Characterizing Properties of Biochar Produced from Simulated Human Feces and Its Potential Applications

Abstract

This study presents a comprehensive characterization of biochar obtained from simulated human feces (SHF) with a view to improve human waste sanitization and stabilization before usage as a resource. The possible applications of SHF are as a fuel, as a soil amendment, or for emerging applications (e.g., activated carbon precursor and odor control), depending on the charring conditions. Simulated human feces were charred under different conditions of peak temperature (200-800°C), heating rate (2-50°C min), and holding time (0.5-6.0 h); these parameters have been shown to have the largest influence on the thermal and physicochemical characteristics of the final product. The peak temperature was shown to have a higher impact than the heating rate or the holding time. At 200°C, the very mild structural changes of the product were characteristic of dry torrefaction, a process useful to remove moisture and sterilize the product. At 400°C the carbon content (76.2 ± 0.4) and the calorific heat value (30.6 ± 0.4 MJ kg) of the product increased by 60%. From 600°C onward, the improved degree of aromatization verified by Fourier transform infrared spectrometry (alkene [C=C] stretching around 1680-1450 cm) and C nuclear magnetic resonance (C=C stretching at 140-110 ppm) made the biochar increasingly suitable for carbon sequestration or commercial fabrication of briquettes of charcoal. In conclusion, SHF proved to be a suitable feedstock to produce a biochar whose characteristics depended mostly on the peak charring temperature. Ultimately, the selection of a suitable application may depend on local and sociological considerations.

Sequential Ammonia and Carbon Dioxide Adsorption on Pyrolyzed Biomass to Recover Waste Stream Nutrients

“…3−5 Technologies for N removal from wastewater can help reduce environmental contamination while promoting recovery of fertilizer nutrients as soil amendments. 6,7 Zeolites, ion-exchange resins, and activated carbon have been investigated to trap plant-available N species such as ammonium (NH 4 + ) and nitrate (NO 3 − ) from liquid streams. 8−15 Ammonia gas (NH 3 ) is another concern due to its high toxicity, with point-source pollution arising from fertilizer, 16,17 animal production, 18 and composting.…”

“…In communities lacking sewerage, indiscriminate disposal of nutrient-enriched liquids and pathogen-laden solid wastes poses environmental and sanitation hazards. , At the same time, between 70 and 90% of waste nitrogen (N) is excreted in the urine in the form of urea (CH 4 N 2 O), a commonly applied N fertilizer worldwide. − Technologies for N removal from wastewater can help reduce environmental contamination while promoting recovery of fertilizer nutrients as soil amendments. , …”

Quality and suitability of fecal biochar in structurally stable urban tree substrates

“…Due to its abundant macronutrients, pyrolyzed fecal biochar also has great potential as a tree substrate component that replaces mineral fertilizers and closes nutrient cycles using natural recycled products, as shown in Fig. 1 (Bleuler et al, 2020;Ilango and Lefebvre, 2016). However, while much research is available on the effect of biochar from plant biomass, there are few studies on the use of fecal biochar from animal or human excreta.…”

“…The use of fecal biochar has not been extensively researched and it is rarely used in practice, probably due to the fear of diseases and heavy metals that may be present in the fecal matter (Bleuler et al, 2020;Ilango and Lefebvre, 2016). However, studies by Ebert et al (2021), Bleuler et al (2020) and Gold et al (2017) indicated that the heavy metal content of fecal biochar is even lower than in previously studied sewage sludge-based biochar.…”

Characterization and ammonia adsorption of biochar prepared from distillers' grains anaerobic digestion residue with different pyrolysis temperatures

“…Biochar is a carbon‐rich residue produced from the thermal decomposition of a large number of types of feedstock, including crop residues, sewage sludge as well as manure under oxygen limited condition. Great interest has been shown for both agricultural and environmental purposes due to its unique physicochemical properties, such as highly heterogeneous composition and high organic carbon content .…”