scholarly journals Faecal sludge drying beds: increasing drying rates for fuel resource recovery in Sub-Saharan Africa

2014 ◽  
Vol 5 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Alsane Seck ◽  
Moritz Gold ◽  
Seydou Niang ◽  
Mbaye Mbéguéré ◽  
Cheikh Diop ◽  
...  
Keyword(s):  
Financial Incentive ◽  
Resource Recovery ◽  
Sub Saharan Africa ◽  
Fuel Production ◽  
Disposal Options ◽  
Sub Saharan ◽  
Drying Rates ◽  
Sludge Drying ◽  
Treatment And Disposal ◽  
Faecal Sludge

In urban Sub-Saharan Africa, the collection and transport of faecal sludge (FS) typically ends up with FS directly dumped into the urban environment, as safe treatment and disposal options are too expensive or non-existent. Resource recovery from FS treatment, such as dried FS as an industrial fuel, could provide a financial incentive to increase access to FS management services. In Dakar, Senegal, enhanced drying to reduce the footprint of drying beds for fuel production was evaluated. Greenhouses did not increase drying rates over uncovered beds, however, daily mixing of FS on the surface of the beds resulted in a 6 day reduction to achieve 90% total solids (TS). FS was dried to 90% TS in 2 weeks for loading rates of 100 kg TS/m2*year, and 3 weeks for 150 kg TS/m2*year. The results indicate that with simple but innovative adaptations, footprints of treatment plants could be reduced and/or treatment capacities increased by 20%. FS can be adequately dried in Dakar to produce fuel, meaning 8.25 tons of dried FS could currently be produced daily, contributing 31,403 GJ/year fuel to industries. In addition, this financial incentive could reduce FS that is currently discharged untreated to the environment, and provide an additional 116,705 GJ/year.

scholarly journals To char or not to char? Review of technologies to produce solid fuels for resource recovery from faecal sludge

2019 ◽  
Vol 9 (2) ◽  
pp. 210-224 ◽  
Author(s):  
Nienke Andriessen ◽  
Barbara J. Ward ◽  
Linda Strande
Keyword(s):  
Solid Fuel ◽  
Calorific Value ◽  
Resource Recovery ◽  
Hydrothermal Carbonization ◽  
Pilot Scale ◽  
Market Potential ◽  
Sub Saharan Africa ◽  
Combustion Technology ◽  
Sub Saharan ◽  
Faecal Sludge

Abstract Resource recovery from faecal sludge can take many forms, including as a fuel, soil amendment, building material, protein, animal fodder, and water for irrigation. Resource recovery as a solid fuel has been found to have high market potential in Sub-Saharan Africa. Laboratory- and pilot-scale research on faecal sludge solid fuel production exists, but it is unclear which technology option is most suitable in which conditions. This review offers an overview and critical analysis of the current state of technologies that can produce a dried or carbonized solid fuel, including drying, pelletizing, hydrothermal carbonization, and slow-pyrolysis. Carbonization alters fuel properties, and in faecal sludge, it concentrates the ash content and decreases the calorific value. Overall, a non-carbonized faecal sludge fuel is recommended, unless a carbonized product is specifically required by the combustion technology or end user. Carbonized and non-carbonized fuels have distinct characteristics, and deciding whether to char or not to char is a key judgement in determining the optimal solid fuel technology option. Based on the existing evidence, this review provides a decision-making structure for selecting the optimal technology to produce a faecal sludge solid fuel and identifies the top research needs prior to full-scale implementation.

scholarly journals Inhibition of Ammonia and Hydrogen Sulphide Using Plant Waste Materials for Faecal Sludge Odour Control in Dry Sanitation Toilet Facilities

2021 ◽  
Author(s):  
Bernice Mawumenyo Senanu ◽  
Patrick Boakye ◽  
Sampson Oduro-Kwarteng ◽  
Divine Damertey Sewu ◽  
Esi Awuah ◽  
...  
Keyword(s):  
Rice Husk ◽  
Hydrogen Sulphide ◽  
Cost Effective ◽  
Sub Saharan Africa ◽  
Open Defecation ◽  
Sub Saharan ◽  
Sanitation Systems ◽  
S Peak ◽  
Faecal Sludge ◽  
Peak Value

Abstract On-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilet as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two (2) dry sanitation facilities (T1 and T2). The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed high odour levels, beyond and below the threshold limit for unpleasantness for humans on H2S (peak value: T1 = 3.17 ppm; T2 = 0.22 ppm > 0.05 ppm limit) and NH3 (peak value: T1 = 6.88 ppm; T2 = 3.16 ppm < 30 ppm limit), respectively. The biomasses exhibited low pH (acidic = 5-7) whereas the biochars and ashes had higher pHs (basic = 8-13). Acidic biocovers generally reduced NH3 emission significantly (12.5% to 64.8%) whereas basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%). In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that locally available waste plant-based materials, like sawdust, when converted to biochar can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.

scholarly journals Faecal sludge as a solid industrial fuel: a pilot-scale study

2017 ◽  
Vol 7 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Moritz Gold ◽  
Daniel Isaac Waya Ddiba ◽  
Alsane Seck ◽  
Patrick Sekigongo ◽  
Alassane Diene ◽  
...  
Keyword(s):  
Calorific Value ◽  
Pilot Scale ◽  
Wastewater Sludge ◽  
Sub Saharan Africa ◽  
Clay Bricks ◽  
Financial Benefits ◽  
Treatment Technologies ◽  
Sub Saharan ◽  
Faecal Sludge

Revenues from faecal sludge (FS) treatment end products could offset treatment costs and contribute to financially viable sanitation. In urban sub-Saharan Africa, energy-producing resource recovery has the potential to generate greater revenue than use as soil conditioner. In contrast with wastewater sludge, the technical feasibility of using dried FS as solid fuel in industries has not been investigated. This study evaluated it through characterization of dried FS from drying beds and by assessing the combustion performance in two pilot-scale kilns, in Kampala and Dakar. Results from the fuel characterization demonstrate that dried FS had comparable fuel characteristics as wastewater sludge considering calorific value and ash content. The calorific values and ash contents were 10.9–13.4 MJ/kg dry matter (DM) and 47.0–58.7%, respectively. Results from pilot-scale experiments suggest that dried FS can be effective in providing energy for industries. Temperatures in pilot-scale kilns fueled by FS were 800 °C, sufficient for curing of clay bricks, and 437 °C, sufficient for waste oil regeneration. In Kampala and Dakar, an estimated 20,000 tons of FS DM per year accumulate. Tapping the industrial fuel market and financial benefits could be realized through optimization of onsite sanitation and treatment technologies.

scholarly journals Modelling Faecal Sludge Dewatering Processes in Drying Beds Based on the Results from Tete, Mozambique

2021 ◽  
Vol 13 (16) ◽  
pp. 8981
Author(s):  
Osvaldo Moiambo ◽  
Raúl Mutevuie ◽  
Filipa Ferreira ◽  
José Matos
Keyword(s):  
Low Cost ◽  
Model Parameters ◽  
African Countries ◽  
Sludge Dewatering ◽  
Climate Conditions ◽  
Cost Treatment ◽  
Sub Saharan ◽  
Sludge Drying ◽  
Sanitation Systems ◽  
Faecal Sludge

Currently, in sub-Saharan African countries, 65 to 100% of the urban population is served by on-site sanitation systems, typically pit latrines and septic tanks. Faecal sludge dewatering in drying beds is one of the most commonly adopted low-cost treatment technologies in developing countries due to favourable climate conditions in terms of temperature and radiation and because their operation and maintenance are simple. Nevertheless, research in tropical dry zones regarding these processes is scarce. In this paper, a mathematical model for faecal sludge dewatering in sludge drying beds (SDBs) focusing on gravity drainage and evaporation processes is presented and discussed. Experimental campaigns were carried out at a pilot site in Tete, Mozambique, to determine the model parameters. The results suggest that the model can be used to estimate, in similar situations, the dewatering process of different types of faecal sludge. The present research might be considered as a contribution to the design and operation of SDBs, supporting sludge management and allowing the estimation of drying times and optimal loading cycles, namely, the sludge thickness and final moisture content.

scholarly journals Inhibition of ammonia and hydrogen sulphide as faecal sludge odour control in dry sanitation toilet facilities using plant waste materials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bernice Mawumenyo Senanu ◽  
Patrick Boakye ◽  
Sampson Oduro-Kwarteng ◽  
Divine Damertey Sewu ◽  
Esi Awuah ◽  
...  
Keyword(s):  
Rice Husk ◽  
Hydrogen Sulphide ◽  
Cost Effective ◽  
Sub Saharan Africa ◽  
Open Defecation ◽  
Threshold Limit ◽  
Odour Control ◽  
Sub Saharan ◽  
Sanitation Systems ◽  
Faecal Sludge

AbstractOn-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilets as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two dry sanitation facilities named T1 and T2. The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed that the odour levels for H2S in both T1 (3.17 ppm) and T2 (0.22 ppm) were above the threshold limit of 0.05 ppm, for unpleasantness in humans and vice versa for NH3 odour levels (T1 = 6.88 ppm; T2 = 3.16 ppm; threshold limit = 30 ppm limit). The biomasses exhibited low pH (acidic = 5–7) whereas the biochars and ashes had higher pHs (basic = 8–13). Basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%) than acidic biocovers. The effect of pH on suppression of NH3 was determined to be statistically insignificant at 95% confidence limit. In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that biochar produced from locally available waste plant-based materials, like sawdust, can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.

scholarly journals Assessment of the faecal sludge management practices in households of a sub-Saharan Africa urban area and the health risks associated: the case study of Yaoundé, Cameroon

2019 ◽  
Vol 13 (5) ◽  
pp. 1
Author(s):  
Wilfried Arsène Letah Nzouebet ◽  
Ebenezer Soh Kengne ◽  
Guy Valerie Djumyom Wafo ◽  
Chistian Wanda ◽  
Andrea Rechenburg ◽  
...  
Keyword(s):  
Urban Area ◽  
Health Risks ◽  
Management Practices ◽  
Sub Saharan Africa ◽  
Sludge Management ◽  
Sub Saharan ◽  
Faecal Sludge

scholarly journals Private emptiers' perspectives on the regulation of faecal sludge emptying services in Sub-Saharan Africa

2021 ◽  
Author(s):  
Alix Lerebours ◽  
Rebecca Scott ◽  
Kevin Sansom
Keyword(s):  
Delphi Study ◽  
Sub Saharan Africa ◽  
Regulatory Mechanisms ◽  
Willingness To Accept ◽  
Urban Residents ◽  
The Public ◽  
Fair Competition ◽  
Environmental Health Risks ◽  
Sub Saharan ◽  
Faecal Sludge

Abstract Using a two-round Delphi study, 15 faecal sludge emptiers from 11 cities in Sub-Saharan Africa have expressed views on the regulation of faecal sludge emptying services. Their responses identify the regulatory mechanisms in place where they operate, their opinions of these mechanisms, and prioritisation of those considered most useful to enable safe emptying services for all urban residents. All respondents (100%) support regulation, with 80% finding the regulation they encounter useful. However, all also state that regulatory mechanisms should extend beyond only rules and sanctions, to incorporate support, incentives and pro-poor mechanisms. This study is the first to provide a first-hand account of Sub-Saharan African private emptiers' willingness to accept clear regulation. In that regard, regulation should be flexible and adapted to the context in order to facilitate fair competition, safe and satisfactory service for customers and workers alike, and to alleviate the public and environmental health risks.

scholarly journals Operating parameters for three resource recovery options from slow-pyrolysis of faecal sludge

2018 ◽  
Vol 8 (4) ◽  
pp. 707-717 ◽  
Author(s):  
M. Gold ◽  
M. Cunningham ◽  
M. Bleuler ◽  
R. Arnheiter ◽  
A. Schönborn ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Lignocellulosic Biomass ◽  
Hold Time ◽  
Resource Recovery ◽  
Operating Parameters ◽  
Pathogen Inactivation ◽  
Fuel Production ◽  
Slow Pyrolysis ◽  
Soil Enhancement ◽  
Faecal Sludge

Abstract Slow-pyrolysis is a treatment technology that is being explored for treatment of faecal sludge (FS) from onsite sanitation technologies. Next to pathogen inactivation, the technology produces treatment products. Revenues from these products could offset treatment costs and contribute to financially viable sanitation. In comparison to lignocellulosic biomass and other biowastes, little information is available on operating parameters for FS pyrolysis to produce char for different resource recovery options. In Kampala, Uganda, this bench-scale study investigated the influence of two major operating parameters, hold time (10, 20 and 40 minutes) and pyrolysis temperature (350, 450 and 600 °C) for pyrolysis of FS into char for solid fuel production, soil enhancement and carbon sequestration. Hold time: 10 min was the most suitable hold time for all resource recovery options as char characteristics had only minor variations between hold times. Temperature: Char characteristics identified 350 °C as the most suitable for fuel production and 450 or 600 °C for carbon sequestration. FS char had characteristics for soil enhancement comparable to biowaste and lignocellulosic biomass chars, with heavy metal concentration exceeding guideline concentrations. The most suitable temperature needs to be selected based on plant and soil type, and legal regulations.

scholarly journals Decentralized options for faecal sludge management in urban slum areas of Sub-Saharan Africa: A review of technologies, practices and end-uses

2015 ◽  
Vol 104 ◽  
pp. 109-119 ◽  
Author(s):  
Swaib Semiyaga ◽  
Mackay A.E. Okure ◽  
Charles B. Niwagaba ◽  
Alex Y. Katukiza ◽  
Frank Kansiime
Keyword(s):  
Urban Slum ◽  
Sub Saharan Africa ◽  
Sludge Management ◽  
Sub Saharan ◽  
Faecal Sludge ◽  
Slum Areas ◽  
End Uses
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