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Sand Dam
A sand dam is a small dam built on and into the riverbed of a seasonal sand river. Its purpose is to capture and store water beneath sand: sand is transported during periods of high flow and accumulates upstream of a sand dam, resulting in additional groundwater storage capacity of riverbed and –banks. This reservoir fills during the wet season, providing water to cover dry periods. Synonyms: Sand Storage Dam
Sand River
Dry and sandy riverbeds are seasonal watercourses that transport runoff-water from catchment areas to rivers or swamps once or several times a year. Dry riverbeds are also called ephemeral streambeds, seasonal watercourses or sand rivers. Most of the rainwater that is being transported downstream in riverbeds occurs as floods of several meters height. Sand rivers are only suitable as sand dams if coarse sand is available and the river is bedded on impervious bedrock (or clay like black cotton soil). Synonyms: Dry Riverbeds, Ephemeral Streambeds, Seasonal Watercourses
In order to prevent ingress to the aquifer of any potential contaminants from the surface via the borehole itself, it is necessary to seal the uppermost section of the annulus between the outermost casing string and the wall of the borehole. The sealing material commonly used is cement grout or a bentonite mixture. It is also prudent to ensure that no potential contaminants can enter the borehole from the surface via the space between any other internal casing strings.
The framework proposed by the International Water Association (IWA) task force for the analysis and selection of appropriate sanitation systems is called Sanitation 21. It is a comprehensive approach for the assessment of planned or existing sanitation situations. However, it does not provide in-depth guidance for planners and operators. The Sanitation 21 task force argues that technical planners and designers have to develop more sophisticated planning systems that respond to the needs of rapidly growing cities. As regards the human and political context, this will require a change in the manner of making technical decisions. Quality and effectiveness of sanitation investments are not particularly about technologies (although the appropriate application of technology is important), but are rather about developing an explicit understanding of what the objectives of a system are and then designing a system which meets those objectives. Synonyms: Sanitation21
To mitigate the effects of lacking sanitation, various approaches have been developed that should help people to improve their sanitary situation. These approaches include guidelines on how to conceptualise, plan and carry out sanitation projects.
Sanitation System
Sanitation systems are a combination of functional units that together allow managing and reusing or disposing the different waste flows (i.e. waste, organic waste, excreta, blackwater, greywater, etc.) from households, institutions, agriculture or industries in order to protect people and the environment. Sanitation systems are designed to approach the whole water and nutrient cycle, from the toilet user up to the final point of reuse or disposal, including the main steps of wastewater generation, collection, treatment and reuse. Thus, sanitation systems are more than the toilets and has to do with management issues including treatment and reuse of waste and wastewaters, comfort, affordability, health aspects, gender aspects, etc.
Sanitised
Hygienised describes any wastewater product (e.g. faeces, blackwater etc.) that has undergone a transformation which turns it into a hygienically safe product for handling, reuse or disposal. Synonyms: Hygienised, Hygienized, Sanitized
SARAR approach
SARAR is an education/training methodology for working with stakeholders at different levels to engage their creative capacities in planning, problem solving and evaluation. The acronym SARAR stands for the five attributes and capacities that are considered the minimum essentials for participation to be a dynamic and self-sustaining process: Self-esteem, a sense of self-worth as a person as well as a valuable resource for development; Associative strength, the capacity to define and work toward a common vision through mutual respect, trust, and collaborative effort; Resourcefulness, the capacity to visualise new solutions to problems even against the odds, and the willingness to be challenged and take risks; Action planning, combining critical thinking and creativity to come up with new, effective, and reality-based plans in which each participant has a useful and fulfilling role; Responsibility, for follow-through until the commitments made are fully discharged and the hoped-for benefits achieved. SARAR was developed during the 1970s and 1980s by Dr. Lyra Srinivasan and colleagues for a variety of development purposes. The major work describing the methodology for the water and sanitation sector is entitled Tools for Community Participation, A Manual for Training Trainers in Participatory Techniques.
The screening of wastewater consists in the removal of large matter such as napkins, rags and other materials that may damage mechanical equipment further down the treatment plant. It is generally done by sieving the influent on bar screens, which consist of vertical bars separated by a distance of about 1 cm.
Scum is the general name given to the floating layer of dirt or froth on the surface of a liquid. It is most noticeable in septic tanks where distinct layers of scum, water, and sludge form over time.
The application of a disinfectant, either at the exit of the treatment plant or in the distribution system, with the objective of ensuring that a disinfectant residual is present throughout the distribution system, thus preventing recontamination of water.
Seeding refers to the introduction of a sample of a living and active community of microorganisms (an inoculum) into a reactor in order to initiate a biological degradation process (e.g. anaerobic digestion, activated sludge). The microorganism, if they feel comfortable, will grow and create the optimum conditions for the metabolic degradation or elimination of pollutants entering the tank. Synonyms: Inoculation
SARAR stands for self-esteem, associate strengths, resourcefulness, action planning and responsibility. SARAR is a participatory approach to adult education that builds on local knowledge and strengthens local ability to assess, prioritise, plan, create, organise, and evaluate. SARAR's purpose is to (a) provide an approach to team building through training, (b) encourage participants to learn from local experience rather than from external experts, and (c) empower people to initiate action.
Semi-arid climate generally describes regions (non-polar) that receive low annual rainfall (from 250 to 500 mm) and that are characterised by short-grass or scrub vegetation.
(Semi-)centralised drinking water treatments include middle- and large-scale units that produce water for several households and consequently required most often more operation and maintenance.
Semi-centralised System
Centralised-systems correspond to the conventional wastewater management concept, consisting of a water-borne wastewater collection system (sewers) leading to a central treatment plant. Apart from its proven benefits, the centralised wastewater management system is nothing else than a transportation system for human excreta and industrial wastes to a central discharge place or a treatment unit. Using valuable drinking water as transport medium, these systems are wasteful not only of water but also of human waste elements that can be easily treated and reused. Semi-centralised systems are like centralised systems, but parts of the treatment processes are done on a decentralised level for clusters of households. This can significantly simplify the collection (/distribution) system what results generally in a reduction of construction costs (e.g. small-bore sewer systems). Synonyms: (Semi-) Centralised Wastewater Treatment, Semi-central System
Semi-circular bunds are well suited for planting trees due to their half-moon shape. They collect water runoff and therefore increase soil moisture and prevent soil erosion. They bunds are usually filled with organic matter to add nutrients for improved crop yield. Synonyms: Bunds
Allowing passage of certain, especially small, molecules or ions but acting as a barrier to others. Use of biological and synthetic membranes. Synonyms: Semi-permeable
Separate sewerage consists in the separate collection of municipal wastewaters (blackwater from toilets, greywater and industrial wastewater) and surface run-off (rainwater and stormwater). The separate collection prevent the overflow of sewer systems and treatment stations during rainy periods and the mixing of the relatively little polluted surface run-off with chemical and microbial pollutants from the municipal wastewater. The design of the sewers and the (semi-) centralised treatment stations thus needs to consider the volume of the wastewater only and the surface run-off and rainwater can be reused (e.g. for landscaping or agriculture) after a simplified treatment.
Septage
Contents of septic tanks (usually comprising settled and floating solids as well as the liquid portion).
SBRs are wastewater treatmentreactors based on an activated sludge process where all the different stages of nitrification/denitrification, settling and separation take place in the same reactor but dislocated in time. The treatment consists of a cycle of five stages: fill, react, settle, draw and idle. The reactor containing active biomass is first charged with influent, closed and than aerated to satisfy the oxygen demand of the wastewater. During this phase, bacteria oxidize the organic matter as in activated sludge systems. Then, aeration is finally stopped to allow sludgesettling. In the next step, the water and the sludge are separated by decantation and the clear layer (supernatant) is discharged from the reaction chamber. Depending on the rate of sludge production, some sludge may also be purged. After a phase of idle the tank is filled with a new batch of wastewater. At least two tanks are needed for the batch mode of operation as continuous influent needs to be stored during the operation phase. SBRs are suited to smaller flows, because the size of each tank is determined by the volume of wastewater produced during the treatment period in the other tank and the need to be seeded for starting up reactors. Synonyms: SBR
The service delivery approach is a conceptual approach taken at sector level to the provision of rural water supply services, which emphasises the entire life-cycle of a service, consisting of both the hardware (engineering or construction elements) and the software (awareness raising, capacity building, institutional support) required to provide a certain level of access to water.
The settlement phase describes the fourth and last period after an emergency. It can last for several years after an event. It typically includes disaster preparedness activities and reduction of vulnerability towards different hazards. The exact duration depends on the event and the context of the emergency.
An open channel or underground pipe used to carry off drainage water and sewage.
Sewer Discharge Stations
A sewer discharge stations is a point along the sewermain that can be legally accessed and used for discharging septage and sludge directly into the sewer so that it can be transported to a (semi-)centralised treatment facility. Sewer discharge stations are intermediate transfer points for sludge that cannot easily be transported to a dedicated treatment facility. Sludge can be dumped in a local discharge station rather than either dumping it illegally.
The pipe through which water from an engine is delivered to an elevated level. Synonyms: Sewer Rising Main
Sewer Pumping Stations
Pumping stations in sewage collection systems, also called lift stations, are designed to handle raw sewage that is fed from underground gravity pipelines. Sewage is fed into and stored in an underground pit, commonly known as a wet well. Electrical instrumentation is installed to detect the level of sewage. When the level rises to a predetermined point, a pump will be started to lift the sewage upward through a pressurized pipe system (sewer force main or rising main) from where it is discharged into a gravity manhole again. From here the cycle starts all over again until the sewage reaches its point of destination – usually a treatment plant. Pumping stations thus are used to move wastewater to higher elevations. Synonyms: Lift Stations
The simplest and cheapest method of lifting groundwater from an open dug well or surface water source is by means of a rope and a bucket. The job of drawing water from the well can be made easier by adding a “windlass” (a horizontal cylinder with a winch which can be turned to raise the bucket on a rope) or a “Shadouf” (an upright frame with a long pole suspended on top with the bucket hanging from one end and a weight which serves as the counterpoise of a lever at the other).
The basic Shadouf consists of a rope, pole, bucket and counterweight and is capable of lifting water up to 4 metres. The counterweight can be just a heavy rock, however, in the more advanced picottah design, one person guides the bucket while the other acts as a moving counterweight. The Shadouf is generally used for lifting water from unlined wells, streams or ponds for irrigating small fields. Approximately 60 litres/min can be lifted from a depth of 2 to 3 metres.
Advantages
• A relatively inexpensive traditional technology, which can be locally made and maintained.
• Easy to operate
• Relatively efficient (30-60%)
Disadvantages
• Limited to lifts of less than 4 metres
• Limited water yield, 60 l/min suitable for small fields
A short rotation plantation is an integrated agro-forestry land-use system combining biomass production with wastewater use and purification. Fast growing tree species are managed in short coppicing cycles. These non-food/non-fodder crops have a high demand for nutrients and water, which may alternatively be met by reusing pre-treated wastewater and sewagesludge, enabling a sustainablenutrient recycling. The woody biomass produced can be used as a renewable and clean fuel for heat and power generation, or for further processing into liquid biofuels. Synonyms: SRP
Simplified sewer systems are similar to conventional sewer systems but constructed with much less conservative design criteria, allowing significant reduction of costs. Typical simplification consists in smaller pipe diameters, flatter pipe gradients, shallow pipe depths, fewer access chamber and smaller pumps. They are particularly adapted to solid-free sewer systems. Synonyms: Simplified Sewer, Simplified Sewer System
Simplified sewers describe a sewerage network that is constructed using smaller diameter pipes laid at a shallower depth and at a flatter gradient than conventional sewers. The simplified sewer allows for a more flexible design associated with lower costs and a higher number of connected households. This might be particularly of interest in rocky areas or where the groundwater table is high. Simplified sewers can be built and repaired with locally available materials. However, expert design and construction supervision is essential and repairs and removal of blockages may be required more frequently than for a conventional gravity sewer. Moreover, effluent and sludge (from interceptors) requires secondary treatment and/or appropriate discharge. Synonyms: Condominial Sewers
A siphon is instrument, usually in the form of a tube bent to form two legs of unequal length, for conveying liquid over the edge of a vessel and delivering it at a lower level. Siphons may be of any size; they are used in civil engineering to transfer water or other fluids over elevations. The action depends upon the influence of gravity (not, as sometimes thought, on the difference in atmospheric pressure—a siphon will work in a vacuum) and upon the cohesive forces that prevent the columns of liquid in the legs of the siphon from breaking under their own weight. Water has been lifted more than 35 feet (11 m) by a siphon.
Sitter
General name given to someone who prefers to sit on the the toilet, rather than squat over it.
To develop adequate and sustainable solutions, the situation and current problems have to be analysed thoroughly. A number of tools such as SWOT, Problem Ranking etc. can help in this analysis.
Slow Sand Filter
Slow sand filtration is a biological, physical and chemical purification process. As the water flows through a porous filter-bed, its quality improves considerably by reduction of the number of micro-organisms, viruses, protozoa, turbidity, heavy metals, organic matter, iron and arsenic. Synonyms: SSF
Abbreviation: SSF
Slow-release Fertiliser
A compound, which, dissolves slowly due to its low solubility, releasing nutrients constantly over time.
Sludge
Sludge is the solids that are produced from human excreta or from the treatment of wastewater. It is the thick, viscous layer of materials that settles at the bottom of septic tanks, ponds, sewerage and wastewater treatment systems. Sludge is comprised mostly of organics, but also sand, grit, metals, and various chemical compounds.
Sludge thickening consists in the separation of solids and liquids in order to process each separately (e.g. composting for the solid and waste stabilisation ponds or infiltration for the liquid). It can be done in thickening ponds (settling tanks or sedimentation ponds) or planted and unplanted drying beds.
Sludge Volume Index (SVI) is a very important indicator that determines your control or rate of desludging on how much sludge is to be returned to the aeration basin and how much to take it out from the system. It actually serves as a very important empirical measurement that can be used as a guide to maintain sufficient concentration of activated sludge in the aeration basin whereby too much or too little can be considered detrimental to the system’s overall health. Synonyms: SVI
In water supply, SSS refers to decentralised water supply systems that can supply from 1,000-10,000 l/day. They are most often used for community water supply but also in emergency water supply and to purify water to be sold as bottled water or at water kiosks. Synonyms: SSS
Solids-free sewer systems are similar to conventional sewer systems with the difference that the wastewater is pre-settled and solids removed (e.g. in septic tanks) before entering the system. As solids are removed, sewers diameter can be much smaller (i.e. small-bore sewers) and they can be constructed using less conservative design criteria (lower gradients, fewer pumps, less pipe depth, etc.) resulting in significantly lower investment costs. Synonyms: Settled Sewer, Solid-free Sewer System, Solids-free Sewer
Socio-Cultural Issues
The socio-cultural issues section deals with water and sanitation practices, which are often strongly influenced by society and prevailing cultures. It is crucial to understand underlying preferences, taboos, or practices to improve water management, sanitation and hygiene.
Soft Systems Methodology
Methodology to provide a framework for dealing with complex, real-life situations where there is a lack of formal problem definition. It can be employed to systematically deal with messy, problematic situations in a seven-step process that starts with entering the problem situation and ends with taking action to improve the real-world situation. Synonyms: SSM
A soil amend-ment is any material added to a soil to improve its physical properties, such as water retention, permeability, water holding capacity, water infiltration, drainage, aeration and structure. The goal is to provide a better envi-ronment for roots. Synonyms: Soil Conditioner
Compaction resulting from heavy vehicles putting strong pressure on the soil and reduceing pore volume. Consequently, oxygen and water are squeezed out and can hardly infiltrate again. Synonyms: Soil Consolidation
Soil solarisation is a non-pesticidal method of controlling soilborne pests by placing plastic sheets on moist soil during periods of high ambient temperature. The plastic sheets allow the sun's radiant energy to be trapped in the soil, heating the upper levels. Solarisation during the hot summer months can increase soil temperature to levels that kill many disease-causing organisms (pathogens), nematodes, and weed seed and seedlings. It leaves no toxic residues and can be easily used on a small or large scale. Soil solarisation also improves soil structure and increases the availability of nitrogen (N) and other essential plant nutrients.
Solar pasteurisation is the process of pasteurisation using solely solar thermal energy. It is mostly applied for water. It is applied by using a solar cooker that can absorb solar thermal energy and transmit it to a black container e.g. a black jar. Typically, the significant time of heating by solar heat and cooling down contributes to the pasteurisation process.
Applied to water, the solar pasteurisation (heating to 60°C (140°F)) can inactivate both bacteria and rotaviruses, the main causes for severe diarrhea in children. Synonyms: Solar Pasteurization
Solar water disinfection - the SODIS method - is a simple procedure to disinfect drinking water. Contaminated water is filled in a transparent PET-bottle or glass bottle and exposed to the sun for 6 hours. During this time, the UV-radiation of the sun kills diarrhoea generating pathogens. Synonyms: SODIS
Abbreviation: SODIS
Solid Waste
Solid waste refers to the products that are thrown away by households, agriculture and industry because they do not assign any value to the material anymore. It is generally classified into organic waste, which can be used for the production of biogas or compost; or non-organic waste which either can be recycled as a material (e.g. PET) or, if there is no possibility for recycling anymore, needs to be incinerated and disposed off.
The solids retention time (SRT) is the time the solid fraction of the wastewater spends in a treatment unit. It is the quantity of solids maintained in the reactor divided by the quantity of solids coming out of the reactor each day: SRT = V *Cd / Qout* Cout. Where V is the digester volume; Cd is the solids concentration; Qout is the volume wasted each day and Cout is the solids concentration of the effluent. In a conventional, completely mixed, or plug flow reactor, the HRT equals the SRT. In retaining biomassreactors (e.g. anaerobic biogas settlers, septic tanks) the SRT exceeds the HRT. Synonyms: SRT
A solids-free sewer is a network of small-diameter pipes that transports solids-free or pre-settled wastewater (such as the effluent from septic tank or biogas settlers) to a treatment facility for further treatment or to a discharge point. They can be built for new areas or where soil infiltration of septic tanks effluents (e.g. via leach fields) is not appropriate anymore (i.e. densely populated areas; clogging of sub-surface). Due to the simplified design, solids-free sewers can be built for 20% to 50% less than conventional sewerage. However, expert design and construction supervision is essential and repairs and removal of blockages may be required more frequently than for a conventional gravity sewer. Moreover, effluent and sludge (from interceptors) requires secondary treatment and/or appropriate discharge. Small-bore sewers also require a certain level of responsibility of users, because maintenance is high due to the high risk of clogging. Synonyms: Settled Sewers; Small-bore Sewers; Small-diameter Sewers; Septic Tank Effluent Gravity Sewers
The splitting or decomposition of a chemical compound by means of ultrasounds.
Source Separation
Source separation refers to the separate collection of different wastes and wastewaters (e.g. greywater and blackwater). The separate collection facilitates the reuse of water, nutrients and energy contained in the different waste streams, depending on their composition.
Spate irrigation diverts seasonal flood water from valleys, rivers, riverbeds and gullies onto farm land situated at lower elevation than the origin of the flood water. In sandy riverbeds flood water seeps into the voids between sand particles pushing air to the surface where it forms thousands of air bubbles making the floodwater appear to be boiling.
The specific surface area describes how much surface contains a material per volume. It is expressed as surface per volume or (e.g. m2/m3). Synonyms: SSA
Abbreviation: SSA
Spring
When groundwater makes its way to the earth’s surface and emerges as small water holes or wet spots, this feature is referred to as a spring. Synonyms: Surface seepage
The spring catchment area is divided into immediate catchment area and the enlarged catchment area. The immediate catchment area is where human activity is not allowed. It is defined by a watershed specialist and should be fenced off immediately. The enlarged catchment area extends further beyond the immediate catchment area. Here some form of human activity may be allowed with the advice of a watershed specialist.
Sprinkler irrigation is a method of providing rainfall-like irrigation to the crops. Water is distributed through a system of pipes usually by pumping. Spray heads at the outlets distribute the water over the entire soil surface. Sprinklers provide efficient coverage for small to large areas and are suitable for all types of crops. They can be adapted to nearly all irrigable soils since sprinklers are available with a variety of discharge capacities. However, sprinkler systems can easily clog with the presence of sediment or debris and large systems incur high capital costs.
Squatter
The general name given to someone who prefers to squat to do its toilet, rather than to sit.
The page “SSWM in Africa” (STEP Africa) is a capacity development tool for the public and private sectors working within and beyond the water and sanitation sector, initiating, planning, carrying out and following-up WASH (Water, Sanitation and Health) initiatives in the African context. It complements the SSWM Toolbox with factsheets, reading material, case studies and contacts specific to Sub-Saharan Africa. Synonyms: SSWM in Africa, STEP Africa
Abbreviation: STEP Africa
SSWM Specific Topic Entry Page “Business Development”
The SSWM Specific Topic Entry Page “Business Development” (STEP Business Development) is developed in collaboration with cewas, the international centre for water management services and the International Water Management Institute (IWMI). It addresses professionals and practitioners from the water and sanitation sector establishing their own business. The module is designed in a logical sequence, accompanying the user during the entrepreneurial process from self-discovery and identification of business opportunities up to running a sustainable company. Each module contains an introduction with further readings and important links and presents a list of tools to facilitate the conception of start-ups.
This page complements the SSWM Toolbox with a comprehensive tutorial for entrepreneurs, who plan to develop a new business in the dynamic and challenging water and sanitation sector. Synonyms: Business Development in SSWM, STEP Business Development
Abbreviation: STEP Business Development
SSWM Specific Topic Entry Page “Support to the National Urban Sanitation Policy in India”
The page “Support to the National Urban Sanitation Policy in India” (STEP SNUSP) was developed in collaboration with the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, as part of the programme “Support to the National Urban Sanitation Policy in India”. The information is based on experience in the planning and implementation of city sanitation plans in India gathered by GIZ in cooperation with the government of India. It is a platform for knowledge sharing, promotion and dissemination of the activities carried out by the Indian Ministry of Urban Development (MoUD) and the Delegation of the GIZ in India in the framework of the National Urban Sanitation Policy (NUSP).
This page supplements the SSWM Toolbox with detailed practice-proofed information and guidelines for decision-makers and practitioners in the field of urban sanitation management. Synonyms: SNUSP, Specific Topic Entry Page: "Support to the National Urban Sanitation Policy in India", STEP CSP, STEP SNUSP, Support to the National Urban Sanitation Policy in India, “Support to the National Urban Sanitation Policy in India"
Abbreviation: STEP SNUSP, SNUSP, STEP CSP
SSWM Specific Topic Entry Page “University Course”
The STEP University is developed in collaboration with the Norwegian University of Life Sciences (UMB), Tribhuvan University in Nepal and COMSATS University in Abbottabad (Pakistan). It has been designed for the students of the web-based training course “Introduction to Sustainable Water and Sanitation” conducted by these three universities.
This page complements the SSWM Toolbox with teaching material (lectures, presentations, video lectures, exercises, case studies) and learning material targeted at higher-education teachers and students. It can be used by a larger audience learning or teaching in research institutions from all over the world. Synonyms: SSWM University Course, STEP University
Abbreviation: STEP University
SSWM Specific Topic Entry Pages
Specific Topic Entry Pages (STEPs) are pages within the SSWM Toolbox providing an entry point and tailored information on a particular topic or specific group of users. According to the specific topic, STEPs give an easily accessible overview on the most relevant concepts and show how these concepts are linked to the different areas within sustainable sanitation and water management (SSWM) and the SSWM Toolbox. Both, the concepts presented within the STEP as well as the linked information from the SSWM Toolbox are complemented with further readings, awareness raising and training material, case study documentation, ready-made PowerPoint presentations and a glossary. The design, based on a pedagogic approach, guides the user in a logical sequence through the topic. STEPs are not only a powerful knowledge management and sharing tool for the specific topics, but also allow for positioning the topic within SSWM and the SSWM Toolbox and present it to a globally growing user community. Synonyms: Specific Topic Entry Page, Specific Topic Entry Pages, STEP, STEPs
Abbreviation: STEPs, STEP
Stabilisation Phase
The stabilisation phase describes the second period following an event. Estimation of the duration of the stabilisation emergency phase varies: while Davis & Lambert (2002) define it to typically start two to four weeks after the event and last for two to six months, Harvey (2007) estimates that the stabilisation and recovery phase together last for several months or years after the event, depending on the type and severity of the emergency. The exact duration depends on the event and the context of the emergency. Duration is not time-bound but rather depends on the achievement of set targets (indicators).
Stabilised is used to describe the state of organic material that has been completely oxidized and sterilized. When most of the organic matter has been degraded, bacteria begin to starve and consume their own cytoplasm. The organic matter left by the dead bacteria is then degraded by other organisms, which results in a fully stabilised product.
The stack effect can be described as follows: warm air is lighter than cool air and it rises being replaced by cooler air. In UDDTs for instance, the solar radiation heat the vent pipe, which is constructed outside (exposed to the sun) and painted in black. When the air in the pipe heats up, it rises upwards out of the vent; a downward draught of cooler air of higher density then flows in through the squat plate hole, replacing the vacuum space created after warm air rising. The rate of ventilation is directly proportional to the size of openings ant the height difference between inlet and outlet. Aeration of the toilet cabin can increase the airflow and allow wind to pass through the cabine.
Stakeholder
Stakeholders are people, groups, or institutions which are likely to be affected by a proposed intervention (either negatively or positively), or those which can affect the outcome of the intervention (WORLDBANK 1998).
Stakeholder Analysis
Stakeholder analysis is the process of identifying the individuals or groups that are likely to affect or be affected by a proposed action, and sorting them according to their impact on the action and the impact the action will have on them. This information is used to assess how the interests of those stakeholders should be addressed in a project plan, policy, program, or other action.
The State Sanitation Strategy is framed looking at the requirements of urban state, emerging out from situational analysis and also as per the requirements of NUSP through extensive consultations with all the stakeholders. Synonyms: SUSS
Abbreviation: SUSS
Steam Engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.
Stormwater is water which results from storm and rainfall and flows over surfaces such as roofs and roads before flowing towards low- lying land. It is the portion of rainfall that does not infiltrate into the soil. Synonyms: Rainfall Run-off, Run-off
The overall culmination of techniques used to reduce surface run-off from causing flooding and dispersing pollutants. Stormwater management consists in detaining, retaining, or providing a discharge point for stormwater to be reused or infiltrated into the groundwater. It should best preserve or mimic the natural hydrologic cycle and fit within the capacity of existing infrastructure.
SFP brings planning and financing – which are typically done separately – onto convergent tracks, so that spending ambitions are more compatible with available financial resources. Conversely, financing strategies can be tailored to what is actually needed, which improves the prospects of getting funding.”
A strategy is a planning framework aimed at achieving a vision.
Stream Erosion
Valley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward, deepening the valley, and head ward, extending the valley into the hillside. In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is relatively steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat, and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles, pebbles and boulders can also act erosively as they traverse a surface. Synonyms: Valley Erosion
The process of crystallizing magnesium, ammonium and phosphate such that they are removed from solution.
Struvite Reactor
A Struvite reactor is a mixing chamber into which a waste stream (high in phosphate and ammonium) is reacted with magnesium. The reactor allows for the subsequent separation of the precipitated struvite from the solution.
Subsurface drip irrigation is a variation of the conventional surface drip irrigation. The laterals are buried in a depth below the soil surface depending mostly on the tillage practices and the crop to be irrigated. It is using water more efficiently than traditional irrigation techniques like surface irrigation by minimising evaporation. Synonyms: Subsurface Drip Irrigation
The production of a partial vacuum by the removal of air in order to force fluid into a vacant space or procure adhesion.
Superstructure
The superstructure of a toilet is the name given to the housing construction around a toilet that provides privacy to the user and protection from rain, wind and animals to the toilet. Superstructures can be constructed in any material, they may be permanent (e.g. concrete or bricks) or mobile (e.g. bamboo or cloth).
Surface irrigation is an umbrella term for irrigation methods (the three most common methods are: basin, border and furrow) in which water is distributed by gravity over the surface of a field.
Surface water is water that does not infiltrate and runs or ponds over-land. Surface water, unlike ground water is generally not safe for consumption because it accumulates pathogens, metals, nutrients and chemicals as it flows across contaminated surfaces. Synonyms: Surface water sources
Organic compounds with a hydrophilic (attracted by water) head and a hydrophobic (repelled by water) end. Surfactants reduce the surface tension of water by adsorbing at the air-water interface. They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface. Surfactants are the main components of cleaning products.
Sustainable
Something that is sustainable 'meets the needs of the present generation without compromising the ability of future generations to meet their own needs' (Brundtland Commission, 1987).
Sustainable High Rate Ammonium Removal Over Nitrate
Sustainable Land Management (SLM) refers to the use of renewable land resources (soils, water, plants, and animals) for the production of goods – to meet changing human needs – while at the same time protecting the long-term productive potential of these resources. The main concern of SLM is not to preserve nature in a pristine state, but to coexist with nature in a sustainable manner so that the productive, physiological, cultural and ecological functions of natural resources are maintained for the benefit of society. SLM tries to harmonise the complementary but often conflicting goals of production and environmental protection.
The main objective of a sanitation system is to protect and promote human health by providing a clean environment and breaking the cycle of disease. In order to be sustainable, a sanitation system has to be not only economically viable, socially acceptable, and technically and institutionally appropriate, it should also protect the environment and the natural resources.
Sustainable Sanitation and Health Development Project
Different departments/units of Xavier University have united under the “Sustainable Sanitation and Health Development Project”, which is being carried out in Barangay Lumbia, since 2011. It is also called the (XU) Convergence Project. Synonyms: Convergence Project, XU Convergence Project
The SuSan Center is a college-based center of the XU Jose P. Rizal School of Medicine under the Research and Social Outreach cluster of Xavier University, working on sustainable sanitation solutions in the Philippines, mainly Northern Mindanao. Synonyms: SuSan Center
Intimate living together of two organisms (called symbionts) of different species, for mutual or one-sided benefit. A good example of mutually beneficial symbiosis is the clownfish and the sea anemone. The clownfish can come in contact with the stinging tentacles of the sea anemone and not be harmed by them. At the same time, it receives protection from its enemies. The clownfish feeds the anemone by gathering nutrients and also leaving nutritional waste on the tentacles.