Biochar Types from Latrine Waste and Sewage Sludge Differ in Physico-Chemical Properties and Cadmium Adsorption

Koetlisi, Koetlisi Andreas; Muchaonyerwa, Pardon

doi:10.3844/ajassp.2017.1039.1048

Cited by 16 publications

(20 citation statements)

References 48 publications

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“…Cation exchange capacity has been found to increase in biochar because of an increase in surface area. A similar study showed no significant difference in biochar pyrolysed at 550 C and 650 C, indicating that increasing pyrolysis temperature did not affect CEC (Koetlisi and Muchaonyerwa, 2017). However, on the contrary, M endez et al ( 2013) reported that the increase in CEC might be caused by the formation of phenolic functional groups when sewage sludge was used as feedstock.…”

Section: Resultsmentioning

confidence: 92%

“…Biochar yields decreased significantly with increasing pyrolysis temperature (p < 0.001) from 51.5 to 56.9% at 300 and 500 C, respectively (Figure 1). The observed decrease in yield could probably be attributed to thermal dehydration of hydroxyl groups as moisture is lost through evaporation and the volatilisation of organic fractions (Koetlisi and Muchaonyerwa, 2017;Liu et al, 2014). During pyrolysis, organic C is lost due to the thermal degradation of lignocellulose material in the human excreta (Liu et al, 2014).…”

Section: Resultsmentioning

confidence: 99%

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Optimising pyrolysis conditions for high-quality biochar production using black soldier fly larvae faecal-derived residue as feedstock

Nkomo¹,

Odindo²,

Musazura³

et al. 2021

Heliyon

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The disposal of feacal matter from Urine Diversion Dry Toilets is a significant challenge due to limited land availability, possible underground water contamination, and the risk of spreading diseases. The collected faecal matter can be fed to Black Soldier Fly Larvae to produce protein-rich larvae used as animal feed. The disposal of the leftover waste (BSFL residue) is still a problem due to the risk of residual pathogen contamination. The BSFL residue contains residual plant nutrients and can be further processed into biochar. Faecal matter biochar offers an exciting value proposition where the pyrolysis process guarantees a 100% pathogen elimination. It also results in significant waste reduction in transport, storage weight, and volume. A preliminary study was conducted to (i) optimise pyrolysis conditions (optimal temperature treatment and residence time) for biochar production using residue obtained after faecal matter from urine diversion dry toilets was fed to black soldier fly larvae as feedstock; and (ii) determine the physicochemical and morphological characteristics of biochar produced. The residue was pyrolysed at 300, 400, and 500 C and characterised for chemical, biological and physical characteristics. Surface area (6.61 m 2 g À1), pore size, and C: N (9.28) ratio increased at 500 C for 30 min. Exchangeable bases, (Calcium) Ca, (Magnesium) Mg, (Potassium) K, and (Sodium) Na increased with increasing pyrolysis temperature. The increase in basic cations resulted in an increase in pH from 6.7 in the residue to 9.8 in biochar pyrolysed at 500 C. Biochar pyrolysed at 500 C can therefore be used to improve acidic soils. Phosphorus increased with increasing pyrolysis temperature to 3 148 mg kg À1 at 500 C. Biochar produced at 500 C for 30 min had desirable characteristics: surface area, exchangeable bases, and pH. Also, biochar can be used as a phosphorus source with potential for crop production, although an external nitrogen source is needed to meet crop nutrient requirements.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Optimising pyrolysis conditions for high-quality biochar production using black soldier fly larvae faecal-derived residue as feedstock

Nkomo¹,

Odindo²,

Musazura³

et al. 2021

Heliyon

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“…The extremely high concentration of Zn could have precipitated with the increased P in the sewage sludge biochar, suppressing Cu sorption on the same biochar. The decrease in Cu sorption on sewage sludge biochar, with increasing pyrolysis temperature could be due to loss of oxygen-containing functional group such C=O stretching of aldehyde and carbonate ions at 550 and 650 °C [28]. The reason for the decline of Zn sorption and no change in Cu sorption on latrine waste with increasing pyrolysis temperature was not clear.…”

Section: Discussionmentioning

confidence: 99%

“…Biochar from human faecal wastes [28] differed in their physicochemical properties, with higher cadmium (Cd) sorption capacity, compared to those from pine-bark [29]. The Cd sorption generally declined with increase in pyrolysis temperature (350–650 °C) from 200 to 167 for latrine waste biochar, and from 143 to 36 mg kg −1 for sewage sludge biochar [28], while it slightly increased from 20 to 34 mg kg −1 for pine-bark biochar [29]. Whereas ash content and phosphorus composition explained the sorption of Cd on faecal biochar, fixed C, pH and Brunauer-Emmett-Teller (BET) surface area appeared to be more important in pine-bark biochars.…”

Section: Introductionmentioning

confidence: 99%

Sorption of Selected Heavy Metals with Different Relative Concentrations in Industrial Effluent on Biochar from Human Faecal Products and Pine-Bark

Koetlisi

Muchaonyerwa

2019

Materials

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The removal of heavy metals from effluents at source could reduce contamination of soil and water bodies. A batch sorption experiment was performed to determine the effects of feedstock of biochars pyrolysed at increasing temperature on sorption capacities of Cu, Cr and Zn from industrial effluent and aqueous solutions. Sewage sludge, latrine faecal waste and pine-bark biochars were used. The sorption data were fitted to the Langmuir isotherm. Maximum sorption capacities of latrine waste, sewage sludge and pine-bark biochar (350 °C) were, respectively, 313, 400 and 233 mg kg−1 for Zn, 102, 98.0 and 33.3 mg kg−1 for Cu, and 18.9, 13.8 and 67.1 mg kg−1 for Cr from industrial effluent. Conversely, sorption capacities from single metal solutions were 278, 227 and 104 mg Zn kg−1, 97.1, 137 and 21.3 mg Cu kg−1, 122, 106 and 147 mg Cr kg−1 on latrine waste, sewage sludge and pine-bark biochar, respectively. Step-wise regression analysis showed that the combined effects of ash, fixed C, pH influenced Zn sorption, ash and fixed C affected Cu sorption, and Cr sorption by ash and specific surface area of the biochar. The findings of the study imply that biochar from human faecal waste, particularly sewage sludge, has the potential to be utilized as sorbents of heavy metals from multiple metal effluent and that the sorption is affected by relative concentrations.

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“…Overall, both biochars contained numerous surface functional groups, which is expected for biochars obtained at relatively low pyrolysis temperature (450 °C). For example, Koetlisi and Muchaonyerwa (2017) showed that biochars produced from latrine waste had N-H functional groups at 350 °C (3694.07 cm -1 ) and 550 °C (3691.69 cm -1 ) but not at 650 °C. BS was enriched in amino functional groups and comprised 1.8% N ( Table 1).…”

Section: A B Cmentioning

confidence: 99%

Alleviation of aluminum and cadmium toxicity by biochar and its potential toxicity to sorghum

Almeida

Santos

Pandey

et al. 2020

SCA

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Highlights:Use of biochar to mitigate soils contaminated by trace elements. Pyrolysis as an alternative to sewage sludge disposal in the environment. Some mechanisms involved in the alleviation of soil acidity by biochar. A rapid and simple test to assess biochar toxicity. Biochar as a strong and effective sorbent for aluminum and cadmium. AbstractBiochar has been used as an alternative in organic wastes management and to alleviate trace elements toxicity. The aim of this research was to use a rapid and simple test to detect the potential toxic effects of biochar and its ability to alleviate aluminum and cadmium toxicity to seeds and seedlings of Sorghum bicolor L. Two experiments were carried out in Petri dishes with two different biochars where sorghum seeds were exposed to aluminum (experiment 1) and cadmium (experiment 2) solutions. The experimental designs were completely randomized, with five doses of aluminum or cadmium in aqueous solution (0, 0.5, 1, 2, and 4 mmol/L of Al or Cd), combined with or without the addition of 0.25 g of biochar from sugarcane bagasse or from sewage sludge. Compared to treatments without biochar, in the treatments with biochar, higher seed germination rate and growth of sorghum seedlings were obtained. Moreover, the biochars were not toxic to sorghum and they decreased the toxicity of aluminum and cadmium, mainly the biochar from sewage sludge that presented higher pH and greater occurrence of functional groups in its particles. ResumoO biochar tem sido utilizado como uma alternativa para o manejo de resíduos orgânicos e na remedição da toxidez por elementos traços. Objetivou-se com essa pesquisa usar um teste rápido e simples para detectar os potenciais efeitos tóxicos do biochar e sua capacidade de minimizar a toxidez por alumínio e cádmio para sementes e plântulas de Sorghum bicolor L. Conduziu-se dois experimentos em placas de Semina: Ciências Agrárias, Londrina, v. 41, n. 1, p. 95-108, jan./fev. 2020 Almeida, J. B. et al.Petri com dois diferentes biochars onde as sementes de sorgo foram expostas às soluções de alumínio (experimento 1) e cádmio (experimento 2). Os delineamentos experimentais foram inteiramente casualizados, com cinco doses de alumínio ou cádmio na solução aquosa (0, 0,5, 1, 2 e 4 mmol L-1 de Al ou Cd), combinados com ou sem a adição de 0,25g de biochar de bagaço de cana-de-açúcar (BB) ou de lodo de esgoto (BS). Nos tratamentos com biochar, obtém-se maior percentagem de germinação de sementes e crescimento de plântulas de sorgo em relação a ausência de biochar. Além disso, os biochars não são tóxicos para o sorgo e minimizam a toxicidade por alumínio e cádmio, principalmente o BS que apresenta maior pH e maior ocorrência de grupos funcionais em suas partículas. Palavras-chave: Sorghum bicolor. Elementos traços. Acidez do solo. Pirólise. Resíduos orgânicos.

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Biochar Types from Latrine Waste and Sewage Sludge Differ in Physico-Chemical Properties and Cadmium Adsorption

Cited by 16 publications

References 48 publications

Optimising pyrolysis conditions for high-quality biochar production using black soldier fly larvae faecal-derived residue as feedstock

Optimising pyrolysis conditions for high-quality biochar production using black soldier fly larvae faecal-derived residue as feedstock

Sorption of Selected Heavy Metals with Different Relative Concentrations in Industrial Effluent on Biochar from Human Faecal Products and Pine-Bark

Alleviation of aluminum and cadmium toxicity by biochar and its potential toxicity to sorghum

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