant operators should not have to, and do not have to, take on this battle alone. Researchers worldwide are developing PFAS-destroying technologies to remove these persistent toxic foes. However, as plant personnel, municipalities, and private wastewater treatment companies look for applicable PFAS removal and destruction solutions, they often need to balance removing PFAS with other operational challenges, including costs and logistics. Interviews with wastewater professionals emphasise the complexity of implementing novel technologies into the rigidly controlled and highly regulated wastewater ecosystem.
Radical initiated hydrothermal liquefaction, or RI-HTL, is a new multipurpose technology invented at Worcester Polytechnic Institute (WPI) and licensed for commercialisation by River Otter. RI-HTL has the potential to destroy PFAS and reduce the volume of sludge waste requiring disposal while producing beneficial green energy.
RI-HTL is based on hydrothermal liquefaction (HTL), a decades-old waste-to-fuel technology using hot pressurised water. Traditional HTL has not been widely adopted due to its low waste conversion efficiency. RI-HTL uses a green radical chemical to turbocharge the HTL process, increasing the breakdown of PFAS while improving waste conversion into useful crude oil. Initial RI-HTL PFAS destruction results have been promising: WPI’s technology removed 99% of 40 known PFAS from the processed water while converting sewage sludge into crude oil.
Sludge conversion into crude oil during PFAS destruction provides both environmental and economic benefits for wastewater treatment by decreasing the solid waste requiring disposal. RI-HTL bypasses the challenges with landfilling, incineration, and land application, which have hindered PFAS containment and destruction efforts in the past. River Otter estimates that RI-HTL can reduce sludge waste disposal costs by roughly 45–70% through converting sludge waste into crude oil and reclaiming nearly 99% of the processed water through simple oil-water separation.
Our history as an extractive economy, which uses natural resources and discards them as waste, has made PFAS a major challenge that must be addressed to preserve the environment and human health. Instead of viewing wet waste as a source of toxins, we envision a future in which communities use these wastes to recover billions of gallons of water and millions of kilojoules of energy.
River Otter is actively fundraising to build a large-scale demonstration unit to prove the reliability and performance of the technology. Please reach out for additional information and to help bring us one step closer to putting an end to forever chemicals.
