The population of Nigeria is always on the increase, with the World Bank estimating the population of Nigeria to hit over a 300 million in the year 2035, the gap between the supply and demand for water is widening and is reaching such alarming levels that in some parts of the world it is posing a threat to human existence. Since 1950 the world population has doubled while water consumption has increased six- fold. By 2025, it is expected that 3.4 billion people will be living in countries defined as water-scarce. Scientists around the globe are working on new ways of conserving water. It is an opportune time to refocus on one of the ways to recycle water-through the use of wastewater for irrigation and other purposes.
Wastewater refers to water whose quality might pose a threat to sustainable agriculture and/or human health, but which can be used safely for irrigation provided certain precautions are taken. It describes water that has been polluted as a result of mixing with Waste or agricultural drainage (Cornish et al 1999). Pierce and Turner (1990) defined wastewater as water that possesses certain characteristics which have the potential to cause problems when it is used for an intended purpose. In this work, it is assumed that wastewater may be a combination of some or all of the following:
Storm water and other runoff.
Domestic effluent consisting of black water (excreta, urine and associated sludge) and grey water (kitchen and bathroom wastewater).
Wastewater from farm houses and fish ponds.
Reserved wastewater from residences.
Water from commercial establishments and institutions, e.g. hospitals.
The main sources of wastewater are domestic and industrial. As a general rule 80-85% of water used is wasted (Spore 2002).