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Novel semi-decentralised mobile system for the sanitization and dehydration of septic sludge
Published in Eva Kocbek, A Novel Approach to Sludge Treatment using Microwave Technology, 2021
Implementing effective strategies for preventing outbreaks of contagious and potentially deadly diseases is a priority for sanitation providers worldwide. Faecal sludge (FS) contain various types of pathogenic organisms such as bacteria, viruses, and parasites; therefore, they need to be properly treated and disposed in an environmentally sound manner (Jiménez et al., 2009). Their proper collection, treatment, and disposal has significantly contributed to strengthening public health (Sykes et al., 2015). Particularly, for those persons living under low-income (Ingallinella et al., 2002; Jiménez et al., 2010). Pit latrines and septic tanks are the most common alternatives worldwide for FS collection. However, such collection facilities enable only the separation of faeces from human contact providing marginal treatment; thus, if not properly treated at a later stage, such large amounts of FS only accumulate creating a subsequent waste disposal problem (Ingallinella et al., 2002; Jiménez et al., 2010; Rose et al., 2015).
Contextualizing the Sanitation Problem
Published in Pedi Chiemena Obani, Strengthening the Human Right to Sanitation as an Instrument for Inclusive Development, 2018
Although the pathogens contained in the faecal sludge undergo some natural degradation onsite, there is need for further treatment before reuse or disposal, to prevent pollution (Tilley 2008). While the type of sludge treatment required depends on the concentrations of pollutants and pathogens, legal requirements including the terms of the discharge consent, and the proposed use of the effluent, most treatment technologies often combine both physical processes, like the removal of large particles by coarse screening or the sedimentation of particles through the force of gravity, and biochemical processes such as aerobic and anaerobic degradation (Mengistu, Simane, Eshete & Workneh, 2015; Parkinson et al., 2008). The effluent from these processes may be further subjected to tertiary treatment to facilitate the removal of nitrogen, phosphorus, and heavy metals or other industrial pollutants (Fan, Zhou & Wang, 2014; Vinneras 2007). Sludge treatment may result in a solid fraction which requires additional treatment before reuse, and a liquid fraction which requires polishing treatment in order to meet legal requirements for discharge consent or to prevent negative environmental impacts where infiltration of effluents is permissible (Parkinson et al., 2008). Short term alternatives are also available where the required treatment level cannot be achieved before reuse, including restricting the types of crops irrigated with wastewater, employing drip irrigation, and equipping farm workers with protective gear (Parkinson et al., 2008).
Inequality Beyond the Toilet
Published in Oliver Cumming, Tom Slaymaker, Equality in Water and Sanitation Services, 2018
The primary purpose of sanitation facilities is to provide safe separation of feces from human contact.1 To accomplish this goal, human waste must be safely contained along the entire sanitation chain, including at the sanitation facility itself using onsite storage, emptying of the storage and transport, and downstream treatment before disposal or reuse.2 However, in the world’s poorest countries, the sanitation sector has to-date invested more on delivery of household-level sanitation facilities (e.g. slab or toilet and associated superstructure) and improvement of toilet coverage than wastewater and sludge management.3,4 Historically the investment in downstream sanitation infrastructure has been highly subsidized, large public works.4 The majority of households with sanitation, even urban households, are served by pit latrines, septic tanks, or other on-site systems that retain biosolids (sludge) that accumulates and must be safely managed.5,6 Thus, fecal sludge management (FSM) services are critically important for reducing exposure risks among communities. Many of the world’s poorest people lack available, accessible, and affordable ways to manage fecal sludge, making them, their communities, and neighboring communities disproportionately more vulnerable to diarrheal disease, enteric infection, and longer term sequelae. Notably, those living in areas with high population density, annual flooding, or nearby dumpsites are the most at risk from poor management of fecal wastes. This chapter will describe the inequalities in availability, accessibility, and affordability of fecal waste management services and their consequences for the poorest of the poor. We conclude with a discussion of policy and measurement needs, in the context of the sustainable development goals (SDGs), to ensure successful delivery of safely managed sanitation in an equitable fashion.
Permeable membrane dewatering of faecal sludge from pit latrines at a transfer station in Nairobi, Kenya
Published in Environmental Technology, 2022
Leandra Rhodes-Dicker, Barbara J. Ward, Wali Mwalugongo, Lindsay Stradley
Approximately 2.8 billion people worldwide rely on onsite sanitation services, or sanitation services which are not connected to a sewer [1]. In Nairobi, Kenya, it is estimated that 46% of the population is served by onsite sanitation [2]. Faecal sludge from onsite sanitation services is defined as the excreta and blackwater collected in the containment (e.g. pit latrine or septic tank), and can also include greywater and trash [3]. In most cases, proper management of faecal sludge from these onsite sanitation services is lacking [3]. According to the Shit Flow Diagram (SFD) for Nairobi, approximately 93% of the onsite sanitation systems are releasing untreated waste streams into the surrounding environment, accounting for 2/3 of all untreated waste in Nairobi [2]. Cities are looking for ways to improve faecal sludge management to support growing urban populations and to progress in Sustainable Development Goal 6 [4].
Water and sanitation in Dhaka slums: access, quality, and informality in service provision
Published in Water International, 2020
Sabrina Sharmin Haque, Monica Yanez-Pagans, Yurani Arias-Granada, George Joseph
On sanitation, open defaecation and use of unimproved sanitation technology is minimal in Dhaka slums. However, there is a high dependence on shared or public toilets. Over 90% of households share sanitation facilities, and the average ratio of households to sanitation facilities is 16 to 1. Using JMP standards to exclude improved sanitation that is shared between two or more households, only 9% have access. These findings suggest that there is need to reduce shared sanitation, or at least reduce the sharing ratio and improve the management of public toilets. When considering faecal sludge management, we estimate that 2% have access to the JMP’s conceptualization of ‘safely managed sanitation’. The issue of safe faecal sludge management is not limited to slum communities. One study estimates that 2% of the human excreta in Dhaka is safely managed, while the rest is discharged into open water. This is mostly due to the lack of regular maintenance of on-site sanitation facilities such as pit latrines and septic tanks (Blackett et al., 2014). Policy makers have urged better faecal sludge management by implementing city-wide sanitation initiatives that include both on-site and off-site sanitation technologies. It is vital that slum communities are also included in these strategies and that formal, regulated faecal sludge management services are made available to residents.
Enhancing faecal sludge dewaterability and end-use by conditioning with sawdust and charcoal dust
Published in Environmental Technology, 2018
Swaib Semiyaga, Mackay A. E. Okure, Charles B. Niwagaba, Philip M. Nyenje, Frank Kansiime
Sanitation needs of over 80% of the urban population in sub-Saharan Africa (SSA) countries are met by use of some form of on-site sanitation technology, such as septic tanks and pit latrines [1,2]. Consequently, pit latrines are the dominant excreta disposal technologies in urban slums (densely populated areas in cities, inhabited by the poor) of low-income SSA countries [3,4]. When these pits are full, large quantities of semi-solid slurry material known as faecal sludge (FS) is generated, often mixed with non-faecal materials (solid wastes) that are deposited in the pits [2]. The users and/or owners face challenges, among which are the high costs of emptying and subsequent transportation of FS to treatment facilities outside of the slums due to high density of housing units and long haulage distances to treatment facilities [5]. A number of slum dwellers resort to emptying FS in the living environment, which is not only a high risk to public health, but also environmental pollution. Such costs and risks can be minimised by adoption of decentralised treatment of FS within urban slums [6]. However, dewatering (solid–liquid separation) forms a crucial part in decentralised treatment of FS since it contains >90% water [7]. Dewatering reduces solid fraction volumes and subsequently the costs of transportation and handling [8].