Azolla pinnata | |
---|---|
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | Polypodiophyta |
Class: | Polypodiopsida |
Order: | Salviniales |
Family: | Salviniaceae |
Genus: | Azolla |
Species: | A. pinnata |
Binomial name | |
Azolla pinnata | |
Azolla pinnata is a species of fern known by several common names, including mosquitofern, [2] feathered mosquitofern and water velvet. It is native to much of Africa, Asia (Brunei Darussalam, China, India, Japan, Korea, and the Philippines) and parts of Australia. It is an aquatic plant, it is found floating upon the surface of the water. It grows in quiet and slow-moving water bodies because swift currents and waves break up the plant. [3] At maximum growth rate, it can double its biomass in 1.9 days, with most strains attaining such growth within a week under optimal conditions. [4]
A. pinnata is a small fern with a triangular stem measuring up to 2.5 centimeters in length that floats on the water. The stem bears many rounded or angular overlapping leaves each 1 or 2 millimeters long. They are green, blue-green, or dark red in color and coated in tiny hairs, giving them a velvety appearance. [3] The hairs make the top surface of the leaf water-repellent, keeping the plant afloat even after being pushed under. [3] A water body may be coated in a dense layer of the plants, which form a velvety mat that crowds out other plants. [3] The hairlike roots extend out into the water. [3] The leaves contain the cyanobacterium Anabaena azollae , which is a symbiont that fixes nitrogen from the atmosphere that the fern can use. [3] [5] This gives the fern the ability to grow in habitats that are low in nitrogen. [5]
The plant reproduces vegetatively when branches break off the main axis, or sexually when sporocarps on the leaves release spores. [6]
It is present in New Zealand as an introduced species and an invasive weed that has crowded out a native relative, Azolla rubra . [3] It is a pest of waterways because its dense mats reduce oxygen in the water. [7] The weevil Stenopelmus rufinasus is used as an agent of biological pest control to manage Azolla filiculoides , and it has been found to attack A. pinnata as well. [8]
Rice farmers sometimes keep this plant in their paddies because it generates valuable nitrogen via its symbiotic cyanobacteria. [3] [6] The plant can be grown in wet soil and then plowed under, generating a good amount of nitrogen-rich fertilizer. [9] The plant has the ability to absorb a certain amount of heavy metal pollution, such as lead, from contaminated water. [10] It is 25-30% protein and can be added to chicken feed. [11] [12]
Recent studies show the usefulness of Azolla pinnata in the remediation of environmental pollutants. There are two main methods for utilising A. pinnata to clean up environmental pollutants. The first method is by adsorption, which required the A. pinnata fronds to be processed into powder and agitated with the wastewater for a fixed duration. The pollutant will adhere to the organic functional groups on the surface of the A. pinnata powder. In adsorption studies, A. pinnata was reported in the remediation of dye wastewater containing methyl violet 2B, [13] malachite green, [14] rhodamine B, [15] acid red 88 [16] and acid blue 25. [17]
The second remediation method is phytoremediation, where living A. pinnata is suspended on the surface of the wastewater. A. pinnata was primarily studied due to its high tolerance to environmental pollutants, and ability to hyperaccumulate heavy metals. [18] Phytoremediation of industrial wastewater containing heavy metals (such as zinc, lead, [19] chromium, [20] mercury, cadmium, [21] copper, arsenic [18] ) as well as organic dyes such as methyl violet 2B [22] and malachite green [23] are reported in literature. A.pinnata is also reported to be useful for treating the wastewater (remove nitrogenous waste and phosphorus) of poultry farms. [24]
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water pollution is the contamination of water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants mix with these water bodies. Contaminants can come from one of four main sources. These are sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. Water pollution may affect either surface water or groundwater. This form of pollution can lead to many problems. One is the degradation of aquatic ecosystems. Another is spreading water-borne diseases when people use polluted water for drinking or irrigation. Water pollution also reduces the ecosystem services such as drinking water provided by the water resource.
Bioremediation broadly refers to any process wherein a biological system, living or dead, is employed for removing environmental pollutants from air, water, soil, flue gasses, industrial effluents etc., in natural or artificial settings. The natural ability of organisms to adsorb, accumulate, and degrade common and emerging pollutants has attracted the use of biological resources in treatment of contaminated environment. In comparison to conventional physicochemical treatment methods bioremediation may offer advantages as it aims to be sustainable, eco-friendly, cheap, and scalable.
Wastewater treatment is a process which removes and eliminates contaminants from wastewater. It thus converts it into an effluent that can be returned to the water cycle. Once back in the water cycle, the effluent creates an acceptable impact on the environment. It is also possible to reuse it. This process is called water reclamation. The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater the treatment plant is called a Sewage Treatment. Municipal wastewater or sewage are other names for domestic wastewater. For industrial wastewater, treatment takes place in a separate Industrial wastewater treatment, or in a sewage treatment plant. In the latter case it usually follows pre-treatment. Further types of wastewater treatment plants include Agricultural wastewater treatment and leachate treatment plants.
Casuarina equisetifolia, commonly known as coastal she-oak, horsetail she-oak, ironwood,beach sheoak, beach casuarina, whistling tree or Australian pine is a species of flowering plant in the family Casuarinaceae and is native to Australia, New Guinea, Southeast Asia and India. It is a small to medium-sized, monoecious tree with scaly or furrowed bark on older specimens, drooping branchlets, the leaves reduced to scales in whorls of 7 or 8, the fruit 10–24 mm (0.4–0.9 in) long containing winged seeds (samaras) 6–8 mm (0.2–0.3 in) long.
Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc, Cylindrospermum, and Anabaena. They fix nitrogen from dinitrogen (N2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis.
Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronomic techniques to either contain, remove or render toxic environmental contaminants harmless". The term is an amalgam of the Greek phyto (plant) and Latin remedium. Although attractive for its cost, phytoremediation has not been demonstrated to redress any significant environmental challenge to the extent that contaminated space has been reclaimed.
A constructed wetland is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development. Constructed wetlands are engineered systems that use the natural functions of vegetation, soil, and organisms to provide secondary treatment to wastewater. The design of the constructed wetland has to be adjusted according to the type of wastewater to be treated. Constructed wetlands have been used in both centralized and decentralized wastewater systems. Primary treatment is recommended when there is a large amount of suspended solids or soluble organic matter.
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans. This applies to industries that generate wastewater with high concentrations of organic matter, toxic pollutants or nutrients such as ammonia. Some industries install a pre-treatment system to remove some pollutants, and then discharge the partially treated wastewater to the municipal sewer system.
Artocarpus odoratissimus is a species of flowering plant in the Moraceae family. It is a commonly called marang, madang, timadang, terap, tarap, kiran, green pedalai, or johey oak. It is native to Borneo, Palawan, and Mindanao Island, and is closely related to the jackfruit, cempedak, and breadfruit trees which all belong to the same genus, Artocarpus.
Mycoremediation is a form of bioremediation in which fungi-based remediation methods are used to decontaminate the environment. Fungi have been proven to be a cheap, effective and environmentally sound way for removing a wide array of contaminants from damaged environments or wastewater. These contaminants include heavy metals, organic pollutants, textile dyes, leather tanning chemicals and wastewater, petroleum fuels, polycyclic aromatic hydrocarbons, pharmaceuticals and personal care products, pesticides and herbicides in land, fresh water, and marine environments.
Electrocoagulation (EC) is a technique used for wastewater treatment, wash water treatment, industrially processed water, and medical treatment. Electrocoagulation has become a rapidly growing area of wastewater treatment due to its ability to remove contaminants that are generally more difficult to remove by filtration or chemical treatment systems, such as emulsified oil, total petroleum hydrocarbons, refractory organics, suspended solids, and heavy metals. There are many brands of electrocoagulation devices available, and they can range in complexity from a simple anode and cathode to much more complex devices with control over electrode potentials, passivation, anode consumption, cell REDOX potentials as well as the introduction of ultrasonic sound, ultraviolet light and a range of gases and reactants to achieve so-called Advanced Oxidation Processes for refractory or recalcitrant organic substances.
Bioretention is the process in which contaminants and sedimentation are removed from stormwater runoff. The main objective of the bioretention cell is to attenuate peak runoff as well as to remove stormwater runoff pollutants.
Advanced oxidation processes (AOPs), in a broad sense, are a set of chemical treatment procedures designed to remove organic (and sometimes inorganic) materials in water and wastewater by oxidation through reactions with hydroxyl radicals (·OH). In real-world applications of wastewater treatment, however, this term usually refers more specifically to a subset of such chemical processes that employ ozone (O3), hydrogen peroxide (H2O2) and UV light or a combination of the few processes.
Rhizofiltration is a form of phytoremediation that involves filtering contaminated groundwater, surface water and wastewater through a mass of roots to remove toxic substances or excess nutrients.
The electrochemical regeneration of activated carbon based adsorbents involves the removal of molecules adsorbed onto the surface of the adsorbent with the use of an electric current in an electrochemical cell restoring the carbon's adsorptive capacity. Electrochemical regeneration represents an alternative to thermal regeneration commonly used in waste water treatment applications. Common adsorbents include powdered activated carbon (PAC), granular activated carbon (GAC) and activated carbon fibre.
Ranunculus trichophyllus, the threadleaf crowfoot, or thread-leaved water-crowfoot, is a plant species in the genus Ranunculus, native to Europe, Asia and North America.
Bioremediation of petroleum contaminated environments is a process in which the biological pathways within microorganisms or plants are used to degrade or sequester toxic hydrocarbons, heavy metals, and other volatile organic compounds found within fossil fuels. Oil spills happen frequently at varying degrees along with all aspects of the petroleum supply chain, presenting a complex array of issues for both environmental and public health. While traditional cleanup methods such as chemical or manual containment and removal often result in rapid results, bioremediation is less labor-intensive, expensive, and averts chemical or mechanical damage. The efficiency and effectiveness of bioremediation efforts are based on maintaining ideal conditions, such as pH, RED-OX potential, temperature, moisture, oxygen abundance, nutrient availability, soil composition, and pollutant structure, for the desired organism or biological pathway to facilitate reactions. Three main types of bioremediation used for petroleum spills include microbial remediation, phytoremediation, and mycoremediation. Bioremediation has been implemented in various notable oil spills including the 1989 Exxon Valdez incident where the application of fertilizer on affected shoreline increased rates of biodegradation.
Electro-oxidation(EO or EOx), also known as anodic oxidation or electrochemical oxidation (EC), is a technique used for wastewater treatment, mainly for industrial effluents, and is a type of advanced oxidation process (AOP). The most general layout comprises two electrodes, operating as anode and cathode, connected to a power source. When an energy input and sufficient supporting electrolyte are provided to the system, strong oxidizing species are formed, which interact with the contaminants and degrade them. The refractory compounds are thus converted into reaction intermediates and, ultimately, into water and CO2 by complete mineralization.
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