Treatment pond

A treatment pond is a type of pond which is constructed to treat lightly polluted water or wastewater. A treatment pond may be used in combination with a rainwater reservoir to form an ecological, self-purifying irrigation reservoir or swimming pond.

Waste treatment ponds are very efficient even though their design has not changed in years. The plants work well in nearly all environments and can treat most forms of wastewater produced. Treatment ponds are used for smaller purposes in the United States but are used for major cities and factories in the rest of the world, as it is a simple and effective method to treat water. Many improvements have been made to improve their effectiveness and efficiency at turning harmful chemicals and sewage into less harmful forms of the previous. With ponds there is a variety of key elements to take care of in order to be properly maintained for the wastewater to be properly treated. Factors such as oxygen levels and flow through the ponds are just a few of the critical factors to properly maintaining the ponds. These factors are constantly monitored to maintain the pond and gain information on what factors are working the best in order to speed up the breakdown of harmful chemicals at the most efficient rate. Treatment ponds that are aerobic, anaerobic or facultative flow through basins are used in order to begin the water treatment process. Anaerobic ponds are used to treat water with industrial waste whereas aerobic ponds are used to treat water contaminated from other plant processes. Facultative ponds are good to treat raw wastewater and water that was not treated properly in the other ponds because it is both aerobic and anaerobic. Aerobic ponds are saturated with dissolved oxygen throughout the entire pond and are shallow enough for light to penetrate the entire depth of the pond. Anaerobic ponds allow the solid waste to settle down at the bottom as a waste sludge while dissolving organic material.

Typically fresh wastewater has a musty odor and is cloudy with a grayish coloration as it is fresh and untreated. When deprived of oxygen the water becomes black from further with a foul odor. The odor is that of rotten eggs and the water becomes corrosive inviting problems to form in the pipes, so usually treatment workers try to keep it from getting too oxygen deprived while in pipes. Temperature can be anywhere between 45–75 °F (7–24 °C), but the temperature of water entering the system usually does not affect the pond, because it is designed to handle a variety of temperatures. The pH of the system is a huge factor in pond water characteristics with the water either being acidic 0.0–7.0 or basic 7.0–14.0. The pH levels are monitored to make sure that the water does not get too acidic and start to corrode the pipes. It is most desirable for the water to be more basic so as to prevent corrosion from the acid. Another set of characteristics is the contents of the water, like solids, suspended solids and dissolved solids. Dissolved solids are able to pass through most filters whereas suspended solids are just particles suspended in the water column easily caught in strainers or filters. Solids is just a general term for what would remain if all of the water was evaporated from a sample of the wastewater. To get into more technical terms colloidal solids are particles that are so small that they will not settle by gravity on their own. Settleable solids are pretty much self-explanatory as they are the solids that will settle on their own in a given period of time.

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