A SEMINAR PAPER ON (THE CONCEPT OF PHYTO-DISINFECTANT OF WATER PURIFICATION )
Water is essential for human survival. It has been reported that the total amount of water in the world is about 1400 million cubic km (= 1018 tonnes) and remains constant (ref. water cycle 207) Apparently, more than 97% of this total volume is seawater of the rest 22% is ground water and 97% is ice locked away in the glaciers and the polar ice cap. This obviously leaves less than 1% of the supply of fresh water, which takes in the water hydrological cycle, but half of this is found in rivers, lakes, and swamps. Most of the fresh water is polluted. In Northern Nigeria, for instance, 95% of the surface water, and this remains true for sub-Saharan Africa, is considerably polluted. This seminar paper discusses the concept of phyto-disinfectant of water purification. The process in water purification, types of phyto disinfectant, application of phyto disinfectant and importance of phyto disinfectant in water purification were discussed. Summary, recommendations and conclusion were put-forward.
Water is under increasing and competing demands from agricultural, industrial and domestic uses with increasing pollution threatening this scarce resource. The total volume of water as dictated by hydrological remains constant but contamination of water by geological, industrial and anthropogenic sources remains the greatest deterrent to Man’s usage. About 1.6 million people are forced to use contaminated water globally, (WHO, 1990). Uncontaminated water is rarely obtainable in rural Africa, Asia and especially in Subsaharan Africa where the prevalence of waterborne infectious diseases is sharply rising, (UNESCO, 2007)
Water borne diseases contribute to the death of about 4 million children in the developing countries per annum. As such, the world health organization has estimated that up to 80% of all disease and sickness in the world is caused by inadequate sanitation, polluted water or unavailability of water (Yongabi, 2009). The need to treat waste water both for domestic use and safe disposal to the environment is obviously exigent. In most developing nations, there are legislation/legal framework established to have industries and factories treat their wastewater before disposal but the cost has been prohibitive for most companies and as such very few companies treat their wastewater. Unlike in the Western countries, most companies treat their wastewater although at high cost, high energy inputs with complex and most often technologies that are not ecological (Gunnel, 2005).
Water management has become a global phenomenon. The beginning of the 21st century has experienced heightened awareness on ecological matters. Humankind has fully come to terms with the rapid urbanization and population growth that is invariably accompanied by adverse environmental problems. There are a number of natural, social and economic activities that affect water quality and availability (Prasad, 2009). There are some water bodies that are naturally defective due to the geology of the area. Besides, there are also natural and artificial water bodies like ponds that contain a lot of nutrients and unacceptable for consumption.
Natural disasters like the Tsunami in last December 2004 have generated a social quagmire and a scandal to the scientific world, as clean water and other embarrassing environmental challenges abound. Furthermore, conflict prone areas around Africa like the Dafur region of Sudan, DR Congo, to name a few, experience acute water crises. It has been estimated that 125 litres of water (potable) is required per person per day, yet, many households cannot actually boast of 25 litres of clean water per person per day. In tandem with this, water purification technologies would have to be reviewed in terms of its simplicity, accessibility (cost) and efficiency (Cofie and Keiaita, 2003). The search for simple, reliable and effective method of water treatment led to the use of plant materials including seeds of Moringa oleifera (WHO, 1990). Standard methods for the treatment of water include coagulation, flocculation, sedimentation and disinfection. These methods are often inappropriate due to prohibitive cost and low availability of chemical coagulants and disinfectants. Dosage and technique poses some local challenges, and for this reasons efforts to establish appropriate chlorination techniques for wells in rural communities is imperative (K.A Yongabi (2004).
Regrettably, the available technologies in present day do appear complex and still expensive. No doubt, despite tremendous awareness campaign during the water and sanitation decade of 1981-1990, water and sanitation problems today still remain a major task to reckon with. If the Millennium Development Goals in the water and sanitation sector are something to go by, then the need to focus on integrated low cost water purification systems at grassroots stands unequivocal.
In Nigeria, 80-90% of all infectious diseases are water borne. Governments in these countries spend a significant proportion of their budgets importing alum and chlorine from western nations for municipal water treatment. More than 1.2 million people lack safe drinking water in developing countries. Apart from high cost of treating water in sub-Saharan Africa, waterborne microorganisms are developing resistance to currently used disinfectants such as chlorine. To meet the United Nations Millennium Development Goals (MDG) of providing safe drinking water, alternative and complimentary approaches such as the application of Moringa oleifera plant materials and sand filters are being studied. Previous research regarding the application of Moringa oleifera (MO) seeds have focused on the isolation of bioactive coagulant ingredients for more than four decades, with little attention directed toward field application in small and large scale water treatment applications. Slow sand filters take more than two weeks to generate clean water but there have been few studies directed towards integrating Moringa oleifera and other plant disinfectants with sand filters to generate clean water in a relatively short retention times at faster flow rates
1.1 Background of the Study
Safe drinking water and adequate sanitation are essential for human health and dignity. However, 1.2 billion people do not have (Pritchard et al., 2009; UNICEF, 2009). Approximately, 2.5 billion people in the world lack adequate sanitation facilities (UNICEF, 1993; UNEP 2002; Zhang et al., 2006; UNESCO, 2007; UNICEF, 2009). Waterborne and water related diseases such as diarrhea, typhoid, cholera and drancunculiasis are fast becoming endemic in certain parts of Africa (Cheesbrough, 1984; Yongabi, 2004; Pritchard et al., 2009). Yet, the present well documented technologies used in water treatment such as reverse osmosis, ion exchange, uv sterilization, aluminum sulphate and chlorine are becoming unsustainable, unecological, expensive to run, managed and maintained, particularly in Africa (Pritchard et al., 2009). For example, Chlorine is known to produce trichloromethane, a cancer precursor (Yongabi, 2004) while Aluminum sulphate has been linked to Alzheimer’s disease (Zhang et al., 2009). Furthermore, the cost of purchasing synthetic coagulants and disinfectants is in hard currency leading to high pricing for treated water in Africa (Kebreab et al., 2005). Simple technologies such as the application of plant coagulants such as Moringa oliefera to treat water has been extensively reported (Oliver, 1959; Jahn, 1981; Muyibi et al., 2002; Yongabi, 2004; Pritchard et al., 2009).
Interest in isolating and purifying bioactive Moringa oleifera coagulant ingredient has grown and outweighed efforts on taking inventory of other potential plant coagulants and disinfectants. The most important step in water treatment is disinfection. Attention has been focused on screening plants for coagulant activity (Eilert, 1978; Jahn, 1981; Muyibi et al., 2002a; Kebreab et al., 2005; Amir et al., 2010), but not all coagulants are disinfectant. The flora of Africa is rich with a lot of medicinal plants and Macro fungi which people in the rural areas are quite familiar. Sofowora (1982) and Yongabi (2004) reported that Africa has as much as 300, 00 medicinal plants while Chang (1993) reported that the world mushroom biodiversity is as much as 1.5 million species. There is, therefore, an urgent need to explore and utilize these rich biodiversity through researches that could translate to direct benefit to humankind (Yongabi, 2009). Plant disinfectants could provide useful insight for the production of natural disinfectants and coagulants which are environment friendly and with much reduced risk of handling. The ultimate purpose of this seminar is to carry out an inventory of plants used as disinfectants in rural Afaha Nsit community, conduct an in vitro evaluation of crude plant powders and solvent extracts on directly disinfecting turbid surface water from the area.
1.2 Definition of Terms
(i) Phyto: Phyto means plant. Word-forming element meaning “plant,” from Greek phyton “plant,” literally “that which has grown,” from phyein “to grow”. In the direct in-situ removal of pollutants, (hyper) accumulating crops are cultivated. The crops are cut and transported for composting or controlled incineration. In farming areas, the intention is for these activities to be carried out by the farmers themselves.
The plant-types that are suited to this technique are those that have a high in-take capacity. In addition to this, it is important that the crops have a high return of (mowable) dry matter. If the crop has another economic and/or agricultural value, this is definitely a plus point.
Grasses and clover appear to be ideal for phyto-remediation because they have a fibrous root system which forms a permanently-compact rhizosphere (the soil in the immediate surrounding of the plant roots). This also provides the additional benefit that soil is protected against water and wind erosion. Literature makes reference to the following grasses: Alfalfa, clover, fescue grass, Bermuda grass and rye-grass.
Plants can also be transformed to selectively extract and accumulate heavy metals, so that potential metal-rich residues can be recycled. Transgenic tobacco and potato are good examples. By way of this transformation, the tolerance to heavy metals is also increased.
(ii) Disinfectant: Disinfectants are antimicrobial agents that are applied to the surface of non-living objects to destroy microorganisms that are living on the objects. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical and/or chemical process that kills all types of life. Disinfectants are different from other antimicrobial agents such as antibiotics, which destroy microorganisms within the body, and antiseptics, which destroy microorganisms on living tissue. Disinfectants are also different from biocides — the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by destroying the cell wall of microbes or interfering with their metabolism.
In wastewater treatment, a disinfection step with chlorine, ultra-violet (UV) radiation or ozonation can be included as tertiary treatment to remove pathogens from wastewater, for example if it is to be reused to irrigate golf courses. An alternative term used in the sanitation sector for disinfection of waste streams, sewage sludge or fecal sludge is sanitisation orsanitization.
Therefore, disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical and/or chemical process that kills all types of life. Disinfectants work by destroying the cell wall of microbes or interfering with their metabolism.
(iii) Purification: Purification is the removal of impure elements from something. After purification, water is safe to drink. Most cities have a system of water purification, so people get clean fresh drinking water without any parasites or goldfish in it.
Purification is when things are cleaned and made pure. Salt water must undergo purification before it’s safe to drink. Some filters do a purification of the air to reduce allergens Water purification, process by which undesired chemical compounds, organic and inorganic materials, and biological contaminants are removed from water. The purification procedure reduces the concentration of contaminants such as suspended particles, parasites, bacteria, algae, viruses, and fungi.
Phyto Disinfectant: Phyto-disinfectants are plant materials used in treating turbid water and can be applied in wastewater treatment.
Water: Water in its natural state is a liquid; it is ever-changing, when heated it becomes steam (vapor) and when cooled it becomes ice (a solid). Water covers over 70% of the Earth’s surface and is vital for the existence of all forms of life, yet less than 3% of water is in its consumable form and 98% of that is either ice or underground. About 96% of the planet’s water is in the salty seas and oceans. Water is important to life, industry, food, recreation, and energy. It is considered the universal solvent. There is no man-made or natural obstacle that water cannot overcome through time, erosion, pressure, or change of state.
the concept of phyto-disinfectant of water purification
2. Literature Review
2.1 Concept of Phytodisinfectant in Water Purification
Despite the technological advancement in water treatment and supply, one major challenge facing many developing countries today is the lack of clean and safe drinking water to its citizens. It has been estimated that 1.2 billion people do not have clean and safe drinking water (Pritchard et al., 2009).
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