Fecal sludge management (FSM) is the storage, collection, transport, treatment and safe end use or disposal of fecal sludge. Together, the collection, transport, treatment and end use of fecal sludge constitute the "value chain" or "service chain" of fecal sludge management. Fecal sludge is defined very broadly as what accumulates in onsite sanitation systems (e.g. pit latrines, septic tanks and container-based solutions) and specifically is not transported through a sewer. It is composed of human excreta, but also anything else that may go into an onsite containment technology, such as flushwater, cleansing materials (e.g. toilet paper and anal cleansing materials), menstrual hygiene products, grey water (i.e. bathing or kitchen water, including fats, oils and grease), and solid waste. Fecal sludge that is removed from septic tanks is called septage.
It is estimated that one-third of the world's population is served by onsite sanitation, and that in low-income countries less than 10% of urban areas are served by sewers. In low-income countries, the majority of fecal sludge is discharged untreated into the urban environment, placing a huge burden on public and environmental health. Hence, FSM plays a critical role in safely managed sanitation and the protection of public health. FSM services are provided by a range of formal and informal private sector services providers, local governments, water authorities, and public utilities. This can also result in unreliable services with relatively high costs at the household level.
Although new technology now allows for fecal sludge to be treated onsite (see Mobile Treatment Units below) the majority of fecal sludge is collected and either disposed of into the environment or treated offsite. Fecal sludge collection can be arranged on a scheduled basis or on a call-for-service basis (also known as on-demand, on-request, or non-scheduled services). The collected fecal sludge may be manually or mechanically emptied, and then transported to treatment plants with a vacuum truck, a tank and pump mounted on a flatbed truck, a small tank pulled by a motorcycle, or in containers on a handcart. The wider use of multiple decentralized sludge treatment facilities within cities (to avoid long haulage distances) is currently being researched and piloted.
Fecal sludge is different to wastewater and cannot simply be co-treated at sewage treatment plants. Small additions of fecal sludge are possible if plants are underutilized and able to take the additional load, and facilities to separate liquids and solids are available.Strande, L., Ronteltap, M., Brdjanovic, D. (eds.) (2014). Faecal Sludge Management (FSM) book – Systems Approach for Implementation and Operation IWA Publishing, UK. . A variety of mechanized and non-mechanized processing technologies may be used, including settling tanks, planted and unplanted drying beds, and waste stabilization ponds. The treatment process can produce resource recovery end-products such as treated effluent that can be used for irrigation, co-composting as a soil conditioner, anaerobic digestion for the production of biogas, forms of dry-combustion fuel such as pellets or biochar, charcoal, biodiesel, sludge and plants or protein production as animal fodder.
Definitions Fecal sludge management refers to the storage, collection, transport, treatment, and safe end use or disposal of fecal sludge. Collectively, the collection, transport, treatment and end use or reuse of excreta constitute the "value chain" of fecal sludge management.
Fecal sludge Fecal sludge is defined very broadly as what accumulates in onsite sanitation technologies and specifically is not transported through a sewer. It is composed of human excreta, but also anything else that may go into an onsite containment technology, such as flushwater, cleansing materials and menstrual hygiene products, grey water (i.e. bathing or kitchen water, including fats, oils and grease), and solid waste. Hence, fecal sludge is highly variable, with a very wide range of quantities (i.e. produced and accumulated volumes) and qualities (i.e. characteristics). Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Fecal sludge is stored onsite, and is periodically collected and transported to a fecal sludge treatment plant, followed by safe disposal or end use. When safely managed, fecal sludge that is collected from pit latrines can also be called "pit latrine sludge", whereas fecal sludge collected from septic tanks can also be called "septic tank sludge" or "septage".
Septage Septage or "septic tank sludge" is fecal sludge that is accumulated and stored in a septic tank. Septage tends to be more dilute, as septic tanks are typically used with flush toilets (blackwater) and can also include grey water. Septic tanks also tend to have less solid waste, as they only receive things that can be flushed down a toilet (e.g. toilet paper). When operating as designed, a sludge blanket layer accumulates on the bottom of the tank, a scum layer that contains fats, oil and grease accumulates at the top, and the effluent or supernatant contains less solids.
Septage is periodically removed (with a frequency depending on tank capacity, system efficiency, and usage level, but typically less often than annually) from the septic tanks by specialized vehicles known as vacuum trucks. They pump the septage out of the tank, and transport it to a local fecal sludge treatment plant. It can also be used by farmers for fertilizer, or stored in large septage waste storage facilities for later treatment or use on crops.
The term "septage" has been used in the United States since at least 1992.USAID (1992), "Guide to Septage Treatment and Disposal", United States Environmental Protection Agency. It has also been used in projects by the United States Agency for International Development in Asia.AECOM International Development, Inc. and the Department of Water and Sanitation in Developing Countries (Sandec) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag) (2010), "A Rapid Assessment of Septage Management in Asia - Policies and in India, Indonesia, Malaysia, the Philippines, Sri Lanka, Thailand, and Vietnam". Another definition of septage is: "A historical term to define sludge removed from septic tanks."Tilley, E., Ulrich, L., Lüthi, C., Reymond, Ph. and Zurbrügg, C. (2014). Compendium of Sanitation Systems and Technologies (2nd Revised Edition). Swiss Federal Institute of Aquatic Science and Technology (Eawag), Duebendorf, Switzerland
In India some government policy documents are using the term FSSM for "Fecal sludge and septage management".National Institute of Urban Affairs and Urban Management Centre (2018), "Faecal Sludge and Septage Management: An Orientation Module".
Purposes and benefits
The overall goal of FSM is the protection of public and environmental health. FSM forms a key component of city-wide inclusive sanitation (CWIS), which considers all types of sanitation technologies in order to provide equitable, safe, and sustainable sanitation for everyone. CWIS employs a service delivery approach along the entire service chain, rather than just infrastructure provision.
Adequately and safely managed fecal sludge has the following benefits: Reduce the potential for human contact with fecal-borne pathogens by improving the functioning of onsite sanitation systems; Minimize odors and nuisances, and the uncontrolled discharge of organic matter from overflowing tanks or pits; Reduce indiscriminate disposal of collected fecal sludge; Production and sale of the end-products of the sludge treatment process. These products may include recycled water for agriculture and industry, soil conditioners from composting or co-composting materials, and energy products such as biogas, biodiesel, charcoal pellets, industrial powdered fuel, or electricity. Stimulate economic development, and job creation and livelihood opportunities, while addressing the issues of the social stigma and operator health and safety that continue to impact informal workers. This can also include jobs for contractors and equipment installers; for sanitation workers such as sludge collection personnel including drivers and emptiers; and for treatment and reuse systems operators.
Developments in the sector Since the wider recognition of the importance of sanitation, marked by the UN declaring 2008 as the 'Year of Sanitation', there has been a steady increase in commitment, uptake, implementation, and knowledge generation in non-sewered sanitation. The incorporation of the entire sanitation management service chain in the Sustainable Development Goal (SDG) 6, as opposed to just providing access to toilets, has further established acknowledge of the importance of FSM. The SDGs were launched in 2015, and SDG 6 is for "clean water and sanitation for all by 2030"), launched in 2015, has further established acknowledgement of its importance. There has also been an increase in the incorporation of fecal sludge management in national regulations and development agency agendas, increased funding from foundations and governments, and implementation of infrastructure and service provision.
There has been a rapid increase in evidence-based research and journal publications on the topic (e.g. for Africa and AsiaOxfam (2016), "Septage Management Leader's Guidebook – Philippines Edition".WRC (2015). The Status of Faecal Sudge Management in Eight Southern and East African Countries. WRC Report No. KV 340/15, prepared for the Sanitation Research Fund for Africa (SRFA) Project of the Water Research Commission (WRC), Pretoria, South Africa, ). There are rapidly evolving technology developments along the entire service chain. Some have the potential to alter the existing service chain, such as container-based sanitation, decentralized options, and innovations developed through the Bill & Melinda Gates Foundation 'Reinvent the Toilet Challenge' since at least 2012.Chowdhry, S., Koné, D. (2012). Business Analysis of Fecal Sludge Management: Emptying and Transportation Services in Africa and Asia – Draft final report. Bill & Melinda Gates Foundation, Seattle, Wash.
Curriculums have been, and are continuing to be, developed and implemented. Initiatives include the Global Sanitation Graduate School, and freely available online courses, such as the Sandec MOOC series.
In 2014, the SFD Initiative, funded by a grant by the Bill and Melinda Gates Foundation, was created to develop and promote the use of shit flow diagrams.
Challenges
In many LMICs, fecal sludge is still not properly managed. This may be due to a lack of mandated institutions and low awareness of the impact of poor sanitation; a lack of technical expertise and experience; an inability to source funds for to purchase of vacuum trucks and treatment, as well as a lack of knowledge necessary to initiate and implement successful FSM programs. Another factor is that the transporting fecal sludge has a real cost to vacuum truck operators and there is thus an incentive to dispose of the untreated waste into the environment (primarily into waterways, but also directly onto the land.) Failure to properly manage fecal sludge can result in the poor performance of onsite sanitation facilities (OSSFs), fecal sludge overflowing from containments, and the unsafe emptying and dumping of untreated fecal sludge into the environment.WIN-SA (2011). What happens when the pit is full? – Developments in on-site faecal sludge management (FSM). Water Information Network South Africa
Fecal sludge contains pathogens, can generate odors, and causes surface water pollution, as well as groundwater pollution.
Components