Mechanical properties of faecal sludge

Velkushanova, Konstantina; Zuma, Lungi; Buckley, C.A.

doi:10.12688/gatesopenres.13049.1

Cited by 6 publications

(7 citation statements)

References 4 publications

(1 reference statement)

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“…A low methane content, approximately around 23%, along with a diminished methanogenic potential, was also noted in faecal sludge in Bobo Dioulasso, Burkina Faso, as reported by Christiane [84]. These values align closely with those reported in the literature, ranging between 45 and 50 NL CH4/KgVS for septic tank sludge [85]. On the other hand, other works have found values ranging from 0.009 m 3 to 0.028 m 3 /kg VS [27,86].…”

Section: Unitsupporting

confidence: 87%

Characterization and Methanogenic Potential Evaluation of Faecal Sludge: Case of the Kossodo Biogas Plant in Ouagadougou

Ouedraogo,

Konaté,

Sawadogo

et al. 2023

Sustainability

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The use of faecal sludge (FS) in anaerobic digestion (AD) requires a perfect knowledge of their composition. Considered as a very heterogeneous material, the high variability of FS can disturb biodigesters’ functionality and impact biogas production. Unique in West Africa, Kossodo’s biogas plant in Ouagadougou receives sludge from septic tanks and pit latrines. To evaluate the quality of sludge discharged in this treatment plant and its ability for AD, a characterization of 130 FS trucks from several onsite sanitation facilities was carried out. Physico-chemicals, including heavy metals and microbiological parameters, were analyzed using standard protocols. A biochemical methane potential test was employed to evaluate biogas yield. Results showed that raw sludge averaged 1.12% total solids (TS), 54.74% volatile solids (VS), 9253 mg/L chemical oxygen demand (COD), and 1645 mg/L biochemical oxygen demand (BOD). Settled faecal sludge exhibited higher levels of total coliforms, E. coli, helminth eggs, and heavy metals. Heavy metal levels met AD standards defined by VDI 4630, with decreasing toxicity order: Zn > Mn > Cu > Cr > Ni > Pb > As ≥ Hg. The carbon-to-nitrogen (C/N) ratio was 6.7 ± 4.3, indicating unsuitability for AD. Sludge settling increased C/N ratio by 46%, which was still below optimal AD conditions (20–30). Methane yield of raw and settled FS averaged 61 ± 0.2 and 156 ± 3.2 NL CH4/kg VS removed, respectively. Co-substrate addition could enhance the methanogenic yield of these sludges. This study provides a valuable database on the characteristics of FS, supporting sustainable recovery options.

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Section: Unitsupporting

confidence: 87%

Characterization and Methanogenic Potential Evaluation of Faecal Sludge: Case of the Kossodo Biogas Plant in Ouagadougou

Ouedraogo,

Konaté,

Sawadogo

et al. 2023

Sustainability

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“…However, most of the laboratory replicates in this study have an acceptable variation of <10%, albeit more than 5%, which is the standard for wastewater analysis (APHA, 2017). Although progress is being made on method development, standard methods and standards for laboratory error specifically for fecal sludge have not yet been established (Velkushanova et al, 2021). Precise and accurate measurements of fecal sludge are challenging, and as standards are developed, it needs to be determined what acceptable variations are.…”

Section: Laboratory Qa/qc Resultsmentioning

confidence: 99%

“…Laboratory analysis was done at the local laboratory of each of the collaborating institutions. Total solids (TS), volatile solids (VS), pH, and electrical conductivity (EC) were quantified according to Velkushanova et al (2021). In Sierra Leone, VS was not measured due to a lack of required laboratory equipment.…”

Section: Analytical Methodsmentioning

confidence: 99%

“…However, approaches remain time and resource intensive, highlighting the need for more efficient approaches to data collection and analysis. At the same time, progress is being made on developing methods of analysis for characteristics of fecal sludge (Velkushanova et al, 2021). However, rigorous attempts at validation of precision and ruggedness are still required prior to the development of standard methods (APHA, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Quantities and qualities of fecal sludge: Experiences from field implementation with a Volaser in 7 countries during a pandemic

et al. 2023

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Reasonable estimates for quantities and qualities (Q&Q) of fecal sludge that accumulate in onsite sanitation containments are fundamental for the design of appropriate management and treatment solutions, from community to city-scale. There are increasing attempts to improve Q&Q estimates, but current approaches are still at a conceptual level, and are not yet standardized with confirmed statistical relationships. To reach this level, we will need consistent approaches for planning, measuring, and global collaborations. Hence, the objectives of this study were: (1) to assess and compare Q&Q of fecal sludge from seven cities and communities, and explore statistical relationships that could be used to increase accuracy of Q&Q estimations; (2) to test and launch the Volaser device for measuring in situ volumes of fecal sludge; and (3) to capture lessons learned from field implementation with collaborators in seven countries during a global pandemic when no international travel was possible. The study took place in Ghana, India, Lebanon, Kenya, Sierra Leone, Uganda, and Zambia during the COVID-19 pandemic. Q&Qs were measured in 204 containments with a Volaser, laboratory analysis, and questionnaire. Results indicate that there are differences in Total Solids (TS) and Chemical Oxygen Demand (COD) in fecal sludge based on containment type, toilet type, source, and whether there is a water connection on the premises. Based on the results of this study, together with previously published open-source data, an empirical relationship for Volatile Solids (VS) and TS of 0.49 (R2 = 0.88) was established using 1,206 data points. For COD/TS, no significant relationship was observed. Developing such empirical relationships will be useful for planning and modeling approaches. An external evaluation was conducted to evaluate overall project management, Volaser technology transfer, and effects of collaborating during the COVID-19 pandemic. Success factors for collaborating with new and existing partners without face-to-face meetings included laboratory capacity and experience with analytical methods, study objectives that were relevant for the partner and locality, and a strong quality assurance plan to ensure comparability of results. The lessons learned can be taken forward as ways to reduce carbon footprint, and contribute to resilient, inclusive development research projects.

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“…This collectively emphasizes the feasibility and profitability of the dewatering machine investment. Ultimately, these findings support the selection of the Constant pitch screw with a tapered shaft design for the pressing screw and highlight the potential for improved dewatering and sun-drying processes in the management and utilization of biogas slurry [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The repayment duration in this research is computed as 1 year 10 months and 23 days, which is less than the payback period in Sherpa et al's 2017 study.…”

Section: Chapter 4: Conclusionmentioning

confidence: 88%

Design, Validation, and Examination on the Performance Improvement of Dewatering System Implemented for Biogas Slurry

2023

Eart & Envi Scie Res & Rev

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The project addresses the pressing need for organic fertilizers in Nepal and explores an eco- friendly alternative to chemical fertilizers. By dewatering biogas residue, this research contributes to sustainable agriculture practices. The project's methodology involved a combination of research, literature recommendations, and guidance from experienced supervisors. SolidWorks was utilized for the design phase, while ANSYS facilitated simulation works. Subsequently, the testing of the dewatering machine was conducted. The biogas slurry used for testing and sun-drying was sourced from a prototype 1m3 capacity biogas plant. The machine's performance was evaluated at various operating speeds, with 8 rpm identified as the most efficient. Notable outcomes included a liquid yield of 52.51%, an extraction efficiency of 79.11%, and extraction losses amounting to 22.80%. To enhance the quality of the organic fertilizer, the slurry sample underwent sun-drying for different durations: 24, 48, and 72 hours. Nutrient concentrations (TS, N, P, K) were analyzed, that came with the 48-hour sun-drying period proving to be the most effective in reducing Total Solid contents. Comparatively, pre-treating the slurry sample for 24 and 48 hours prior to testing in the dewatering machine allowed for an assessment of the machine's efficiency, offering valuable insights to be contrasted with the sun-drying process. This research paves the way for a greener, more efficient method of dewatering biogas slurry, aligning with Nepal's agricultural and environmental sustainability goals.

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Mechanical properties of faecal sludge

Cited by 6 publications

References 4 publications

Characterization and Methanogenic Potential Evaluation of Faecal Sludge: Case of the Kossodo Biogas Plant in Ouagadougou

Characterization and Methanogenic Potential Evaluation of Faecal Sludge: Case of the Kossodo Biogas Plant in Ouagadougou

Quantities and qualities of fecal sludge: Experiences from field implementation with a Volaser in 7 countries during a pandemic

Design, Validation, and Examination on the Performance Improvement of Dewatering System Implemented for Biogas Slurry

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