Commonly Used Terms
ALADYR provides the community with this glossary of terms to standardize concepts among interested parties such as the media, educational institutions, commercial and non-profit companies, organizations, government agencies, among others. It is still under construction, and we aim to add more and more terms every day and become a reference and consultation source for interested parties. If you wish to contribute with a new term or enhance the existing ones, please reach us at [email protected]. Your contribution will be credited to your company. (Only applies for ALADYR members)
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Abrasion (membrane): gradual wear or damage of the RO membrane due to friction and mechanical action of solid particles present in the water flowing through the system. This abrasion can result in the formation of holes or cracks in the membrane, which in turn reduces filtration efficiency and can lead to a decrease in RO system performance.

Acid-: a substance that has a pH of less than 7, which is neutral. Specifically, an acid has more free hydrogen ions (H+) than hydroxyl ions (OH-). (USGS)

Activated carbon filters: They are mainly used for the removal of chlorine and organic compounds in water. The operating system is similar to sand filters, with the retention of contaminants by passing the water through a filtering bed composed of activated carbon (Se Filtra).

Activated carbon adsorbent: A material used to remove organic contaminants from water by adsorption.

Activated sludge:  a system is a wastewater treatment process based on the use of microorganisms (mainly facultative heterotrophic bacteria), which grow in the wastewater, converting dissolved organic matter into simpler products such as new bacteria, carbon dioxide and water. It is a secondary or biological treatment in a wastewater treatment plant (WWTP) and is the most commonly used both municipally and industrially (Source: Iagua).

Activated Sludge Process (ASP): A biological wastewater treatment process that speeds up the decomposition of wastes in the wastewater being treated. Activated sludge is added to wastewater and the mixture (mixed liquor) is aerated and agitated. After some time in the aeration tank, the activated sludge is allowed to settle out by sedimentation and is disposed of (wasted) or reused (returned to the aeration tank) as needed. The remaining wastewater then undergoes more treatment. (Sacramento State)

Aeration: A technique used in water treatment that requires a source of oxygen, commonly known as aerobic biological water purification. This technique brings water into contact with air droplets or by spraying the air with aeration facilities. Then presses the air through the water surface, and bubbles and supplies water with oxygen.

Adhesion: the process of water being attracted or adhering to other substances (USGS).

Adsorbent resins: These resins have the ability to adsorb or retain molecules and particles on their surface. They are used to remove organic compounds, chemicals and other impurities from water.

Adsorption: The process in which particles, atoms or molecules attach or adhere to the surface of a solid or liquid.

Absorption wells: Subway structures used for infiltration of rainwater or treated wastewater into the ground.

Advanced oxidation: A treatment process that uses strong oxidizing agents, such as ozone or hydrogen peroxide, to degrade pollutants in water.

Alkalinity: the capacity of water for neutralizing an acid solution. (USGS)

Advanced Wastewater Treatment (AWT): Any process which reduces the level of impurities in a wastewater below that attainable through conventional secondary or biological treatment. Includes the removal of nutrients such as phosphorus and nitrogen and a high percentage of suspended solids (Source: Institute for Sustainability).

Aerobic bacteria bed: A biological system that uses aerobic microorganisms to treat wastewater by oxidizing organic compounds.

Air-assisted chemical precipitation: A process in which air is injected into the water to aid in the removal of contaminants through the formation of precipitates.

Air-assisted direct osmosis (AIDRO): A direct osmosis process that uses the addition of air to improve efficiency and reduce salinity concentration.

Algal bloom:  is a rapid increase in the population of algae in an aquatic system. (Source: Science Daily)

Aluminum oxide: A compound used in coagulation and flocculation processes in water treatment.

Aluminum polyhydroxychlorosulfate (PACl): An inorganic coagulant used in the treatment of drinking water and wastewater for the removal of suspended solids and turbidity.

Aluminum sulfate [alum, Al2(SO4)3]: The most widely used inorganic coagulant for metal removal, oil and grease separation, and water clarification. Easy to handle. Optimum pH range of 6.5 to 7.5. Widely used and cost-effective. Low effectiveness at pH>7.5. Causes aluminum fouling in case of overdosage (Source: H2O Innovation).

Anaerobic treatment: A biological treatment process that is carried out in the absence of oxygen.

Aqueduct: is a system or set of irrigation systems that enables water to be conveyed in a continuous flow from a place where it is accessible in nature to a distant point of consumption, generally a city or town.

Aquifers: a geologic formation(s) that is water bearing. A geological formation or structure that stores and/or transmits water, such as to wells and springs (USGS). 

Antiscalants: a family of chemicals designed to inhibit the formation and precipitation of crystallized mineral salts that form scale. (Source: Ahmad Fauzi Ismail, Kailash Chandra Khulbe, Takeshi Matsuura)

Artificial recharge: a process where water is put back into groundwater storage from surface-water supplies such as irrigation, or induced infiltration from streams or wells (USGS).

Attenuated Total Reflection (ATR- FTIR): Fourier Transform Infrared Spectroscopy is a powerful tool for identifying types of chemical bonds. When infrared radiation passes through a sample, some of the radiation is absorbed by the sample and some is transmitted. The resulting signal at the detector is a molecular "fingerprint" of the sample. This test makes it possible to see the spectral fingerprints of different chemical structures (Source: AWC)

Autotrophic microorganisms: Organisms that can synthesize their food using energy from sunlight or inorganic chemicals.