A high temperature oven used to thermally decompose an ore; usually limestone, but also magnesium carbonate.
California Water Environment Association
Founded in 1927, the California Water Environment Association is a not-for-profit public benefit association of 9,300-plus water quality professionals who work for public agencies and collection systems, engineering firms, and equipment and service suppliers. CWEA members are responsible for cleaning California's water and returning it safely to the environment.
Founded in 1927, CWEA is a not-for-profit association of 9,000-plus professionals in the wastewater industry. They are committed to keeping California's water clean. They train and certify wastewater professionals, disseminate technical information, and promote sound policies to benefit society through protection and enhancement of the water environment. They offer services at the state level as well as locally, through the 17 geographical Local Sections.
Capacity-Linked water and sanitation for Africa's peri-urban and Rural Areas
A Collaborative Project (Contract # 265676; duration: 1.3.2011 – 28.2.2014) within the EU 7th Framework Programme Theme 6 – 'Environment (including climate change)'
Capillary water is held in pores that are small enough to hold water against gravity, but not so tightly that roots cannot absorb it. This water occurs as a film around soil particles and in the pores between them and is the main source of plant moisture. As this water is withdrawn, the larger pores drain first. The finer the pores, the more resistant they are to removal of water. As water is withdrawn, the film becomes thinner and harder to detach from the soil particles. This capillary water can move in all directions in response to suction and can move upwards through soil for up to two meters, the particles and pores of the soil acting like a wick.
The capillary zone is the area in the soil where water can rise up slightly through the cohesive force of capillary action. It is generally an intermediate zone in the vadose zone between the dry zone, above the groundwater table.
Funds spent for the acquisition of a fixed asset, such as sanitation infrastructure.
Capital expenses cover the costs of assets and investments to start and keep a business running like machinery, a factory building, reparations etc.
Carbon credit is a tradable commodity to compensate carbon emissions. One carbon credit permits a buyer to emit an equivalent of 1 ton of CO2. Carbon credits are traded on different carbon credit markets.
Carbon finance is a payment system to reward climate change mitigation. It pays for the reduction of carbon dioxide (CO2) emissions and other greenhouse gases (GHG). To compensate their emissions, emitters (polluting countries, industries, companies or individuals) can buy carbon credits on different carbon markets. Credits on the other hand are created through verified carbon emission reductions generated through innovative projects in developing countries.
Virtual exchange place where people buy and sell carbon credits.
Carbon to Nitrogen Ratio
The ratio of the mass of carbon to the mass of nitrogen in a substrate. It is often expressed as a single number representing the carbon content. A balanced carbon – nitrogen ratio is relevant for composting and anaerobic digestion. If the digestion process is hampered by a lack of carbon (low C/N ration) organic material (e.g. household waste) can be added. To prevent a lack of nitrogen urine can be added.
Synonyms: C/N, X:N, C:N Ratio
In the absence of sewers and if wastes and wastewater cannot be reused on-site, these products need to be collected and transported in a human-powered or motorised vehicle.
Central American Industrial Research Institute
Central American Industrial Research Institute
Central Public Health and Environmental Engineering Organisation
The Central Public Health and Environmental Engineering Organisation (CPHEEO) is Technical Wing of the Ministry of Urban Development, Government of India
Centralised systems are infrastructures such as drinking water or wastewater treatment plants, which treat large amounts of water from many households in one single spot. Centralised systems thus require either the collection of waste and wastewater from individual houses or the redistribution to the households (i.e. drinking water). Centralised systems thus imply the construction of a piping system (water distribution system or sewers) and / or other means of collection and distribution (e.g. cartage).
Centralised Water Supply
Centralised (drinking) water supply refers to the centralised treatment and purification of water sources and subsequent distribution to different water users (households, industry, agriculture) through a large water distribution network.
A cesspit is an ambiguous term either used to describe an underground holding tank or a soak pit. An underground pool (also called cesspool) is a tank pit used for the temporary collection and storage of faeces, excreta or faecal sludge. The pit is lined with bricks or concrete, covered with a slab and needs to be emptied frequently. When soil conditions allow, the pit is not constructed watertight (similar to a soak pit) allowing liquid to leach out, while solids decay and collect in the base. A soak pit requires less frequent emptying but leachate infiltration may cause groundwater pollution.
Synonyms: Cesspool, Cess Pit
Colony forming units (CFU) is a measure indicating the number of microorganisms in a sample capable of multiplying and forming a colony on cultivation plates. CFU are often used to control or monitor the removal of pathogens in water and wastewater treatments.
Channelling occurs, when a flow in a reactor does not follow the prospected flow schema, but directly flows from the inlet to the outlet without mixing with the rest of the reactor content. In water purification and treatment units, this results in a non-respect of the hydraulic retention time and in consequence insufficient treatment.
A system with open ditches for the discharge of rainwater exist in most urbanised areas. The ditches usually drain-off rainwater into rivers or sometimes into agricultural irrigation canals. Unauthorised discharge of domestic waste into the system is quite common leading to surface water pollution and spreading of pathogens. However, where no wastewater infrastructure exists, drainage of wastewater through the system could be a possible temporary solution considering an appropriate treatment (e.g. waste stabilisation ponds, constructed wetlands) before reuse or discharge. In this case drains should be covered by concrete slabs to prevent blockages by litter and humans from getting in contact with their contents and rainwater should be allowed to enter the systems in periodic inlets.
Charcoal is a lightweight, black, porous material similar to coal. It consists of carbon (about 50 to 95 %) and volatile chemicals and ash. Charcoal is usually produced by slow pyrolysis, the heating of wood, sugar, bone char, or other substances in the absence of oxygen. It can also be produced by some enzymatic conversion of organic mater. The backbones of charcoal are polycondensed aromatic moieties which are chemically and biologically persistent. Charcoal is a valuable soil amendment (see also terra preta), retaining nutrients at their surface and improving the soil structure leading to enhanced water and air retention.
Chemical Oxygen Demand
A measure of the amount of oxygen required for chemical oxidation of organic material in water by a strong chemical oxidant (expressed in mg/L). COD is always equal to or higher than BOD since it is the total oxygen required for complete oxidation. It is an indirect measure of the amount of organic material present in water or wastewater: the more the organic content, the more oxygen is required to chemically oxidise it (high COD). A high organic content is generally an indictor for water pollution. The COD subtracted by the BOD gives an indication of the non-biodegradable chemicals and thus the toxicity of the water. See also: COD/BOD5 Ratio
Chemical sedimentation is like normal sedimentation but coagulants are used in order to neutralise repelling surface charge of particles. Once these repelling surface charges are neutralised, the particles attach to each other forming clusters and flocs, which become heavier and therefore settle more easily to the bottom.
Chemical treatment of wastewaters uses chemicals to degrade and remove pollutant or pathogens form wastewaters. In regard to wastewater, a typical chemical treatment is the co-precipitation of iron and phosphorus (e.g. in activated sludge systems). Other common chemical treatments are advanced oxidation processes (e.g. ozonation) used, where pollutants are toxic to bacteria and a biological treatment is not possible. A typical drinking water chemical treatment is chlorination
Chlorination generally refers to the addition of chlorine to water or sewage in order to kill pathogen and achieve disinfection.
Chlorination is one of many methods that can be used to disinfect water. It is a chemical disinfection method that uses various types of chlorine or chlorine-containing substances for the oxidation and disinfection of what will be the potable water source.Centralised chlorination refers to the use of chlorine to disinfect water in a centralised drinking water treatment plant as a primary or secondary disinfection. Primary disinfection is when water is disinfected within the treatment plant, while secondary disinfection is when water is disinfected throughout the distribution system.
Chlorine residual is a level of chlorine remaining in water after initial treatment. It constitutes an important safeguard against the risk of subsequent microbial recontamination and inhibits the growth of bacteria.
Cholera is an acute infection of the intestine, which begins suddenly with painless watery diarrhoea, nausea and vomiting. Most people who become infected have very mild diarrhoea or symptom-free infection. Malnourished people in particular experience more severe symptoms. Severe cholera cases present with profuse diarrhoea and vomiting. Severe, untreated cholera can lead to rapid dehydration and death. If untreated, 50% of people with severe cholera will die, but prompt and adequate treatment reduces this to less than 1% of cases. Cholera outbreaks can occur sporadically in any part of the world where water supplies, sanitation, food safety and hygiene practices are inadequate. Overcrowded communities with poor sanitation and unsafe drinking-water supplies are most frequently affected.
Cistern Flush Toilet
The cistern flush toilet is usually made of porcelain and is a mass-produced, factory-made user interface. The flush toilet consists of a water tank that supplies the water for flushing the excreta and a bowl into which the excreta are deposited. Excreta are flushed away with water stored in the cistern (depending on the type between 6 to 20 litres per flush). Cistern-flush toilets provide a high level of convenience for the user but their installation can result in a significantly increase of the fresh water consumption and increase of wastewater to be collected and treated. Dual flush toilets (with a smaller flush-volume for urine), low-flush toilet and urine diverting toilets are available in order to reduce the amount of generated blackwater.
City Sanitation Plan
City Sanitation Plans are strategic planning processes for citywide sanitation sector development. Addressing technical and non-technical aspects of sanitation services, City Sanitation Plans include the vision, missions, and goals of sanitation development as well as strategies to meet these goals.
Synonyms: CSP, CSPs
City Sanitation Task Force
City Sanitation Task Force
Clay Pot and Porous Capsule Irrigation Network
This is an old irrigation system that has been modernised and reapplied in water scarce areas. It consists of using clay pots and porous capsules (see also [4033-pitcher irrigation]) to improve irrigation practices by increasing storage and improving the distribution of water in the soil.
Synonyms: Clay Pot Irrigation Network
Clean Development Mechanism
The Clean Development Mechanism allows a country with an emission-reduction or emission-limitation commitment under the Kyoto Protocol (often, industrialised countries) to implement an emission-reduction project in developing countries. The former are hence able to buy emission reductions by achieving them in countries where it is cheaper to reduce greenhouse gas emissions – at the same times, they fund investments into clean technologies in developing countries.
Co-composting is the controlled aerobic degradation of organics, using more than one feedstock (faecal sludge, excreta, organic solid waste, etc.). Faecal sludge has a high moisture and nitrogen content, while biodegradable solid waste is high in organic carbon and has good bulking properties (i.e., it allows air to flow and circulate). By combining the two, the benefits of each can be used to optimize the process and the product. Other organic materials, which can be used or subjected to co-composting, comprise animal manure, sawdust, wood chips, bark, and slaughterhouse waste, sludge or solid residues from food and beverage industry. See also compost or composting.
Coagulants are chemicals used to enhance sedimentation. Coagulants neutralise surface charges of repelling particules, allowing them to approach, attach and form clusters. The clusters are larger in size and heavier and thus more easy to settle and remove from the water. See also coagulation or chemical sedimentation.
The destabilization of particles in water by adding chemicals (e.g., aluminium sulphate or ferric chloride) so that they can aggregate and form larger flocs. Coagulation is often used in combination with flocculation.
Coagulation and floculation describe the chemical process of contact and adhesion whereby the particles of a dispersion (colloids) form larger-size cluster (flocs or flakes) allowing them to be more easely removed from water (e.g. by settling). The coagulation-flocculation processes facilitate the removal of suspended and colloidal particles. It’s used in the first stage of solids-liquids separation: settling, flotation or filtration.
The ratio within the chemical oxygen demand (COD) and the biological oxygen demand over 5 days (BOD5) indicates the level of biodegradability of a sample. A low ratio COD/BOD5 (less than 2.0 or 2.5) indicates a high biodegradability, what means that it can be treated easily by a biological treatment.
Synonyms: COD:BOD5 ratio, COD/BOD5
Coliform bacteria are defined as rod-shaped, Gram-negative organisms, which ferment lactose and produce acids and aldehydes. The coliforms include Escherichia, Klebsiella, Enterobacter, Citrobacter and may include Serratia and Edwardsiella. Coliforms are normally found in the aquatic environment and on vegetation but also in bodies and excreta. Therefore, they are also used as an indicator of faecal contamination of water.
Collection and Storage/Treatment
Collection and storage/treatment describes the ways of collecting, storing, and sometimes treating the products that are generated at the User Interface. Treatment that is provided by these technologies is often a function of storage and usually passive (e.g. no energy inputs). Thus, products that are ‘treated’ by these technologies often require subsequent treatment before Use and/or Disposal.
Colloidal silver are tiny silver particles suspended in liquids. They are used as disinfectant in ceramic filters, preventing bacterial growth and assisting inactivation of bacteria.
Combined Cycle Power Plant
A combined cycle is characteristic of a power producing engine or plant that employs more than one thermodynamic cycle. Heat engines are only able to use a portion of the energy their fuel generated (usually less than 50%). The remaining heat (e.g., hot exhaust fumes) from combustion is generally wasted. Combining two or more thermodynamic cycles, such as the Brayton cycle and Rankine cycle, results in improved overall efficiency.
Combined Heat and Power
Cogeneration or combined heat and power (CHP) describe the simultaneously generation of both electricity and useful heat. By-product heat at moderate temperatures (100-180°C) can also be used in absorption chillers for cooling. A plant producing electricity, heat and cold is sometimes called trigeneration or more generally: polygeneration plant.
Combined sewers collect blackwater, greywater and stormwater runoff in one ant the same single pipe system. Combined sewers provoke the pollution of little polluted water by mixing it with heavily polluted water. This particularly results in pollution when sewers overflow during heavy rain periods. As combined sewers need to be large, they can also be more expensive to install. Today, combined sewers are perceived as obsolete and in newer construction separated sewer systems are installed instead, although many systems remain combined as the replacement of an existing systems would be too expensive.
Combined Sewer Overflow
A combined sewer overflow, or CSO, is the discharge of wastewater and stormwater from a combined sewer system directly into a river, stream, lake or ocean.
Command and Control Tools
Command and Control Tools are direct regulations of requirements, bans and rules. With command and control tools, you only change the behaviour of people because they want to avoid penalties for non-compliance. People don't necessarily also change their values; that is also the reason why command and control tools only work when they can really be enforced, and when those who do not comply are actually charged.
The area of the spate irrigation scheme that can be irrigated (provided that water is available) and is fit for cultivation.
Community Action Planning
Community Action Planning
Community Aided Total Sanitation
Community Aided Total Sanitation
Community Based Organisation
A community based organisation is a small organization that does not have the registered status of an NGO but is a structured group of volunteers who work together to achieve a common goal of the community. Anyone can start their own CBO.
Synonyms: CBO, CBOs
Community Health Clubs
Community Health Clubs
Community-led Total Sanitation
The CLTS is a methodology for mobilising communities to completely eliminate open defecation by taking their own action.
Community-Led Urban Environmental Sanitation
Community-Led Urban Environmental Sanitation (CLUES) presents comprehensive guidelines for the planning and implementation of environmental sanitation infrastructure and services in disenfranchised urban and peri-urban communities, emphasising stakeholder participation.
Compact Constructed Wetland
A CCW is a small-scale constructed wetland, built individually for one household. It works in connection to a three chambered septic tank, from where blackwater flows from the last chamber, passing through the constructed wetland into an impounding basin. The basin accumulates the treated blackwater as well as grey water from the sink, laundry and bathroom plus storm water.
Synonyms: CCW constructed wetland
Completely Autotrophic Nitrogen Removal Over Nitrite
Aerobic ammonium oxidising bacteria (nitrifiers) with Anammox bacteria perform simultaneously a two step reaction under oxygen-limited conditions in one reactor.
Compost is decomposed organic matter that results from a controlled aerobic degradation process. In this biological process, microorganisms (mainly bacteria and fungi) decompose the biodegradable waste components and produce an earth-like, odourless, brown/black material. Compost has excellent soil-conditioning properties and a variable nutrient content. Because of leaching and volatilization, some of the nutrients maybe lost, but the material is still rich in nutrients and organic matter. Generally, Excreta or Sludge should be composted long enough (2 to 4 months) under thermophilic conditions (55 to 60 °C) in order to be sanitized sufficiently for safe agricultural use. This temperature is not guaranteed in most Composting Chambers, but considerable pathogen reduction can normally be achieved.
A compost filter is a novel alternative pre-treatment method. Wastewaterflows through an aerobic filter. Solids (toilet paper, faeces) are held back in the filter, liquids are pumped to a secondary treatment facility (e.g. constructed wetland or waste stabilisation pond). There are two types of compost filters: chamber filter or hanging bags.
Synonyms: Rottebehaelter, Pre-composting Tank
In this composting method, the waste is put in piles on the ground and regularly turned to allow aeration. The size of the pile may vary depending on the amount of waste and available space, but generally, it should be 1 to 2 m on each side and not more than 1.5 m in height. Chicken wire or wooden planks can be used to keep the pile together.
Composting is the process of controlled decomposition of organic solid matter (e.g. organic wastes such as plant residues, kitchen wastes, excreta, etc.) into CO2 and heat in the presence moisture. Composting is carried out by aerobic (requiring free or molecular oxygen found in air) microorganisms, mainly bacteria and funghi. Composting is simple and practiced by individuals in their homes, farmers on their land, and industrially by industries and cities. The desired end-product is an inoffensive and safe-to-handle (free of pathogens and weed seeds) material, that can be used as soil amendment to enhance organic matter and nutrient content
A composting chamber is designed to convert excreta and organics into compost. In composting toilets, faeces or excreta fall into a composting chamber together with cleansing material. Dry organic material such as sawdust is added to adjust moisture content and C/N ratio in order to obtain optimum conditions for thermophilic composting. Organic household waste can also be added for co-composting. Depending on the process, shorter or longer maturation periods and maybe also secondary treatment are required. Urine might be diverted to decrease humidity of the compost and to be reused separately.
One simple method for composting organic waste is to put it in pits and let it turn into compost over a period of six months or more. This process requires some space and time but the main benefit is that the waste is not visible as it is buried in the pit.
Composting toilets are toilet systems comprised of a superstructure, a pan or slab, and a vault or pit in which faeces or excreta fall together with cleansing material (the composting chamber). Dry organic material such as sawdust is added to adjust moisture content and C/N ratio in order to obtain optimum conditions for thermophilic composting. Composting toilets allow to treat bothexcreta and faeces as well as organic household or garden waste and to transform it into a valuable soil amendment.
Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. The increased pressure can directly be transformed into mechanical energy.
Condominial sewerage is the application of simplified sewerage coupled with consultations and on-going interactions between users and agencies during planning and implementation. The term is used primarily in Latin America and is derived from the term condominio/condominium (housing block).
Synonyms: Condominial Sewerage
Saturated permeable soil (sand or gravel) capped by an impermeable layer.
Conjunctive use describes the combined use of groundwater and surface water. In order to achieve higher water reliability, the natural hydrologic connection between ground and surface water is used as efficiently as possible. The idea of this management approach is to use surface water when the water table is high and change to groundwater when the water table is low.
Conservation agriculture aims to achieve sustainable and profitable agriculture and subsequently aims at improved livelihoods of farmers through the application of the three conservation agriculture principles: minimal soil disturbance, permanent soil cover and crop rotations. Conservation agriculture holds tremendous potential for all sizes of farms and agro-ecological systems, but its adoption is perhaps most urgently required by smallholder farmers, especially those facing acute labour shortages. It is a way to combine profitable agricultural production with environmental concerns and sustainability and it has been proven to work in a variety of agro-ecological zones and farming systems. It has been perceived by practitioners as a valid tool for Sustainable Land Management (SLM).
Conservation tillage embraces one principle of conservation agriculture "minimum soil disturbance" and includes practices that keep the disturbance of the soil and loss of organic matter to a minimum, reducing soil and water losses. Mostly, the soil is not turned using ploughs.
Consortium for Dissemination of DEWATS
Consortium for Dissemination of DEWATS
Constant Vacuum System
A vacuum system where vacuum is maintained in the piping at all times. Used in large systems with more than 4 to 10 toilets and/or long pipes.
A treatment technology for wastewater that aims to replicate the naturally occurring processes in wetlands. Constructed shallow ponds are lined and filled with some sort of filter material (substrate), usually sand, gravel, rock or soil, and planted with vegetation tolerant of saturated conditions (e.g. reeds). As wastewater flows through the ponds, the filter material filters out particles and microorganisms degrade the organics. See also free-water surface constructed wetland, horizontal subsurface flow constructed wetland, Vertical flow constructed wetland.
Contact time is the product of the residual concentration of disinfectant (C), measured in mg/L at the outlet of the contact chamber, and the disinfectant contact time (T), measured in minutes. Contact time is increased when either the disinfectant concentration or the disinfectant contact time are increased, indicating a higher level of disinfection. The CT values required to achieve the necessary inactivation will depend on the microorganism targeted, pH, and temperature.
A process, in anticipation of potential crises, of developing strategies, arrangements and procedures to address the humanitarian needs of those adversely affected by crises.
Continuous Stirred-tank Reactor
Continuous stirred tank reactors are reactors, in which there is a constant in- and out-flow and the content is completely mixed. Complete mixing occurs when the particles entering the tank are dispersed immediately throughout the tank. The particles leave the tank in proportion of their statistical population. The reactors can be round or square as long as the contents of the tanks are uniformly and continuously distributed.
Contour bunds are bunds constructed along the contour lines. They are usually made of stones or soil (sometimes in variation with crop remains). They are constructed along a contour in order to best slow the water flowing down the slope, which increases the green water pool of the soil and prevents erosion.
Conventional Biological Treatment
Conventional biological treatment means active sludge or enhanced active sludge systems and fixed film systems such as trickling filters or rotating biological contactors.
Conventional Gravity Sewer
Conventional gravity sewers are large networks of underground pipes that convey blackwater, greywater and, in many cases, stormwater from individual households to a (Semi-) Centralized Treatment facility, using gravity (and pumps when necessary). When blackwater and stormwater are collected in the same pipe, conventional sewers are also called combined sewers.
Conveyance describes the transport of products from one functional group of a sanitation system to another. Although sanitation products may need to be transferred in various ways between functional groups, the longest, and most important gap is between User Interface or Collection and Storage/Treatment and (Semi-) Centralized Treatment. Therefore, for the sake of simplicity, Conveyance only describes the technologies used to transport products between these functional groups.
Cooling towers are one of the most common water recycling technologies in use by industry today. By taking advantage of water’s high heat of evaporation, cooling towers offer effective and relatively inexpensive cooling for a wide range of industrial uses. 2/3 industrial water is used for cooling water (removal of heat). In some industries such as electric power plants or oil refineries, even up to 90% of intake water is used for cooling. Cooling water is easy to treat and sometimes even of quite a good quality. It can therefore easily be reused for example for washing processes. However, once used for washing and eventually contaminated, an appropriate treatment system before reuse is required.
Cooling water is the water used in industry to remove heat from processes. 2/3 industrial water is used as cooling water (removal of heat). In some industries such as electric power plants or oil refineries, even up to 90% of intake water is used as cooling. Cooling water is often not much polluted and can easily be reused for instance for cleaning processes. The heat, stored in the water after cooling can also be reused in other industrial or agricultural processes that require heating instead of cooling.
Core Humanitarian Standard
Core Humanitarian Standard
Corporate Social Responsibility
Corporate Social Responsibility does not have one particular definition. Some define it as operating in a manner that meets or exceeds the ethical, legal, commercial and public expectations that society has of business; whereas other define it as doing business in an ethical way that respects people, society and the environment.
Corporation of Kochi
Corporation of Kochi
The objective of valuing costs and benefits is to understand their relation and compare them in monetary units, in order to utilise these operationalized benefits for better advocacy and decision-making.
Creating an Enabling Environment
With Tools to Create an Enabling Environment you take care of a sound framework for sustainable sanitation and water management. A functioning enabling environment is the precondition for the implementation any other software or hardware tools. Certain basics such as a legal or institutional framework, sound enforcement bodies and human skills need to be developed before you can implement any other measures.
Crop rotation is a practice of growing different crops on the same land in a regular recurring sequence. It means the planned order of specific crops planted on the same field. It also means that the succeeding crop belongs to a different family than the previous one. The planned rotation may vary from 2 or 3 years to longer period. Rotation of crops is not only necessary to offer a diverse "diet" to the soil microorganisms, but as they are rooting at different soil depths hence are capable to explore the different soil layers for nutrients.
Cryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhoea in humans.
An environmentally resistant stage of a microorganism that helps it to survive periods of environmentally harsh conditions. Some protozoan parasites form infective, highly resistant cysts (e.g., Giardia) and oocysts (thick-walled spores, e.g., Cryptosporidium) during their life cycle.