Background: The dumping of untreated faecal sludge from non-sewered onsite sanitation facilities causes environmental pollution and exacerbates poor public health outcomes across developing nations. Long-term mechanisms to treat faecal sludge generated from these facilities are needed to resolve the global sanitation crisis and realize the Sustainable Development Goal (SDG) 6 “ensure availability and sustainable management of water and sanitation for all” by 2030.  Pyrolysis of faecal sludge removes pathogens and generates biochar, which can be used as a soil enhancer. Methods: The properties of faecal sludge biochars from three full-scale treatment plants in India were determined via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, crystal x-ray diffraction (XRD), proximate analyses, and BET surface area porosimetry. Results:  Results showed that all three biochars had low specific surface area, high alkaline pH values, high ash content, and negative surface charge. Fourier transform infrared spectra showed the same surface functional groups present in each biochar. X-ray diffraction analysis showed the mineral composition of each biochar differed slightly. Scanning electron microscopy analysis indicated a porous structure of each biochar with ash particles evident. Conclusions: Slight differences in the ash content, surface area, pH and mineral content was observed between the three biochars.

Background: The dumping of untreated faecal sludge from non-sewered onsite sanitation facilities causes environmental pollution and exacerbates poor public health outcomes across developing nations. Long-term mechanisms to treat faecal sludge generated from these facilities are needed to resolve the global sanitation crisis and realize the Sustainable Development Goal (SDG) 6 “ensure availability and sustainable management of water and sanitation for all” by 2030.  Pyrolysis of faecal sludge removes pathogens and generates biochar, which can be used as a soil enhancer. Methods: The properties of faecal sludge biochars from three full-scale treatment plants in India were determined via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, crystal x-ray diffraction (XRD), proximate analyses, and BET surface area porosimetry. Results:  Results showed that all three biochars had low specific surface area, high alkaline pH values, high ash content, and negative surface charge. Fourier transform infrared spectra showed the same surface functional groups present in each biochar. X-ray diffraction analysis showed the mineral composition of each biochar differed slightly. Scanning electron microscopy analysis indicated a porous structure of each biochar with ash particles evident. Conclusions: Slight differences in the ash content, surface area, pH and mineral content was observed between the three biochars.

Full-scale pyrolysis of faecal sludge is a credible technology for the safe removal of pathogens and the concurrent creation of biochar, which has been shown to enhance crop productivity. Faecal sludge biochar has the potential to improve acidic, low nutrient soils and crop yield in developing nations more at risk of climate change and food insecurity. Little research has been conducted into public acceptance of faecal sludge biochar as a soil enhancer in agriculture. In this study of the public in Swansea, Wales, an online survey examines their awareness of, and comfort levels of eating food grown using biosolids, wood biochar and faecal sludge biochar. Our findings show that males were almost twice as likely than females to have a positive perception of biosolids (OR 1.91, p value 0.004) and faecal sludge biochar (OR 2.02, p value 0.03). Those in the oldest age group (65+) were almost five times more likely to have a positive view of faecal sludge biochar than the youngest age group (OR 4.88, p value 0.001). Deployment of faecal sludge biochar must overcome a “disgust effect” related to its human faecal origins. This factor must be centrally taken into account when implementing management and policy decisions regarding the land application of biosolids and faecal sludge biochar.

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