Sources of heavy metals are various and mainly depend on countries’ activities. Researchers worldwide have carried out lots of studies to examined heavy metals pollutant current status and its causes in their own countries. Africa recently has been a serious concern over the increase of heavy metal pollution and its diverse effects. Population and urbanization have grown and spread rapidly without suitable plan and adequate waste disposal facilities. As a result, the quantities of wastes produced has been increasing and exceeds capacities for collection, however, only 35% of solid waste produced is collected and less than 2% of that is recycled.
Waste water has always been a major threat to the environmental imbalance. Process waste streams from the mining operations, metal plating facilities, paper industries, power generation facilities, electronic device manufacturing units, and tanneries may contain plethora of heavy metals, for example zinc, copper, cadmium, lead, chromium, mercury, nickel etc are disposed above the hazardous limit of the local discharge zones. These heavy metals are not biodegradable and pose great threat to human health and environment. Heavy metal pollution is a problem related with areas and zones where intensive industry, road ways, areas of dumpsites and automobiles activities takes place. Usage and their uncontrolled discharge in to the environment has
These are mainly comprised of COD, BOD, heavy metals, chlorinated organic compounds, mineral oil, phenols, sulphates, mineral acids, salts etc. Broad classification of industrial effluents includes; a) inorganic industrial wastewater i. e. wastewater from steel or iron industry majorly constitutes settable metal particles which could be easily removed through sedimentation/gravimetric method. Wastewater recovered from Blast Furnace usually comprising of dissolved CO2, cyanides and compounds of alkali earth metal. Wastewater from rolling mills composed of mineral oil as a major portion. b) Organic industrial wastewater i. e. wastewater from organic industries comprising of high carbon compounds, metallic ions, charcoal, organic compounds such as steroids, fermentation waste, etc.
Humans and industry are one of the best wellspring of contamination, representing the greater part the volume of all water contamination and for the most savage poisons. Some assembling offices utilize enormous amounts of freshwater to divert squanders of numerous sorts. The waste-bearing water, or gushing, is released into streams, lakes, or seas, which thus scatter the dirtying substances. The poisons incorporate coarseness, asbestos, phosphates and nitrates, mercury, lead, harsh pop and other sodium mixes, sulfur and sulphuric corrosive, oils, and petrochemicals. Furthermore, various assembling plants spill out undiluted corrosives, harms, and different toxic side-effects.
There is more prevalence of hookworm and infectious ascariasis in children (Feenstra et al, 2002; Cifuentes et al, 2002; & Habbari et al, 2000). Also, heavy metal in wastewater, if ingested in high concentrations can be hazardous to human health. Although, uptake of heavy metal by crops and the risk posed to consumers may not be an issue as plants cannot resist high level of these pollutant and die off before they become a potential threat to
Heavy metals are elements having atomic weights between 63.5 and 200.6, and a specific gravity greater than 5.0 . With the rapid development of industries such as metal plating facilities, mining operations, fertilizer industries, tanneries, batteries, paper industries and pesticides, etc., heavy metals wastewaters are directly or indirectly discharged into the environment increasingly, especially in developing countries. Unlike organic contaminants, heavy metals are not biodegradable and tend to accumulate in living organisms and many heavy metal ions are known to be toxic or carcinogenic. Toxic heavy metals of particular concern in treatment of industrial wastewaters include zinc, copper, mercury, cadmium, chromium, lead and nickel.
Dissipating wastes are those industrial discharges into the sea that very quickly diluted to harmless levels after they enter the water. 3. Conservative wastes are heavy metals, halogenated hydrocarbons and radioactive isotopes. This type of wastes is not subject to bacterial attack and therefore they are essentially permanent addition in to the sea, regarded as serious
The existence of wastewater and the need for wastewater treatment is not a new problem. The production of excreta and urine is a natural part of human life, and has a history as long as mankind. In parallel to growing civilizations and increasing urbanity, and with the introduction of the water closet and centralized wastewater collection, problems related to large accumulations of wastewater has arisen. In centralized systems for wastewater collection one could also find other sources to wastewater than only domestic, such as storm water and industrial wastewater sources. Wastewater is generally looked upon as a negative resource, both from an aesthetic perspective and because of its characteristic bad odour, and the fact that its main component
An example of a heavy metal is Mercury (Hg), Cadmium (Cd), Arsenic (As), Chromium (Cr), Thallium (TI), and lead (Pb). The heavy metals that are present in almost all the wastewater are Lead and Cadmium. As the researchers know, Lead and Cadmium is one of the most toxic heavy metals existed on earth, a lead poisoning could lead to a serious brain damage like seizures, coma, or even death. Cadmium concentrations may cause to either acute or chronic poisoning (Cafasso, 2016). There are already experiments about the possible lead contaminated drinking water (Centers for Disease Control and Prevention, 2016) and because of that the researchers achieves to create a prototype filterer that could filter out the heavy metal in any variety of water.
However, heavy metal on soils has been increased due to applying sewage sludge and possibly will represent risk to humans, animals and plants (Bondarczuk et al., 2016). The most heavy metals commonly found in sewage sludge are zinc (Zn), copper (Cu), lead (Pb), and nickel (Ni) and cadmium (Cd). Zinc and Cu must be carefully checked and controlled because when the sewage sludge is applied to soil, a huge volume of these elements are produced might reach the plants