Dewaterability of faecal sludge and its implications on faecal sludge management in urban slums

Semiyaga, Swaib; Okure, Mackay; Niwagaba, Charles; Nyenje, Philip M.; Kansiime, Frank

doi:10.1007/s13762-016-1134-9

Cited by 30 publications

(21 citation statements)

References 35 publications

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“…The mean and median values of the physical and chemical properties were slightly lower than the values reported in the literature (Bassan et al 2013;Appiah-Effah et al 2014;Semiyaga et al 2017;Prasad et al 2021;Ward et al 2021) but were within the range identified in studies in Kampala (Strande et al 2018), Vietnam (Gold et al 2018), and selected cities in developing countries (Koné & Strauss 2004). Strande et al (2018) found that households with access to a piped water connection seem to have slightly diluted faecal sludge, resulting in lower TS concentration.…”

Section: Physicochemical Characteristics Of Faecal Sludgementioning

confidence: 47%

Factors influencing physicochemical characteristics of faecal sludge in Phnom Penh, Cambodia

Chea

Vinnerås

Zurbrügg

et al. 2021

Journal of Water, Sanitation and Hygiene for Development

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Comprehensive knowledge of faecal sludge characteristics is needed for sludge management planning, but it is lacking for the city of Phnom Penh, Cambodia. Thus, this study characterised physicochemical properties of faecal sludge from households in Phnom Penh and related these to sludge containment unit type, unit age, connectedness to the urban drainage network, type of wastewater captured, watertight containment units, number of users, and emptying practices. In total, 194 faecal sludge samples collected during containment unit emptying were analysed for physicochemical parameters. Information on containment units was collected in a survey of emptiers and users. Mean values of faecal sludge chemical parameters were found to be slightly lower than previously reported values for low-/middle-income countries, whereas physicochemical properties were within similar ranges. The main factor influencing organic matter content in faecal sludge was containment unit connection to the urban drainage network, whereas emptying practice and capture of only blackwater affected nutrient levels. The concentrations of nutrients and organic pollutants greatly exceeded Cambodian discharge standards for wastewater. This causes environmental impacts, so treatment is needed before discharge. The faecal sludge characteristics and influencing factors identified here can serve as a baseline for sanitation stakeholders planning faecal sludge management systems in Phnom Penh and similar cities.

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Section: Physicochemical Characteristics Of Faecal Sludgementioning

confidence: 47%

Factors influencing physicochemical characteristics of faecal sludge in Phnom Penh, Cambodia

Chea

Vinnerås

Zurbrügg

et al. 2021

Journal of Water, Sanitation and Hygiene for Development

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“…The cake solids were determined using a centrifuge (MISTRAL1000 type, UK). A 50 mL FS sample was centrifuged at 3,000 rpm for 20 min, which corresponds to 1,500 g (Semiyaga et al 2017). The supernatant was decanted, and the wet and oven-dried (1050C) cake weights were analyzed using the standard method to determine the per cent solids content (wet basis) in the centrifuged cake.…”

Section: Dewatering Performancementioning

confidence: 99%

A multiple regression model for prediction of optimal dose of Moringa Oleifera in faecal sludge dewatering

Doglas

Kimwaga

Mayo

2021

Water Practice and Technology

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Moringa Oleifera (MO) is a highly effective conditioner in the dewatering of Fecal sludge (FS). However, the model for the prediction of its optimal dose has not yet been documented. This article presents the results of the developed model for the prediction of MO optimal doses. The developed model was based on assessing the FS parameters and MO stock solution. The FS samples were obtained from a mixture of a pit latrine and septic tank and were analyzed at the water quality laboratory of the University of Dar es Salaam. The multiple linear regression model was used to establish a relationship between MO optimal dose as a function of FS characteristics (pH, Electrical Conductivity, Total Solids and Total Suspended Solids) and concentration of MO stock solution. The results indicated that the main contributing factors which determine the MO optimal dose were the concentration of MO stock solution, followed by pH of FS. The model results showed a good agreement between the predicted and observed MO optimal dose with a coefficient of determination of R2 = 0.72 and 0.9 for calibration and validation respectively. Therefore, the model can be adapted to determine the MO optimal dose without running the Jar-test experiment.

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“…Preparation of FS samples before analysis involved passing them through a 5 mm sieve to remove the extraneous materials (Burton, 2007;Semiyaga et al, 2017a). The raw FS samples from lined pit latrines were characterised for total solids (TS), total volatile solids (TVS), ash content, pH, electrical conductivity (EC), sand content and bulk density (Table 1).…”

Section: Preparation Of Fs Samplesmentioning

confidence: 99%

“…Extensive usage of sedimenting centrifuges has been reported, and it has been found that suspensions containing considerable amount of fine solids of less than µm easily clog filtering centrifuges (Buerger and Concha, 2001). Semiyaga et al (2017a) reported that FS from pit latrines in Kampala slums contain over 70% fine particles of less than 45 µm, justifying the need for sedimentation centrifuge type.…”

Section: Introductionmentioning

confidence: 99%

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Optimisation of centrifuge operating conditions for dewatering physically conditioned faecal sludge from urban slums

Semiyaga

Okure

Niwagaba

et al. 2017

Environmental Technology & Innovation

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Decentralised faecal sludge (FS) dewatering in urban slums using centrifugation technology has potential to reduce public health risks and environmental pollution caused by indiscriminate disposal of untreated FS. A laboratory-scale centrifuge was applied to dewater FS from lined pit latrines, conditioned with sawdust and charcoal dust. Response surface methodology and central composite design were used to construct and model relationships between independent variables (FS volume, centrifugation time and speed) and the dependent variable (per cent cake solids) for unconditioned and conditioned (sawdust and charcoal dust) FS. The results demonstrated that the centrifugation technology can yield more per cent cake solids at reduced speeds when physically conditioned. Rotational speed was a significant parameter for unconditioned (original) (p=0.0020) and charcoal dust conditioned FS (p=0.0019). Significant parameters for sawdust conditioned FS were speed (p=0.0001) and quadratic effect of time (p=0.0494). An optimal centrifugation time of 20 minutes and centrifugation container volume of 50 mL at 70-80% full of FS for conditioned FS were obtained. The centrifugation speeds tested in this paper provide critical information for prototype design of a hand-powered centrifuge, the operating conditions and its subsequent setup. This can serve as an option for dewatering FS from commonly used sanitation facilities in urban slums, thereby enabling decentralised treatment to reduce costs of FS management and support resource recovery at the source.

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Dewaterability of faecal sludge and its implications on faecal sludge management in urban slums

Cited by 30 publications

References 35 publications

Factors influencing physicochemical characteristics of faecal sludge in Phnom Penh, Cambodia

Factors influencing physicochemical characteristics of faecal sludge in Phnom Penh, Cambodia

A multiple regression model for prediction of optimal dose of Moringa Oleifera in faecal sludge dewatering

Optimisation of centrifuge operating conditions for dewatering physically conditioned faecal sludge from urban slums

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