Glossary
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- F-diagram
- The F-diagram shows faecal-oral disease transmission routes. Faeces which are not disposed or stored safely represent a health risk for humans, since pathogens in faeces can be transmitted through many different routes to humans – i.e. flies, contaminated foods, fingers (unwashed hands), through fields (crops) and fluids (water). The F-diagram depicts those relationships in a simple manner so that everyone can understand them.
- Facultative Pond
- Relatively shallow pond (1 to 2 m) used for wastewater treatment and consisting of both, an aerobic zone close to the surface and an anaerobic zone in the bottom. Algae grow on the surface producing photosensitized oxygen which is provided to bacteria in the middle of the pond for aerobic degradation of the BOD. In the bottom of the pond, anaerobic digestion takes place. Some pathogens are also removed and nitrogen is released as ammonia to the atmosphere. The phosphorus in water is either incorporated in the algae biomass or precipitated. Synonyms: FP
- Faecal Coliform
- Faecal coliforms are a group of bacteria (e.g. Escherichia coli) present in excreta. They are not necessarily harmful, but they are present in high numbers and relatively easy to detect. Therefore they are used to indicate the presence of other faecal bacteria, which may be present in small numbers only, but associated to a high health risk. Synonyms: FC
- Faecal Indicator Bacteria
- Faecal indicator bacteria are bacteria used as indicator organism of faecal contamination. Typical faceal indicator bacteria are faecal coliforms or E. coli.
- Faecal Sludge
- General term for undigested or partially digested sludges of variable consistency (slurry or solid) collected from on-site sanitation systems storing or treating blackwater and excreta (e.g. latrines, non-sewered public toilets, septic tanks, aqua privies, cesspits, etc.).
- Faeces
- Faeces are the solid part of excreta without any urine or water.
- Faecophile
- Describes people or cultural groups who feel or express a relatively low inhibition when being exposed to or handling excreta
- Faecophobic
- Describes people or cultural groups who react inhibited or dismissive in when being exposed to or handling excreta
- Feedstock
- Feedstock is the raw material entering anaerobic digesters and which is transformed for the production of biogas. Such feedstock can be agricultural wastes and manures, municipal or industrial wastewater, organic solid wastes or any other biodegradable vegetables (e.g. maïze, water hyacinths) or non-vegetal material.
- Fenton
- This is the iron-salt-dependent decomposition of hydrogen peroxide, generating the highly reactive hydroxyl radical. This reaction is enhanced by solar irradiation (referred to as photo-Fenton).
- Fermentation
- Fermentation is the second step of anaerobic digestion. Fermentative bacteria transform sugars and other monomeric organic products from hydrolysis into organic acids, alcohols, carbon dioxide (CO2), hydrogen (H) and ammonia (NH3). Synonyms: Acidogenesis
- Ferric Chloride
- Ferric Chloride Synonyms: FeCl3
- Ferric Sulphate
- Ferric Sulphate Synonyms: FeSO4
- Fertigation
- The combined irrigation and fertilisation is called fertigation. There are different way how fertigation can be done: mixing chemical fertiliser with irrigation water; using partly treated wastewater which contains still nutrients; mixing (separately collected) urine as a nutrient source and mixing it to the irrigation water. Fertigation helps saving freshwater resources and decreases the dependency on depleting mineral fertilisers. Generally, drip irrigation and subsurface drip irrigation are the most appropriate application method for fertigation.
- Fertigation Water
- Fertigation water is the water used for fertigation (the combined irrigation and fertilisation). In the SSWM toolbox, it refers to wastewater that has been partly treated but still contains sufficient nutrients to be used in fertigation. Fertigation water, depending on its initial composition, should have undergone both physical treatment, to prevent clogging of the irrigation system, and biological treatment to reduce pathogens and to limit the risk of crop contamination and the health risk to workers and end consumers.
- Fertiliser
- Fertilisers are soil amendments applied to promote plant growth; the main nutrients present in fertiliser are nitrogen (N), phosphorus (P), and potassium (K) (the macronutrients). Other nutrients (micronutrient) are sometimes added in smaller amounts. There are inorganic fertilisers (mined or synthetically produced) or organic fertilisers. Due to a growing world population, today, the mineral resources of the main components of fertiliser (e.g. P) are depleting leading to exaggerate prices and the difficulty of small-farmer to provide them with sufficient fertiliser for food production. In sustainable sanitation systems, nutrients, initially contained in food, is recycled from wastewater products (e.g. urine, faeces etc.) providing an affordable and environmentally sound source of fertiliser at a local level. Synonyms: Fertilizer
- Field Capacity
- Field capacity is the amount of soil moisture or water content held in soil after excess water has drained away and the rate of downward movement has materially decreased, which usually takes place within 2–3 days after a rain or irrigation in previous soils of uniform structure and texture.
- Field Trenches
- Field trenches increase precipitation harvesting by breaking the slope of the ground and therefore reducing the velocity of water runoff. By decreasing runoff, they enhance water infiltration and prevent soil erosion. Trenches can be seen as an extended practice of ploughing fields. They may be applied to all soil types and are not dependent on slope or rainfall conditions Synonyms: Contour Furrows
- Filtrate
- Filtrate is the liquid that has passed through a filter.
- Financial Sustainability of WASH Services
- Financing WASH Services sustainably – in the sense of securing service delivery after implementation – has proven to be a challenge. This is mainly due to a lack of planning and knowledge of post-installation costs and assigned responsibilities. Hence, a planning tool, such as an indicator framework for financial sustainability of WASH services is needed. Different organisations have recently produced such frameworks (e.g. the life-cycle cost approach from WASHCOST) that provide an overview of important aspects for reaching financial sustainability. Synonyms: Financial Sustainability Framework
- Financing
- Financing means the organisation and acquisition of funds to pay for the full costs of a project (planning, building/ carrying out, operation & maintenance, monitoring & evaluation, etc.).
- First Flush Device
- First flush devices are used in rooftop rainwater harvesting (RTRWH) systems, in order to prevent debris, dirt, dust and droppings that collect on the catchment area from entering the collection and storage tank. Different types exist, such as float valve types, overflow flow types, flow rate types or electronic conductivity types. First flush diverter devices improve water quality, reduce tank maintenance and protect pumps. Synonyms: First Flush Diverter, First Water Diverter
- Fixed Bed Reactor
- Fixed bed, fixed film or attached growth reactors are biological wastewater treatment processes that employ an inert medium such as rock, plastic, wood, or other natural or synthetic solid material, that will support attached growth of active biomass responsible for degradation on its surface and within its porous structure reactors. Typical aerobic fixed bed reactors are trickling filters and biological disks or moving bed reactor (of type Kalness or Biostyr). Typical anaerobic fixed film reactors are anaerobic upflow filters. Synonyms: Attached Growth Reactor, FBR, Fixed Film Reactor
- Fixed-film System
- Fixed-film systems (also attached-growth systems) are biological wastewater treatment processes that employ a inert medium such as rock, plastic, wood, or other natural or synthetic solid material, that will support attached growth of biomass on its surface and within its porous structure. Wastewater comes into contact with the film contaiining the active fixed biomass either by pumping the water past the media in packed towers (i.e. trickling filter) or by moving the media past the wasewater to be treated (e.g. rotating biological contactor). Synonyms: Attached-growth Systems, FFS
- Floatation
- Flotation is the process whereby lighter fractions of a wastewater, including fats, oils, soaps, etc., rise above the water and the solids, and can thus be separated. Synonyms: Flotation
- Floating Plant Ponds
- Floating Plant Ponds are modified maturation ponds containing floating (macrophyte) plants. Such water hyacinths or duckweed float on the surface while the roots reach into the water to uptake nutrients and filter the water that flows by.
- Floc
- A very fine, fluffy mass formed by the aggregation of fine suspended particles, as in a precipitate. See also flocculation.
- Flocculation
- Flocculation is the agglomeration of destabilized particles into microfloc and after into bulky floccules which can be settled called floc. The addition of another reagent called flocculant or a flocculant aid may promote the formation of the floc. Floculation is used to separate solids from a solution; most commonly, after coagulation.
- Flow Rate
- The volumetric flow rate is the volume of fluid which passes through a given surface per unit time (e.g. m3/s, cubic meters or litres per second). Mass flow rate is the mass of substance which passes through a given surface per unit time. Synonyms: Q
- Fluidised-bed incinerator
- A type of incinerator in which the stoker grate is replaced by a bed of limestone or sand that can withstand high temperatures. The heating of the bed and the high air velocities used cause the bed to bubble, which gives rise to the term “fluidised”
- Flush Toilet
- Cistern flush toilets consist of a toilet bowl and a cistern. The siphon provides a water seal against odours from the effluent pipe. Excreta are flushed away with water stored in the cistern (depending on the type between 6 to 20 litres per flush). Dual flush toilets (with two different flush-volumes) are available to reduce water used to flush urine. There are also flush toilets on the market that collect the urine separately and use a very low-flush volume to flush the urine away. Cistern-flush toilets provide a high level of convenience for the user but they use large amounts of water. Installing them results in a significantly increase of the water consumption by the users and the generation of huge amounts of wastewater that needs to be treated. Synonyms: Cistern Flush Toilet
- Flushing Point
- A flushing point is a capped pipe which is accessible on the surface for maintenance. Blockages can be cleaned or flushed out. They can be found at pipe junctions or where small-bore sewers are connected to a conventional sewerage. Synonyms: Cleanout
- Flushwater
- Flushwater is the water used to flush excreta, urine and/or faeces from away from where it is produced (e.g. toilet) to a treatment unit (if present).
- Flux
- In the study of transport phenomena (heat transfer, mass transfer and fluid dynamics); flux is defined as flow per unit area, where flow is the movement of some quantity per unit time.
- Fog
- Fog is the same as clouds except that it touches the ground, whereas clouds have their base above the ground. When wind blows clouds over a mountain, fog is present wherever the clouds touch the ground. To a meteorologist, fog is present when visibility is less than 300 meters. Fog is composed of tiny liquid water droplets from less than a milimeter in diameter.
- Fog Drip
- Fog drip is a method to harvest the water contained in the fog. Fog harvesting provides a cheap complementary water source for arid and semiarid, rural regions. As the wind blows the fog through specially designed nets (fog collectors), tiny droplets of condensed water form on the mesh and are collected in a gutter and transported to a storage site. The collected water does meet the WHO standards and can be used as drinking water. One large fog collector, with a 40 m2 collecting surface, can produce up to an average of 200 litres per day throughout the year, costs around 1000 to 1500 USD each and can last 10 years.
- Food Product
- Any nutritious substance that people (or animals) eat or drink in order to maintain life and growth. Basic food products are produced in agriculture requiring soil, sun, water and nutrients.
- Forage
- Forage are plants grown to feed animals.
- Fossa Alterna
- The fossa alterna toilet system consists of two partially lined pits, pit covers with a hole or a toilet bowl and a superstructure. One of the pits is used at a time. When the first pit is filled up it is closed and the other pit is put in use. Soil, ash, and/or leaves should be added to the pit after each defecation or urination. The soil and leaves introduce a variety of organisms, which help in the degradation process. The dry material also absorbs humidity (reducing flies and odours), adjusts the C/N ratio and leads to an increased pH (pathogen die-off). After one year the decomposed faecal material can be used as compost (ecohumus) to improve soil quality.
- Fouling
- Fouling refers to the accumulation of unwanted material on solid surfaces, most often in an aquatic environment. The fouling material can consist of either living organisms (biofouling) or a non-living substance (inorganic or organic). Fouling is usually distinguished from other surface-growth phenomena in that it occurs on a surface of a component, system or plant performing a defined and useful function, and that the fouling process impedes or interferes with this function. Synonyms: Biofouling, Inorganic fouling, Organic Fouling
- Framework Issues
- Frameworks include institutional and legal frameworks, the former meaning the different institutions that are involved in planning and managing water and sanitation issues, and the latter meaning the laws that regulate the management of water and wastewater.
- Free Water Constructed Wetland
- In surface flow constructed wetlands (CW), the water moves above the soil in a planted marsh or swamp exposed to the air and direct sunlight. Although the soil layer below the water is anaerobic, the plant roots release oxygen into the areas immediately surrounding the root hairs, thus creating an environment for complex biological and chemical degradation. Synonyms: Free Water Surface Flow CW (FWS CWs), Free-Surface Constructed Wetland, Free-Surface CW, FWS, Surface Flow Constructed Wetland
- Freshwater
- Water naturally occurring on the Earth's surface (lakes, rivers, etc) and underground (groundwater in aquifers and underground streams). Freshwater is characterized by having low concentrations of dissolved salts and other total dissolved solids. The term specifically excludes seawater and brackish water.
- Fuel Cell
- A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel (often hydrogen) and an oxidant generating heat and water steam as by-products which then are transformed into mechanical energy and electricity. Natural gas is often used as a source of hydrogen and air as a source of oxygen.
- Fulvic Acids
- Fulvic acids are humic acids of lower molecular weight and higher oxygen content than other humic acids.
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