1.0 Introduction
Around 1.1 billion people worldwide do not have access to improved water supply sources, where as 2.4 billion people do not have access to any type of improved sanitation facilities (Bodzewan and Lange, 2014). According to WHO (2014), every year more than 3.4 million people die as a result of water-related diseases, making it the leading cause of morbidity and mortality around the world. Bodzewan and Lange (2014) reported that poor water sanitation and lack of safe drinking water take a greater human toll than war, terrorism and weapons of mass destruction.
Among the main problems which are responsible for this situation were lack of priority given to the sector, lack of financial resources, lack of water supply and sanitation services, poor hygiene behaviors and inadequate sanitation in public places including hospitals, health centers and schools providing access to sufficient quantities of safe water (Bodzewan and Lange, 2014). The provision of facilities for sanitary disposal of excreta and introducing sound hygiene behaviors, are of capital importance to reduce the burden of disease caused by these risk factors. According to an assessment commissioned by the United Nations, 4,000 children die each day as a result of diseases caused by ingestion of filthy water (Alrumman et al., 2016). The report says four out of every 10 people in the world, particularly those in Africa and Asia, do not have clean water to drink and these leads to diseases such as Cholera, typhoid fever, hepatitis A and so on (Boyd and Tucker, 2012). Other illnesses, such as dysentery, are caused by parasites that live in water contaminated by the feces of sick individuals (Bodzewan and Lange, 2014). Waterborne diseases have been estimated to cause more than two million deaths and four billion cases of diarrhea annually (WHO, 2000). Most of the victims are young children, the vast majority of whom die of illnesses caused by organisms that thrive in water sources contaminated by raw sewage (WHO, 2014).
1.1 Profile of Nigeria’s Water Resources
Nigeria has an estimated total surface area of about 94,185 000 hectares of land mass of which 12,244,050 hectares (13%) is made up of inland waters in lakes, rivers and dams (Lwahas et al., 2010). The Federal Ministry of Information and Communication gave estimates of surface and underground water as 267.3 billion m3 and 52 billion m3 respectively, with just 10% of these enormous amounts of water being currently exploited (Federal Ministry of Information Communication, 2008).
A good number of these water resources have been dammed for some specific purposes. According to (Akinbode 2002), the total water income of Nigeria is derived from two major sources namely: Rainfall and surface water. Rivers Niger, Benue and Cross bring in water from neighbouring countries while part of the rain that falls is returned back to the atmosphere through the process of evapo-transpiration; yet the last part sinks into the ground to become part of underground water. The bulk of the water resources are found in numerous rivers dissecting the country. There is indeed, no part of the country without at least a major river. There are mainly four major hydrological centres serving as watersheds of Nigerian rivers: the North Central Highlands, Eastern Highlands, Western Highlands and Eastern Scarpland. The major rivers from the North Central highlands are Kaduna, Yobe, Zamfara, Sokoto and Gongola; from the Eastern Highlands are rivers Donga and Katsina–Ala; from Eastern Scarpland are rivers Imo and Anambra and from Western Highlands are rivers Ogun, Osun and Osse. Of the total water surface in Nigeria, only about 853, 600 hectares (0.9%) constitutes inland water: 13 lakes and about 200 dams of varying sizes like Lakes Chad, Pandam, Tiga, Bakolori, Kiri, Oyan, to mention but a few (Lwahas et al. 2010), gave startling statistics of Nigeria’s water situation thus: total water withdrawals for domestic, industrial and agricultural is 13.11 km3 per year; annual budget allocation to water sector is less than 5%; of the150 million people only 43% have access to safe water (which translates to only 64.089 million people); of the 64.089 million people that have access to clean and safe water, 39.731 million (62%) are urbanites and only 24.358 million (38%) people are in rural areas, enjoying the facility. The above analysis clearly shows that most Nigerians have no access to clean and safe water and by implication, they drink and prepare food daily with water that is already polluted.
1.2 Sewage
Sewage is a complex mixture containing nutrients, suspended solids, pathogens, oxygen’s dissolving substances and other contaminants and each has different environmental impact (Odetola and Awoniyi, 2007). Waste water refers to water whose quality is affected by the contribution of anthropogenic activities. Waste water discharged from agricultural activities, industries, residential houses, institutions and commercial areas pollutes drinking water sources (Ladan 2014).
Sewage is a complex mixture containing nutrients, suspended solids, pathogens, oxygen’s dissolving substances and other contaminants and each has different environmental impact. Most aquatic ecosystems around the world, especially rivers, lakes and reservoirs, have been polluted by untreated domestic sewage/waste water, mining waste, industrial waste water, agricultural waste, and other pollutants (Kuang et al., 2004). The nutrients, nitrogen and phosphorous, are dominant in these municipal discharges, posing a great risk of eutrophication-related problems to the receiving water bodies. (Nhapi et al., 2004). Biomas and diversity of communities are to be expected when large amount of toxic materials are released into the streams, lakes and coastal waters in the ocean. This makes water to have odour, taste and sometimes colour. Ultimately, the ecological balance of a body of water is altered. Sulphur dioxide and nitrogen oxides cause acid rain which lowers the pH value of soil and emission of carbon dioxide cause ocean acidification, the ongoing decrease in the pH of the Earth’s Oceans as CO2 becomes dissolved. (Musa, 2013).
Sewage is a mixture of natural organic and inorganic materials with a small ratio of man-made substances (de Mora and Harrison, 2013). The main source of sewage polluted is human excreta with food preparation from contributions and surface drainage. The physical and chemical nature of water wastes can be further complicated by industrial wastes that are composed of strong spent liquors from main industrials processes. Domestic wastewater comes mainly from the residence, commercial buildings, and institutions such as schools and hospitals, whereas, industrial wastewater comes from manufacturing plants. Inevitably, large towns and cities have a mixture of domestic and industrial wastewater, which is commonly referred to as municipal wastewater (de Mora and Harrison, 2013). The other wastewater that rich in organic materials and readily biodegraded are the agro industrial wastes, these wastes varied according to agricultural practice, manufacturing processes and from intensive animal rearing, silage production, food processing and the dairy industry (VikranthPridhvi and Musalaiah, 2015).
