Treatment pond
Encyclopedia
A treatment pond treats water fouled by anaerobic
bacteria
. It is used mainly by tree nurseries, dairy
farms and other agricultural companies near horse or cattle shed
s or barns. The pond treats polluted stormwater
and animal wastewater
so that it may be returned to the environment as fertilizer
and irrigation
water.
to form an ecological, self-purifying irrigation reservoir or swimming pond. A pond may dispose or treat industrial liquid wastes. An example is the Martinez, California
treatment ponds developed by IT Corporation
. Small-scale treatment can be done in small pond
s if the effluent
is given time to break into harmless nutrients. However, smaller ponds may need to be divided in much the same manner as septic tank
s.
All three are placed in a closed basin with a substrate. For most commercial purposes (e.g., agriculture) ponds are lined with rubber to ensure being watertight (essential in urban areas). The substrate can be gravel
, sand
or lavastone.
Surface flow reedbeds use a horizontal flow of waste water between plant roots. They are no longer much used, as they need considerable space (A person requires 20 m2 to purify the water they use.) They have increased smell and poorer purification in winter.
With subsurface flow reedbeds, the flow of waste water is between plant roots, but not at the water surface. This is more efficient, less smelly and less sensitive to winter conditions. The soil to purify water is 5–10 m2 per person. Intakes, which can clog easily, are a potential problem.
Vertical flow reedbeds are similar to subsurface flow reedbeds (subsurface wastewater flow is present here as well). Therefore they have similar efficiency and winter hardiness. Wastewater flow is somewhat different though, as it is vertical. The water is distributed through a set of perforated distribution pipes in the top layer of gravel. The wastewater then passes a layer of fine sand mixed with iron and chalk and there it is purified by bacteria that live on the sand grains and in higher concentrations near the plant roots. The purified water is then collected in drainage pipes that are embedded in the bottom layer of gravel. Other than the two previous systems, this system almost makes exclusive use of fine sand
to increase bacteria counts. Intake of oxygen into the water is better. Pumping is done in pulse
s to reduce obstructions with the intakes. Only 3 m2 is needed to purify the water for one person.
are used in treatment ponds (e.g., in greywater treatment systems to purify wastewater). In self-purifying water reservoirs(used to purify rainwater), other plants are used as well. These reservoirs need to be filled with 1/4 lavastones and water-purifying plants.
Treatment ponds use a wide variety of plants, depending on the local climate and other conditions. Plants are generally chosen which are indigenous, for environmental reasons and optimum performance. In addition to water purifying (de-nutrifying) plants, plants that supply oxygen, and shade are added in ecological water catchments
, ponds. This allows a complete ecosystem
. Local bacteria
and non-predatory fish may be added to eliminate pests. The bacteria are usually grown by submerging straw
in water and allowing bacteria from the surrounding air to form on it. Plants are divided in four water depth-zones:
Three non-predatory fish (surface, bottom and ground-swimmers) are chosen. This ensures the fish 'get along'. Examples for temperate climates are:
The plants are usually grown on coconut
fibre. At the time of implantation to water-purifying ponds, de-nutrified soil is used to prevent growth of algae
and other unwanted organisms
s may be added.
s can be built from a simple substrate (as is being done in Dongtan) or with plant-based ponds (as is being done by WaterWorks UK Grow System). Waterzuiveren.be Plants used include calamus, Menyanthes trifoliata, Mentha aquatica, ...
Anaerobic organism
An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
. It is used mainly by tree nurseries, dairy
Dairy
A dairy is a business enterprise established for the harvesting of animal milk—mostly from cows or goats, but also from buffalo, sheep, horses or camels —for human consumption. A dairy is typically located on a dedicated dairy farm or section of a multi-purpose farm that is concerned...
farms and other agricultural companies near horse or cattle shed
Shed
A shed is typically a simple, single-storey structure in a back garden or on an allotment that is used for storage, hobbies, or as a workshop....
s or barns. The pond treats polluted stormwater
Stormwater
Stormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...
and animal wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
so that it may be returned to the environment as fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
and irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
water.
Uses of treatment ponds
A treatment pond may be used in combination with a rainwater reservoirReservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
to form an ecological, self-purifying irrigation reservoir or swimming pond. A pond may dispose or treat industrial liquid wastes. An example is the Martinez, California
Martinez, California
Martinez is a city and the county seat of Contra Costa County, California, United States. The population was 35,824 at the 2010 census. The downtown is notable for its large number of preserved old buildings...
treatment ponds developed by IT Corporation
IT Corporation
IT Corporation was a United States industrial company whose principal business was the disposal of industrial hazardous waste. At least as early as the 1970s the company was one of the largest market share holders of the liquid hazardous waste disposal sector in the western U.S...
. Small-scale treatment can be done in small pond
Pond
A pond is a body of standing water, either natural or man-made, that is usually smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens, water features and koi ponds; all designed for aesthetic ornamentation as landscape or architectural...
s if the effluent
Effluent
Effluent is an outflowing of water or gas from a natural body of water, or from a human-made structure.Effluent is defined by the United States Environmental Protection Agency as “wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers...
is given time to break into harmless nutrients. However, smaller ponds may need to be divided in much the same manner as septic tank
Septic tank
A septic tank is a key component of the septic system, a small-scale sewage treatment system common in areas with no connection to main sewage pipes provided by local governments or private corporations...
s.
Constructed wetlands
Urban areas
Three reedbed flow configurations are commonly in use. Each is being used in commercial systems (usually together with septic tanks). They are:- Surface flow (SF) reedbeds
- Subsurface Flow (SSF) reedbeds
- Vertical Flow (VF) reedbeds
All three are placed in a closed basin with a substrate. For most commercial purposes (e.g., agriculture) ponds are lined with rubber to ensure being watertight (essential in urban areas). The substrate can be gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
, sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
or lavastone.
Design characteristics
With subsurface flow reedbeds, the flow of waste water is between plant roots, but not at the water surface. This is more efficient, less smelly and less sensitive to winter conditions. The soil to purify water is 5–10 m2 per person. Intakes, which can clog easily, are a potential problem.
Vertical flow reedbeds are similar to subsurface flow reedbeds (subsurface wastewater flow is present here as well). Therefore they have similar efficiency and winter hardiness. Wastewater flow is somewhat different though, as it is vertical. The water is distributed through a set of perforated distribution pipes in the top layer of gravel. The wastewater then passes a layer of fine sand mixed with iron and chalk and there it is purified by bacteria that live on the sand grains and in higher concentrations near the plant roots. The purified water is then collected in drainage pipes that are embedded in the bottom layer of gravel. Other than the two previous systems, this system almost makes exclusive use of fine sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
to increase bacteria counts. Intake of oxygen into the water is better. Pumping is done in pulse
Pulse
In medicine, one's pulse represents the tactile arterial palpation of the heartbeat by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed against a bone, such as at the neck , at the wrist , behind the knee , on the inside of the elbow , and near the...
s to reduce obstructions with the intakes. Only 3 m2 is needed to purify the water for one person.
Organisms
Usually, common reed or Phragmites australisPhragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...
are used in treatment ponds (e.g., in greywater treatment systems to purify wastewater). In self-purifying water reservoirs(used to purify rainwater), other plants are used as well. These reservoirs need to be filled with 1/4 lavastones and water-purifying plants.
Treatment ponds use a wide variety of plants, depending on the local climate and other conditions. Plants are generally chosen which are indigenous, for environmental reasons and optimum performance. In addition to water purifying (de-nutrifying) plants, plants that supply oxygen, and shade are added in ecological water catchments
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
, ponds. This allows a complete ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
. Local bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and non-predatory fish may be added to eliminate pests. The bacteria are usually grown by submerging straw
Straw
Straw is an agricultural by-product, the dry stalks of cereal plants, after the grain and chaff have been removed. Straw makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has many uses, including fuel, livestock bedding and fodder, thatching and...
in water and allowing bacteria from the surrounding air to form on it. Plants are divided in four water depth-zones:
- A water depth from 0–20 cm. Iris pseudacorusIris pseudacorusIris pseudacorus is a species of Iris, native to Europe, western Asia and northwest Africa. Common names include yellow iris and yellow flag...
, Sparganium erectumSparganiumSparganium is a genus of flowering plants, containing about 20 species in temperate regions of both the Northern and Southern Hemispheres. It was previously placed alone in the family Sparganiaceae...
may be placed here (temperate climates). - A water depth from 40–60 cm. Stratiotes aloidesStratiotesStratiotes is a genus of submerged aquatic plant commonly known as water soldiers. A characteristic of the genus is the habit of the plants rising to the surface at flowering time.-Description:...
, Hydrocharis morsus-ranaeHydrocharisHydrocharis is a genus of aquatic plants within the family Hydrocharitaceae.The best known species is Hydrocharis morsus-ranae, commonly called common or European frogbit, and occasionally water-poppy. The name "American frogbit" refers to another aquatic plant, Limnobium spongia....
may be placed here (temperate climates). - A water depth from 60–120 cm. Nymphea albaNymphaeaNymphaea is a genus of aquatic plants in the family Nymphaeaceae. There are about 50 species in the genus, which has a cosmopolitan distribution.-Name:The common name, shared with some other genera in the same family, is Water Lily....
, may be placed here (temperate climates). - A submerged water depth. Myriophyllum spicatumMyriophyllumMyriophyllum is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The center of diversity for Myriophyllum is Australia with 43 recognized species...
may be placed here (temperate climates).
Three non-predatory fish (surface, bottom and ground-swimmers) are chosen. This ensures the fish 'get along'. Examples for temperate climates are:
- Surface swimming fish: Leuciscus leuciscus, Leuciscus idus, and Scardinius erythrophthalmus
- Middle-swimmers: Rutilus rutilus
- Bottom-swimming fish: Tinca tinca
The plants are usually grown on coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...
fibre. At the time of implantation to water-purifying ponds, de-nutrified soil is used to prevent growth of algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and other unwanted organisms
Finishing
These systems, for example, aerate the water after the final reedbed using cascades such as flowforms before holding the water in a shallow pond. Primary treatments such as septic tanks, and pumps such as grinder pumpGrinder pump
A grinder pump is a waste management device. Waste from water-using household appliances flows through the home’s pipes into the grinder pump’s holding tank. Once the waste inside the tank reaches a specific level, the pump will turn on, grind the waste into a fine slurry, and pump it to the...
s may be added.
Rooftop treatment ponds
Rooftop water purifying ponds are being used on rooftops. These green roofGreen roof
A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems...
s can be built from a simple substrate (as is being done in Dongtan) or with plant-based ponds (as is being done by WaterWorks UK Grow System). Waterzuiveren.be Plants used include calamus, Menyanthes trifoliata, Mentha aquatica, ...