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  2. Recirculating aquaculture system - Wikipedia

    en.wikipedia.org/wiki/Recirculating_aquaculture...

    All RAS relies on biofiltration to convert ammonia (NH 4 + and NH 3) excreted by the fish into nitrate. [4] Ammonia is a waste product of fish metabolism and high concentrations (>.02 mg/L) are toxic to most finfish. [5] Nitrifying bacteria are chemoautotrophs that convert ammonia into nitrite (NO 2 −) then nitrate (NO 3 −).

  3. Raceway (aquaculture) - Wikipedia

    en.wikipedia.org/wiki/Raceway_(aquaculture)

    However, in most cases it is necessary to frequently clean raceways. The simplest way is to lower the water level in the raceway units, which increases the speed of the water current, and then herd the fish together till they flush the waste from the raceway. [17] Solid wastes which accumulate at the raceway bottom can be removed by pumps. [19]

  4. Agricultural wastewater treatment - Wikipedia

    en.wikipedia.org/wiki/Agricultural_wastewater...

    Excess sediment causes high levels of turbidity in water bodies, which can inhibit growth of aquatic plants, clog fish gills and smother animal larvae. [6] Farmers may utilize erosion controls to reduce runoff flows and retain soil on their fields. Common techniques include: contour ploughing [7] crop mulching [8] crop rotation; planting ...

  5. Aquarium filter - Wikipedia

    en.wikipedia.org/wiki/Aquarium_filter

    Canister filters were initially designed to filter drinking water, under low pressure. Canister filters for aquariums [17] use high water pressure, from a properly powered pump, to force water through the dense filter media. A pump can draw water from an under-gravel filter, and run it into a canister for double filtration.

  6. Nutrient pollution - Wikipedia

    en.wikipedia.org/wiki/Nutrient_pollution

    Sources of nutrient pollution include surface runoff from farm fields and pastures, discharges from septic tanks and feedlots, and emissions from combustion. Raw sewage is a large contributor to cultural eutrophication since sewage is high in nutrients. Releasing raw sewage into a large water body is referred to as sewage dumping, and still ...

  7. Ammonia poisoning - Wikipedia

    en.wikipedia.org/wiki/Ammonia_poisoning

    The source of ammonia in fish tanks is fish's excretion. [1] Fish excrete ammonia as a nitrogenous waste product. A build-up of ammonia in the fish tank leads to ammonia poisoning. Species of ammonia-oxidizing bacteria (AOB) can break down the ammonia and convert it to other, less toxic, nitrogen products.

  8. Leaching (agriculture) - Wikipedia

    en.wikipedia.org/wiki/Leaching_(agriculture)

    soil type and structure. For example, sandy soil holds little water while clay soils have high water-retention rates; the amount of water used by the plants/crops; how much nitrate is already present in the soil. [3] The level of nitrous oxide (N 2 O) in the Earth's atmosphere is increasing at a rate of 0.2 to 0.3% annually.

  9. Deep sand bed - Wikipedia

    en.wikipedia.org/wiki/Deep_sand_bed

    A deep sand bed is commonly defined as a bed of fine sand with a minimum depth of four to six inches which ensures that a portion of the sand at the bottom will not be exposed to significant circulation of water.