Water hyacinth is a free-floating perennial aquatic plant(or hydrophyte) native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in height. The leaves are 10–20 cm across, and float above the water surface. They have long, spongy and bulbous stalks. The feathery, freely hanging roots are purple-black. An erect stalk supports a single spike of 8-15 conspicuously attractive flowers, mostly lavender to pink in colour with six petals. When not in bloom, water hyacinth may be mistaken for frog's-bit (Limnobium spongia).
Water hyacinth is listed as one of the most productive plants on earth and is considered the world's worst aquatic plant.
Uses
Since the water hyacinths are so prolific, harvesting them for industrial use serves also as a means of environmental control.
Since the plant has abundant nitrogen content, it can be used a substrate for biogas production and the sludge obtained from the biogas. However, due to easy accumulation of toxins, the plant is prone to get contaminated when used as feed.
The plant is extremely tolerant of, and has a high capacity for, the uptake of heavy metals, including Cd, Cr, Co, Ni, Pb and Hg, which could make it suitable for the biocleaning of industrial wastewater. In addition to heavy metals, Eichhornia crassipes can also remove other toxins, such as cyanide, which is environmentally beneficial in areas that have endured gold mining operations.
Water hyacinth removes arsenic from arsenic contaminated drinking water. It may be a useful tool in removing arsenic from tube well water in Bangladesh.
Water hyacinth is also observed to enhance nitrification in waste water treatment cells of living technology. Their root zones are superb micro-sites for bacterial communities.
Water hyacinth is a common fodder plant in the third world especially Africa though excessive use can be toxic. It is high in protein (nitrogen) and trace minerals and the goat feces are a good source of fertilizer as well.
Bio-indicator/phytoremediator:
Ogunlana noted that the plant is a bio-indicator because "wherever you see water hyacinth, it means that the water is polluted or contaminated. So for you to see water hyacinth in a body of water means that there are pollutants in the water.
"The water hyacinth helps to remove pollutants like heavy metals. It is a mode of phytoremediation (using plants to clean up soils/water); it is a phytoremediation plant. It absorbs these contaminants."
Source of carotene:
Human beings can use water hyacinth as vegetable as it is a very good source of carotene. She, however, noted that to be on the safe side, it is advisable for one to cultivate it by oneself, within his environment where he is rest assured it will be free from heavy metals.
Other uses
Wood substitute: Water hyacinth is an aquatic plant which could well be used, instead of wood, in generating an alternative source of energy. The processing of water hyacinth into briquette would have a significant role not only in the development of an alternative fuel, but also in the preservation of the environment. The water hyacinth that was harvested, dried, and pulverized was mixed with cassava starch and acacia seed binder by being compressed into briquettes in a manually-operated machine. The experimental set-up made use of dry and fresh water hyacinth while a traditional charcoal served as the control. In all the quality tests done, T- test showed that there was no significant difference between the experimental product and the commercial product in terms of various parameters, at 0.05 level of significance. The results of experimentation and data analysis showed that the experimental product is just as effective as the commercial briquette, with better potential of helping the environment by reducing the negative consequences brought about by water hyacinth’s rapid profusion. Thus, the environmental briquette made from water hyacinth with acacia seeds as binding agent could be an effective alternative to the traditional charcoal made from burning of wood.
Handcraft: "If you intend to use it for handcraft like basket, slippers, wristwatch starp, earrings and bangles, all you need is the stem which you sundry. I tried to oven-dry but it did not turn out well. The reason why I will not suggest oven-drying is because when it is oven-dried, it becomes crispy and tends to break and so will not serve the purpose it is meant to serve. But if you sun-dry, you can monitor the texture of the stem while it is drying. If it dries to your satisfaction, you remove and use," she stated.
Fertiliser: "If you want to use it for fertiliser, all you need is the roots. That is the main ingredient for fertiliser. "
Fish feed:" For fish feed, all you need is just the leaves."
Biogas: "Water hyacinth, combined with animal waste is an efficient source of biogas." Sources say it releases about 249.1 m3 of methane per kilogram , enough to produce 9.54 gigajoules (GJ) of energy.
Animal feed: "Water hyacinths are used as low-cost animal feed. In China for instance, sun-dried and chopped water hyacinths have been used to replace alfalfa for breeding rabbits , while cooked hyacinth leaves and stems are an effective supplement in commercial fattening of Yorkshire pigs .
Medicinal use: "The only known medicinal use is that the flower is used as a tonic for medicating the skin of horses. Whenever it is in bloom, you extract the tonic from the purple flower and use it for the horse," she said.
Since the water hyacinths are so prolific, harvesting them for industrial use serves also as a means of environmental control.
Disadvantages
When not controlled, water hyacinth will cover lakes and ponds entirely; this dramatically impacts water flow, blocks sunlight from reaching native aquatic plants, and starves the water of oxygen, often killing fish (or turtles). The plants also create a prime habitat for mosquitos[citation needed], the classic vectors of disease, and a species of snail known to host a parasitic flatworm which causes schistosomiasis (snail fever)
Water hyacinth often invades bodies of water that have been impacted by human activities[citation needed]. For example, the plants can unbalance natural lifecycles in artificial reservoirs or in eutrophied lakes that receive large amounts of nutrients.
BIBLIOGRAPHY
Anderson, E. F. 2001. The cactus family. Timber Press, Portland, Oregon, USA.
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