Researchers at the Ben-Gurion University (BGU) in Israel have come up with a process of using hydrothermal carbonization (HTC) to convert human waste into hydrochar: a safe, reusable biomass fuel resembling charcoal. Their research was published in the Journal of Cleaner Production on November 14, just days ahead of the United Nations’ World Toilet Day on Monday (today).
BGU researchers conducted similar research on poultry excrement last year.
Using HTC, researchers subjected raw waste to three temperatures (180, 210 and 240° C) and reaction times (30, 60 and 120 minutes). This dehydrated the solid waste, creating combustible hydrochar, as well as a nutrient-rich aqueous phase liquid.
The process itself sterilizes the waste material, therefore the hydrochar is safe to handle and can be used for household heating and cooking.
“Human excreta are considered hazardous due to their potential to transmit disease,” says Professor Amit Gross, who is the newly appointed director of the BGU’s Zuckerberg Institute for Water Research. “While it is rich in organic matter nutrients such as nitrogen, phosphorus and potassium, human waste also contains micro pollutants from pharmaceuticals, which can lead to environmental problems if not disposed or reused properly.”
This technology can be used to address issues plaguing the developing world: waste management and growing energy needs.
According to the World Health Organization (WHO), 2.3 billion people across the globe still lack basic sanitation services. Of these, 892 million — mostly residents of rural areas — defecate in the open. This leads to the micro pollutants found in fecal matter seeping into water tables, which goes on to cause outbreaks of diarrhea, typhoid, polio, cholera and hepatitis. In 2013 UNICEF revealed that 2000 children under the age of five die everyday due to diarrhoeal disease and of these, 1,800 cases were related to water, sanitation and hygiene.
Expanding energy needs also pose environmental concerns. According to the study, approximately two billion people worldwide are dependent on solid biomass — mostly wood and wood turned into coal — for their energy needs. This leads to greenhouse gas emissions, soil erosion and deforestation.
“By treating human waste properly, we can address both of these issues at once,” says Professor Gross.
Earlier this month, the Bill & Melinda Gates Foundation hosted the first Reinvented Toilet Expo in Beijing alongside global innovators, development banks and corporate partners. The expo featured the unveiling of new products and commitments towards the funding of innovative, pro-poor sanitation technologies.
In a recent report, the World Bank pointed out that Pakistan had failed to reduce diarrhea and stunting in children because it did not make sufficient investment in waste management infrastructure. Pakistan continued to suffer from high levels of E.Coli contamination even though open defecation was reduced by 50 percent. Last November, WaterAid reported that 79 million Pakistanis did not have access to a decent toilet, and declared the country the seventh worst in terms of access to basic sanitation.