GLOSSARY

Base flow: sustained flow of a stream in the absence of direct runoff. It includes natural and human-induced streamflows (USGS).

Basin: an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay, or any point along a stream channel (USGS).

Bipolar electrodialysis (EDBM): It is a membrane technique that uses the particular property of the bipolar membrane which consists in dissociating water (H+ and OH-) under the action of an electric field (water splitting). A bipolar electrodialysis module (stack) consists of the assembly of bipolar and monopolar membranes (cationic/anionic) that allow the conversion of saline solutions (mineral or organic) into acids and bases. This term is provided by Flor Etchebarne - Water Treatment Business Manager at Eurodia Group.

BOO: (build, own, operate). Contracting model. This type of agreement requires the private provider to build and operate the assets for the provision of the service. In this particular case, the State will only regulate and supervise the provision of the public service, since the ownership of the asset always belongs to the provider investor.

BOOT: (build, own, operate and transfer). Contracting model. In the Public-Private Partnerships established under the BOOT contractual figure, the assets are built and operated by the private company. In this sense, the ownership of these assets belongs to the private consortium until the end of the contract term, at which time they must be transferred to the State. However, the private provider has the right to charge for the direct use of the assets. 

BOT: (build, operate and transfer). Contracting model. This type of contract establishes that the project vehicle company (SVP) must build, operate and then transfer the assets or all the components of the project to the State. In other words, the private company is in charge of executing the work at its own risk and, at the end, charges for the direct use of the project.

Brackish Water: according to the definition of the adjective brackish given by the RAE, it is water with salt. However, in the field of water treatment, it is usually applied to saltwater that does not come from the sea.

Brine mining: Brine mining consists of obtaining salt and chemical products from this salt concentrate. Some other salts or chemical products that can be obtained from the concentrate arise greater interest for their economic value, whether it comes from seawater desalination or brackish water. On the one hand, we can generate Sodium hypochlorite in situ through technologies like electrochlorination or use new technologies based on different variants of electrodialysis to produce chemical products, like Hydrochloric acid or Sodium hydroxide. (Sacyr)

BWRO: Reverse Osmosis Water Desalination

Carbon footprint: The set of greenhouse gasses emissions (CO2, CH4, Nitrous oxide N2O, hydrofluorocarbons HFCs, Perfluorocarbons PFCs and sulphur exafluoride SF) of the Life Cycle, attributable to an organization or a product are called Carbon Footprint (CF). (Source: https://www.ccpb.it/en/blog/certificazione/carbon-and-water-footprint/)

Chlorination: Chlorination of wastewater is a method of chlorine disinfection used in wastewater and drinking water treatment.  It is used to prevent the transmission of diseases and to prevent the development of microscopic algae that cloud the water. Chlorine is added to the wastewater in sufficient quantity to react with all reducing substances, organic matter and ammonia, forming organic chlorine and chloramine compounds (iAgua).

Chlorination systems: traditional system for water disinfection. To be effective, this system also requires proper water maintenance: good filtration, cleaning of surfaces and good water condition (no turbidity and proper pH).

Circular economy: In the water context, it is defined as an economic concept that is interrelated with sustainability. The objective is that the value of products, materials and resources (water, energy, others) is maintained in the economy for as long as possible, and that waste generation is minimized.

Condensation: the process of water vapor in the air turning into liquid water. Water drops on the outside of a cold glass of water are condensed water. Condensation is the opposite process of evaporation (USGS).

- Conventional electrodialysis (EDC): Allows purification, concentration and demineralization. Two types of membranes are used: Cationic membranes that only allow the passage of cations and anionic membranes that only allow the passage of anions. They are impermeable to liquids. An electrodialysis module (stack) is composed of a large number of pairs of cells that delimit the product and brine compartments. This term is provided by Flor Etchebarne - Water Treatment Business Manager at Eurodia Group.

Conveyance loss: water that is lost in transit from a pipe, canal, or ditch by leakage or evaporation. Generally, the water is not available for further use; however, leakage from an irrigation ditch, for example, may percolate to a groundwater source and be available for further use. (USGS).

Dam: A dam is a barrier that stops or restricts the flow of surface water or groundwater. The reservoirs created by dams not only prevent flooding, but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture and navigability.

DB: (Design-Build) Contracting Model. Construction contract where the design and construction of a structure are the responsibility of the same contractor.

DBFO: (Design-Build-Finance-Operate) Contracting model. The private sector party obtains a contract to design, build, finance and operate a capital project. In consideration for fulfilling its obligations under the agreement, the private sector party may be paid by the government agency (e.g., availability payments) or from fees charged to the end users of the project. The government or government-owned entity holds ownership of the project.

Discharge: the volume of water that passes a given location within a given period of time. Usually expressed in cubic feet per second (USGS).

Domestic water use: water used for household purposes, such as drinking, food preparation, bathing, washing clothes, dishes, and dogs, flushing toilets, and watering lawns and gardens (USGS).

Drought: a period of drier-than-normal conditions that results in water-related problems (USGS).

Electrodeionization (EDI)  It is a combination of electrodialysis and ion exchange. Its function is to remove ions from water. The technology consists of a combination of ion exchange resins, both cationic and anionic, ion-selective membranes, an anode, a cathode and the cyclic application of an electric potential. In combination with reverse osmosis (RO), EDI as a final stage allows obtaining deionized water with a much lower salt concentration than that produced by RO.

Electrodialysis (ED): An electrochemical separation process where ions are transferred through ion exchange membranes by means of a direct current (DC) voltage. The process uses a driving force to transfer ionic species from the source water through the cathode (positively charged ions) and anode (negatively charged ions) to a concentrated wastewater stream, creating a more dilute stream (called product). This term is provided by Flor Etchebarne - Water Treatment Business Manager at Eurodia Group.

Electrodialysis reversal (EDR): This is a variation of the EDC process, which uses electrode polarity reversal. EDR works in the same way as EDC, except that the DC polarity is reversed two to four times per hour. In this way, the dilute and concentrated source water compartments are also reversed, as are the chemical reactions at the electrodes. This reversal acts as a self-cleaning mechanism that minimizes fouling and extends membrane life. The configuration is very similar to that of an EDC system, except for the presence of reversing valves This term is provided by Flor Etchebarne - Water Treatment Business Manager at Eurodia Group.

Effluent: the output or outflows from any system that discharges water flows as a result of urban, industrial, or agricultural activities.  

Emerging Contaminants: Contaminants that are discovered in the water supply, chemicals that had not previously been detected (or were previously found in much lower concentrations). These chemicals are known as "contaminants of emerging concern" or simply "emerging contaminants".

Energy recuperator: Mechanical equipment designed to reuse energy from brine water.  They can be isobaric or centrifugal equipment.

EPC: (Engineering - Procurement - Construction) Under this model, the financing to carry out preliminary studies, publish prequalification and tender documents, covering all technical, legal and guarantee disciplines, as well as the investment or operation of the plants are covered by these administrations or utilities.

 EPCC: (Engineering, Procurement, Construction and Commissioning)

Erosion: Weathering and modeling of the earth's crust caused by the action of wind, rain, fluvial, maritime and glacial processes, and by the action of living beings.

Evaporation: the process of liquid water becoming water vapor, including vaporization from water surfaces, land surfaces, and snow fields, but not from leaf surfaces (USGS).

Evapotranspiration: the sum of evaporation and transpiration (USGS).

Flujo de retorno de tratamiento de aguas residuales: agua devuelta al medio ambiente por las instalaciones de tratamiento de aguas residuales (USGS).

Forever chemicals: PFAS (Per- and Polyfluoroalkyl Substances) are a group of synthetic chemicals used to prevent corrosion, reduce friction and make products waterproof and stain resistant (The Guardian).

Freshwater, fresh water: water that contains less than 1,000 milligrams per liter (mg/L) of dissolved solids; generally, more than 500 mg/L of dissolved solids is undesirable for drinking and many industrial uses (USGS).

Giardiasis: a disease that results from an infection by the protozoan parasite Giardia Intestinalis, caused by drinking water that is either not filtered or not chlorinated. The disorder is more prevalent in children than in adults and is characterized by abdominal discomfort, nausea, and alternating constipation and diarrhea (USGS).

Greywater: wastewater from clothes washing machines, showers, bathtubs, hand washing, lavatories and sinks (USGS).

Green energy: is any energy type that is generated from natural resources, such as sunlight, wind or water. It often comes from renewable energy sources that don’t harm the environment through factors such as releasing greenhouse gases into the atmosphere. (Fuente: https://www.twi-global.com/)

Greenwashing: The process of conveying a false impression or providing misleading information about how a company's products are more environmentally friendly (Investopedia).

Hardness: a water quality indication of the concentration of alkaline salts in water, mainly calcium and magnesium. If the water you use is "hard" then more soap, detergent or shampoo is necessary to raise a lather (USGS).

High-temperature electrodialysis: This is a variant of conventional and bipolar electrodialysis that allows solutions to be treated at high temperatures (up to 65°C). This temperature level allows, depending on the application, to reduce the viscosity of the treated solutions, to reduce energy consumption and to reduce the development of most of the microorganisms that can disturb the functioning of the modules (stacks) (Eurodia).

Hydroelectric power water use: the use of water in the generation of electricity at plants where the turbine generators are driven by falling water (USGS).

Hydrologic cycle: the cyclic transfer of water vapor from the Earth's surface via evapotranspiration into the atmosphere, from the atmosphere via precipitation back to earth, and through runoff into streams, rivers, and lakes, and ultimately into the oceans (USGS).

Hydrograph: The hydrograph is a graph that shows the variation over time of some hydrological information such as: water level, flow, sediment load, among others.

Industrial water use: water used for industrial purposes in such industries as steel, chemical, paper, petroleum refining and other (USGS).

Infiltration: flow of water from the land surface into the subsurface (USGS).

Injection well: refers to a well constructed for the purpose of injecting treated wastewater directly into the ground. Wastewater is generally forced (pumped) into the well for dispersal or storage into a designated aquifer. Injection wells are generally drilled into aquifers that don't deliver drinking water, unused aquifers, or below freshwater levels (USGS).

Ion Exchange: is a water treatment process generally used for water softening or demineralization, although it is also used to remove other substances from water in processes such as desalination, deionization, and disinfection.

Irrigation water use: water application on lands to assist in the growing of crops and pastures or to maintain vegetative growth in recreational lands, such as parks and golf courses (USGS).

Liquid Industrial Waste (LIW). These are "waters" resulting from the processing and manufacturing of different products that must be properly treated to avoid harming the sewage system, and finally lakes, rivers and the sea. Term mainly used in Chile.

Livestock water use: water used for livestock watering, feed lots, dairy operations, fish farming, and other on-farm needs (USGS).

Membrane based brine:

Membrane flux: related to the amount of water that reverse osmosis, nanofiltration, or ultrafiltration membrane produces per active area of the membrane.

Membrane recovery: it is the recovery of reverse osmosis membranes at the end of their useful life, which reduces the impact associated with treatment plant waste and its implementation costs. 

Microfiltration: membrane filtration process in which hydrostatic pressure pushes a liquid towards a semi-permeable membrane. Microfiltration membranes have a pore size of 0.1-10 µm.

Milligrams per liter (mg/l): a unit of the concentration of a constituent in water or wastewater. It represents 0.001 gram of a constituent in 1 liter of water. It is approximately equal to one part per million (PPM) (USGS).

Minimum liquid discharge (MLD): near-zero liquid discharge processes that produce highly concentrated waste streams. Typically, MLD is defined as a process that recovers at least 95% of the water (Cleanteq Water).

Mining water use: water use during quarrying rocks and extracting minerals from the land (USGS).

Multimedia filters: They are designed to filter suspended solids in water through several layers of filter media from coarser to finer.  This design results in larger particles being trapped in the upper layers and smaller particles in the lower layers.

Nature-based solutions (NBS): a new concept that encompasses all actions that rely on ecosystems and the services they provide to respond to various societal challenges such as climate change, food security or disaster risk (IUCN).

Nanofiltration: is a membrane filtration process in which hydrostatic pressure pushes a liquid against a semi-permeable membrane. The nanofiltration process can retain particles with a size of 0.1 nm-0.001.

Nano-structured Membranes: nanostructured membranes can be defined as membranes having internal or surface nanostructure. The nanostructured membrane can be a dense membrane incorporated with nanomaterials, a porous membrane with nanoscale pores, or a combination of both. (Witopo Salim, and W.S. Winston Ho (2019) Recent developments on nanostructured polymer-based membranes)

Nephelometric turbidity unit (NTU): unit of measure for the turbidity of water. Essentially, a measure of the cloudiness of water as measured by a nephelometer. Turbidity is based on the amount of light that is reflected off particles in the water (USGS).

Non-point source (NPS) pollution: pollution discharged over a wide land area, not from one specific location. These are forms of diffuse pollution caused by sediment, nutrients, organic and toxic substances originating from land-use activities, which are carried to lakes and streams by surface runoff. Non-point source pollution is contamination that occurs when rainwater, snowmelt, or irrigation washes off plowed fields, city streets, or suburban backyards. As this runoff moves across the land surface, it picks up soil particles and pollutants, such as nutrients and pesticides (USGS).

Non-revenue water (NRW): the difference between the volume of water entering the network and the water charged to the end user. NRW is expressed as a percentage.

Outfall: the place where a sewer, drain, or stream discharges; the outlet or structure through which reclaimed water or treated effluent is finally discharged to a receiving water body (USGS).

Osmosis: is a physical phenomenon related to the movement of a solvent through a semi-permeable membrane. Such action implies a simple diffusion across the membrane without energy consumption. Water osmosis is an important biological phenomenon for the cellular metabolism of living beings.

Osmotized water: water produced from the Reverse Osmosis process which is of very high purity.

Ozonation: Ozonated water is a water potabilization method that consists of diluting ozone in water. Ozone is a disinfectant of bacteria, viruses, parasites and helps in the micro-flocculation and reduction of suspended solids (iAgua).

Particle size: the diameter, in millimeters, of suspended sediment or bed material (USGS).

Particle-size classifications are:
[1] Clay—0.00024-0.004 millimeters (mm);
[2] Silt—0.004-0.062 mm;
[3] Sand—0.062-2.0 mm; and
[4] Gravel—2.0-64.0 mm.

Parts per million: the number of "parts" by weight of a substance per million parts of water. This unit is commonly used to represent pollutant concentrations (USGS).

Pathogen: a disease-producing agent; usually applied to a living organism. Generally, any viruses, bacteria, or fungi that cause disease (USGS).

PFAS: Perfluoroalkylated and polyfluorinated substances are widely used, long-lasting chemicals whose components break down very slowly over time. Many PFASs are found in the blood of people and animals around the world and are present at low levels in a variety of food products and in the environment. PFASs are found in water, air, fish and soil in locations across the country and around the world. Scientific studies have shown that exposure to some PFASs in the environment may be associated with adverse health effects in people and animals. There are thousands of PFAS chemicals, and they are found in many consumer, commercial and industrial products. (Environmental Protection Agency)

pH: a measure of the relative acidity or alkalinity of water. Water with a pH of 7 is neutral; lower pH levels indicate increasing acidity, while pH levels higher than 7 indicate increasingly basic solutions (USGS).

PPP: Public-Private Partnership (PPP) is a type of contract that can be self-sustaining or co-financed. In this type of association between the State and the private sector, the latter provides public services or executes and runs specific public infrastructure works within a given time frame.

Permeate: related to a liquid: to diffuse through or penetrate something

Point-source pollution: water pollution coming from a single point, such as a sewage-outflow pipe (USGS).

Polychlorinated biphenyls (PCBs): a group of synthetic, toxic industrial chemical compounds once used in making paint and electrical transformers, which are chemically inert and not biodegradable. PCBs were frequently found in industrial wastes, and subsequently found their way into surface and groundwaters. As a result of their persistence, they tend to accumulate in the environment. In terms of streams and rivers, PCBs are drawn to sediment, to which they attach and can remain virtually indefinitely (USGS).

Potable water: water of a quality suitable for drinking (USGS).

PPP: Public Private Partnership (PPP) is a type of concession, which can be self-sustaining or co-financed. In this partnership scheme between the State and the private sector, the latter provides public services or executes and exploits certain public infrastructure works, in a determined period of time.

Primary wastewater treatment: the first stage of the wastewater-treatment process where mechanical methods, such as filters and scrapers, are used to remove pollutants. Solid material in sewage also settles out in this process (USGS).

Process Water: water used for multiple purposes, such as cooling systems, boilers, processes, steam production, etc. 

Produced Water: is a term used in the oil industry to describe water produced along with oil and gas.

Public water use: water supplied from a public-water supply and used for such purposes as firefighting, street washing, and municipal parks and swimming pools (USGS).

Raw water: Raw water is water that has not received any treatment and has not yet been introduced into the distribution network. It is found in natural sources and reservoirs, both surface water and groundwater.

Reclaimed wastewater: wastewater-treatment plant effluent that has been diverted for beneficial uses such as irrigation, industry, or thermoelectric cooling instead of being released to a natural waterway or aquifer (USGS).

Recycled Water: is the reuse of treated wastewater for beneficial purposes, such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishment of a groundwater basin.

Reverse Osmosis: For the Royal Academy of Engineering, this is the process that separates one component from another in a solution through the force applied to a semi-permeable membrane.

RO Membranes: Semi-permeable membranes used in the Reverse Osmosis process to remove ions, molecules and larger particles in drinking water.

Saline water: water that contains significant amounts of dissolved solids (USGS).

Seawater brine: the effluent from a desalination process that results in water with a salt concentration greater than 69 grams per liter.

Secondary wastewater treatment: treatment (following primary wastewater treatment) involving the biological process of reducing suspended, colloidal, and dissolved organic matter in effluent from primary treatment systems and which generally removes 80 to 95 percent of the Biochemical Oxygen Demand (BOD) and suspended matter. Secondary wastewater treatment may be accomplished by biological or chemical-physical methods. Activated sludge and trickling filters are two of the most common means of secondary treatment. It is accomplished by bringing together waste, bacteria, and oxygen in trickling filters or in the activated sludge process. This treatment removes floating and settleable solids and about 90 percent of the oxygen-demanding substances and suspended solids. Disinfection is the final stage of secondary treatment (USGS).

Sediment: usually applied to material in suspension in water or recently deposited from suspension. In the plural the word is applied to all kinds of deposits from the waters of streams, lakes, or seas (USGS).

Sedimentation: Process by which materials transported by different agents (gravity, runoff, glaciers or wind) and coming from the erosion and weathering of rocks are deposited or precipitated, becoming sediment.

Sedimentation tanks-: wastewater tanks in which floating wastes are skimmed off and settled solids are removed for disposal (USGS).

Septic tank: a tank used to detain domestic wastes to allow the settling of solids prior to distribution to a leach field for soil absorption. Septic tanks are used when a sewer line is not available to carry them to a treatment plant. A settling tank in which settled sludge is in immediate contact with sewage flowing through the tank, and wherein solids are decomposed by anaerobic bacterial action (USGS).

Settling pond (water quality): an open lagoon into which wastewater contaminated with solid pollutants is placed and allowed to stand. The solid pollutants suspended in the water sink to the bottom of the lagoon and the liquid is allowed to overflow out of the enclosure (USGS).

Sewerage / Sewer: a system of underground pipes that collect and deliver wastewater to treatment facilities or streams (USGS).

Sewage treatment plant: a facility designed to receive the wastewater from domestic sources and to remove materials that damage water quality and threaten public health and safety when discharged into receiving streams or bodies of water. The substances removed are classified into four basic areas:greases and fats; solids from human waste and other sources; dissolved pollutants from human waste and decomposition products; and  dangerous microorganisms. Most facilities employ a combination of mechanical removal steps and bacterial decomposition to achieve the desired results. Chlorine is often added to discharges from the plants to reduce the danger of spreading disease by the release of pathogenic bacteria (USGS).

Smart Water: This is a term related to using modern technological tools such as sensors, drones and techniques such as machine learning or big data to help optimize the water treatment process.

Supernatum: the top level of a fluid at rest; important in many applications of water and wastewater treatment. In particular, it is of concern and often measured in settling tanks and skimmers (USGS).

Suspended sediment: very fine soil particles that remain in suspension in water for a considerable period of time without contact with the bottom. Such material remains in suspension due to the upward components of turbulence and currents and/or by suspension (USGS).

Suspended solids: solids that are not in true solution and that can be removed by filtration. Such suspended solids usually contribute directly to turbidity. Defined in waste management, these are small particles of solid pollutants that resist separation by conventional methods (USGS).

SWRO: acronym for Seawater Reverse Osmosis Desalination

Tertiary wastewater treatment: selected biological, physical, and chemical separation processes to remove organic and inorganic substances that resist conventional treatment practices; the additional treatment of effluent beyond that of primary and secondary treatment methods to obtain a very high quality of effluent. The tertiary wastewater treatment process consists of flocculation basins, clarifiers, filters, and chlorine basins or ozone or ultraviolet radiation processes (USGS).

Thermal pollution: a reduction in water quality caused by increasing its temperature, often due to disposal of waste heat from industrial or power generation processes. Thermally polluted water can harm the environment because plants and animals can have a hard time adapting to it (USGS).

Thermoelectric power water use: water used in the process of the generation of thermoelectric power. Power plants that burn coal and oil are examples of thermoelectric-power facilities (USGS).

Turbidity: the amount of solid particles that are suspended in water and that cause light rays shining through the water to scatter. Thus, turbidity makes the water cloudy or even opaque in extreme cases. Turbidity is measured in nephelometric turbidity units (USGS).

Ultrafiltration: membrane filtration process, in which hydrostatic pressure pushes a liquid against a semi-permeable membrane. Ultrafiltration separates particles with a size of 0.001-0.1 µm.

Ultrapure Water. The Royal Academy of Engineering defines it as laboratory water that has been filtered and purified by reverse osmosis. The term comes from the patented commercial treatment.

UV disinfection: is the treatment of water with the use of lamps that emit ultraviolet radiation that can eliminate pathogens and produce high-quality water.

Wastewater: water that has been used in homes, industries, and businesses that is not for reuse unless it is treated (USGS).

Wastewater-treatment return flow: water returned to the environment by wastewater-treatment facilities (USGS).

Water cycle: the circuit of water movement from the oceans to the atmosphere and to the Earth and return to the atmosphere through various stages or processes such as precipitation, interception, runoff, infiltration, percolation, storage, evaporation, and transportation (USGS).

Watershed: A watershed is a system, a geographical and hydrological unit, consisting of a major river and all its associated territories between the river's source and its mouth. (IUCN)

Water balance: It is based on the application of the principle of conservation of water masses. This measurement method analyzes the inflow and outflow of water from a territorial space over time. (Aquabook)

Water bodies: according to the European Environment Agency Water Glossary is any water body that has defined hydrological, physical, chemical, and biological characteristics that is useful for one or more purposes. 

Water footprint: This is the total freshwater used by a person, community, company or country to produce the goods and services consumed.

Water hammer: A water hammer is a sudden increase in pressure caused by a rapid change in pipe flow velocity that can burst pipes, rupture joints and cause damage to the pump and/or motor.

Water positive: A company is water positive when it creates more water than what it uses rather than simply replacing water that is taken from the environment (Piperepair).

Water purification: The RAE states that purification is the action of making water potable (i.e., suitable for human consumption and not representing a health risk). It refers specifically to water for human consumption for drinking, and it can be done with water extracted from different sweet and brackish sources and even from effluent treatment.

Water quality: a term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose (USGS).

Water Stress: Different international organizations define it and make it part of their goals. The European Environment Agency, through the Water Information System for Europe (WISE), states that Water Stress occurs when the water demand exceeds the amount available during a given period or when poor quality limits its use. Water stress causes the deterioration of freshwater resources in both quantity (overexploitation of aquifers, dry rivers, etc.) and quality (eutrophication, organic matter contamination, saline intrusion, etc.).