Reclamation

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Reclamation is the process of reclaiming something from loss or from a less useful condition. It is generally used of water reclamation, which, a century ago meant damming streams (thus the US Bureau of Reclamation owning dams), and now has come to be used to describe wastewater reclamation.

Water reclamation is a process by which water used in houses and businesses goes down the drain and becomes wastewater, which is then cleaned using biological and chemical processes so the water can be returned to the environment safely to augment the natural systems from which they came. It is used today as both aquifer and stream enhancement strategy.

[edit] Reclamation Processes

Wastewater must pass through numerous systems before being returned to the environment. Here is a partial listing from one particular plant system:

  • Barscreens - Barscreens remove large solids that are sent into a grinder. All solids are then dumped into a sewer pipe at a Treatment Plant.
  • Primary Settling Tanks - Readily settable and floatable solids are removed from the wastewater. These solids are skimmed from the top and bottom of the tanks and sent to the Treatment Plant.
  • Secondary Treatment - The wastewater is cleaned through a biological treatment method that uses microorganisms, bacteria which digest the sludge and reduce the nutrient content. Air bubbles up to keep the organisms suspended and to supply oxygen to the areobic bacteria so they can metabolize the food, convert it to energy, CO2, and water, and reproduce more microorganisms. This helps to remove ammonia also through nitrification.
  • Secondary Settling Tanks - The force of the flow slows down as sewage enters these tanks, allowing the microorganisms to settle to the bottom. As they settle, other small particles suspended in the water are picked up, leaving behind clear wastewater. Some of the microorganisms that settle to the bottom are returned to the system to be used again.
  • Tertiary Treatment - Deep-bed, single-media, gravity sand filters receive water from the secondary basins and filter out the remaining solids. As this is the final process to remove solids, the water in these filters is almost completely clear.
  • Chlorine Contact Tanks - Three chlorine contact tanks disinfect the water to decrease the risks associated with discharging wastewater containing human pathogens. This step protects the quality of the waters that receive the wastewater discharge.

One of two procedures are then followed according to the future disposal site:

  1. Reclaimed Water Pump Station - The pump station distributes reclaimed water to users around the City. This may include golf courses, agricultural uses, cooling towers, or in land fills.
  2. Water is passed through high level purification to be returned to the environment. Currently this means a reverse osmosis system.

[edit] See also